rf100

RF100 - 1July, 2008 Introduction to Wireless & CDMA -- RF100 v3.0 - (c) 2008 Scott Baxter

A Technical Introductionto Wireless and CDMA

A Technical Introductionto Wireless and CDMA


How Did We Get Here?

Days before radio.....• 1680 Newton first suggested

concept of spectrum, but for visible light only

• 1831 Faraday demonstrated that light, electricity, and magnetism are related

• 1864 Maxwell’s Equations: spectrum includes more than light

• 1890’s First successful demos of radio transmission

UN S

LF HF VHF UHF MW IR UV XRAY


TelegraphySamuel F.B. Morse had the idea of the telegraph on a sea cruise in the 1833. He studied physics for two years, and In 1835 demonstrated a working prototype, which he patented in 1837.Derivatives of Morse’ binary code are still in use today The US Congress funded a demonstration line from Washington to Baltimore, completed in 1844.1844: the first commercial telegraph circuits were coming into use. The railroads soon were using them for train dispatching, and the Western Union company resold idle time on railroad circuits for public telegrams, nationwide1857: first trans-Atlantic submarine cable was installed

Samuel F. B. Morseat the peak of his career

Field Telegraphyduring the US Civil War, 1860’s

Submarine Cable Installationnews sketch from the 1850’s


TelephonyBy the 1870’s, the telegraph was in use all over the world and largely taken for granted by the public, government, and business. In 1876, Alexander Graham Bell patented his telephone, a device for carrying actual voices over wires. Initial telephone demonstrations sparked intense public interest and by the late 1890’s, telephone service was available in most towns and cities across the USA

Telephone Line Installation Crew1880’s

Alexander Graham Bell and his phonefrom 1876 demonstration


Radio Milestones1888: Heinrich Hertz, German physicist, gives lab demo of existance of electromagnetic waves at radio frequencies1895: Guglielmo Marconi demonstrates a wireless radio telegraph over a 3-km path near his home it Italy1897: the British fund Marconi’s development of reliable radio telegraphy over ranges of 100 kM1902: Marconi’s successful trans-Atlantic demonstration 1902: Nathan Stubblefield demonstrates voice over radio1906: Lee De Forest invents “audion”, triode vacuum tube

• feasible now to make steady carriers, and to amplify signals1914: Radio became valuable military tool in World War I1920s: Radio used for commercial broadcasting1940s: first application of RADAR - English detection of incoming German planes during WW II1950s: first public marriage of radio and telephony - MTS, Mobile Telephone System1961: transistor developed: portable radio now practical1961: IMTS - Improved Mobile Telephone Service1970s: Integrated circuit progress: MSI, LSI, VLSI, ASICs1979, 1983: AMPS cellular demo, commercial deployment

Guglielmo Marconiradio pioneer, 1895

Lee De Forestvacuum tube inventor

MTS, IMTS


Frequencies Used by Wireless SystemsOverview of the Radio Spectrum

3 4 5 6 7 8 9 10 12 14 16 18 20 22 24 26 28 30 GHz30,000,000,000 i.e., 3x1010 Hz

Broadcasting Land-Mobile Aeronautical Mobile TelephonyTerrestrial Microwave Satellite

0.3 0.4 0.5 0/6 0.7 0.8 0.9 1.0 1.2 1.4 1.6 1.8 2.0 2.4 3.0 GHz3,000,000,000 i.e., 3x109 Hz

UHF TV 14-69UHF GPSDCS, PCSCellular

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.4 1.6 1.8 2.0 2.4 3.0 MHz3,000,000 i.e., 3x106 Hz

AM LORAN Marine

3 4 5 6 7 8 9 10 12 14 16 18 20 22 24 26 28 30 MHz30,000,000 i.e., 3x107 Hz

Short Wave -- International Broadcast -- Amateur CB

30 40 50 60 70 80 90 100 120 140 160 180 200 240 300 MHz300,000,000 i.e., 3x108 Hz

FM VHF TV 7-13VHF LOW Band VHFVHF TV 2-6


In the late 1970’s, the FCC (USA Federal Communications Commission) and the Canadian government allocated 40 MHz. of spectrum in the 800 MHz. range for public mobile telephony. FCC adopted Bell Lab’s AMPS (Advanced

Mobile Phone System) standard, creating cellular as we know it today

• The USA was divided into 333 MSAs(Metropolitan Service Areas) and over

300 RSAs (Rural Service Areas)By 1990, all MSAs and RSAs had competing licenses granted and at least one system operating. Canadian markets also developed.In 1987, the FCC allocated 10 mHz. of expanded spectrum In the 1990’s, additional technologies were developed for cellular

• TDMA (IS-54,55,56, IS-136) (also, GSM in Europe/worldwide)• CDMA (IS-95)

US Operators did not pay for their spectrum, although processing fees (typically $10,000’s) were charged to cover license administrative cost

Development of North American Cellular

333 MSAs300+ RSAs


North American Cellular Spectrum

In each MSA and RSA, eligibility for ownership was restricted• “A” licenses awarded to non-telephone-company applicants only• “B” licenses awareded to existing telephone companies only • subsequent sales are unrestricted after system in actual operation

Downlink Frequencies(“Forward Path”)

Uplink Frequencies(“Reverse Path”)

Frequency, MHz824 835 845 870 880 894

869

849

846.5825

890

891.5

Paging, ESMR, etc.A B A B

Ownership andLicensing

Frequencies used by “A” Cellular OperatorInitial ownership by Non-Wireline companies

Frequencies used by “B” Cellular OperatorInitial ownership by Wireline companies


By 1994, US cellular systems were seriously overloaded and looking for capacity relief

• The FCC allocated 120 MHz. of spectrum around 1900 MHz. for new wireless telephony known as PCS (Personal Communications Systems), and 20 MHz. for unlicensed services

• allocation was divided into 6 blocks; 10-year licenses were auctioned to highest bidders

Development of North America PCS

51 MTAs493 BTAs

PCS Licensing and Auction Details• A & B spectrum blocks licensed in 51 MTAs (Major Trading Areas )

• Revenue from auction: $7.2 billion (1995) • C, D, E, F blocks were licensed in 493 BTAs (Basic Trading Areas)

• C-block auction revenue: $10.2 B, D-E-F block auction: $2+ B (1996)• Auction winners are free to choose any desired technology

A D B E F C unlic.data

unlic.voice A D B E F C

1850 MHz.

1910 MHz.

1990 MHz.

1930 MHz.

15 15 155 5 5 15 15 155 5 5

PCS SPECTRUM ALLOCATIONS IN NORTH AMERICA


Global and US Wireless Subscribers 1Q 2008

Total Worldwide Wireless customers surpassed total worldwide landline customers at year-end 2002, with 1,00,080,000 of each.4/5 of worldwide wireless customers use the GSM technologyCDMA is second-most-prevalent with 14.8%In the US, CDMA is the most prevalent technology at 52.5% penetrationBoth CDMA and GSM are growing in the US

• IS-136 TDMA systems were converted to GSM + GPRS + EDGE

Total 3,051,659,279 252,018,131GSM 2,571,563,279 84.3% 102,200,000 40.6%CDMA 451,400,000 14.8% 132,243,131 52.5%IDEN 28,696,000 0.9% 17,575,000 7.0%

Global USA


Wireless Systems:Modulation and Signal BandwidthWireless Systems:

Modulation and Signal Bandwidth

Chapter 2

fc

fc

Upper Sideband

Lower Sideband

fc

fc

I axis

Q axis

a

b

φc

QPSK

I axis

Q axis

c

a

φ

b

p

r

vπ/4 shifted DQPSK

1 0 1 0

1 0 1 0

1 0 1 0


Characteristics of a Radio Signal

The purpose of telecommunications is to send information from one place to anotherOur civilization exploits the transmissible nature of radio signals, using them in a sense as our “carrier pigeons”To convey information, some characteristic of the radio signal must be altered (I.e., ‘modulated’) to represent the informationThe sender and receiver must have a consistent understanding of what the variations mean to each otherRF signal characteristics which can be varied for information transmission:

• Amplitude• Frequency• Phase

SIGNAL CHARACTERISTICS

S (t) = A cos [ ωc t + ϕ ]

The complete, time-varying radio signal

Amplitude (strength) of the signal

Natural Frequencyof the signal

Phase of the signal

Compare these Signals:

Different Amplitudes

Different Frequencies

Different Phases


Modulation and Occupied Bandwidth

The bandwidth occupied by a signal depends on:

• input information bandwidth• modulation method

Information to be transmitted, called “input” or “baseband”

• bandwidth usually is small, much lower than frequency of carrier

Unmodulated carrier• the carrier itself has Zero bandwidth!!

AM-modulated carrier• Notice the upper & lower sidebands• total bandwidth = 2 x baseband

FM-modulated carrier• Many sidebands! bandwidth is a

complex mathematical functionPM-modulated carrier

• Many sidebands! bandwidth is a complex mathematical function

Voltage

Time

Time-Domain(as viewed on an

Oscilloscope)

Frequency-Domain(as viewed on a

Spectrum Analyzer)Voltage

Frequency0

fc

fc

Upper Sideband

Lower Sideband

fc

fc


The Emergence of AM: A bit of History

The early radio pioneers first used binary transmission, turning their crude transmitters on and off to form the dots and dashes of Morse code. The first successful demonstrations of radio occurred during the mid-1890’s by experimenters in Italy, England, Kentucky, and elsewhere.Amplitude modulation was the first method used to transmit voiceover radio. The early experimenters couldn’t foresee other methods (FM, etc.), or today’s advanced digital devices and techniques.Commercial AM broadcasting to the public began in the early 1920’s. Despite its disadvantages and antiquity, AM is still alive:

• AM broadcasting continues today in 540-1600 KHz.• AM modulation remains the international civil aviation standard,

used by all commercial aircraft (108-132 MHz. band).• AM modulation is used for the visual portion of commercial

television signals (sound portion carried by FM modulation)• Citizens Band (“CB”) radios use AM modulation• Special variations of AM featuring single or independent

sidebands, with carrier suppressed or attenuated, are used for marine, commercial, military, and amateur communicationsSSB

LSB USB


Frequency Modulation (“FM”)Frequency Modulation (FM) is a type of angle modulation

• in FM, the instantaneous frequency of the signal is varied by the modulating waveform

Advantages of FM• the amplitude is constant

– simple saturated amplifiers can be used

– the signal is relatively immune to external noise

– the signal is relatively robust; required C/I values are typically 17-18 dB. in wireless applications

Disadvantages of FM• relatively complex detectors are

required• a large number of sidebands are

produced, requiring even larger bandwidth than AM

TIME-DOMAIN VIEW

sFM(t) =A cos [ωc t + mω m(x)dx+ϕ0 ]t

t0where:

A = signal amplitude (constant)ωc = radian carrier frequency

mω = frequency deviation indexm(x) = modulating signal

ϕ0 = initial phase

FREQUENCY-DOMAIN VIEW

Volta

ge

Frequency0 fc

SFM(t)UPPERSIDEBANDS

LOWERSIDEBANDS


The Digital Advantage

The modulating signals shown in previous slides were all analog. It is also possible to quantize modulating signals, restricting them to discrete values, and use such signals to perform digital modulation. Digital modulation has several advantages over analog modulation:Digital signals can be more easily regenerated than analog

• in analog systems, the effects of noise and distortion are cumulative: each demodulation and remodulationintroduces new noise and distortion, added to the noise and distortion from previous demodulations/remodulations.

• in digital systems, each demodulation and remodulation produces a cleanoutput signal free of past noise and distortion

Digital bit streams are ideally suited to many flexible multiplexing schemes

transmission

demodulation-remodulation

transmission


transmission



Theory of Digital Modulation: SamplingVoice and other analog signals first must be sampled (converted to digital form) for digital modulation and transmissionThe sampling theorem gives the criteria necessary for successful sampling, digital modulation, and demodulation

• The analog signal must be band-limited (low-pass filtered) to contain no frequencies higher than fM

• Sampling must occur at least twice as fast as fM in the analog signal. This is called the Nyquist Rate

Required Bandwidth for p(t)• If each sample p(t) is expressed as

an n-bit binary number, the bandwidth required to convey p(t) as a digital signal is at least N*2* fM

• this follows Shannon’s Theorem: at least one Hertz of bandwidth is required to convey one bit per second of data

The Sampling Theorem: Two Parts•If the signal contains no frequency higher than fM Hz., it is comletely described by specifying its samples taken at instants of time spaced 1/2 fM s.•The signal can be completely recovered from its samples taken at the rate of 2 fMsamples per second or higher.

m(t)

Sampling

Recoverym(t)

p(t)


Sampling Example: the 64 kb/s DS-0Telephony has adopted a world-wide PCM standard digital signal employing a 64 kb/s stream derived from sampled voice dataVoice waveforms are band-limited

• upper cutoff between 3500-4000 Hz. to avoid aliasing

• rolloff below 300 Hz. to minimize vulnerability to “hum” from AC power mains

Voice waveforms sampled at 8000/second rate• 8000 samples x 1 byte = 64,000 bits/second• A>D conversion is non-linear, one byte per

sample, thus 256 quantized levels are possible

• Levels are defined logarithmically rather than linearly to accommodate a wider range of audio levels with minimum distortion

– μ-law companding (popular in North America & Japan)

– A-law companding (used in most other countries)

A>D and D>A functions are performed in a CODEC (coder-decoder) (see following figure)

-10dB

-20dB

-30dB

-40dB

0 dB

100 300 1000 3000 10000Frequency, Hz

C-Message Weighting

t

012345687910111213141516

4

16

13

15

8

3 48

A-LAWy= sgn(x) A|x|

ln(1+ A) for 0 ≤ x≤ 1A

(where A = 87.6)

y= sgn(x) ln(1+ A|x)|ln(1+ A) for 1

A < x ≤1

µ-Lawy = sgn(x) ln(1+ μ|x|)

ln(1 + μ)(whereμ = 255)

Companding

Band-Limiting

x = analog audio voltagey = quantized level (digital)


Digital ModulationDigital Modulation


Modulation by Digital Inputs

For example, modulate a signal with this digital waveform. No more continuous analog variations, now we’re “shifting”between discrete levels. We call this “shift keying”.

• The user gets to decide what levels mean “0” and “1” -- there are no inherent values

Steady Carrier without modulationAmplitude Shift Keying

ASK applications: digital microwaveFrequency Shift Keying

FSK applications: control messages in AMPS cellular; TDMA cellular

Phase Shift KeyingPSK applications: TDMA cellular,

GSM & PCS-1900

Our previous modulation examples used continuously-variable analog inputs. If we quantize the inputs, restricting them to digital values, we will produce digital modulation.

Voltage

Time1 0 1 0

1 0 1 0

1 0 1 0

1 0 1 0


Claude Shannon: The “Einstein” of Information Theory and Signal Science

The core idea that makes CDMA possible was first explained by Claude Shannon, a Bell Labs research mathematicianShannon's work relates amount of information carried, channel bandwidth, signal-to-noise-ratio, and detection error probability

• It shows the theoretical upper limit attainable

In 1948 Claude Shannon published his landmark paper on information theory, A Mathematical Theory of Communication. He observed that "the fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point." His paper so clearly established the foundations of information theory that his framework and terminology are standard today.Shannon died Feb. 24, 2001, at age 84.


Modulation Techniques of 1xEV Technologies

1xEV, “1x Evolution”, is a family of alternative fast-data schemes that can be implemented on a 1x CDMA carrier.1xEV DO means “1x Evolution, Data Only”, originally proposed by Qualcomm as “High Data Rates” (HDR).

• Up to 2.4576 Mbps forward, 153.6 kbps reverse

• A 1xEV DO carrier holds only packet data, and does not support circuit-switched voice

• Commercially available in 20031xEV DV means “1x Evolution, Data and Voice”.

• Max throughput of 5 Mbps forward, 307.2k reverse

• Backward compatible with IS-95/1xRTT voice calls on the same carrier as the data

• Not yet commercially available; work continues

All versions of 1xEV use advanced modulation techniques to achieve high throughputs.

QPSKCDMA IS-95,

IS-2000 1xRTT,and lower ratesof 1xEV-DO, DV

16QAM1xEV-DOat highest

rates

64QAM1xEV-DVat highest

rates


Digital Modulation Systems

Each symbol of a digitally modulated RF signal conveys a number of bits of information

• determined by the number of degrees of modulation freedom

More complex modulation schemes can carry more bits per symbol in a given bandwidth, but require better signal-to-noise ratiosThe actual number of bits per second which can be conveyed in a given bandwidth under given signal-to-noise conditions is described by Shannon’s equations

ModulationScheme

Shannon Limit,BitsHz

BPSK 1 b/s/hzQPSK 2 b/s/hz8PSK 3 b/s/hz

16 QAM 4 b/s/hz32 QAM 5 b/s/hz64 QAM 6 b/s/hz256 QAM 8 b/s/hz

SHANNON’S CAPACITY EQUATION

C = Bω log2 [ 1 + ]S N

Bω = bandwidth in HertzC = channel capacity in bits/secondS = signal powerN = noise power


Digital Modulation SchemesThere are many different schemes for digital modulation, each a compromise between complexity, immunity to errors in transmission, required channel bandwidth, and possible requirement for linear amplifiersLinear Modulation Techniques

• BPSK Binary Phase Shift Keying• DPSK Differential Phase Shift Keying• QPSK Quadrature Phase Shift Keying IS-95 CDMA forward link

– Offset QPSK IS-95 CDMA reverse link– Pi/4 DQPSK IS-54, IS-136 control and traffic channels

Constant Envelope Modulation Schemes• BFSK Binary Frequency Shift Keying AMPS control channels• MSK Minimum Shift Keying• GMSK Gaussian Minimum Shift Keying GSM systems, CDPD

Hybrid Combinations of Linear and Constant Envelope Modulation• MPSK M-ary Phase Shift Keying• QAM M-ary Quadrature Amplitude Modulation• MFSK M-ary Frequency Shift Keying FLEX paging protocol

Spread Spectrum Multiple Access Techniques• DSSS Direct-Sequence Spread Spectrum IS-95 CDMA• FHSS Frequency-Hopping Spread Spectrum


Error Vulnerabilities ofHigher-Order Modulation Schemes

Higher-Order Modulation Schemes (16PSK, 32QAM, 64QAM...) are more vulnerable to transmission errors than the simpler, more rugged schemes (BPSK, QPSK)

• Closely-packed constellations leave little room for vector error

Non-linearities (gain compression, clipping, reflections within antenna system) “warp” the constellationNoise and long-delayed echoes cause “scatter”around constellation pointsInterference blurs constellation points into “rings” of error

Q

I

Normal 64QAMQ

I

Distortion(Gain Compression)

Q

I

Noise Q

I

Interference


Error Vector Magnitude and ρ (“Rho”)

A common measurement of overall error is Error Vector Magnitude “EVM”

• usually a small fraction of total vector amplitude, ~0.1

EVM is usually averaged over a large number of symbols

• Root-mean-square (RMS)Commercial test equipment for BTS maintenance measures EVMSignal quality is often expressed as 1-EVM

• normally called ρ (“Rho”)• typically 0.89-0.96


Modulation used in IS-95 CDMA Systems

CDMA mobiles use offset QPSK modulation

• the Q-sequence is delayed half a chip, so that I and Q never change simultaneously and the mobile TX never passes through (0,0)

CDMA base stations use QPSK modulation

• every signal (voice, pilot, sync, paging) has its own amplitude, so the transmitter is unavoidably going through (0,0) sometimes; no reason to include 1/2 chip delay

Base Stations: QPSKQ Axis

I Axis

ShortPN Q

Σ

cos ωt

sin ωt

User’schips

ShortPN I

Mobiles: OQPSKQ Axis

I Axis

ShortPN Q

Σ

cos ωt

sin ωt

User’schips

1/2 chip

ShortPN I


CDMA Base Station Modulation Views

The view at top right shows the actual measured QPSK phase constellation of a CDMA base station in normal serviceThe view at bottom right shows the measured power in the code domain for each walsh code on a CDMA BTS in actual service

• Notice that not all walsh codes are active

• Pilot, Sync, Paging, and certain traffic channels are in use



Wireless Systems:Multiple Access Technologies & Standards

Wireless Systems:Multiple Access Technologies & Standards

Chapter 3


Multiple Access Methods

FrequencyTime

Power

TDMA

Frequency

Time

Power

FDMA

FrequencyTime

Power

CDMA

CODE

FDMA: AMPS & NAMPS•Each user occupies a private Frequency, protected from interference through physical separation from other users on the same frequency

TDMA: IS-136, GSM•Each user occupies a specific frequency but only during an assigned time slot. The frequency is used by other users during other time slots.

CDMA•Each user occupies a signal on a particular frequency simultaneously with many other users, but is uniquely distinguishable by correlation with a special code used only by this user


FOURTH GENERATION

THIRD GENERATION

SECOND GENERATION

A Quick Survey of Wireless Data Technologies

This summary is a work-in-progress, tracking latest experiences and reports from all the high-tier (provider-network-oriented) 2G, 3G and 4G wireless data technologiesHave actual experiences to share, latest announced details, or corrections to the above? Email to [email protected]. Thanks for your comments!

IS-136 TDMA19.2 – 9.6 kb/s

GSM CSD9.6 – 4.8 kb/s

GSM HSCSD32 – 19.2 kb/s

IDEN19.2 – 19.2 kb/s

IS-9514.4 – 9.6 kb/s

IS-95B64 -32 kb/s

CDPD19.2 – 4.8 kb/sdiscontinued

GPRS40 – 30 kb/s DL

15 kb/s UL

EDGE200 - 90 kb/s DL

45 kb/s UL

1xRTT RC4307.2 – 144 kb/s

1xEV-DO A3100 – 800 DL1800 – 600 UL WCDMA 0

384 – 250 kb/s

WCDMA 12000 - 800 kb/s

WCDMA HSDPA12000 – 6000 kb/s

Flarion OFDM1500 – 900 kb/s

TD-SCDMAIn Development

Mobitex9.6 – 4.8 kb/s

obsolete

US CDMA ETSI/GSM

CELLULAR

MISC/NEW

1xEV-DV5000 - 1200 DL307 - 153 UL

LTE12000 – 6000 kb/s

WiMAX12000 – 6000 kb/s

1xRTT RC3153.6 – 90 kb/s

“2.5G”


The CDMA2000 Family of Technologies

1xEV-DORev. A

IS-856

1250 kHz.123 active

users

Higher data rates on data-

only CDMA carrier

3.1 Mb/sDL

1.8 Mb/sUL

RL FLSpectrum

1xEV-DORev. 0IS-856

1250 kHz.59 active

users

High data rates on data-only

CDMA carrier

2.4 Mb/sDL

153 Kb/sUL

CDMAone CDMA2000 / IS-2000

Technology

Generation

SignalBandwidth,

#Users

Features:Incremental

Progress

1G

AMPS

DataCapabilities

30 kHz.1

First System,Capacity

&Handoffs

None,2.4K by modem

2G

IS-95A/J-Std008

1250 kHz.20-35

First CDMA,

Capacity,Quality

14.4K

2G

IS-95B

1250 kHz.25-40

•Improved Access•Smarter Handoffs

64K

2.5G? 3G

IS-2000:1xRTT

1250 kHz.50-80 voice

and data

•Enhanced Access

•Channel Structure

153K307K230K

3G

1xEV-DV1xTreme

1250 kHz.Many packet

users

High data rates on

Data-Voice shared CDMA carrier

5 Mb/s

3G

IS-2000:3xRTT

F: 3x 1250kR: 3687k

120-210 per 3 carriers

Faster data rates on shared 3-carrier bundle

1.0 Mb/s

RL FLRL FLRL FLRL FLRL FLRL FLRL FL


The GSM/ETSI Family of Technologies

Integrated voice/data(Future rates to 12 MBPS using adv.

modulation?)

Technology

Generation

SignalBandwidth,

#Users


Progress

1G

variousanalog

DataCapabilities

various

various

various

2G

GSM

200 kHz.7.5 avg.

Europe’sfirst Digitalwireless

none

2.5G or 3?

GPRS

200 kHz.Many

Pkt. users

•Packet IP access

•Multiple attached

users

9-160 Kb/s(conditionsdetermine)

3G

EDGE

200 kHz.fast data

many users

8PSK for 3x Faster data rates

than GPRS

384 Kb/smobile user

3GUMTSUTRA

WCDMA3.84 MHz.up to 200+voice users

and data

2Mb/sstatic user


The American TDMA Migration Path to 3G

2G

CDPD

30 kHz.Many

Pkt Usrs

19.2kbps

US PacketDataSvc.

Technology

Generation

SignalBandwidth,

#Users


Progress

DataCapabilities

2GTDMAIS-54

IS-136

30 kHz.3 users

USA’sfirst

Digitalwireless

none

2.5G or 3?

GPRS

200 kHz.Many

Pkt. users

•Packet IP access

•Multiple attached

users

9-160 Kb/s(conditionsdetermine)

3G

EDGE

200 kHz.fast data

many users

8PSK for 3x Faster data rates

than GPRS

384 Kb/smobile user

3GUMTSUTRA

WCDMA3.84 MHz.up to 200+voice users

and data

Integrated voice/data(Future rates to 12 MBPS using adv.

modulation?)

1G

AMPS

30 kHz.1

First System,Capacity

&Handoffs

None,2.4K by modem

2Mb/sstatic user

2G

GSM

200 kHz.7.5 avg.

Europe’sfirst

Digitalwireless

none

the familiar GSM path!


Spectrum Usage Capacity Considerations:Signal Bandwidth, C/I and Frequency Reuse

Each wireless technology (AMPS, NAMPS, D-AMPS, GSM, CDMA) uses a specific modulation type with its own unique signal characteristicsSignal Bandwidth determines how many RF signals will “fit” in the operator’s licensed spectrumRobustness of RF signal determines tolerable level of interference and necessary physical separation of cochannel cellsNumber of users per RF signal directly affects capacity

GSM

AMPS, D-AMPS, N-AMPS

CDMA

30 30 10 kHz Bandwidth

200 kHz

1250 kHz

1 3 1 Users

8 Users

22 Users1

1

11

11

11

111

111

1 23

4

43

2

56 17

Typical Frequency Reuse N=7



Vulnerability:C/I ≅ 17 dB

Vulnerability:C/I ≅ 6.5-9 dB

Vulnerability:EbNo ≅ 6 dB


Comparison of Wireless System Capacities

Technology AMPSTDMA IS136 GSM IDEN

CDMA IS95

IS-2000 RC3

IS-2000 RC4

Available Spectrum, KHz. 12,500 12,500 12,500 12,500 12,500 12,500 12,500Req'd. C/I +17 db +17 db +9 db +21 db +6 db +5 db +3 db

Freq. Reuse Factor N 7 7 3 7 1 1 1Signal Bandwidth, KHz. 30 30 200 25 1229 1229 1229

How Many Signals in BW 416.7 416.7 62.5 500.0 10.2 10.2 10.2Signals per Cell due to reuse 59.5 59.5 20.8 71.4 10.2 10.2 10.2

" Adjusted for Guard Band needs 59.5 59.5 20.8 71.4 9.0 9.0 9.0How Many Sectors Per Cell 3 3 3 3 3 3 3

Signals Per Sector 19.8 19.8 6.9 23.8 9.0 9.0 9.0Control Ch. Signals Per Sector 1 1 0 0 0 0 0Traffic Ch. Signals Per Sector 18.8 18.8 6.9 23.8 9.0 9.0 9.0

Voice Conversations per Signal 1 3 7.5 6 35 50 100Voice Conversations per Sector 18.8 56.5 52.1 142.9 315.0 450.0 900.0

SH Avg Sectors per User 1 1 1 1 1.8 1.8 1.8SH Diluted Conversations/Sector 18.8 56.5 52.1 142.9 175.0 250.0 500.0

Blocking Target % (GOS) 0.02 0.02 0.02 0.02 0.02 0.02 0.02Carried Erlangs Per Sector 11.5 45.9 42.1 128.9 161.4 235.8 486.4Total P.02 Erlangs per Site 34.5 137.6 126.4 386.8 484.3 707.5 1459.3

Capacity Comparison 1 3.99 3.67 11.22 14.05 20.53 42.34


Capacity of Multicarrier CDMA Systems

Fwd/Rev Spectrum kHz. 12,500 1,800 3,050 4,300 5,550 6,800 8,050 9,300 10,550 11,800 13,050 14,300 Technology AMPS CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA CDMA

Req'd C/I or Eb/No, db 17 6 6 6 6 6 6 6 6 6 6 6Freq Reuse Factor, N 7 1 1 1 1 1 1 1 1 1 1 1

RF Signal BW, kHz 30 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250Total # RF Carriers 416 1 2 3 4 5 6 7 8 9 10 11

RF Sigs. per cell @N 59 1 2 3 4 5 6 7 8 9 10 11# Sectors per cell 3 3 3 3 3 3 3 3 3 3 3 3#CCH per sector 1 0 0 0 0 0 0 0 0 0 0 0

RF Signals per sector 18 1 2 3 4 5 6 7 8 9 10 11Voicepaths/RF signal 1 22 22 22 22 22 22 22 22 22 22 22

SH average links used 1 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66Unique Voicepaths/carrier 1 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3

Voicepaths/Sector 18 22 44 66 88 110 132 154 176 198 220 242Unique Voicepaths/Sector 18 13 26 39 53 66 79 92 106 119 132 145

P.02 Erlangs per sector 11.5 7.4 18.4 30.1 43.1 55.3 67.7 80.2 93.8 105.5 119.1 130.9P.02 Erlangs per site 34.5 22.2 55.2 90.3 129.3 165.9 203.1 240.6 281.4 316.5 357.3 392.7

Capacity vs. AMPS800 1 0.64 1.60 2.6 3.7 4.8 5.9 7.0 8.2 9.2 10.4 11.4

f

1 2 3 4 5 6 7 8 9 1011

CDMA Carrier Frequencies


Physical Principles of Propagation

Physical Principles of Propagation

Chapter 4


Introduction to Propagation

Propagation is a key process within every radio link. During propagation, many processes act on the radio signal.

• attenuation– the signal amplitude is reduced by various natural mechanisms; if there is

too much attenuation, the signal will fall below the reliable detection threshold at the receiver. Attenuation is the most important single factor in propagation.

• multipath and group delay distortions– the signal diffracts and reflects off irregularly shaped objects, producing a

host of components which arrive in random timings and random RF phases at the receiver. This blurs pulses and also produces intermittent signal cancellation and reinforcement. These effects are combattedthrough a variety of special techniques

• time variability - signal strength and quality varies with time, often dramatically• space variability - signal strength and quality varies with location and distance• frequency variability - signal strength and quality differs on different

frequenciesEffective mastery of propagation relies on

• Physics: understand the basic propagation processes • Measurement: obtain data on propagation behavior in area of interest• Statistics: characterize what is known, extrapolate to predict the unknown• Modelmaking: formalize all the above into useful models


Influence of Wavelength on Propagation

Radio signals in the atmosphere propagate at almost speed of light

λ = wavelengthC = distance propagated in 1 secondF = frequency, Hertz

The wavelength of a radio signal determines many of its propagation characteristics

• Antenna elements size are typically in the order of 1/4 to 1/2 wavelength

• Objects bigger than a wavelength can reflect or obstruct RF energy

• RF energy can penetrate into a building or vehicle if they have apertures a wavelength in size, or larger

λ/2

λ = C / Ffor AMPS: F= 870 MHz

λ = 0.345 m = 13.6 inches

for PCS-1900: F = 1960 MHzλ = 0.153 m = 6.0 inches


Dominant Mechanisms of Mobile PropagationMost propagation in the mobile

environment is dominated by these three mechanisms:Free space

• No reflections, no obstructions– first Fresnel Zone clear

• Signal spreading is only mechanism• Signal decays 20 dB/decade

Reflection• Reflected wave 180°out of phase• Reflected wave not attenuated much• Signal decays 30-40 dB/decade

Knife-edge diffraction• Direct path is blocked by obstruction• Additional loss is introduced• Formulae available for simple cases

We’ll explore each of these further...

Knife-edge Diffraction

Reflection with partial cancellation

BA

d

D

Free Space


Free-Space PropagationThe simplest propagation mode• Antenna radiates energy which spreads in space• Path Loss, db (between two isotropic antennas)

= 36.58 +20*Log10(FMHZ)+20Log10(DistMILES )• Path Loss, db (between two dipole antennas)

= 32.26 +20*Log10(FMHZ)+20Log10(DistMILES )• Notice the rate of signal decay:• 6 db per octave of distance change, which is

20 db per decade of distance changeFree-Space propagation is applicable if:• there is only one signal path (no reflections)• the path is unobstructed (i.e., first Fresnel zone

is not penetrated by obstacles)

First Fresnel Zone =Points P where AP + PB - AB < λ/2 Fresnel Zone radius d = 1/2 (λD)^(1/2)

1st Fresnel Zone

BA

d

D

Free Space “Spreading” Lossenergy intercepted by receiving antenna is proportional to 1/r2

r


Reflection With Partial Cancellation

Mobile environment characteristics:• Small angles of incidence and reflection• Reflection is unattenuated (reflection coefficient =1)• Reflection causes phase shift of 180 degrees

Analysis• Physics of the reflection cancellation predicts signal

decay of 40 dB per decade of distance

Heights Exaggerated for Clarity

HTFT

HTFT

DMILES

Comparison of Free-Space and Reflection Propagation ModesAssumptions: Flat earth, TX ERP = 50 dBm, @ 1950 MHz. Base Ht = 200 ft, Mobile Ht = 5 ft.

Received Signal in Free Space, DBMReceived Signal inReflection Mode

DistanceMILES

-52.4-69.0

1-58.4-79.2

2-64.4-89.5

4-67.9-95.4

6-70.4-99.7

8-72.4-103.0

10-75.9-109.0

15-78.4-113.2

20

Path Loss [dB ]= 172 + 34 x Log (DMiles )- 20 x Log (Base Ant. HtFeet)

- 10 x Log (Mobile Ant. HtFeet)

SCALE PERSPECTIVE


Signal Decay Rates in Various Environments

We’ve seen how the signal decays with distance in two basic modes of propagation:Free-Space

• 20 dB per decade of distance• 6 db per octave of distance

Reflection Cancellation• 40 dB per decade of distance• 12 db per octave of distance

Real-life wireless propagation decay rates are typically somewhere between 30 and 40 dB per decade of distance

Signal Level vs. Distance

-40

-30

-20

-10

0

Distance, Miles1 3.16 102 5 7 86

One Octaveof distance (2x)

One Decadeof distance (10x)


Knife-Edge DiffractionSometimes a single well-defined obstruction blocks the path, introducing additional loss. This calculation is fairly easy and can be used as a manual tool to estimate the effects of individual obstructions.First calculate the diffraction parameter ν from the geometry of the pathNext consult the table to obtain the obstruction loss in dbAdd this loss to the otherwise-determined path loss to obtain the total path loss.Other losses such as free space and reflection cancellation still apply, but computed independently for the path as if the obstruction did not exist

H

R1 R2

ν

attendB

0-5

-10-15-20-25

-4 -3 -2 -1 0 1 2 3-5

ν = -Hλ R1 R2

2 ( R1 + R2)


Combating Rayleigh Fading: Space Diversity

Fortunately, Rayleigh fades are very short and last a small percentage of the timeTwo antennas separated by several wavelengths will not generally experience fades at the same time“Space Diversity” can be obtained by using two receiving antennas and switching instant-by-instant to whichever is bestRequired separation D for good decorrelation is 10-20λ

• 12-24 ft. @ 800 MHz.• 5-10 ft. @ 1900 MHz.

Signal received by Antenna 1

Signal received by Antenna 2

Combined Signal

D


Types Of Propagation Models And Their Uses

Simple Analytical models • Used for understanding and

predicting individual paths and specific obstruction cases

General Area models• Primary drivers: statistical• Used for early system

dimensioning (cell counts, etc.)Point-to-Point models

• Primary drivers: analytical• Used for detailed coverage

analysis and cell planningLocal Variability models

• Primary drivers: statistical• Characterizes microscopic level

fluctuations in a given locale, confidence-of-service probability

Simple Analytical• Free space (Friis formula)• Reflection cancellation• Knife-edge diffraction

Area• Okumura-Hata• Euro/Cost-231• Walfisch-Betroni/Ikegami

Point-to-Point• Ray Tracing

- Lee’s Method, others• Tech-Note 101• Longley-Rice, Biby-C

Local Variability• Rayleigh Distribution• Normal Distribution• Joint Probability Techniques

Examples of various model types


General Principles Of Area Models

Area models mimic an averagepath in a defined areaThey’re based on measured data alone, with no consideration of individual path features or physical mechanismsTypical inputs used by model:

• Frequency• Distance from transmitter to

receiver• Actual or effective base

station & mobile heights• Average terrain elevation • Morphology correction loss

(Urban, Suburban, Rural, etc.)Results may be quite different than observed on individual paths in the area

RSSI, dBm

-120

-110

-100

-90

-80

-70

-60

-50

0 3 6 9 12 15 18 21 24 27 30 33

Distance from Cell Site, km

FieldStrength,dBµV/m

+90

+80

+70

+60

+50

+40

+30

+20

Green Trace shows actual measured signal strengths on a drive test radial, as determined by real-world physics.Red Trace shows the Okumura-Hataprediction for the same radial. The smooth curve is a good “fit” for real data. However, the signal strength at a specific location on the radial may be much higher or much lower than the simple prediction.


The Okumura Model: General Concept

The Okumura model is based on detailed analysis of exhaustive drive-test measurements made in Tokyo and its suburbs during the late 1960’s and early 1970’s. The collected date included measurements on numerous VHF, UHF, and microwave signal sources, both horizontally and vertically polarized, at a wide range of heights.

The measurements were statistically processed and analyzed with respect to almost every imaginable variable. This analysis was distilled into the curves above, showing a median attenuation relative to free space loss Amu (f,d) and correlation factor Garea(f,area), for BS antenna height ht = 200 m and MS antenna height hr = 3 m.

Okumura has served as the basis for high-level design of many existing wireless systems, and has spawned a number of newer models adapted from its basic concepts and numerical parameters.

Med

ian

Atte

nuat

ion

A(f,

d), d

B

1

2

5

40

70

80

100

100 3000500Frequency f, MHz

10

50

70 Urban Area

d, k

m

30

850

26

35

100 200 300 500 700 1000 2000 3000Frequency f, (MHz)

5

10

15

20

25

30

Cor

rect

ion

fact

or, G

area

(dB

)

9 dB

850 MHz

Open area

Quasi open area

Suburban area


Structure of the Okumura Model

The Okumura Model uses a combination of terms from basic physical mechanisms and arbitrary factors to fit 1960-1970 Tokyo drive test dataLater researchers (HATA, COST231, others) have expressed Okumura’s curves as formulas and automated the computation

Path Loss [dB] = LFS + Amu(f,d) - G(Hb) - G(Hm) - Garea

Free-Space Path Loss

Base StationHeight Gain

= 20 x Log (Hb/200)

Mobile StationHeight Gain

= 10 x Log (Hm/3)

Amu(f,d) Additional Median Loss

from Okumura’s Curves

Med

ian

Atte

nuat

ion

A(f,d

), dB

1

2

5

40

70

80

100

100 3000500

Frequency f, MHz10

50

70 Urban Area

d, k

m

30

850

26

Morphology Gain0 dense urban5 urban10 suburban17 rural

35

100 200 300 500 700 1000 2000 3000Frequency f, (MHz)

5

10

15

20

25

30

Cor

rect

ion

fact

or, G

area

(dB

)

850 MHz

Open area

Quasi open area

Suburban area


Examples of Morphological ZonesSuburban: Mix of residential and business communities. Structures include 1-2 story houses 50 feet apart and 2-5 story shops and offices.Urban: Urban residential and office areas (Typical structures are 5-10 story buildings, hotels, hospitals, etc.)Dense Urban: Dense business districts with skyscrapers (10-20 stories and above) and high-rise apartments

Suburban SuburbanSuburban

UrbanUrbanUrban

Dense Urban Dense UrbanDense Urban

Although zone definitions are arbitrary, the examples and definitions illustrated above are typical of practice in North American PCS designs.


Example Morphological Zones

Rural - Highway: Highways near open farm land, large open spaces, and sparsely populated residential areas. Typical structures are 1-2 story houses, barns, etc.Rural - In-town: Open farm land, large open spaces, and sparsely populated residential areas. Typical structures are 1-2 story houses, barns, etc.SuburbanSuburban

RuralRural

Suburban

Rural

Rural Rural -- HighwayHighwayRural - Highway

Notice how different zones may abruptly adjoin one another. In the case immediately above, farm land (rural) adjoins built-up subdivisions (suburban) -- same terrain, but different land use, penetration requirements, and anticipated traffic densities.


Typical Model Results Including Environmental Correction

TowerHeight,

mEIRP

(watts)C,dB

Range,kmf = 870 MHz.

Dense UrbanUrban

SuburbanRural

30303050

200200200200

-2-5

-10-26

4.04.96.7

26.8

Okumura/Hata

TowerHeight,

mEIRP

(watts)C,dB

Range,kmf =1900 MHz.

Dense UrbanUrban

SuburbanRural

30303050

200200200200

0-5

-10-17

2.523.504.8

10.3

COST-231/Hata


Propagation at 1900 MHz. vs. 800 MHz.

Propagation at 1900 MHz. is similar to 800 MHz., but all effects are more pronounced.

• Reflections are more effective• Shadows from obstructions are deeper• Foliage absorption is more attenuative• Penetration into buildings through openings is more effective,

but absorbing materials within buildings and their walls attenuate the signal more severely than at 800 MHz.

The net result of all these effects is to increase the “contrast” of hot and cold signal areas throughout a 1900 MHz. system, compared to what would have been obtained at 800 MHz.Overall, coverage radius of a 1900 MHz. BTS is approximately two-thirds the distance which would be obtained with the same ERP, same antenna height, at 800 MHz.


Walfisch-Betroni/Walfisch-Ikegami Models

Ordinary Okumura-type models do work in this environment, but the Walfisch models attempt to improve accuracy by exploiting the actual propagation mechanisms involved

Path Loss = LFS + LRT + LMS

LFS = free space path loss (Friis formula)LRT = rooftop diffraction lossLMS = multiscreen reflection loss

Propagation in built-up portions of cities is dominated by ray diffraction over the tops of buildings and by ray “channeling” through multiple reflections down the street canyons

-20 dBm-30 dBm-40 dBm-50 dBm-60 dBm-70 dBm-80 dBm-90 dBm

-100 dBm-110 dBm-120 dBm

Signal Level

Legend

Area View


Elements of Typical Measurement Systems

WirelessReceiver

PC or Collector

GPSReceiver

DeadReckoning

Main FeaturesField strength measurement

• Accurate collection in real-time• Multi-channel, averaging

capabilityLocation Data Collection Methods:

• Global Positioning System (GPS)• Dead reckoning on digitized map

database using on-board compass and wheel revolutions sensor

• A combination of both methods is recommended for the best results

Ideally, a system should be calibrated in absolute units, not just raw received power level indications

• Record normalized antenna gain, measured line loss


Typical Test Transmitter Operations

Typical Characteristics• portable, low power needs• weatherproof or weather resistant• regulated power output• frequency-agile: synthesized

Operational Concerns• spectrum coordination and proper

authorization to radiate test signal• antenna unobstructed• stable AC power• SAFETY:

– people/equipment falling due to wind, or tripping on obstacles

– electric shock– damage to rooftop


Antennas for Wireless Systems

Antennas for Wireless Systems

Chapter 5

Dipole

Typical WirelessOmni Antenna

Isotropic


Understanding Antenna RadiationThe Principle Of Current Moments

An antenna is just a passive conductor carrying RF current

• RF power causes the current flow

• Current flowing radiates electromagnetic fields

• Electromagnetic fields cause current in receiving antennas

The effect of the total antenna is the sum of what every tiny “slice” of the antenna is doing

• Radiation of a tiny “slice” is proportional to its length times the magnitude of the current in it, at the phase of the current

TX RX

Width of banddenotes current

magnitude

Zero currentat each end

Maximum currentat the middle

Current induced inreceiving antennais vector sum of

contribution of everytiny “slice” of

radiating antenna

each tiny imaginary “slice”of the antennadoes its share

of radiating


Antenna Gain

Antennas are passive devices: they do not produce power

• Can only receive power in one form and pass it on in another, minus incidental losses

• Cannot generate power or “amplify”However, an antenna can appear to have “gain”compared against another antenna or condition. This gain can be expressed in dB or as a power ratio. It applies both to radiating and receivingA directional antenna, in its direction of maximum radiation, appears to have “gain” compared against a non-directional antennaGain in one direction comes at the expense of less radiation in other directionsAntenna Gain is RELATIVE, not ABSOLUTE

• When describing antenna “gain”, the comparison condition must be stated or implied

Omni-directionalAntenna

DirectionalAntenna


Reference AntennasDefining Gain And Effective Radiated Power

Isotropic Radiator• Truly non-directional -- in 3 dimensions• Difficult to build or approximate physically,

but mathematically very simple to describe• A popular reference: 1000 MHz and above

– PCS, microwave, etc.Dipole Antenna

• Non-directional in 2-dimensional plane only• Can be easily constructed, physically

practical• A popular reference: below 1000 MHz

– 800 MHz. cellular, land mobile, TV & FM

IsotropicAntenna

(watts or dBm) ERP Effective Radiated Power Vs. DipoleEffective Radiated Power Vs. Isotropic

Gain above Dipole referenceGain above Isotropic radiator

(watts or dBm) EIRP dBddBi

Quantity Units Dipole Antenna

Notice that a dipolehas 2.15 dB gaincompared to an isotropic antenna.


Radiation PatternsKey Features And Terminology

An antenna’s directivity is expressed as a series of patternsThe Horizontal Plane Pattern graphs the radiation as a function of azimuth (i.e..,direction N-E-S-W)The Vertical Plane Pattern graphs the radiation as a function of elevation (i.e.., up, down, horizontal)Antennas are often compared by noting specific landmark points on their patterns:

• -3 dB (“HPBW”), -6 dB, -10 dB points

• Front-to-back ratio• Angles of nulls, minor lobes, etc.

Typical ExampleHorizontal Plane Pattern

0 (N)

90(E)

180 (S)

270(W)

0 -10

-20

-30 dB

Notice -3 dB points

Front-to-back Ratio

10 dBpoints

MainLobe

a MinorLobe

nulls orminima


In phase

Out of phase

How Antennas Achieve Their Gain

Quasi-Optical Techniques (reflection, focusing)• Reflectors can be used to concentrate

radiation– technique works best at microwave frequencies,

where reflectors are small• Examples:

– corner reflector used at cellular or higher frequencies

– parabolic reflector used at microwave frequencies

– grid or single pipe reflector for cellular

Array techniques (discrete elements)• Power is fed or coupled to multiple

antenna elements; each element radiates• Elements’ radiation in phase in some

directions• In other directions, a phase delay for each

element creates pattern lobes and nulls


Types Of Arrays

Collinear vertical arrays• Essentially omnidirectional in

horizontal plane• Power gain approximately

equal to the number of elements

• Nulls exist in vertical pattern, unless deliberately filled

Arrays in horizontal plane• Directional in horizontal

plane: useful for sectorization• Yagi

– one driven element, parasitic coupling to others

• Log-periodic– all elements driven– wide bandwidth

All of these types of antennas are used in wireless

RF power

RF power


Omni AntennasCollinear Vertical Arrays

The family of omni-directional wireless antennas:Number of elements determines

• Physical size• Gain• Beamwidth, first null angle

Models with many elements have very narrow beamwidths

• Require stable mounting and careful alignment

• Watch out: be sure nulls do not fall in important coverage areas

Rod and grid reflectors are sometimes added for mild directivity

Examples: 800 MHz.: dB803, PD10017, BCR-10O, Kathrein 740-198

1900 MHz.: dB-910, ASPP2933

beamwidth

Angleof

firstnull

θ

-3 dB

Vertical Plane Pattern

Number ofElements

PowerGain

Gain,dB

Angleθ

0.00 n/a3.01 26.57°4.77 18.43°6.02 14.04°6.99 11.31°7.78 9.46°8.45 8.13°9.03 7.13°9.54 6.34°10.00 5.71°10.41 5.19°10.79 4.76°11.14 4.40°

1234567891011121314

1234567891011121314 11.46 4.09°

Typical Collinear Arrays


Sector AntennasReflectors And Vertical Arrays

Typical commercial sector antennas are vertical combinations of dipoles, yagis, or log-periodic elements with reflector (panel or grid) backing

• Vertical plane pattern is determined by number of vertically-separated elements

– varies from 1 to 8, affecting mainly gain and vertical plane beamwidth

• Horizontal plane pattern is determined by:

– number of horizontally-spaced elements

– shape of reflectors (is reflector folded?)

Vertical Plane PatternUp

Down

Horizontal Plane PatternN

E

S

W


Example Of Antenna Catalog Specifications

Frequency Range, MHz.Gain - dBd/dBiVSWRBeamwidth (3 dB from maximum)PolarizationMaximum power input - WattsInput Impedance - OhmsLightning ProtectionTermination - StandardJumper Cable

Electrical DataAntenna Model ASPP2933 ASPP2936 dB910C-M

1850-1990 1850-1990 1850-19703/5.1

<1.5:132°

Vertical400

50Direct Ground

N-FemaleOrder Sep.

6/8.1<1.5:1

15°Vertical

40050

Direct GroundN-Female

Order Sep.

10/12.1<1.5:1

5°Vertical

40050

Direct GroundN-Female

Order Sep.

Mechanical DataAntenna ModelOverall length - in (mm)Radome OD - in (mm)Wind area - ft2 (m2)Wind load @ 125 mph/201 kph lb-f (n)Maximum wind speed - mph (kph)Weight - lbs (kg)Shipping Weight - lbs (kg)Clamps (steel)

ASPP293324 (610)

1.1 (25.4).17 (.0155)

4 (17)140 (225)

4 (1.8)11 (4.9)

ASPA320

ASPP293636 (915)

1.0 (25.4).25 (.0233)

6 (26)140 (225)

6 (2.7)13 (5.9)

ASPA320

dB910C-M77 (1955)

1.5 (38).54 (.05)

14 (61)125 (201)

5.2 (2.4)9 (4.1)

Integral


Example Of Antenna Catalog Radiation Pattern

Vertical Plane Pattern • E-Plane (elevation plane)• Gain: 10 dBd• Dipole pattern is superimposed at

scale for comparison (not often shown in commercial catalogs)

• Frequency is shown• Pattern values shown in dBd• Note 1-degree indices through

region of main lobe for most accurate reading

• Notice minor lobe and null detail!


Other Parts of Antenna Systems

Other Parts of Antenna Systems


Antenna SystemsAntenna systems include more than just antennasTransmission Lines

• Necessary to connect transmitting and receiving equipment

Other Components necessary to achieve desired system function

• Filters, Combiners, Duplexers - to achieve desired connections

• Directional Couplers, wattmeters - for measurement of performance

Manufacturer’s system may include some or all of these items

• Remaining items are added individually as needed by system operator

F R

Duplexer

Combiner

BPF

TX

RX

TX

Tran

smis

sion

Lin

e

Jumper

Jumpers

DirectionalCoupler

Antenna


Types of Transmission Lines

Physical CharacteristicsType of line

• Coaxial, stripline, open-wire

• Balanced, unbalancedPhysical configuration

• Dielectric:– air– foam

• Outside surface– unjacketed– jacketed

Size (nominal outer diameter)• 1/4”,1/2”, 7/8”, 1-1/4”, 1-

7/8”, 2-1/4”, 3”Foam

DielectricAir

Dielectric

Typical coaxial cablesUsed as feeders in wireless applications


Attenuation, Impedance, Velocity, Power Handling

Electrical CharacteristicsAttenuation

• Varies with frequency, size, dielectric characteristics of insulation

• Usually specified in dB/100 ft and/or dB/100 m

Characteristic impedance Z0 (50 ohms is the usual standard; 75 ohms is sometimes used)

• Value set by inner/outer diameter ratio and dielectric characteristics of insulation

• Connectors must preserve constant impedance (see figure at right)

Velocity factor• Determined by dielectric characteristics

of insulation. Power-handling capability

• Varies with size, conductor materials, dielectric characteristics

dD

Characteristic Impedanceof a Coaxial Line

Zo = ( 138 / ( ε 1/2 ) ) Log10 ( D / d )ε = Dielectric Constant

= 1 for vacuum or dry air


Transmission LinesImportant Installation Practices

Respect specified minimum bending radius!

• Inner conductor must remain concentric, otherwise Zo changes

• Dents, kinks in outer conductor change Zo

Don’t bend large, stiff lines (1-5/8” or larger) to make direct connection with antennas Use appropriate jumpers, weatherproofed properly.Secure jumpers against wind vibration.

ObserveMinimumBendingRadius!


Transmission LinesImportant Installation Practices, Continued

During hoisting• Allow line to support its own

weight only for distances approved by manufacturer

• Deformation and stretching may result, changing the Zo

• Use hoisting grips, messenger cable

After mounting• Support the line with proper

mounting clamps at manufacturer’s recommended spacing intervals

• Strong winds will set up damaging metal-fatigue-inducing vibrations

200 ft~60 mMax.

3-6 ft


RF FiltersTypes And Applications

Filters are the basic building blocks of duplexers and more complex devicesMost manufacturers’ network equipment includes internal bandpass filters at receiver input and transmitter outputFilters are also available for special applications Number of poles (filter elements) and other design variables determine filter’s electrical characteristics

• Bandwidth rejection• Insertion loss• Slopes• Ripple, etc.

Notice construction: RF input excites one quarter-wave element and electromagnet fields propagate from element to element, finally exciting the last element which is directly coupled to the output.

Each element is individually set and forms a pole in the filter’s overall response curve.

Typical RF Bandpass Filter

∼λ/4


RF FiltersBasic Characteristics And Specifications

Types of Filters• Single-pole:

– pass

– reject (notch)• Multi-pole:

– band-pass– band-reject

Key electrical characteristics• Insertion loss• Passband ripple• Passband width

– upper, lower cutoff frequencies

• Attenuation slope at band edge• Ultimate out-of-band attenuation

Typical bandpass filters have insertion loss of 1-3 dB. and passband ripple of 2-6 dB.

Bandwidth is typically 1-20% of center frequency, depending on application. Attenuation slope and out-of-band attenuation depend on # of poles & design

Typical RF bandpass filter0

Atte

nuat

ion,

dB

Frequency, megaHertz

passband rippleinsertion loss

-3 dB passbandwidth


Basics Of Transmitting Combiners

Allows multiple transmitters to feed single antenna, providing

• Minimum power loss from transmitter to antenna

• Maximum isolation between transmitters

Combiner types• Tuned

– low insertion loss ~1-3 dB– transmitter frequencies must be

significantly separated• Hybrid

– insertion loss -3 dB per stage– no restriction on transmitter

frequencies• Linear amplifier

– linearity and intermodulation are major design and operation issues

Typical tuned combiner application

TX TX TX TX TX TX TX TX

Antenna

Typical hybrid combiner application

TX TX TX TX TX TX TX TX

Antenna

~-3 dB

~-3 dB

~-3 dB


Duplexer Basics

Duplexer allows simultaneous transmitting and receiving on one antenna

• Nortel 1900 MHz BTS RFFEsinclude internal duplexer

• Nortel 800 MHz BTS does not include duplexer but commercial units can be used if desired

Important duplexer specifications• TX pass-through insertion loss• RX pass-through insertion loss• TX-to-RX isolation at TX

frequency (RX intermodulationissue)

• TX-to-RX isolation at RX frequency (TX noise floor issue)

• Internally-generated IMP limit specification

fR fT

RX TX

Antenna

Duplexer

Principle of operationDuplexer is composed of individualbandpass filters to isolate TX fromRX while allowing access to antennafor both. Filter design determinesactual isolation between TX and RX,and insertion loss TX-to-Antennaand RX-to-Antenna.


Directional Couplers

Couplers are used to measure forward and reflected energy in a transmission line; it has 4 ports:

• Input (from TX), Output (to load)

• Forward and Reverse SamplesSensing loops probe E& I in line

• Equal sensitivity to E & H fields• Terminations absorb induced

current in one direction, leaving only sample of other direction

Typical performance specifications• Coupling factor ~20, ~30,

~40 dB., order as appropriate for application

• Directivity ~30-~40 dB., f($)– defined as relative

attenuation of unwanteddirection in each sample

Principle of operation

ZLOAD= 50Ω

Input

Reverse Sample

Forward Sample

RT

RT

Typical directional coupler

Main line’s E & I induce equal signals in sense loops. E is direction-independent, but I’s polarity depends on direction andcancels sample induced in one direction.Thus sense loop signals are directional.One end is used, the other terminated.


Testing Antenna SystemsTesting Antenna Systems


Testing Communications Feedlines and Antennas

AC power wiring and voice telephone wiring do not require extremely critical wiring practices

• just make sure the connections and insulation are good, heat is not allowed to build up, and you’ll have good results

• AC power frequencies and audio signal frequencies have wavelengths of many miles

– a few feet of wire won’t radiate much energyHigh frequency RF wiring practice is much more critical since signal wavelengths are only a few inches or feet

• any bend or protruding bit of wire can serve as an unintentional antenna, “leaking” energy

• even splices and connections can leak energy unless their shape and dimensions are closely controlled

• abrupt changes in cable shape “reflect” energy back down the transmission line, causing many problems

Precisely shaped cables and connectors, careful installation and accurate testing are required to avoid significant antenna system performance problems


Forward and Reflected Energy

In a perfect antenna system, the transmission line and the antenna have the same impedance

• we say they are “impedance matched”All the energy from the transmitter passes through and is radiated from the antenna

• virtually no energy is reflected back to the transmitter

Transmission Line

Antenna

TransmitterForward PowerVirtually no reflected power

50Ω50Ω

50Ω


Forward and Reflected Energy

Transmission Line

Antenna

Transmitter

Significant Reflected Power

50Ω

42-j17Ω

Forward Power

dent or kink37Ω

In a damaged antenna system, the impedance match is not good• there could be a dent, kink, or a spot with water in the transmission

line– the different impedance in the line at this spot will cause some of

the energy to be reflected backwards• the antenna could be damaged or dangling, causing it to have an

altered impedance– the antenna’s different impedance will reflect some of the energy

backwards down the lineThe Site Master® Distance-To-Fault mode will be helpful in finding the location of the damage


How Much Reflection? Four Ways to Say ItThere are four ways of expressing how much energy is being reflected

• different users like different methodsVoltage Standing Wave Ratio (VSWR) (used by hobbyists and consumers)

• the reflected voltage is in phase with the incident voltage at some places and out of phase at others

• VSWR is the ratio of Vmax/VminReflected Power as % of Forward Power (used by field personnel in some industries)

• just divide Rev by Fwd, use percentReturn Loss (used by field personnel)

• how many db weaker is the reflected energy than the forward energy

Reflection Coefficient (academic users)• vector ratio of reflected/incident voltage

or current• usually expressed as a polar vector, with

magnitude and phase

Vmax

Vmin

SWR: Standing Wave Ratio

= Vmax/ Vmin

FORWARD

REFLECTED

Reflected Power (%)

= 100 x RevPwr

FwdPwr

FORWARD

REFLECTED

Return Loss (db)

= 10 x Log10

RevPwrFwdPwr

FORWARD

REFLECTED

Reflection Coefficient (vector ratio)Vreflected

Vincident

=


Comparing Reflection Reports in Different FormsReflection expressed in one form can be converted and expressed in the other formsFor example, consider a VSWR of 1.5 : 1

• this is 4% reflected power• this is a return loss of 14 db• to calculate the reflection coefficient, the

phase of the reflection is also needed

VSWR vs. Return Loss

VSWR

0

10

20

30

40

50

1 1.5 2 2.5 3

FORWARD

REFLECTED

Reflected Power (%)

= 100 x RevPwr

FwdPwr

FORWARD

REFLECTED

Return Loss (db)

= 10 x Log10

RevPwrFwdPwr

FORWARD

REFLECTED

Reflection Coefficient (vector ratio)Vreflected

Vincident

=

Vmax

Vmin

SWR: STANDING WAVE RATIO= Vmax/ Vmin

=

Reflected PowerForward Power

Reflected PowerForward Power

1 +

1 -


The Anritsu®/Wiltron Site Master®

The Site Master® is one of the most convenient and popular “combination” instruments for testing communications feedlines and antennasBuilt Into a Site Master® are:

• sweep signal generator• directional coupler• signal detector• processing software to

display return loss and distance to fault

• Optional: Spectrum Analyzer

• Optional: Power Meter• Battery and charging circuit

The Site Master® is a “combination”instrument not much larger than a cigar box. In the field, it provides the functions of a spectrum analyzer with tracking sweep generator, directional coupler, and power meter. In the past, a trunk full of instruments were required to test communications antenna systems. Today, a Site Master® can even be carried to the tower top if needed.


Estimating Isolation Between Antennas

Often multiple antennas are needed at a site and interaction is troublesomeElectrical isolation between antennas

• Coupling loss between isotropic antennas one wavelength apart is 22 dB

• 6 dB additional coupling loss with each doubling of separation

• Add gain or loss referenced from horizontal plane patterns

• Measure vertical separation between centers of the antennas

– vertical separation usually is very effective

One antenna should not be mounted in main lobe and near-field of another

• Typically within 10 feet @ 800 MHz• Typically 5-10 feet @ 1900 MHz


Types Of Downtilt

Mechanical downtilt• Physically tilt the antenna• The pattern in front goes

down, and behind goes up• Popular for sectorization

and special omni applications

Electrical downtilt• Incremental phase shift is

applied in the feed network• The pattern “droops” all

around, like an inverted saucer

• Common technique when downtilting omni cells


Traffic EngineeringTraffic Engineering

Chapter 6

Typical Traffic Distributionon a Cellular System

0%10%20%30%40%50%60%70%80%90%

100%

Hour

SUN

MON

TUE

WED

THU

FRI

SAT

# Trunks

Efficiency %

Capacity,Erlangs

1 50

80%

41


A Game of Avoiding Extremes

The traffic engineer must walk a fine line between two problems:Overdimensioning

• too much cost• insufficient resources to construct• traffic revenue is too low to

support costs• very poor economic efficiency!

Underdimensioning• blocking• poor technical performance

(interference)• capacity for billable revenue is low• revenue is low due to poor quality• users unhappy, cancel service• very poor economic efficiency!


Basics of Traffic EngineeringTerminology & Concept of a Trunk

Traffic engineering in telephony is focused on the voice paths which users occupy. They are called by many different names:• trunks• circuits• radios (AMPS, TDMA), transceivers (“TRXs” in GSM),

channel elements (CDMA)Some other common terms are:• trunk group

– a trunk group is several trunks going to the same destination, combined and addressed in switch translations as a unit , for traffic routing purposes

• member– one of the trunks in a trunk group


Units of Traffic Measurement

General understanding of telephone traffic engineering began around 1910. An engineer in the Danish telephone system, Anger K. Erlang, was one of the first to master the science of trunk dimensioning and publish the knowledge for others. In his honor, the basic unit of traffic is named the Erlang. An Erlang of traffic is one circuit continuously used during an observation period one hour long.

Other units have become popular among various users:CCS (Hundred-Call-Seconds)MOU (Minutes Of Use)It’s easy to convert between traffic units if the need arises:

1 Erlang = 60 MOU = 36 CCS

Traffic is expressed in units of Circuit Time


How Much Traffic Can One Trunk Carry?Traffic studies are usually for periods of one hourIn one hour, one trunk can carry one hour of traffic -- One ErlangIf nothing else matters, this is the limit!If anyone else wants to talk -- sorry!

Absolute Maximum Capacityof One Trunk

One Trunk

One ErlangConstantTalker

We must not plan to keep trunks busy all the time. There must be a reserve to accommodate new talkers! How much reserve? next!


Traffic Engineering And Queuing Theory

Traffic engineering is an application of a science called queuing theory

• Queuing theory relates user arrival statistics, number of servers, and various queue strategies, with the probability of a user receiving service

• If waiting is not allowed, and a blocked call simply goes away, Erlang-Bformula applies (popular in wireless)

• If unlimited waiting is allowed before a call receives service, the Erlang-Cformula applies

• If a wait is allowed but is limited in time, Binomial & Poisson formulae apply

• Engset formulae apply to rapid, packet-like transactions such as paging channels

Ticket counter analogy

User population

Queue

Servers

Queues we face in everyday life

1) for telephone calls2) at the bank3) at the gas station4) at the airline counter


Offered And Carried TrafficOffered traffic is what users attempt to originateCarried traffic is the traffic actually successfully handled by the systemBlocked traffic is the traffic that could not be handled

• Since blocked call attempts never materialize, blocked traffic must be estimated based on number of blocked attempts and average duration of successful calls

CarriedTraffic

BTS BTS BTS BTS BTS BTS

OfferedTraffic

BSCMTX

BlockedTraffic

PSTN or otherWireless user

TOff = NCA x TCD

TOff = Offered trafficNCA = Number of call attemptsTCD = Average call duration

Offered Traffic = Carried Traffic + Blocked Traffic


Blocking is inability to get a circuit when one is neededProbability of Blocking is the likelihood that blocking will happenIn principle, blocking can occur anywhere in a wireless system:

• not enough radios, the cell is full• not enough paths between cell site and switch• not enough paths through the switching complex• not enough trunks from switch to PSTN

Blocking probability is usuallyexpressed as a percentage

using a “shorthand” notation:• P.02 is 2% probability, etc.• Blocking probability sometimes

is called “Grade Of Service”Most blocking in cellular systems

occurs at the radio level.• P.02 is a common goal at the

radio level in a system

Principles of Traffic EngineeringBlocking Probability / Grade of Service

PSTN Office

DMS-MTX

Cell

Cell

Cell

P.001 P.005

P.02

P.005

Typical Wireless SystemDesign Blocking Probabilities


Number of Trunks vs. Utilization Efficiency

Imagine a cell site with just one voice channel. At a P.02 Grade of Service, how much traffic could it carry?

• The trunk can only be used 2% of the time, otherwise the blocking will be worse than 2%.

• 98% availability forces 98% idleness. It can only carry .02 Erlangs. Efficiency 2%!

Adding just one trunk relieves things greatly. Now we can use trunk 1 heavily, with trunk 2 handling the overflow. Efficiency rises to 11%

The Principle of Trunking EfficiencyFor a given grade of service, trunk

utilization efficiency increases as the number of trunks in the pool grows larger.

• For trunk groups of several hundred, utilization approaches 100%.

# Trunks

Efficiency %

Capacity,Erlangs

1 50

80%

41

Erl Eff%Trks12

0.020.22

2%11%

Erlang-B P.02 GOS


Number of Trunks,Capacity, and Utilization Efficiency

The graph at left illustrates the capacity in Erlangs of a given number of trunks, as well as the achievable utilization efficiencyFor accurate work, tables of traffic data are available

• Capacity, Erlangs• Blocking Probability

(GOS)• Number of Trunks

Notice how capacity and utilization behave for the numbers of trunks in typical cell sites

051015202530354045

Capacity and Trunk UtilizationErlang-B for P.02 Grade of Service

Trunks

0102030405060708090

50403020100UtilizationEfficiencyPercent

Capacity,Erlangs


Traffic Engineering & System Dimensioning

Using Erlang-B Tables to determine Number of Circuits Required

A = f (E,n)

Probability of blocking

0.0001 0.002 0.02

7

E

n

12

300

2.935

0.2

Capacity in Erlangs

Number of available circuits


Erlang-B Traffic TablesAbbreviated - For P.02 Grade of Service Only


Wireless Traffic Variation with Time:A Cellular Example

Peak traffic on cellular systems is usually daytime business-related traffic; on PCS systems, evening traffic becomes much more important and may actually contain the system busy hourEvening taper is more gradual than morning riseWireless systems for PCS and LEC-displacement have peaks of residential traffic during early evening hours, like wirelinesystemsFriday is the busiest day, followed by other weekdays in backwards order, then Saturday, then SundayThere are seasonal and annual variations, as well as long term growth trends

Typical Traffic Distributionon a Cellular System

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Hour

SUN

MON

TUE

WED

THU

FRI

SAT

Actual traffic from a cellular system in the mid-south USA in summer 1992. This system had 45 cells and served an area of approximately 1,000,000 population.


Busy-Hour

In telephony, it is customary to collect and analyze traffic in hourly blocks, and to track trends over months, quarters, and years

• When making decisions about number of trunks required, we plan the trunks needed to support the busiest hour of a normalday

• Special events (disasters, one-of-a-kind traffic tie-ups, etc.) are not considered in the analysis (unless a marketing-sponsored event)

Which Hour should be used as the Busy-Hour?• Some planners choose one specific hour and use it every day• Some planners choose the busiest hour of each individual day

(“floating busy hour”)• Most common preference is to use “floating (bouncing)” busy

hour determined individually for the total system and for each cell, but to exclude special events and disasters

• In the example just presented, 4 PM was the busy hour every day


Wireline telephone systems have a big advantage in traffic planning.

• They know the addresses where their customers generate the traffic!

Wireless systems have to guess where the customers will be next

• on existing systems, use measured traffic data by sector and cell

– analyze past trends

– compare subscriber forecast

– trend into future, find overloads

• for new systems or new cells, we must use all available clues

11 711

1019

85 7

652

73

8 167 166

99

7

Existing SystemTraffic In Erlangs

Where is the Traffic?


Traffic Clues

Subscriber Profiles: • Busy Hour Usage, Call Attempts, etc.

Market Penetration: • # Subscribers/Market Population• use Sales forecasts, usage forecasts

Population Density• Geographic Distribution

Construction ActivityVehicular Traffic Data

• Vehicle counts on roads• Calculations of density on major

roadways from knowledge of vehicle movement, spacing, market penetration

Land Use Database: Area ProfilesAerial Photographs: Count Vehicles!

22,100

3620 66201230

51104215

920

Vehicular Traffic

Land UseDatabases

Population Density

27 mE/Sub in BH

103,550 Subscribers1,239,171 Market Population

adding 4,350 subs/month

new Shopping Center


Traffic Density Along RoadwaysNumber of lanes and speed are the main variable determining number of vehicles on major highways

• Typical headway ~1.5 seconds• Table and figure show capacity of 1

lane When traffic stops, users generally increase calling activityMultiply number of vehicles by percentage penetration of population to estimate number of subscriber vehicles

Vehicle Speed,MPH

Vehicle Spacing,

feet

Vehicles per mile,per lane

0 20 26410 42 12620 64 8330 86 6145 119 4460 152 35

Vehicle spacing 20 ft. @stopRunning Headway 1.5 seconds

Vehicles per mile

Vehicle Spacing At Common Roadway Speeds0

50 MPH40 MPH30 MPH20 MPH10 MPH0 MPH

100 200 300 400 500 600 700 800 feet


Planning & Growing Networks

Planning & Growing Networks

Chapter 7

Link BudgetsPerformance MeasurementsRe-Radiators


Basic Network Objectives

The basic basic objectives of a wireless system are:• COVERAGE: provide sufficient cells to deliver RF coverage of the

entire desired area• BUILDING/VEHICLE PENETRATION: deliver sufficient signal levels

to adequately penetrate buildings and vehicles where appropriate• TRAFFIC: ensure that no cell captures more traffic than it can handle

at the desired grade of service (i.e., blocking percentage)• SCHEDULE: construct the network and bring it to successful

commercial launch at a date which will prevent significant loss of potential customers to competitors

• PERFORMANCE: design, construct, and adjust the network to deliver reliable service free from excessive origination and call delivery failures, dropped calls, quality impairments, and service outages

• ECONOMICS: provide return on investment sufficient to support operating and capital expenses, expand the network to take advantage of growth opportunities, and retire costs of construction prior to depreciation of the network equipment


General Design Considerations and Examples

Network design impacts every network objective listed on the previous page. The first three items actually drive successful network designs, while the final three are largely results of a good network design.The following design example in a typical large market shows thehigh-level planning and decision-making that goes into successful network design, and provides data to illustrate the tradeoffs involved.A spreadsheet file will be provided on diskette by your instructor for your own interactive use in exploring a test network design for your own market


Link BudgetsLink Budgets


Link Budget Example: Usage Model and Service Assumptions

This section outlines the number of subscribers and amount of traffic by yearThis section shows the variability of outdoor and indoor signals, and the building penetration loss

Interactive Initial System Design Example v1.2fill in GREEN fieldsYELLOW fields calculate automatically

Step 1. Basic Business Plan Details

Year Launch 1 2 3 4 5Population 3,886,000 3,949,350 4,012,700 4,076,050 4,139,400 4,202,750Penetration, % 0.05% 1.85% 3.72% 5.64% 7.60% 9.57%#Customers 1,781 72,933 149,453 229,941 314,451 402,360BH Erl/Cust 0.1 0.05 0.045 0.05 0.05 0.05Total BH erl 178.1 3,646.7 6,725.4 11,497.0 15,722.6 20,118.0

2. Enter building penetration loss and standard deviations from measurements.

Composite Probability Of Service & Required Fade MarginEnvironment

Type ("morphology")

Building Median

Loss, dB

Building Std. Dev,

dB

Outdoor Std. Dev,

dB.

Composite Standard Deviation

Desired Reliability at Cell Edge, %

Fade Margin,

dB.Dense Urban 20 8 8 11.31 75.0% 7.63Urban 15 8 8 11.31 75.0% 7.63Suburban 15 8 8 11.31 75.0% 7.63Rural 10 8 8 11.31 75.0% 7.63Highway 8 6 8 10.00 75.0% 6.74


Reverse Link Budget Example

The Reverse Link Budget describes how the energy from the phone is distributed to the base station, including the major components of loss and gain within the system

3. Construct Link Budgets

Reverse Link Budget

Term or Factor GivenDense Urb. Urban Suburban Rural Highway Formula

MS TX Power (dbm) (+) 23MS antenna gain and body loss (+/-) 0MS EIRP (dBm) (+) 23.00 23.00 23.00 23.00 23.00 AFade Margin, (dB) (-) -7.63 -7.63 -7.63 -7.63 -6.74 BSoft Handoff Gain (dB) (+) 4 4 4 4 4 CReceiver Interf. Margin (dB) (-) -3 -3 -3 -3 -3 DBuilding Penetration Loss (dB) (-) -20.00 -15.00 -15.00 -10.00 -8.00 EBTS RX antenna gain (dBi) (+) 17 17 17 17 17 FBTS cable loss (dB) (-) -3 -3 -3 -3 -3 G

kTB (dBm/14.4 KHz.) -132.4 HBTS noise figure (dB) 6.5 I

Eb/Nt (dB) 5.9 JBTS RX sensitivity (dBm) (-) -120.0 -120.0 -120.0 -120.0 -120.0 H+I+J

Survivable Uplink Path Loss (dB) (+) 130.4 135.4 135.4 140.4 143.3

A+B+C+D+E+F+G-(H+I+J)


Forward Link Budget Example

This section shows the forward link power distribution, and compares the relative balance of the forward and reverse links

Forward Link Budget

Term or Factor GivenDense Urb. Urban Suburban Rural Highway Formula

BTS TX power (dBm) (+) 45 45 45 45 45BTS TX power (watts) 31.62 31.62 31.62 31.62 31.62% Power for traffic channels 74.0% 74.0% 74.0% 74.0% 74.0%Number of Traffic Channels in use 19 19 19 19 19BTS cable loss (dB) (-) -3 -3 -3 -3 -3BTS TX antenna gain (dBi) (+) 17 17 17 17 17BTS EIRP/traffic channel (dBm) (+,-) 44.9 44.9 44.9 44.9 44.9 AFade margin (dB) (-) -7.63 -7.63 -7.63 -7.63 -6.74 BReceiver interference margin (db) (-) -3 -3 -3 -3 -3 CBuilding Penetration Loss (dB) (-) -20.0 -15.0 -15.0 -10.0 -8.0 DMS antenna gain & body loss (dB) (+,-) 0 0 0 0 0 E

kTB (dBm/14.4 KHz.) -132.4Subscriber RX noise figure (dB) 10.5

Eb/Nt (dB) 6Subscriber RX sensitivity (dBm) (-) -115.9 -115.9 -115.9 -115.9 -115.9 F

Survivable Downlink Path Loss, dB (+) 130.2 135.2 135.2 140.2 143.1A+B+C+D

+E-F

Forward/Reverse Link Balance DenseUrban Urban Suburban Rural Highway

Which link is dominant? Reverse Reverse Reverse Reverse ReverseWhat advantage, dB? 0.2 0.2 0.2 0.2 0.2


Link Budgets: What is the Radius of a Cell?

This section uses the Okumura-Hata/Cost-231 model to describe the frequency, antenna heights, and environmental factors, and their relationship on the cell’s coverage distance

4. Explore propagation model to figure coverage radius of cell.

Frequency, MHz. 870Subscriber Antenna Height, M 1.5

DenseUrban Urban Suburban Rural Highway

Base Station Antenna Height, M 20 20 30 50 50

DenseUrban Urban Suburban Rural Highway

Environmental Correction, dB -2 -5 -10 -17 -17Coverage Radius, kM 1.30 2.17 6.87 20.86 25.40

Coverage Radius, Miles 0.81 1.35 4.27 12.96 15.78


Link Budgets: Putting It All Together

Step 4 estimates the number of cells required to serve each distinct environment within the systemSteps 5, 6, and 7 estimate the RF coverage from each cell, and the number of cells required

5. Calculate number of cells required for coverage, ignoring traffic considerations.

Dense TotalUrban Urban Suburban Rural Highway # Cells

Covered Area of this type, kM 2 55 450 1700 3400 1400 RequiredOne cell's coverage in this zone, kM 2 5.35 14.73 148.46 1367.34 2026.72 for System

# Cells required to cover zone 10.3 30.6 11.5 2.5 0.7 55.5

6. What is the traffic capacity (in erlangs) of your chosen BTS configuration, year-by-year?

Year Launch 1 2 3 4 5Erlangs which one BTS can carry 18.3 18.3 90 90 450 450

7, 8. What is the total busy-hour erlang traffic on your system? How many BTS are required?

Year Launch 1 2 3 4 5Total System Busy-Hour Erlangs 178.1 3,646.7 6,725.4 11,497.0 15,722.6 20,118.0

Capacity of One BTS, erlangs 18.3 18.3 90 90 450 450# BTS required to handle all the traffic 9.7 199.3 74.7 127.7 34.9 44.7

9. Examine your market, #BTS required for coverage and capacity; estimate totalnumber of BTS required.

Year Launch 1 2 3 4 5#BTS req'd just to achieve coverage 55.5 55.5 55.5 55.5 55.5 55.5

#BTS required just to carry traffic 9.7 199.3 74.7 127.7 34.9 44.7

Estimated total #BTS required 56.3 206.8 206.8 206.8 206.8 206.8


Operational MeasurementsSome Capacity Considerations

Operational MeasurementsSome Capacity Considerations


Total Blocked Call Percentage Example

This is an example of a cumulative system-wide total blocked call percentage chart maintained by one PCS system

Total Block Call Percentage

1.0%1.5%2.0%2.5%3.0%3.5%4.0%4.5%5.0%5.5%6.0%6.5%7.0%7.5%8.0%

Date

Perc

ent

Blkd


Dropped Call Percentage Tracking Example

Dropped call percentage tracking by a PCS system.

Total Drop Call Percentage

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

3.5%

4.0%

4.5%

5.0%

Date

Perc

ent

%Drops


Total System Daily MOU Example

Total system daily MOU plotted by a PCS system

Daily Total System MOU

0

50000

100000

150000

200000

250000

300000

Date

MO

U

Daily Total System MOU


“Top Ten” Performance Tracking Example

Many operators use scripts or spreadsheet macros to produce ranked lists of sites with heavy traffic, performance problems, etc.

Call Attempts

Eng Site

MSC Site Call Att

Call Succ

%Call Succ

Block Calls

%Blck Calls

Acc Fail

%Acc Fail

Drop Calls

%Drop Calls Call Attempts

6.1 13X 2561 2234 87.2 130 5.1 130 5.1 145 5.72.1 2X 2244 2017 89.9 101 4.5 101 4.5 93 4.11.2 1Y 1922 1743 90.7 83 4.3 83 4.3 66 3.464.3 93Z 1833 1549 84.5 137 7.5 136 7.4 110 6.0108.2 30Y 1740 1589 91.3 46 2.6 45 2.6 83 4.81.3 1Z 1630 1495 91.7 31 1.9 31 1.9 81 5.063.2 57Y 1623 1486 91.6 49 3.0 49 3.0 66 4.1102.2 4Y 1615 1495 92.6 18 1.1 18 1.1 70 4.3108.1 30X 1490 1387 93.1 27 1.8 27 1.8 54 3.643.3 42Z 1488 1410 94.8 4 0.3 4 0.3 53 3.6

0

500

1000

1500

2000

2500

3000

6.1

2.1

1.2

64.3

108.

2

1.3

63.2

102.

2

108.

1

43.3

Sector

Cal

ls

% Blocked Calls September 5, 1997Eng Site

MSC Site Call Att

Call Succ

%Call Succ

Block Calls

%Blck Calls

Acc Fail

%Acc Fail

Drop Calls

%Drop Calls % Blocked Calls

64.3 93Z 1833 1549 84.5 137 7.5 136 7.4 110 6.06.1 13X 2561 2234 87.2 130 5.1 130 5.1 145 5.763.3 57Z 1282 1098 85.7 65 5.1 65 5.1 90 7.02.1 2X 2244 2017 89.9 101 4.5 101 4.5 93 4.11.2 1Y 1922 1743 90.7 83 4.3 83 4.3 66 3.463.2 57Y 1623 1486 91.6 49 3.0 49 3.0 66 4.164.1 93X 1027 926 90.2 30 2.9 30 2.9 58 5.726.3 35Z 855 698 81.6 24 2.8 24 2.8 112 13.1108.2 30Y 1740 1589 91.3 46 2.6 45 2.6 83 4.81.3 1Z 1630 1495 91.7 31 1.9 31 1.9 81 5.0

0.01.02.03.04.05.06.07.08.0

64.3 6.1

63.3 2.1

1.2

63.2

64.1

26.3

108.

2

1.3

Sector%


Nortel Operational Capacity Considerations

BSC-BSMMTX BTS

Ch. Card ACC

Σα

Σβ

Σχ

TFU1

GPSRBSM

CDSU

CDSU

SBSVocodersSelectors

CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPSGPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2

Sufficient vocoders/selectors required in BSC SBS, one per

simultaneous call on the system. 8 Vocoders per SBS card, 12 cards per shelf, 4 shelves per

SBS cabinet.

One T-1 can carry all traffic originated by a

one-carrier BTS; special consideration required if

daisy-chaining

Forward RF Capacity: links use available

BTS TX power

Sufficient channel elements required for traffic of all sectors: one CE per link; 20

CE per Channel Card

64 Walsh Codes/sector



DISCO has 192 ports

max. Each BTS uses 1, SBS shelf 1, LPP CIU 1,

Link 2, Ctrl. 2, BSM 4.

Typical CM processorcapacity considerations

PSTN trunk groups must be dimensioned to

support erlang load.

DTC & ENET: One port per Vocoder plus one port per

outgoing trunk.

CDMA LPP: One pair CIUs and One pair CAUs per

approx. 600 erlangs

Reverse RF Capacity: links cause noise floor rise, use mobile power

•1-2001 Current Product Capabilities:•Each BSC can have up to 4 DISCO shelves

•About 240 sites, roughly 6000 erlangs capacity•Each MTX can have up to 2 BSCs


ReradiatorsReradiators


Cell RR

Wireless Reradiators

Reradiators (also called “boosters”, “repeaters”, “cell enhancers”) are amplifying devices intended to add coverage to a cell site or service inside a large building Reradiators are transparent to the host Wireless system

• A reradiator amplifies RF signals in both directions, uplink and downlink

• The system does not control reradiators and has no knowledge of anything they do to the signals they amplify, on either uplink or downlink

Careful attention is required when using reradiators to solve coverage problems

• to achieve the desired coverage improvement

• to avoid creating interference• to ensure the active search window is large

enough to accommodate both donor signal and reradiator signal as seen by mobiles

Reradiators are a ‘“crutch” with definite application restrictions. Many operators prefer not to use re-radiators at all. However, reradiators are a cost-effective solution for some problems.


Wireless Reradiators

Two types of Reradiators commonly are applied to solve two types of situations:

• “filling in” holes within the coverage area of a cell site -- valleys and other obstructed locations, convention centers, etc.

– Low-Power broadbandreradiators are used for this purpose (AMPS, TDMA, GSM, CDMA)

• expanding the service area of a cell to large areas beyond its natural coverage area

– High-Power, channelized frequency-translating reradiatorsare used for this purpose

– Only used in AMPS, TDMA; not currently feasible for CDMA

CellRR

Cell RR


Wireless ReradiatorsPropagation Path Loss Considerations

To solve a coverage problem using a reradiator, path loss and link budget must be considered

• how much reradiator gain is required?• how much reradiator output power is required?• what type of antennas would be best? • how much antenna isolation is needed?• how big will the reradiator footprint be?• how far can the reradiator be from the cell?• will the reradiator interfere with the cell in other areas?• What is the propagation delay through the reradiator, in chips?• Will search windows need to be adjusted for compensation?

CellRR

ERP

GainPath Loss

Path Loss (free space??)

Gain

RRGain

Line Loss

Signal Levelin target area

(free spaceusually applies)


Wireless ReradiatorsSearch Window Considerations

A reradiator introduces additional PN delay• typically 5 to 30 chips • the energy seen by the mobile and by the base station is

spread out over a wider range of delays

DonorCell

RR

ReradiatorSignal

Direct Signal fromDonor Cell

Delay = ? chips

DON’T FORGET THE WINDOWS!Search Windows must be widened byapproximately 2 x reradiator delay toensure capture of both donor and reradenergy by mobile and base station.•Srch_Win_A, Srch_Win_R, Srch_Win_N•Base station Acquisition & Demodulationsearch windows

Reference PNDonor Energy Reradiator Energy


In a few special cases, it is possible to reradiate useful Wireless coverage without any amplifiers involved!Link budget is marginal

• donor cell must be nearby• high-gain antenna required toward

donor cell• distance from RR to user must be

small– ≅100 feet feasible w/omni

antenna– ≅500 feet w/directional antenna

Passive Wireless ReradiatorsTypical Link Budget

Donor cell EIRPPath Loss Donor<>RR

RR Donor Ant. GainSignal Level into Line

RR Line LossRR Serving Ant. GainPath Loss RR<>UserSignal Level @ User

+52-102+22-28-6

+12-69-91

dBmdBdBidBmdBdBidBdBm

Passive ReradiatorLink Budget Example

DonorCell

ERP

Path Loss

Path Loss (250 ft., free space)

(2.1 miles,free space) Basement Auditorium, etc.

Line Loss-6 db


Broadband Low-Power Wireless Reradiators

Used mainly for filling small “holes” in coverage area of a cellInput and output on same frequency

• usable gain: must be less than isolation between antennas, or oscillation occurs

• this gain restriction seriously limits available coverage

• Typically achievable isolations: 70-95 dB

• Good point: every channel in donor cell is re-radiated

BPF:Uplink

BPF:Downlink

Wireless Spectrum

Frequency

Cell

BroadbandReradiator

UnavoidableCoupling

Combiner

Combiner


Broadband low-power reradiators can deliver useful signal levels over footprints up to roughly 1 mile using nearby donor cellsLink budget is usually very “tight”

• paths can’t be seriously obstructed• antenna isolation must be at least

10 db more than desired RR gain• can’t overdrive reradiator 3rd.

order IM

Broadband Low-Power Wireless ReradiatorsTypical Link Budget

DonorCell RR

ERP

GainPath Loss

Path Loss (1/2 mile,

free space)

Gain

RRGain

Line Loss

Signal Levelin target area

(6 miles,free space)

Donor cell EIRPPath Loss Donor<>RR

RR Donor Ant. GainRR Line Loss

Signal Level into RRRR Gain

RR Power OutputRR Line Loss

RR Serving Ant. GainPath Loss RR<>UserSignal Level @ User

+52-111+12

-3-50+50+0-3

+12-89.4-80.4

dBmdBdBidBdBmdBdBmdBdBidBdBm

Broadband ReradiatorLink Budget Example


Other Reradiator Issues

Amplification of Undesired Signals• The reradiator is a broadband device capable of amplifying

other signals near the intended CDMA carrier, both on uplink and downlink. Will these signals capture unwanted traffic, cause unwanted interference, or overdrive CDMA handsets or the base station?

Linearity• CDMA reradiators must be carefully adjusted to ensure they

are not overdriven. Overdriving would produce clipping or other nonlinearities, resulting in code interference

Traffic Capacity• Re-radiators may introduce enough new traffic to create

overloads in the donor cellAlarms

• Separate arrangements must be made for integrating alarms and surveillance reports from reradiators into the system


Technical Introduction to CDMA

Technical Introduction to CDMA

Chapter 8

IS-95, CDMA2000 and a glimpse of 1xEV


CDMA: Using A New Dimension

All CDMA users occupy the same frequency at the same time! Frequency and time are not used as discriminatorsCDMA operates by using CODING to discriminate between usersCDMA interference comes mainly from nearby usersEach user is a small voice in a roaring crowd -- but with a uniquely recoverable code

CDMA

Figure of Merit: C/I(carrier/interference ratio)

AMPS: +17 dBTDMA: +14 to +17 dB

GSM: +7 to 9 dB.CDMA: -10 to -17 dB.CDMA: Eb/No ~+6 dB.


Two Types of CDMA

There are Two types of CDMA:Frequency-Hopping

• Each user’s narrowband signal hops among discrete frequencies, and the receiver follows in sequence

• Frequency-Hopping Spread Spectrum (FHSS) CDMA is NOTcurrently used in wireless systems, although used by the military

Direct Sequence• narrowband input from a user is

coded (“spread”) by a user-unique broadband code, then transmitted

• broadband signal is received; receiver knows, applies user’s code, recovers users’ data

• Direct Sequence Spread Spectrum(DSSS) CDMA IS the method used in IS-95 commercial systems

User 1

Code 1

Composite

Time Frequency

+=

Direct Sequence CDMA

User 1 User 2 User 3 User 4 Frequency Hopping CDMA

User 3 User 4 User 1 unused User 2

User 1 User 4 User 3 User 2 unused

Frequency

unused User 1 User 2 User 4 User 3


DSSS Spreading: Time-Domain View

At Originating Site:Input A: User’s Data @ 19,200 bits/secondInput B: Walsh Code #23 @ 1.2288 McpsOutput: Spread spectrum signal

At Destination Site:Input A: Received spread spectrum signalInput B: Walsh Code #23 @ 1.2288 McpsOutput: User’s Data @ 19,200 bits/second just as originally sent Drawn to actual scale and time alignment

via air interface

XORExclusive-OR

Gate

1

1

Input A: Received Signal

Input B: Spreading Code

Output: User’s Original Data

Input A: User’s Data

Input B: Spreading Code

Spread Spectrum Signal

XORExclusive-OR

Gate

Originating Site

Destination Site


Spreading from a Frequency-Domain View

Traditional technologies try to squeeze signal into minimum required bandwidthCDMA uses larger bandwidth but uses resulting processing gain to increase capacity

Spread Spectrum Payoff:Processing Gain

Spread SpectrumTRADITIONAL COMMUNICATIONS SYSTEM

SlowInformation

SentTX

SlowInformationRecovered

RX

NarrowbandSignal

SPREAD-SPECTRUM SYSTEM

FastSpreadingSequence

SlowInformation

SentTX

SlowInformationRecovered

RX

FastSpreadingSequence

WidebandSignal


The CDMA Spread Spectrum Payoff:Would you like a lump-sum, or monthly payments?

Shannon's work suggests that a certain bit rate of information deserves a certain bandwidthIf one CDMA user is carried alone by a CDMA signal, the processing gain is large - roughly 21 db for an 8k vocoder.

• Each doubling of the number of users consumes 3 db of the processing gain

• Somewhere above 32 users, the signal-to-noise ratio becomes undesirable and the ultimate capacity of the sector is reached

Practical CDMA systems restrict the number of users per sector to ensure processing gain remains at usable levels

# Users Processing Gain1 21 db

2 18 db

4 15 db

8 12 db

16 9 db

32 6 db

64…..Uh, Regis, can I justtake the money I've already

won, and go home now?

CDMA Spreading Gain

Consider a user with a 9600 bps vocoder talking on a

CDMA signal 1,228,800 hzwide. The processing gain is 1,228,800/9600 = 128, which

is 21 db. What happens if additional users are added?


CDMA Uses Code Channels

A CDMA signal uses many chips to convey just one bit of information Each user has a unique chip pattern, in effect a code channelTo recover a bit, integrate a large number of chips interpreted by the user’s known code patternOther users’ code patterns appear random and integrate in a random self-canceling fashion, don’t disturb the bit decoding decision being made with the proper code pattern

Building aBuilding aCDMA SignalCDMA Signal

Bitsfrom User’s Vocoder

Symbols

Chips

Forward Error Correction

Coding and Spreading


CDMA’s Nested Spreading Sequences

CDMA combines three different spreading sequences to create unique, robust channelsThe sequences are easy to generate on both sending and receivingends of each link“What we do, we can undo”

SpreadingSequence

ASpreadingSequence

BSpreadingSequence

CSpreadingSequence

CSpreadingSequence

BSpreadingSequence

A

InputDataX

RecoveredDataX

X+A X+A+B X+A+B+C X+A+B X+ASpread-Spectrum Chip Streams

ORIGINATING SITE DESTINATION


One of the CDMA Spreading Sequences:The Family of Walsh Codes

64 “Magic” Sequences, each 64 chips longEach Walsh Code is precisely Orthogonal with respect to all other Walsh Codes

• it’s simple to generate the codes, or• they’re small enough to use from ROM

WALSH CODES# ---------------------------------- 64-Chip Sequence ------------------------------------------0 00000000000000000000000000000000000000000000000000000000000000001 01010101010101010101010101010101010101010101010101010101010101012 00110011001100110011001100110011001100110011001100110011001100113 01100110011001100110011001100110011001100110011001100110011001104 00001111000011110000111100001111000011110000111100001111000011115 01011010010110100101101001011010010110100101101001011010010110106 00111100001111000011110000111100001111000011110000111100001111007 01101001011010010110100101101001011010010110100101101001011010018 00000000111111110000000011111111000000001111111100000000111111119 0101010110101010010101011010101001010101101010100101010110101010

10 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

EXAMPLE:Correlation of Walsh Code #23 with Walsh Code #59

#23 0110100101101001100101101001011001101001011010011001011010010110#59 0110011010011001100110010110011010011001011001100110011010011001Sum 0000111111110000000011111111000011110000000011111111000000001111

Correlation Results: 32 1’s, 32 0’s: Orthogonal!!

Unique Properties:Mutual Orthogonality

In CDMA2000, user data comes at various speeds, and different lengths of walsh codes can exist.See Course 332 for more details on CDMA2000 1xRTT fast data channels and additional Walsh codes.


The Other Two Spreading Sequences:The Pseudo-random Noise (PN) codes

Other CDMA sequences are generated in shift registersPlain shift register: no fun, sequence = length of registerTapped shift register generates a wild, self-mutating sequence 2N-1 chips long (N=register length)

• Such sequences match if compared in step (no-brainer, any sequence matches itself)

• Such sequences appear approximately orthogonal if compared with themselves not exactly matched in time

• false correlation typically <2%

A Tapped, Summing Shift Register

Sequence repeats every 2N-1 chips,where N is number of cells in register

An Ordinary Shift Register

Sequence repeats every N chips,where N is number of cells in register

A Special Characteristic of SequencesGenerated in Tapped Shift Registers

Compared In-Step: Matches Itself

Complete Correlation: All 0’sSum:Self, in sync:

Sequence:

Compared Shifted: Little Correlation

Practically Orthogonal: Half 1’s, Half 0’sSum:Self, Shifted:

Sequence:


Original IS-95 CDMA PN Scrambling

Short PN Scrambling

New CDMA2000 1x Complex Scrambling

Another CDMA Spreading Sequence:The Short PN Code, used for Scrambling

The short PN code consists of two PN Sequences, I and Q, each 32,768 chips long

• Generated in similar but differently-tapped 15-bit shift registers

• the two sequences scramble the information on the I and Q phase channels

Figures to the right show how one user’s channel is built at the bTS

IQ

32,768 chips long26-2/3 ms.

(75 repetitions in 2 sec.)Σ

RF: cos ωt

RF: sin ωt

user’ssymbols

QPSK-modulated

RFOutput

Same information duplicatedon I and Q

Walsh

I-sequence

Q-sequence

Σ

RF:cos ωt

sin ωtRF

user’ssymbols

QPS

K

Out

put

Walsh

Seria

l to

Para

llel

Σ

Σ

+

DifferentInformationon I and Q

Complex Scrambling

I-sequence

Q-sequence

-+

+


Another CDMA Spreading Sequence:The PN Long Code

Every phone and every BTS channel element has a Long Code generator• Long Code State Register makes long code at system reference timing• A Mask Register holds a user-specific unique pattern of bits

Each clock pulse drives the Long Code State Register to its next state• State register and Mask register contents are added in the Summer• Summer contents are modulo-2 added to produce just a single bit output

The output bits are the Long Code, but shifted to the user’s unique offset

LONG CODE STATE REGISTER dynamic contents, zero timing shift

MASK REGISTER unique steady contents cause unique timing shift

SUMMER holds dynamic modulo-2 sum of LC State and Mask registers

Each clock cycle, all the Summer bits are added into a single-bit modulo-2 sum

The shifted Long Code emerges, chip by chip!

clock


Different Masks ProduceDifferent Long PN Offsets

Ordinary mobiles use their ESNs and the Public Long Code Mask to produce their unique Long Code PN offsets

• main ingredient: mobile ESNMobiles needing greater privacy use the Private Long Code Mask

• instead of 32-bit ESN, the mask value is produced from SSD Word B in a calculation similar to authentication

Each BTS sector has an Access Channel where mobiles transmit for registration and call setup

• the Access Channel Long Code Mask includes Access Channel #, Paging Channel #, BTS ID, and Pilot PN

• The BTS transmits all of these parameters on the Paging Channel

fixed AC# PC# BASE_ID PILOT PN

LONG CODE STATE REGISTER

SUMMING REGISTER


SUMMING REGISTER

fixed PERMUTED ESN


SUMMING REGISTER

calculated PRIVATE LONG CODE MASK

ACCESS CHANNEL (IDLE MODE)USING THE ACCESS CHANNEL LONG CODE MASK

TRAFFIC CHANNEL – NORMALUSING THE PUBLIC LONG CODE MASK

TRAFFIC CHANNEL – PRIVATEUSING THE PRIVATE LONG CODE MASK


IS-95 CDMA Forward and Reverse Channels

IS-95 CDMA Forward and Reverse Channels


The Original IS-95 CDMA Code Channels

Existing IS-95A/JStd-008 CDMA uses the channels above for call setup and traffic channels – all call processing transactions use these channels

• traffic channels are 9600 bps (rate set 1) or 14400 bps (rate set 2)IS-2000 CDMA is backward-compatible with IS-95, but offers additional radio configurations and additional kinds of possible channels

• These additional modes are called Radio Configurations• IS-95 Rate Set 1 and 2 are IS-2000 Radio Configurations 1 & 2

FORWARD CHANNELS

BTS

W0: PILOT

W32: SYNC

W1: PAGING

Wn: TRAFFIC

REVERSE CHANNELS

ACCESS

TRAFFIC


The Code Channels of 1xRTT Rev. 0

CDMA2000 1xRTT has a rich variety of traffic channels for voice and fast dataThere are also optional additional control channels for more effective operation

Includes PowerControl Subchannel

Enhanced Access Channel

CommonControl Channel

DedicatedControl Channel

Reverse FundamentalChannel (IS95B comp.)

Reverse Supplemental Channel

Access Channel(IS-95B compatible)

R-TRAFFIC

REVERSE CHANNELS

R-Pilot

R-CCCH

R-DCCH

R-FCH

R-SCH

R-EACH

1

1

0 or 1

0 or 1

0 to 2

R-ACH or

1

BTS

Dedicated Control Channel

Same coding as IS-95B,Backward compatible



Broadcast Channel

Quick Paging Channel

Common Power Control Channel

Common Assignment Channel

Common Control Channels

Forward Traffic Channels

Fundamental Channel

SupplementalChannels IS-95B only

SupplementalChannels RC3,4,5

F-TRAFFIC

FORWARD CHANNELS

F-Pilot

F-Sync

PAGING

F-BCH

F-QPCH

F-CPCCH

F-CACH

F-CCCH

F-DCCH

1

1

1 to 7

0 to 8

0 to 3

0 to 4

0 to 7

0 to 7

0 or 1

F-FCH

F-SCH

F-SCH

1

0 to 7

0 to 2

IS-95B only

Users:Users:0 to many0 to many

How manyPossible:

See Course 332 for more details.


Spreading Rates & Radio ConfigurationsRadio

Configuration

RC1

RC2

RC3

RC4

RC5

RC6

RC7

RC8

RC9

SpreadingRate

SR11xRTT1 carrier1.2288MCPS

SR33xRTT

Fwd:3 carriers

1.2288MCPSRev:

3.6864MCPS

Forward Link

Required. IS-95B CompatibleNo CDMA2000 coding features

Compatible with IS-95B RS2No CDMA2000 coding features

Quarter-rate convolutional or Turbo Coding, base rate 9600

Half-rate convolutional or Turbo Coding, base rate 9600

Quarter-rate convolutional or Turbo Coding, base rate 14400

1/6 rate convolutionalor Turbo coding, base rate 9600

Required. 1/3 rate convolutionalor Turbo coding, base rate 9600

¼ or 1/3 rate convolutional orTurbo coding, base rate 14400

½ or 1/3 rate convolutional or Turbo encoder, base rate 14400

DataRates

9600

14400

9600153600

9600307200

14400230400

9600307200

9600614400

14400460800

144001036800

Quarter rate convolutional or Turbo coding; Half rate convolutional or Turbo coding;base rate 9600

Quarter rate convolutional or Turbo Coding, base rate 14400

Required. ¼ or 1/3 convolutionalor Turbo coding, base rate 9600

¼ or ½ convolutional or Turboencoding, base rate 14400

Required. IS-95B CompatibleNo CDMA2000 coding features

Compatible with IS-95B RS2No CDMA2000 coding features

RC1

RC2

RC3

RC4

RC5

RC6

9600

14400

9600

153600

307200

14400230400

9600

307200

614400

14400

460800

1036800

Reverse LinkDataRates

RadioConfiguration


Walsh Codes in 1xRTT

Data Rates are different, butChip Rates must stay the same!

SYMBOLS of 2G VOICE or DATAOne Symbol of Information

64 chips of Walsh Code1,228,800 walsh chips/second

19,200 symbols/secondDATA

SYMBOLS

WALSHCODE

SYMBOLS of 3G 153.6 kb/s DATA One Symbol of Fast Data

4 Chips of Walsh Code 1,228,800 walsh chips/second

307,200 symbols/secondDATA

SYMBOLS

WALSHCODE


The Famous Walsh Codes from IS-95 Days

64 “Magic” Sequences, each 64 chips longEach Walsh Code is precisely Orthogonal with respect to all other Walsh Codes and their opposites too!

• it’s simple to generate the codes, or• they’re small enough to use from ROM


10 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

EXAMPLE:Correlation of Walsh Code #23 with Walsh Code #59

#23 0110100101101001100101101001011001101001011010011001011010010110#59 0110011010011001100110010110011010011001011001100110011010011001Sum 0000111111110000000011111111000011110000000011111111000000001111

Correlation Results: 32 1’s, 32 0’s: Orthogonal!!

Unique Properties:Mutual Orthogonality


Families of the Walsh Codes

All Walsh codes can be built to any size from a single zero by replicating and invertingAll Walsh matrixes are square -- same number of codes and number of chips per code


10 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

WALSH CODES# ----------- 32-Chip Sequence -------------0 000000000000000000000000000000001 010101010101010101010101010101012 001100110011001100110011001100113 011001100110011001100110011001104 000011110000111100001111000011115 010110100101101001011010010110106 001111000011110000111100001111007 011010010110100101101001011010018 000000001111111100000000111111119 01010101101010100101010110101010

10 0011001111001100001100111100110011 0110011010011001011001101001100112 0000111111110000000011111111000013 0101101010100101010110101010010114 0011110011000011001111001100001115 0110100110010110011010011001011016 0000000000000000111111111111111117 0101010101010101101010101010101018 0011001100110011110011001100110019 0110011001100110100110011001100120 0000111100001111111100001111000021 0101101001011010101001011010010122 0011110000111100110000111100001123 0110100101101001100101101001011024 0000000011111111111111110000000025 0101010110101010101010100101010126 0011001111001100110011000011001127 0110011010011001100110010110011028 0000111111110000111100000000111129 0101101010100101101001010101101030 0011110011000011110000110011110031 01101001100101101001011001101001

WALSH# ---- 16-Chips -------0 00000000000000001 01010101010101012 00110011001100113 01100110011001104 00001111000011115 01011010010110106 00111100001111007 01101001011010018 00000000111111119 0101010110101010

10 001100111100110011 011001101001100112 000011111111000013 010110101010010114 001111001100001115 0110100110010110

WALSH# 8-Chips 0 000000001 010101012 001100113 011001104 000011115 010110106 001111007 01101001

WALSH# 4-Chips 0 00001 01012 00113 0110

WALSH# 2-Chips 0 001 01

WALSH# 1-Chip0 0

64x64

32x32

16x16

8x84x42x2

Walsh Level MappingThe Walsh Codes shown here are in logical state values 0 and 1.Walsh Codes also can exist as physical bipolar signals. Logical zero is the signal value +1 and Logical 1 is the signal value -1.Mapping: Logical 0,1 > +1, -1 Physical

Walsh Code NamesW1232 = “Walsh Code #12, 32 chips long.”


Walsh Code Trees and Interdependencies

Entire Walsh matrices can be built by replicating and inverting -- Individual Walsh codes can also be expanded in the same way.CDMA adds each symbol of information to one complete Walsh codeFaster symbol rates therefore require shorter Walsh codesIf a short Walsh code is chosen to carry a fast data channel, that walsh code and all its replicative descendants are compromised and cannot be reused to carry other signalsTherefore, the supply of available Walsh codes on a sector diminishes greatly while a fast data channel is being transmitted!CDMA2000 Base stations can dip into a supply of quasi-orthogonal codes if needed to permit additional channels during times of heavy loading

0110

1001

0110

0110

0110

0110 0110 0110 0110

0110 0110 1001 1001

10010110 10010110

10010110 1001 011010010110 1001 0110 10010110 1001 0110

10010110 1001 0110 1001 0110 10010110

10010110 10010110

10010110 10010110

10010110 10010110

100101101001 0110

0110 0110 1001 1001

0110 0110 1001 1001 0110 0110 1001 1001

0110 01101001 1001

0110 0110 0110 0110 0110 0110 0110 0110

0110 0110 0110 0110 1001 1001 1001 1001

W34

W38

W78

W716

W1116

W316

W1516

W732

W2332

W1532

W3132

W2732

W1132

W1932

W332 W364

W3564

W1964

W5164

W1164

W4364

W2764

W5964

W764

W3964

W2364

W5564

W1564

W4764

W3164

W6364


Walsh Code Families and ExclusionsConsider a forward link supplemental channel being transmitted with a data rate of 307,200 symbols/second

• Each symbol will occupy 4 chips at the 1x rate of 1,228,800 c/s.

• A 4-chip walsh code will be used for this channel

If Walsh Code #3 (4 chips) is chosen for this channel:

• Use of W34 will preclude other usage of the following 64-chip walsh codes:

• 3, 35, 19, 51, 11, 43, 27, 59, 7, 39, 23, 55, 15, 47, 31, 63 -- all forbidden!

• 16 codes are tied up since the data is being sent at 16 times the rate of conventional 64-chip walsh codes

The BTS controller managing this sector must track the precluded walsh codes and ensure they aren’t assigned


10 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

0110W34

Which Walsh Codes get tied up by another?Wxxyyties up every YYth Walsh Code starting with #XX.


Forward Link Walsh Codes in 1xRTT

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

Paging 7

Paging 3

Paging 5

Paging

PCH

6

PCH

2

PCH

4

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

76.8ksps

This way of arranging Walsh codes is called “bit reversal order”. It shows each Walsh code’s parents and children. Remember, we cannot use any Walsh code if

another Walsh code directly above it or below it is in use.


IS-95 Today Typical Usage:Pilot, Paging Sync, up to 61 Voice Users

But if the users are highly mobile, forward power may exhaust at typically 30-40 users.In fixed-wireless or “stadium” type applications, all walsh codes may be usable.

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

19.2k19.2kS

yncPilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k ???????Traffic Channels

Voice or Data9.6k/14.4k

76.8ksps

38.4k


Mixed IS-95 / 1xRTT RC3 Voice Typical Usage: Pilot, Paging Sync, up to 61 Voice Users

FCHs of 1xRTT RC3 users consume less power, so more total users are possible than inIS-95. The BTS will probably have enough forward power to carry calls on all 61 walsh codes!

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

19.2k19.2kS

yncPilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

F-FCHs mixedRC1,2,3 Voice

76.8ksps

??


A Possible 1xRTT RC3 BTS Dynamic State:1 F-SCH, 27 Voice IS-95/1xRTT RC3 Users, 16 Active Data Users

The data users can rapidly share the one F-SCH for 153 kb/s peak, ~9Kb/s avg. user rates.But so many active data users F-FCHs consume a lot of capacity, reduce number of voice users!

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

F-SCH 153K RC3

F-FCHs 9.6kRC3 Data

F-FCHs 9.6kRC3 Voice


76.8ksps


A Possible 1xRTT RC3 BTS Dynamic State:1 F-SCH, 39 IS-95/1xRTT RC3 Voice Users, 4 Active+12 Dormant Data Users

But it takes seconds to move various data users from Dormant to Active!Data users will get 153 kb/s peak, ~9 kb/s average, but latency will be high.

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k




F-FCH

sD

ata

F-SCH 153K RC3

76.8ksps


Slightly Improved 1xRTT RC3 BTS Dynamic State:1 F-SCH, 37 IS-95/1xRTT RC3 Voice Users, 4 Active+12 Control-Hold Data Users

Instead of sending 16 data users to Dormant State, let them time-share 2 F-DCCH for Control Hold state. Data users will get 153 kb/s peak, ~9 kb/s average, good latency.

Not yet available or implemented.

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k




F-FCH

sD

ata

F-SCH 153K RC3

F-DC

CH

s76.8ksps


1xRTT RC4 Voice Only:Pilot, Paging Sync, up to 118 Voice Users

Wow! 118 users! But RC4 users F-FCHs consume as much power as old IS-95 calls.BTS may run out of forward power before the all walsh codes are used.

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

F-FCHs 9.6k RC4 Voice



F-FCHs 9.6k RC4 Voice???????

76.8ksps


1xRTT RC4 Voice and Data:1 F-SCH, 80 1xRTT RC4 Voice Users, 4 Active+12 Control-Hold RC4 Data Users

16 data users time-share 2 F-DCCH for Control Hold state. Data users will get 38.4,76.4, 153.6 or 307.2 kb/s peak, ~19 kb/s average, good latency. But fwd power may exhaust!

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

Sync

Pilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

F-SCH 307K RC4



F-FCHs 9.6k RC4 Voice????

F-FCH

sF-D

CC

Hs

76.8ksps


Mature 1xRTT Mixed-Mode Voice and Data:1 RC3/RC4 Shared F-SCH, 20 RC3 Voice Users, 38 RC4 Voice Users,

4 Active+12 Control-Hold RC3 and RC4 Data Users16 data users time-share 2 F-DCCH for Control Hold state. Data users will get

38.4, 76.4, 153.6 or 307.2 kb/s peak, ~9 or 19 kb/s average, good latency. Fwd power tight!

9,6004,8002,400sps

307200sps

153,600sps

76,800sps

38,400sps

19,200sps

Code#

Code#

Code#

Code#

Code#

Code#

128 chips4 chips

8 chips16 chips

32 chips64 chips

Code#

Code#

Code#

Code#

Code#

Code#

73516240

3120

1571131359114610212480

311523727111932913215259171301422626101822812204248160

54

12763953111147791511955872310339717123599127107437511115518319993567312561932910945771311753852110137695121578925105417391134981189733651126629430110467814118862210238706122589026106427410114508218983466212460922810844761211652842010036684120568824104407281124880169632640

0 32 16 48 8 40 24 56 4 36 20 52 12 44 28 60 2 34 18 50 10 42 26 58 6 38 22 54 14 46 30 62 1 33 17 49 9 41 25 57 5 37 21 53 13 45 29 61 3 35 19 51 11 43 27 59 7 39 23 55 15 47 31 63

QPC

HQ

PCH

QPC

HTX

Div PIlot

19.2k

19.2k

19.2k

19.2k

Paging

19.2k

19.2k

19.2k

19.2k19.2kS

yncPilot

38.4k

38.4k38.4k

38.4k

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

76.8ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH153.6 ksps

F-SCH307.2 ksps

F-SCH307.2 ksps

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

38.4k

19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k19.2k19.2k19.2k

19.2k19.2k19.2k19.2k

F-SCH 153K RC3or

F-SCH 307K RC4







F-FCH

sF-D

CC

Hs

Or Combinations

????

76.8ksps


SR1, RC1 9,600 bps F-FCH (IS-95-Compatible)

Same sym

bols go on both I and Q!

PowerControl

Puncturing

Data Bits

8.6 kbps

+CRC &Tail bits

9.6 kbps

1/2 rateConv Encoder Interleaver

User Long Code Mask

Long CodeGenerator

Long CodeDecimator

Power CtrlDecimator

PCPunc

Pwr CtrlBits

GainGain

19.2 ksps

I Short Code

QShort Code

FIRLPF

FIRLPF

II

QQ

OrthogonalSpreading

1228.8 kbps /W

800 bps

800 bps

19.2 ksps

1228.8 kcps

1228.8 kcps

SymbolRepetition Σ

ΣBTS Walsh 64Generator

1228.8 kcps


SR1, RC2 14,400 bps F-FCH (IS-95-Compatible)

Same sym

bols go on both I and Q!

PowerControl

Puncturing

Data Bits

13.35 kbps

+CRC &Tail bits

14.4 kbps


User Long Code Mask

Long CodeGenerator

Long CodeDecimator

Power CtrlDecimator

PCPunc

Pwr CtrlBits

GainGain

19.2 ksps

I Short Code

QShort Code

FIRLPF

FIRLPF

II

QQ

OrthogonalSpreading

1228.8 kbps /W

800 bps

800 bps

19.2 ksps

1228.8 kcps

1228.8 kcps

SymbolRepetition

SymbolPuncturing

28.8 ksps

2 of 6

Σ

ΣBTS Walsh 64Generator

1228.8 kcps


SR1, RC3 F-FCH (9,600 bps)

The stream of symbols is divided into two parts: one on logical I and one on logical Q

Complex scrambling ensures that the

physical I and Q phase planes contain equal

amplitudes at all times. This minimizes the

peak-to-average power levels in the signal.

PowerControl

PuncturingFull RateData Bits8.6 kbps

+CRC &Tail bits

9.6 kbps


User Long Code Mask

Long CodeGenerator

Long CodeDecimator

Power CtrlDecimator

PCPunc

Pwr CtrlBits

GainGain

Serial toParallel

Walsh 64Generator

I

Q

38.4 ksps

I Short Code

QShort Code

FIRLPF

FIRLPF

I

II

Q QQ

OrthogonalSpreading

ComplexScrambling

+

-

+

+Power control informationmay be carried as shown

or on the F-DCCH

1228.8 kbps /W/2

800 bps

800 bps

19.2 ksps

19.2 ksps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

38.4 ksps

Σ

ΣBTS


SR1, RC4 F-FCH (9,600 bps)






PowerControl

PuncturingFull RateData Bits8.6 kbps

+CRC &Tail bits

9.6 kbps


User Long Code Mask

Long CodeGenerator

Long CodeDecimator

Power CtrlDecimator

PCPunc

Pwr CtrlBits

GainGain

Serial toParallel

Walsh 128Generator

I

Q

19.2 ksps

I Short Code

QShort Code

FIRLPF

FIRLPF

I

II

Q QQ

OrthogonalSpreading

ComplexScrambling

+

-

+

+Power control informationmay be carried as shown

or on the F-DCCH

1228.8 kbps /W/2

800 bps

800 bps

9.6 ksps

9.6 ksps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

19.2 ksps

Σ

ΣBTS


SR1, RC3 F-SCH (153,600 bps)






PayloadData Bits

152.4 kbps

+CRC &Tail bits

153.6 kbps


User Long Code Mask

Long CodeGenerator

Long CodeDecimator

GainSerial toParallel

Walsh 4Generator

I

Q

614.4 kspsI

Short Code

QShort Code

FIRLPF

FIRLPF

I

II

Q QQ

OrthogonalSpreading

ComplexScrambling

+

-

+

+

1228.8 kbps /W/2

307.2 ksps

307.2 ksps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

614.4 ksps

614.4 ksps

Σ

ΣBTS


SR1, RC4 F-SCH (307,200 bps)






PayloadData Bits

304.8 kbps

+CRC &Tail bits

307.2 kbps


User Long Code Mask

Long CodeGenerator

Long CodeDecimator

GainSerial toParallel

Walsh 4Generator

I

Q

614.4 kspsI

Short Code

QShort Code

FIRLPF

FIRLPF

I

II

Q QQ

OrthogonalSpreading

ComplexScrambling

+

-

+

+

1228.8 kbps /W/2

307.2 ksps

307.2 ksps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

1228.8 kcps

614.4 ksps

614.4 ksps

Σ

ΣBTS


CDMA Network ArchitectureCDMA Network Architecture


BASE STATIONCONTROLLER

SUPPORTFUNCTIONS

BASE STATIONS

Mobile TelephoneSwitching Office

PSTNLocal CarriersLong Distance

CarriersATM Link

to other CDMANetworks(Future)

Structure of a Typical CDMA System

Voice Mail System SWITCH

HLR Home Location Register(subscriber database)


CDMA Network for Circuit-Switched Voice Calls

The first commercial IS-95 CDMA systems provided only circuit-switched voice calls

t1t1 v CESEL

t1PSTN

BTS

(C)BSC/Access ManagerSwitch


CDMA 1xRTT Voice and Data Network

CDMA2000 1xRTT networks added two new capabilities:• channel elements able to generate and carry independent streams of

symbols on the I and Q channels of the QPSK RF signal– this roughly doubles capacity compared to IS-95

• a separate IP network implementing packet connections from the mobile through to the outside internet

– including Packet Data Serving Nodes (PDSNs) and a dedicated direct data connection (the Packet-Radio Interface) to the heart of the BSC

The overall connection speed was still limited by the 1xRTT air interface

t1t1 v CESEL

t1

PDSNForeign Agent

PDSNHome Agent

BackboneNetworkInternet

VPNs

PSTN

AuthenticationAuthorization

AccountingAAA

BTS



1xEV-DO Overlaid On Existing 1xRTT Network

1xEV-DO requires faster resource management than 1x BSCs can give• this is provided by the new Data Only Radio Network Controller (DO-RNC)

A new controller and packet controller software are needed in the BTS to manage the radio resources for EV sessions

• in some cases dedicated channel elements and even dedicated backhaul is used for the EV-DO traffic

The new DO-OMC administers the DO-RNC and BTS PCF additionExisting PDSNs and backbone network are used with minor upgradingThe following sections show Lucent, Motorola, and Nortel’s specific solutions

t1t1 v CESEL

t1

PDSNForeign Agent

PDSNHome Agent


VPNs

PSTN


AccountingAAA

BTS

(C)BSC/Access ManagerSwitch CE

DORadio

NetworkController

DO-OMC


Voice Call Path through the CDMA Network

BSC-BSMMTX BTS

Ch. Card ACC

Σα

Σβ

Σχ

TFU1

GPSRBSM

CDSU

CDSU


CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS GPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2

DS0 in T1Packets

ChipsRFChannel

ElementVocoder,Selector


1x Data Call Path through the CDMA Network

BSC-BSMMTX BTS

Ch. Card ACC

Σα

Σβ

Σχ

TFU1

GPSRBSM

CDSU

CDSU


CDSU

CDSU

CDSU

CDSU

CDSU

CMSLM

LPP LPPENET

DTCs

DMS-BUS

TxcvrA

TxcvrB

TxcvrC

RFFEA

RFFEB

RFFEC

TFU

GPSR

GPS GPS

IOC

PSTN

CDSU DISCOCDSU

DISCO 1

DISCO 2Packets

ChipsRFChannel

Elements(FCH, SCH)

Selector

PDSNInternetVPNs

R-PInterface


170 OC-192son One Fiber Strand!!

North American Heirarchyin Copper Media

64,512 OC-192 10 Gb/s

32,256 OC-96 5 Gb/s

16,128 OC-48 2.5 Gb/s

8,064 OC-24 1.2 Gb/s

4,032 OC-12 622 Mb/s

2,016 OC-3 155 Mb/sDS-0

Telecom Transmission Standards

Worldwide telecom rides on the standard signal formats shown at leftLower speeds are used on copper twisted pairs or coaxial cableHigher speeds are carried on fiberMultiplexers bundle and unbundle channelsChannelized and unchannelized modes are provided

64 kb/sDS-0

1.544 Mb/s

DS-1/T-1= 24 DS-0

~45 Mb/s

DS-3= 28 DS-1= 672 DS-0

51.84 Mb/s

OC-1= 28 DS-1= 672 DS-0 European Heirarchy

in Copper Media

64 kb/sDS-0

2.036 Mb/s

E-1= 28+2 DS-0

FIBER


IS-95 Operational DetailsVocoding, Multiplexing, Power Control

IS-95 Operational DetailsVocoding, Multiplexing, Power Control


Variable Rate Vocoding & Multiplexing

Vocoders compress speech, reduce bit rate, greatly increasing capacityCDMA uses a superior Variable Rate Vocoder

• full rate during speech• low rates in speech pauses• increased capacity• more natural sound

Voice, signaling, and user secondary data may be mixed in CDMA frames

DSP QCELP VOCODER

Codebook

PitchFilter

FormantFilter

Coded Result Feed-back

20ms Sample

Frame Sizesbits

Full Rate Frame1/2 Rate Frame1/4 Rt.1/824/36

48/7296/144

192/288

Frame Contents: can be a mixture ofPrimaryTraffic(Voice or

data)

Signaling(System

Messaging)

Secondary(On-Air

activation, etc)


How Power Control Works

800 Power Control Bits per second!

TX RF Digital

BTSBSC

Eb/NoSetpoint

Bad FER?Raise Setpoint

Stronger thansetpoint?

OpenLoop Closed

LoopReverse Link

REVERSE LINK POWER ADJUSTMENT

RX RF Digital

IS-95, 1xRTTALL SAME METHOD

TXPO = -(RXdbm) -C + TXGA

MOBILE

FEI Bits Mark Bad Frames Received

BSCSyncPilot

Paging

Short PN

Trans-mitter,

Sector XΣ I QUser 1User 2User 3

Voc-oder

BTS (1 sector)

Forward Link

FORWARD LINK POWER ADJUSTMENT

Selec-tor

MOBILE

Eb/NoSetpoint

FEI Bits

Bad FrameCounterPMRM POWER MEAS. REPORT MSG “2 bad in last 4, Help!!”

POWER CONTROL BITSTREAM RIDING ON MOBILE PILOT

DGU

IS-95 RS1Method

IS-95 RS2Method1xRTTMethod


Details of Reverse Link Power Control

TXPO Handset Transmit Power• Actual RF power output of the

handset transmitter, including combined effects of open loop power control from receiver AGC and closed loop power control by BTS

• can’t exceed handset’s maximum (typ. +23 dBm)

TXGA Transmit Gain Adjust• Sum of all closed-loop

power control commands from the BTS since the beginning of this call

TXPODUP x ≈ IF

LNA

Subscriber Handset

R

R

R

S

Rake

Σ ViterbiDecoder

Vocoder

∼

FECOrthMod

Long PN

xx

xIF Mod

I

Q

x ~LO Open Loop

LO

Closed Loop Pwr Ctrl

IF

Receiver>>

<<Transmitter

PA

BTS

Typical TXPO:+23 dBm in a coverage hole0 dBm near middle of cell-50 dBm up close to BTS

0 dB

-10 dB

-20 dB

Typical Transmit Gain Adjust

Time, Seconds

TXPO = -(RXdbm) -C + TXGAC = +73 for 800 MHz. systems= +76 for 1900 MHz. systems


A Quick Introduction to CDMA Messages and Call Processing

A Quick Introduction to CDMA Messages and Call Processing


Messages in CDMA

In CDMA, most call processing events are driven by messagesSome CDMA channels exist for the sole purpose of carrying messages; they never carry user’s voice traffic

• Sync Channel (a forward channel)• Paging Channel (a forward channel)• Access Channel (a reverse channel)• On these channels, there are only messages, continuously all

of the timeSome CDMA channels exist just to carry user traffic

• Forward Traffic Channel• Reverse Traffic Channel• On these channels, most of the time is filled with traffic and

messages are sent only when there is something to doAll CDMA messages have very similar structure, regardless of thechannel on which they are sent


How CDMA Messages are Sent

CDMA messages on both forward and reverse traffic channels are normally sent via dim-and-burstMessages include many fields of binary dataThe first byte of each message identifies message type: this allows the recipient to parse the contentsTo ensure no messages are missed, all CDMA messages bear serial numbers and important messages contain a bit requesting acknowledgmentMessages not promptly acknowledged are retransmitted several times. If not acknowledged, the sender may release the callField data processing tools capture and display the messages for study

MSG_TYPE (‘00000110’)

ACK_SEQ

MSG_SEQ

ACK_REQ

ENCRYPTION

ERRORS_DETECTED

POWER_MEAS_FRAMES

LAST_HDM_SEQ

NUM_PILOTS

PILOT_STRENGTH

RESERVED (‘0’s)

8

3

3

1

2

5

10

2

4

6

0-7

NUM_PILOTS occurrences of this field:

Field Length (in bits)

EXAMPLE: A POWER MEASUREMENT

REPORT MESSAGE

t


Message Vocabulary: Acquisition & Idle StatesSync Channel

Sync Channel Msg

Pilot Channel

No Messages

Paging Channel

Access Parameters Msg

System Parameters Msg

CDMA Channel List Msg

Extended SystemParameters Msg

Extended NeighborList Msg

Global ServiceRedirection Msg

Order Msg•Base Station Acknowledgment

•Lock until Power-Cycled• Maintenance required

many others…..

AuthenticationChallenge Msg

Status Request Msg

Feature Notification Msg

TMSI Assignment Msg

Channel AssignmentMsg

SSD Update Msg

Service Redirection Msg

General Page Msg

Null Msg Data Burst Msg

Access Channel

Registration Msg

Order Msg• Mobile Station Acknowldgment• Long Code Transition Request

• SSD Update Confirmationmany others…..

Origination Msg

Page Response Msg

Authentication ChallengeResponse Msg

Status Response Msg

TMSI AssignmentCompletion Message

Data Burst Msg

BTS


Message Vocabulary: Conversation State

Reverse Traffic Channel

Order Message• Mobile Sta. Acknowledgment

•Long Code Transition Request

• SSD Update Confirmation• Connect

Authentication ChallengeResponse Msg

Flash WithInformation Msg

Data Burst Message

Pilot StrengthMeasurement Msg

Power MeasurementReport Msg

Send Burst DTMF Msg

OriginationContinuation Msg

Handoff Completion Msg

Parameters ResponseMessage

Service Request Msg

Service Response Msg

Service ConnectCompletion Message

Service Option ControlMessage

Status Response Msg

TMSI AssignmentCompletion Message

Forward Traffic ChannelOrder Msg

• Base Station Acknowledgment • Base Station Challenge

Confirmation• Message Encryption Mode

AuthenticationChallenge Msg

Alert WithInformation Msg

Data Burst Msg

Analog HandoffDirection Msg

In-Traffic SystemParameters Msg

Neighbor ListUpdate Msg

Send Burst DTMF Msg

Power ControlParameters Msg.

Retrieve Parameters Msg

Set Parameters Msg

SSD Update Msg

Flash WithInformation Msg

Mobile StationRegistered Msg

Status Request Msg

Extended HandoffDirection Msg

Service Request Msg

Service Response Msg

Service Connect Msg

Service OptionControl Msg

TMSI Assignment Msg


A Streamlined Visual TourOf CDMA Call Processing

A Streamlined Visual TourOf CDMA Call Processing


What’s In a Handset? How does it work?

ReceiverRF SectionIF, Detector

TransmitterRF Section

Vocoder

Digital Rake Receiver

Traffic CorrelatorPN xxx Walsh xx ΣTraffic CorrelatorPN xxx Walsh xxTraffic CorrelatorPN xxx Walsh xx

Pilot SearcherPN xxx Walsh 0

Viterbi Decoder,Convl. Decoder,Demultiplexer

CPUDuplexer

TransmitterDigital Section

Long Code Gen.

Open Loop Transmit Gain Adjust

Messages

Messages

Audio

Audio

Packets

Symbols

SymbolsChips

RF

RF

AGC

time-

alig

ned

su

mm

ing

pow

er

Traffic CorrelatorPN xxx Walsh xx

Δtcont

rol

bits


Let's Acquire The System!Let's Acquire The System!


Rake Receiver

1. Find the Strongest Pilot!

The pilot searcher of the phone spends about 3.4 seconds measuring the pilot strength at every possible PN delay, in miniscule 1/8 chip delay steps, to see how much energy is being received from every nearby sectorThe sector with the strongest pilot is chosen

BTS W0 PILOT

PN 168

#1 unassigned

#2 unassigned

#3 unassigned

#4 unassigned

Pilot Searcher

Find Strongest

SCANTIME

Ec/

Io

00

32K512

ChipsPN

Pilot Searcher Scans the Entire Range of PNs

0

-20


Stay Locked!

Read Sync C

h. Msg

Rake Receiver

2. Read the Sync Channel Message

Great! We found a signal. Now we know:• The strongest pilot available• The exact timing of this pilot

We do NOT yet know• This pilot’s PN offset• 20 msec frame timing of channels• Long Code State

The SYNC channel is a special channel timed exactly in step with the short PN sequence

• It tells us all these unknown quantities

BTSW32

W0SYNCPILOT

SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYNSYNSYNSYN

PN 168

#1 PN168+0 W32

#2 PN168+2 W32

#3 PN168+9 W32

#4 PN168+5 W32

Pilot Searcher

TIME

The Sync Channel is a“Sesame Street” for mobiles!

MSG_LENGTH, 28, 28 octetsMSG_TYPE, 1, Sync Channel MessageP_REV, 6, IS-2000 Revision 0MIN_P_REV, 1, J-STD-008SID 995, NID 3, PILOT_PN 168 LC_STATE, 0x00 25 93 12 7C FA, SYS_TIME, 0x02 20 34 B7 53, 10/23/2001 11:02:54LP_SEC, 13, LTM_OFF, 54, -660 minutesDAYLT, 1, YesPRAT, 1, 4800 bpsCDMA_FREQ, 274 (IS-95) EXT_CDMA_FREQ, 274 (1xRTT) SR1_BCCH_SUPPORTED, 0SR3_INCL, 0, NoRESERVED, 0,

SYNC CHANNEL MESSAGE


Rake Receiver

TheTim

ingC

hange

3. The Timing Shift: Adjust all Internal Clocks

This timeline shows each step as the mobile acquires the systemFirst search all PNs to find the strongest pilotRead the Sync Channel Message to learn times and LC state

• The times and state refer to a future moment 320 ms after the end of the Sync Channel superframe, minus the BTS PN offset. This waiting period is called the Timing Change.

BTSW32

W0

SYNC

PILOT

SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYNSYNSYNSYN

+320 ms

-PN168

PN 168

Ref Time

#1 unassigned

#2 unassigned

#3 unassigned

#4 unassigned

Pilot Searcher

TIME

Stay Locked!

End of SCHSuperFrame


4. Is This the Right System to Use?Scan the PRL for Anything Better

It’s not enough just to find a CDMA signal

• We want the CDMA signal of our own system or a favorite roaming partner

Phones look in the PRL to see if there is a more preferred signal than whatever they find first

• They check frequencies in the Acquisition Table until they find the best system, or look down the list level by level

ROAMING LIST

Roaming List Type: IS-683APreferred Only: FALSEDefault Roaming Indicator: 0Preferred List ID: 10018

ACQUISITION TABLE

INDEX ACQ TYPE CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 CH90 6 500 425 825 575 850 325 6251 6 575 625 500 4252 6 50 100 75 475 825 850 175 2503 6 25 200 350 375 725 50 475 175 2504 1 Both5 6 450 500 350 575 6506 6 675 500 600 575 4757 6 250 50 1758 6 550 375 425 6259 6 75 50 175 250

10 6 200 250 175 5011 6 425 500 575 25 325 65012 6 500 575 475 25 67513 6 500 625 350 50 375 775 575 725 42514 6 650 500 675 25 75 425 50 57515 6 25 50 375 350 250 17516 6 425 550 225 725 750 77517 6 200 50 175 375 25018 6 825 850 92519 6 350 325 375 675 25 1175 725 600 10020 6 750 725 77521 6 325 725 350 750 375 775 425 575 62522 6 1150 117523 6 350 875 325 375 117524 6 25 1175 825 200 75 175 25025 6 50 200 25 100 250 7526 6 500 1075 850 82527 1 A28 1 B29 5 A30 5 B31 5 C32 5 D33 5 E34 5 F35 4 A36 4 B37 4 Both38 6 350 82539 6 25 10040 6 675 600 750 850 1175 77541 6 85042 6 65043 6 450 47544 6 325 350 375 1025 1050 107545 6 150 475 625 67546 6 1025 1050 1075

SYSTEM TABLE

INDEX SID NIDNEG/ PREF GEO PRI

ACQ INDEX

ROAM IND

296 4144 65535 Pref NEW SAME 13 1297 4812 65535 Pref SAME MORE 21 1298 205 65535 Pref SAME SAME 4 0299 208 65535 Pref SAME MORE 37 0300 208 65535 Pref SAME SAME 4 0301 342 65535 Pref SAME MORE 37 0302 342 65535 Pref SAME SAME 4 0303 478 65535 Pref SAME SAME 4 0304 1038 65535 Pref SAME SAME 4 0305 1050 65535 Pref SAME SAME 4 0306 1058 65535 Pref SAME SAME 4 0307 1375 65535 Pref SAME SAME 4 0308 1385 65535 Pref SAME MORE 4 0309 143 65535 Pref SAME MORE 37 0310 143 65535 Pref SAME MORE 4 0311 4103 65535 Pref NEW SAME 3 1312 4157 65535 Pref SAME MORE 2 1313 312 65535 Pref SAME SAME 4 0314 444 65535 Pref SAME MORE 37 0315 444 65535 Pref SAME SAME 4 0316 1008 65535 Pref SAME SAME 4 0317 1012 65535 Pref SAME SAME 4 0318 1014 65535 Pref SAME SAME 4 0319 1688 65535 Pref SAME MORE 4 0320 113 65535 Pref SAME MORE 37 0321 113 65535 Pref SAME SAME 4 0322 179 65535 Pref SAME MORE 37 0323 179 65535 Pref SAME SAME 4 0324 465 65535 Pref SAME SAME 4 0325 2119 65535 Pref SAME MORE 4 0326 2094 65535 Pref SAME MORE 4 0327 1005 65535 Pref SAME SAME 4 0328 1013 65535 Pref SAME SAME 4 0

a G

EO G

RO

UP

a G

EO G

RO

UP

Clim

b!

PRL: Preferred Roaming ListProgrammed into each phone by the system

operator; can be updated over the air.


Rake Receiver

Collect all the Configuration MessagesAbsorb and store all their parameters.

5. Collect the Configuration Messages!

The Configuration Messages tell the mobile everything it needs to know to successfully operate on the system

• Access Parameters Message (how to behave on the access channel)• System Parameters Message (registration, handoff, window settings)• Extended System Parameters Message (how to identify; packet details)• Channel List Message (list of all carrier frequencies on this sector)• Neighbor List Message (list of nearby sectors to watch out for)• Global Service Redirection Message (“don’t stay here - go over there”)

BTS

W1

W32

W0

PAGING

SYNC

PILOT

SYN SYN SYN

ACK

SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYNSYNSYN

ChASN ACK GPAGChASN ACK

SYN

SYS CHN XSYS NBR GSRM APM

PN 168

Ref Time

#1 PN168+0 W1

#2 PN168+2 W1

#3 PN168+9 W1

#4 PN168+5 W1

Pilot Searcher

System

ParametersM

essage

** CD

MA

Channel

List Message

ExtendedS

ystemParametersM

essage

Neighbor** List

Message

Global Service** RedirectionM

essage

AccessParametersM

essage

TIME

Stay Locked!

Collect all the Configuration Messages(all config.messages are repeated every 1.28 sec)


Rake ReceiverNow monitor thePaging Channel

for anyincoming callsor messages

6. Welcome! Just Monitor the Paging Channel

Listen to see if you get any incoming calls or short messages!

BTS

W1

W32

W0

PAGING

SYNC

PILOT

SYN SYN SYN

ACK

SYN SYN SYN SYN SYN SYN SYN SYN SYN SYN SYNSYNSYN

ChASN ACK GPAGChASN ACK

SYN

SYS CHN XSYS NBR GSRM APM

PN 168

Ref Time

Pilot Searcher

#1 PN168+0 W1

#2 PN168+2 W1

#3 PN168+9 W1

#4 PN168+5 W1

TIME


Registration: Mobile, Sign In Please

After acquiring the system, the mobile must register• This allows the current system to update the HLR with the mobile’s

location, so incoming calls can be delivered here• It also allows the mobile to tell the system if it wants to do slotted

mode paging, and if so, what Slot Cycle Index.A “holdoff” timer delays initial registration 20 seconds after acquisition

• This avoids needless registration by mobiles just being turned on to check who is the owner, or other short power-on/off uses

Registration has many different controlling parameters, all declared by the system on the paging channel in the System Parameters Message

BTS

W1

W32

W0

PAGING

SYNC

PILOT

ACCESS CHANNEL

S

KS

R

20 sec.20 seconds after system acquisition, the mobile sends a Registration Message on the access

channel.

The BTS sends an ACK on the Paging Channel.

The mobile is now Registered and can begin

slotted mode paging.

SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

AKX NC GKP K KSAKX NKPP C GP K KSAKX NKPP C GP K KSAKX NKPP C GP K SAKX NP GKSAKX NKP GKSAKX GP SA

TIME


Stretch Your Battery! IS-95 Slotted Mode Paging

Slotted Mode Paging is a battery-saving trick• After registering with the system, the mobile

goes into sleep mode with low battery drain• It wakes on a schedule to listen for pages

Page slots are 80 ms. LongSlot cycles can be set to many lengthsLonger cycles give better battery life, but introduce longer possible delays in call deliveryEach mobile uses Hashing with its IMSI and SCI to determine which slot it should always monitor

W1

W32

W0

PAGING

SYNC

PILOT

S

1 Slot Cycle

1 Slot 80 ms


NC GKG K KSAKX NKPP C GP K KSAKX NKPP C GP K KSGKX NKPP C GP K SAKX NP GKSAKX NKP GKSAKX GP SA

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4

GK KSAK

5

1 Slot Cycle

Slot CycleIndex (SCI)

Number Slotsin Cycle

Length ofCycle, sec.

0 16 1.28 sec.

1 32 2.56 sec.

2 64 5.12 sec.

3 128 10.24 sec.

4 256 20.48 sec.

5 512 40.96 sec.

6 1024 81.92 sec.

7 2048 163.84 sec.

BatteryDrain

Each mobile has a preferred SCI programmed by the vendor. The system

also declares a maximum slot cycle index, which mobiles may not exceed.

Rake Receiver#1 PN168+0 W1

#2 PN168+2 W1

#3 PN168+9 W1

#4 PN168+5 W1

Pilot SearcherSLEEP

TIME

Mobile listens during its slot, every cycle

BTS


Even Better: CDMA2000 Slotted Mode PagingUsing the Quick Paging Channel (QPCH)

IS-95 mobiles must monitor their PCH slots during every slot cycle

• Must wake up 1000’s of times per hour and run high-drain message parsers, even if they are not paged

The Quick Paging Channel (QPCH) is a simpler bitstream which notifies a 1xRTT mobile to monitor the PCH, only when a page is coming for its IMSI group

• There are at least xx IMSI groups. A mobile knows its group by hashing.

BTS

W48

W32

W0

QPCH

SYNC

PILOT

S

Paging Channel Slots


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5Paging Channel Slots

BatteryDrain


#2 PN168+2 W1

#3 PN168+9 W1

#4 PN168+5 W1

Pilot Searcher

Deeper

SLEEP

TIME

PAGING NC GKG K KSAKX NKPP C GP K KSAKX NKPP C GP K KSGKX NKPP C GP K SAKX NP GKSAKX NKP GKSAKX GP SAGK KSAKW1

2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 651

Mobile hashes using its IMSI to recognize which indicator bits it should monitor. If the bits are on, the mobile wakes up and listen to the next PCH slot – somebody watching those bits

will be paged.

20ms

80 ms

100 ms

QPCH SLOT

GenPGPCH SLOT

80 ms

Mobile listens to PCH only when QPCH requires

QPCH Slots QPCH Slots


Idle Mode Handoff

An idle mobile always uses the best available signal• In idle mode, it isn’t possible to do soft handoff and listen to multiple

sectors or base stations at the same time -- the paging channel information stream is different on each sector, not synchronous -- just like ABC, NBC, CBS, and CNN TV news programs aren’t in word-sync for simultaneous viewing

• Since a mobile can’t combine signals, the mobile must switch quickly, always enjoying the best available signal

The mobile’s pilot searcher is constantly checking neighbor pilotsA Mobile might change pilots for either of two reasons:

• It notices another pilot at least 3 db stronger than the current active pilot, and it stays this good continuously for at least five seconds: mobile switches at end of the next superframe

• Mobile loses the current paging channel. If another signal is better than the old active sector, change immediately to the new one.

On the new paging channel, if the mobile learns that registration is required, it re-registers on the new sector


Idle Mode on the Paging Channel: Meet the Neighbors, track the Strongest Pilot

Ec/

IoAll PN Offsets

00

32K512

ChipsPN

0

-20

Neighbor Set

The phone’s pilot searcher constantly checks the pilots listed in the Neighbor List Message

If the searcher ever notices a neighbor pilot substantially stronger than the current reference pilot, it becomes the new reference pilot

and the phone switches over to its paging channel on the next superframe.This is called an idle mode handoff.

Rake Fingers

Reference PN

Active Pilot

SRCH_WIN_A

SRCH_WIN_N

Mobile Rake RX

Srch PN??? W0

F1 PN168 W01F2 PN168 W01F3 PN168 W01


Receiving An Incoming CallReceiving An Incoming Call


Incoming Call Termination – Voice

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS

TRAFFIC

S SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

NG ACKKS CHasnCP K NKPP C GP K KSGKX NKPP C GP K SAKX NP GKSAKX NKP GKSAKX GP SAGK KS

PgResp

V

ACK

ACK

SVCcon

SVCncmp

GenPag PCP GK KAlert/Inf

ACK Con

ACK V

GSAKX NP GKSAK

SSSSSSSSSSSS

TIME

Scott’s mobile, are you there?

You have a call.

I’m here! Whatshould I do?

I hear you.Just a moment.

Your channelIs ready!Walsh 23

I see frames!

I see frames!

I see you!

I see you, too!

Then let’s useService Option

X, for voicewith 8k EVRC

I accept.

OK! Then startringing andshow this:

615-300-0124

I am.

My owner answered!Connect the audio.

OK.

SEND

χ

β

α

PSTNswitch

HLR VLR

SS7

BSC BTS AMSC


#2 PN168+2 W23

#3 PN168+9 W23

#4 PN168+5 W23

Pilot Searcher


Making an Outgoing Call!Making an Outgoing Call!


G ACKKS CPGK KS PCP GK KGCP G

Outgoing Call Origination – IS-95 Voice

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS

TRAFFIC

S SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

NCHasn K NKPP C GP K KSGKX NKPP C GP K SAKX NP GKSAKX NKP GKSAKX GP SA

Origination

Voice conversation

ACK

ACK

SVCcon

SVCncmp

ACK Voice conversation

GSAKX NP GKSAK

SSSSSSSSSSSS

TIME

Hey system! I am 615-300-0124,

ESN 2E5FC31. Let mecall 615-555-1234using EVRC voice.

I hear you.Just a moment.

Your channelIs ready!Walsh 23

I see frames!

I see frames!

I see you!

I see you, too!

Then let’s useService Option

X, for voicewith 8k EVRC

I accept.

OK!

SEND6 1 5 5 5 5 1 2 3 4


#2 PN168+2 W23

#3 PN168+9 W23

#4 PN168+5 W23

Pilot Searcher

χ

β

α

PSTNswitch

HLR VLR

SS7

BSC BTS AMSC


Power-ControlledReservation Access Mode

Power-ControlledReservation Access Mode


Power Controlled Reservation Access Mode

Reservation Access Mode procedures:• On R-EACH, mobile asks permission to transmit • The associated F-CACH gives permission• Mobile transmits on R-CCCH during scheduled slot• F-CPCCH gives power control during R-CCCH transmission• F-CCCH gives acknowledgment and TCH assignment, if needed

R-EACH

R-CCCH

F-CACH

BTS

Enhanced Access Probe

Early Acknowledgment Channel Assignment Message

Acknowledgment

F-CPCCH

EACH HEADEREACH PREAMBLE

MESSAGE CAPSULE CACH PREAMBLE

Enhanced Access DataCCCH HEADERCCCH PREAMBLEPower Control Bits

F-CCCH


Downloading Data on aForward Link Supplemental Channel

Downloading Data on aForward Link Supplemental Channel


Forward Supplemental Channel Assignment

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

F-FCH

ACCESS CHANNEL

R-FCH

SSSSSSSSSSSSSSSSSSSSSSSSSSS

GK KS P C GP K KSAGK KSAK NNKG K SGP SA GK KS P C GP K KSAGK KSAK NNKG K SGP SA GK KS P CP KGK KSAK NNKG K SGP SA

SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

ESCAM

PN 168

TIME

W2 F-SCH SupplementalChannel Burst

ESCAM

SupplementalChannel Burst

Mobile: Watch Walsh Code 2

Starting in 320 ms For 1000 ms.

Mobile: Watch Walsh Code 2



Uploading Data on aReverse Link Supplemental Channel

Uploading Data on aReverse Link Supplemental Channel


Reverse Supplemental Channel Assignment

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

F-FCH

ACCESS CHANNEL

R-FCH




ESCAM

PN 168

TIME

R-SCH SupplementalChannel Burst

ESCAM

SupplementalChannel Burst

SCRM SCRM

Mobile: Send Walsh Code 1


Mobile: Send Walsh Code 1


System: I need toSend you the

Following blocks:

System: I need toSend you the

Following blocks:


Ending A CallEnding A Call


Normal End of Call

When a call ends normally, it is because the caller on one side of the conversation decided to hang upThe side ending the call sends a “Release – Normal” orderThe other side sends a “Release – No reason” order

• It may send an acknowledgment first, if it cannot give the release order immediately

After the system receives a release order from the mobile, it releases the resources it used for the callAfter the mobile receives a release order from the base station, it stops listening to the traffic channel and freshly reacquires the system

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS CHANNEL

TRAFFIC CHANNEL


GK KS P C GP K KSAGK KSAK

Voice

Voice

RELnorm

RELnoRsn

NNKG K SGP SA

SYN SYN SYN

ACK

SYN SYN SYN SYNSYN

ChASN

SYN

SYS CHN XSYS NBR

Ref TimeRef Time

MOBILE REACQUIRES SYSTEM NORMALLY

SCANTIME


Abnormal End of Call – Forward Link Failure

The mobile is always counting and tracking the bad frames it receives on the forward linkForward Link Fade Timer: If the mobile does not receive any goodframes during a 5-second period, it aborts the callIf a mobile receives 10 consecutive bad frames, it mutes its transmitter until at least 2 consecutive good frames are heard

• If the mobile stays muted 5 seconds, the BTS will release too After a call ends for any reason, the mobile tries to reacquire the system, making an independent cold start

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS CHANNEL

TRAFFIC CHANNEL



Voice

Voice

NNKG K SGP SA

SYN SYN SYN

ACK

SYN SYN SYNSYN

ChASN

SYN

SYS CHN XSYS

Ref TimeRef Time

MOBILE REACQUIRES SYSTEM, if available

SCAN

Mute! No pc

All bad frames5s timer

5s timer

TIME


S

Abnormal End of Call – Reverse Link Failure

The BTS is always counting and tracking the bad frames it receives on the reverse link from the mobileReverse Link Fade Timer: If the BTS does not receive any good frames during a 5-second period, it releases the callAfter a call ends for any reason, the mobile tries to reacquire the system, making an independent cold start

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS CHANNEL

TRAFFIC CHANNEL


Voice

Voice

NNKG K SGP SA

All bad frames

5s timer

SYN SYN SYN

ACK

SYN SYN SYNSYN

ChASN

SYN

SYS CHN XSYS

Ref TimeRef Time

MOBILE REACQUIRES SYSTEM, if available

SCAN

RELnoRsn

A

SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

KS NK GP SA

TIME


Feature Notification:You Have Voicemail!Feature Notification:You Have Voicemail!


Feature Notification

98/06/30 21:16:44.368 [PCH] Feature Notification MessageMSG_LENGTH = 144 bitsMSG_TYPE = Feature Notification MessageACK_SEQ = 0MSG_SEQ = 0ACK_REQ = 1VALID_ACK = 0ADDR_TYPE = IMSIADDR_LEN = 56 bitsIMSI_CLASS = 0IMSI_CLASS_0_TYPE = 3RESERVED = 0MCC = 302IMSI_11_12 = 00IMSI_S = 9055170325RELEASE = 0RECORD_TYPE = Message WaitingRECORD_LEN = 8 bitsMSG_COUNT = 1RESERVED = 0

FEATURE NOTIFICATION MESSAGE

The Feature Notification Message on the Paging Channel tells a specific mobile it has voice messages waiting.

There are other record types to notify the mobile of other features.

The mobile confirms it has received the notification by sending a Mobile Station Acknowledgment Order on the access

channel.

MOBILE STATION ACKNOWLEDGMENT


CDMA Handset ArchitectureCDMA Handoffs

CDMA Handset ArchitectureCDMA Handoffs


What’s In a Handset? How does it work?

ReceiverRF SectionIF, Detector

TransmitterRF Section

Vocoder

Digital Rake Receiver

Traffic CorrelatorPN xxx Walsh xx ΣTraffic CorrelatorPN xxx Walsh xxTraffic CorrelatorPN xxx Walsh xx

Pilot SearcherPN xxx Walsh 0

Viterbi Decoder,Convl. Decoder,Demultiplexer

CPUDuplexer

TransmitterDigital Section

Long Code Gen.

Open Loop Transmit Gain Adjust

Messages

Messages

Audio

Audio

Packets

Symbols

SymbolsChips

RF

RF

AGC

time-

alig

ned

su

mm

ing

pow

er

Traffic CorrelatorPN xxx Walsh xx

Δtcont

rol

bits


The Rake Receiver

Every frame, handset uses combined outputs of the three traffic correlators (“rake fingers”)Each finger can independently recover a particular PN offset andWalsh codeFingers can be targeted on delayed multipath reflections, or even on different BTSsSearcher continuously checks pilots

Handset Rake Receiver

RF

PN Walsh

PN Walsh

PN Walsh

SearcherPN W=0

ΣVoice,Data,

Messages

Pilot Ec/Io

BTS

BTS


CDMA Soft Handoff Mechanics

CDMA soft handoff is driven by the handset• Handset continuously checks available pilots• Handset tells system pilots it currently sees• System assigns sectors (up to 6 max.), tells handset• Handset assigns its fingers accordingly• All messages sent by dim-and-burst, no muting!

Each end of the link chooses what works best, on a frame-by-frame basis!

• Users are totally unaware of handoff


RFPN Walsh

PN Walsh

PN Walsh

SearcherPN W=0

ΣVoice,Data,

Messages

Pilot Ec/Io

BTS

BSCSwitch

BTS

Sel.


The Complete Rules of Soft Handoff

The Handset considers pilots in sets• Active: pilots of sectors actually in use• Candidates: pilots mobile requested, but

not yet set up & transmitting by system• Neighbors: pilots told to mobile by system,

as nearby sectors to check• Remaining: any pilots used by system but

not already in the other sets (div. by PILOT_INC)

Handset sends Pilot Strength Measurement Message to the system whenever:

• It notices a pilot in neighbor or remaining set exceeds T_ADD

• An active set pilot drops below T_DROP for T_TDROP time

• A candidate pilot exceeds an active by T_COMP

The System may set up all requested handoffs, or it may apply special manufacturer-specific screening criteria and only authorize some

65

Remaining

ActiveCandidateNeighbor 20

PILOT SETS

# Req’d`. B

y Std.

T_COMPT_ADD T_DROPT_TDROP

HANDOFF PARAMETERS

Exercise: How does a pilot in one set migrate into another set, for all cases? Identify the trigger, and the messages involved.

IS-95/J-Std008

IS-95B/

1xRTT

61040


Softer Handoff

Each BTS sector has unique PN offset & pilot Handset will ask for whatever pilots it wantsIf multiple sectors of one BTS simultaneously serve a handset, this is called Softer HandoffHandset can’t tell the difference, but softer handoff occurs in BTS in a single channel elementHandset can even use combination soft-softer handoff on multiple BTS & sectors


RFPN Walsh

PN Walsh

PN Walsh

SearcherPN W=0

ΣVoice,Data,

Messages

Pilot Ec/Io

BTS

BSCSwitchSel.


What is Ec/Io?

Ec/Io is the measurement mobiles use to gauge strengths of the various nearby sectors they encounter

• Ec means the energy per chip of the pilot of the observed sector

• Io means the total power currently being picked up by the mobile

≈ x

LO

≈

RX Level(from AGC)

IFLNA

BW~30

MHz.

BW1.25MHz.

Handset Receiver

R

R

R

S

Rake

Why can’t the mobile just measure the signal strength of a sector directly with its receiver?

• all sectors are on the same frequency• the measurable signal strength on that frequency is just the

sum of all the individual signal powers• to distinguish them individually CDMA decoding must be used

Each sector dedicates 10-15% of its power to a steady test signal called the “pilot”. Mobiles can easily measure the pilot of a sector, determining its strength as a percentage of total received power


Light Traffic Loading

Heavily Loaded

How Ec/Io Varies with Traffic Loading

Each sector transmits a certain amount of power, the sum of:

• pilot, sync, and paging• any traffic channels in use

at that momentEc/Io is the ratio of pilot power to total power

• On a sector with nobody talking, Ec/Io is typically about 50%, which is -3 db

• On a sector with maximum traffic, Ec/Io is typically about 20%, which is -7 db.

Ec/Io = (2/4)= 50%

= -3 db.

Ec/Io = (2/10)= 20%

= -7 db.

2w

1.5w

Pilot

PagingSync

I0

EC

Traffic Channels

6w

0.5w

2w

1.5w

Pilot

PagingSync I0EC

0.5w


Many Sectors, Nobody Dominant

One Sector Dominant

How Ec/Io varies with RF Environment

In a “clean situation”, one sector is dominant and the mobile enjoys an Ec/Io just as good as it was when transmittedIn “pilot pollution”, too many sectors overlap and the mobile hears a “soup” made up of all their signals

• Io is the power sum of all the signals reaching the mobile

• Ec is the energy of a single sector’s pilot

• The large Io overrides the weak Ec; Ec/Io is low!

Io = -90 dbmEc = -96 dbmEc/Io = -6 db

Io = 10 signalseach -90 dbm

= -80 dbmEc of any onesector = -96

Ec/Io = -16 db

2w

1.5w

Pilot

PagingSync

I0

ECTraffic

Channels

4w

0.5w

BTS1

I0

EC

BTS2

BTS3

BTS4

BTS5

BTS6

BTS7

BTS8

BTS9

BTS10

PilotSync & Paging

TrafficPilot

Sync & PagingTraffic

PilotSync & Paging

TrafficPilot


PilotSync & Paging

TrafficPilot


PilotSync & Paging

TrafficPilot


PilotSync & Paging

TrafficPilot



A Soft HandoffA Soft Handoff


Basic Soft/Softer Handoff

BTS

W1

W32

W0

W41

PAGING

SYNC

PILOT

TRAFFIC

SSSSSSSSSSSSSSSSSS

GKS P C GP K KSANG K SGP SA

BTS

W1

W32

W0

W23

PAGING

SYNC

PILOT

TRAFFIC

ACCESS CHANNEL

TRAFFIC CHANNEL PSMM

GK KS P C GP K KSAGK KSAK NNKG K SGP SA GK KS P CP KGK KSAK NNKG K SGP SA





ACK EHDM

ACK HOcomp

EHDM ACK

ACK NLum

NLum

ACK

PN 168

PN 344

TIME

Wow! PN344is aboveT_ADD!

Hey system! I want:PN168 (ref), -6, keep

PN344, -11, keep

I hear you.Hang on…

OK! You can use:PN 168 W23PN 344 W41

OK Great! I’m usingPN168 + PN344

OK

OK. Here’s your newNeighbor list:

PN164 PN172 PN340PN420 PN084 PN132PN434 PN504 PN016PN028 PN508 PN372

OK

χβα

ctrlBTSC

χβα

BTSCBSC

BTS A BTS B

!!Rake Receiver#1 PN344+0 W41

#2 PN344+3 W41

#3 PN168+2 W23

#4 PN168+5 W23

Pilot Searcher


Handoff ExampleE

c/Io

All PN Offsets

0

032K

512Chips

PN

0

-20

Neighbor Set

The call is already in progress. PN 168 is the only active signal,and also is our timing reference.

Continue checking the neighbors.

If we ever notice a neighbor with Ec/Io above T_ADD,ask to use it! Send a Pilot Strength Measurement Message!

T_ADD

Rake Fingers

Reference PN

Active Pilot

10752

16832002

50014080

220

! !

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61F2 PN168 W61F3 PN168 W61


Handoff Now In Effect, but still check Pilots!E

c/Io

All PN Offsets

0

032K

512Chips

PN

0

-20

Neighbor Set

Continue checking each ACTIVE pilot. If any are less than T_DROP and remain so for T_TDROP time, send Pilot Strength Measurement Message, DROP IT!!

Continue looking at each NEIGHBOR pilot. If any ever rises above T_ADD, send Pilot Strength Measurement Message, ADD IT!

T_ADD

Rake Fingers

Reference PN

Active Set

10752

16832002

50014080

220

T_DROP

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61F2 PN500 W50F3 PN220 W20


The Complete Picture of Handoff & Pilot Sets

T_ADD

Ec/

IoAll PN Offsets

00

32K512

ChipsPN

0

-20

Neighbor Set

SRCH_WIN_N

Active Set

Candidate SetT_DROP

SRCH_WIN_A

Remaining SetT_ADD

SRCH_WIN_R

SRCH_WIN_A

T_DROP

Rake Fingers

Reference PN

Pilots of sectors now used for communication

Pilots requested by mobile but not set up by system

Pilots suggested by system for more checking

All other pilots divisible by PILOT_INC but not presently in Active, Candidate, or Neighbor sets

Mobile Rake RX

Srch PN??? W0

F1 PN168 W61F2 PN500 W50F3 PN220 W20


CDMA Call ProcessingCDMA Call Processing


CDMA Troubleshooting is like Air Accident Investigation

Air accidents are big news and reporters follow the investigations closely• Everybody’s familiar with the two main information sources at the crash

– Cockpit voice recorder: record of conversation and sounds in the cockpit during the last 30 minutes up to the crash

– Flight data recorder: record of major control settings, mechanical, electrical, and hydraulic systems status for the last 30 minutes

In CDMA, the same sorts of tools are available for problem investigation:• Layer-3 message files contain user and system command/control details• Temporal analyzer data shows the RF environment up to the problem

Control & Parameters Messaging

BTS

1150011500

114.50118.25130.75

AeronauticalInvestigations

CDMAInvestigations

Flight Data Recorder Cockpit Voice Recorder

Temporal Analyzer Data Layer 3 Message FilesPhysical Layer

Data Link LayerMACLAC

MessageApplication

1

2

34

Wireless Protocol Stack

Laye

rs


Troubleshooting Call Processing

CDMA call processing is complex!• Calls are a relationship between mobile and system

– the events driven by messaging– the channels carried by RF transmission

• Multiple codes and channels available for use• Multiple possible problems - physical, configuration, software• Multiple concurrent processes in the mobile and the system

Troubleshooting focuses on the desired call events• What is the desired sequence of events?• Compare the actual sequence of events.

– What’s missing or wrong? Why did it happen?Messaging is a major blow-by-blow troubleshooting toolRF indications reveal the transmission risks and the channel configurations

Bottom Line: To troubleshoot effectively, you’ve got to know call processing steps and details AND the RF basis of the transmission


Introduction to OptimizationIntroduction to Optimization


What is Performance Optimization?

The words “performance optimization” mean different things to different people, viewed from the perspective of their own jobsSystem Performance Optimization includes many different smaller processes at many points during a system’s life

• recognizing and resolving system-design-related issues (can’t build a crucial site, too much overlap/soft handoff, coverage holes, etc.)

• “cluster testing” and “cell integration” to ensure that new base station hardware works and that call processing is normal

• “fine-tuning” system parameters to wring out the best possible call performance

• identifying causes of specific problems and customer complaints, and fixing them

• carefully watching system traffic growth and the problems it causes - implementing short-term fixes to ease “hot spots”, and recognizing problems before they become critical


Performance Optimization Phases/Activities

hello

RF Design and Cell Planning

New Cluster Testing and

Cell Integration

Solve SpecificPerformance

Problems

Well-System Performance Management

Capacity Optimization

Growth Management:

Optimizing both Performance and Capital

Effectiveness

Cover desired area; have capacity for anticipated traffic

Ensure cells properly constructed and

configured to give normal performance

Identify problems from complaints or statistics; fix them!

Ensure present ‘plant’is giving best possible

performance

Manage congested areas for most

effective performance

Overall traffic increases and congestion;

competition for capital during tight times

Phase Drivers/Objectives Activities Main Tools Success Indicators

Plan cells to effectively cover as needed and divide traffic

load appropriately

Drive-test: coverage, all handoff boundaries, all call

events and scenarios

Detect, Investigate, Resolve performance problems

Watch stats: Drops, Blocks, Access Failures; identify/fix hot

spots

Watch capacity indicators; identify problem areas, tune parameters & configuration

Predict sector and area exhaustion: plan and validate effective growth plan, avoid

integration impact

Prop. Models,Test Transmitters,

planning tools Model results

Drive-test tools;cell diagnostics and

hardware test

All handoffs occur; all test cases

verified

Drive-test tools, system stats,

customer reports

Identified problems are

resolved

System statisticsAcceptable levels and good trends for all indicators

Smart optimization of parameters;

system statistics

Stats-Derived indicators; carried

traffic levels

Traffic analysis and trending tools;

prop. models for cell spliiting; carrier

additions

Sectors are expanded soon

after first signs of congestion;

capital budget remains within

comfortable bounds


Good Performance is so Simple!!

One, Two, or Three good signals in handoff• Composite Ec/Io > -10 db

Enough capacity• No resource problems – I’ve got what I

need

BTS BTS

BTS

Pilot

Paging

TrafficChannels

In use

availablepower

Sync

BTS

A

BTS

B

BTS

C

Ec/Io -10

FORWARDLINK


Bad Performance Has Many CausesWeak Signal / Coverage HolePilot Pollution

• Excessive Soft HandoffHandoff Failures, “Rogue” mobiles

• Missing Neighbors• Search Windows Too Small• BTS Resource Overload / No Resources

– No Forward Power, Channel Elements

– No available Walsh Codes– No space in Packet Pipes

Pilot “Surprise” ambush; Slow HandoffsPN Plan errorsSlow Data Problems: RF or IP congestionImproper cell or reradiator configurationHardware and software failuresBut on analysis, all of these problems’ bad effects happen because the simple few-signal ideal CDMA environment isn’t possible.

360

+41

+8

360+33cA

BBTS

BTS

BTS BPN 99

BTS APN 100

1 mile 11 miles

ACTIVE SEARCH WINDOW

xPilot

PagingSync

TrafficChannels

In Use

NoAvailablePower!B

TS Sector Transmitter

CEsVocodersSelectors

BTS Rx PwrOverload


Aeronautical Analogy: Tools for Problem Investigation

To study the cause of an aeronautical accident, we try to recover the Flight Data Recorder and the Cockpit Voice Recorder.

To study the cause of a CDMA call processing accident, we review data from the Temporal Analyzer and the Layer 3 Message Files -- for the same reasons.

Control & Parameters Messaging

BTS

1150011500

114.50118.25125.75

AeronauticalInvestigations

CDMAInvestigations

Flight Data Recorder Cockpit Voice Recorder

Temporal Analyzer Data Layer 3 Message Files


Starting Optimization on a New SystemRF Coverage Control

• try to contain each sector’s coverage, avoiding gross spillover into other sectors

• tools: PN Plots, Handoff State Plots, Mobile TX plotsSearch Window Settings

• find best settings for SRCH_WIN_A, _N, _R• especially optimize SRCH_WIN_A per sector using collected

finger separation data; has major impact on pilot search speedNeighbor List Tuning

• try to groom each sector’s neighbors to only those necessary but be alert to special needs due to topography and traffic

• tools: diagnostic data, system logsAccess Failures, Dropped Call Analysis

• finally, iterative corrections until within numerical goals

Getting these items into shape provides a solid baseline and foundation from which future performance issues can be addressed.


Autonomous Data CollectionBy Stowaway Mobiles

Autonomous Data CollectionBy Stowaway Mobiles


Stowaway Mobiles

Some operators are using “stowaway” mobiles in courier vehicles or public transport (under agreement, of course)A typical installation includes:

• a commercial data collection device by a manufacturer such as ZKcelltest

• two attached phones, one for collection and one as a modem• a PN scanner• a GPS receiver

The data collection begins anytime the vehicle is driven Collected data is uploaded to a server on the systemThe central server also provides post-processing functions via a web interface, allowing remote users to examine data for their areas


Autonomous Data CollectionBy Subscriber Handsets

Autonomous Data CollectionBy Subscriber Handsets


Autonomous Collection:A New Way to See Network Performance

An exciting new trend in network RF performance is to embed datacollection software on mobile platformsOffers big advantages for RF optimization cost/effectiveness

t1t1 v SEL

t1

R-P Interface

PDSN/Foreign Agent

PDSNHome Agent


VPNs

PSTN

T TSECURE TUNNELS


AccountingAAA

BTS


Collection Server•software download•collected data upload•data management, analysis

BTS

BTS

BTS


Using Autonomous Collection

A Server downloads software to a large population of subscriber mobilesMobiles collect on custom profiles

• all or groups of mobiles can be enabled/disabled• new triggers can be rapidly developed and downloaded when desired

Mobiles upload compacted packets to server driven by custom triggers• may be immediately if needed, or at low-traffic pre-programmed times• collected data can include location/GPS/call event/L3

messaging/timestamps/etc.Server manages data, provides filtering and reportingPerformance optimizers use terminals and post-processing software

t1t1 vSELt1

R-P Interface

PDSN/Foreign Agent

PDSNHome Agent


VPNs

PSTN

T TSECURE TUNNELSAuthentication

AuthorizationAccounting

AAABTS


Collection Server•software download•collected data upload•data management, analysis

BTS

BTS

BTS


Advantages of Autonomous Collection

Mobile-reported data can be location-binned

• post-processing provides visual identification of problem areas

Collection can be rapidly enabled per cell or area for immediate investigation of problem reportsRequires less employee drive time for collectionCustomer mobiles cover area more densely than drivetestersCustomer mobiles include in-building populationsIndividual mobile identification can be included with customer permission for direct customer service interaction


Conventional Field ToolsConventional Field Tools


CDMA Field Test ToolsField Collection Tools using Handset Data

There are many commercial CDMA field test toolsCharacteristics of many test tools:

• capture data from data ports on commercial handsets• log data onto PCs using proprietary software• can display call parameters, messaging, graphs, and maps• store data in formats readable for post-processing analysis• small and portable, easy to use in vehicles or even on foot

A few considerations when selecting test tools:• does it allow integration of network and mobile data?• Cost, features, convenience, availability, and support• new tools are introduced every few months - investigate!

QualcommMDM, CAIT

Grayson

Comarco

Willtech

EricssonTEMS

Motorola

PN Scanners

Agilent(HP + SAFCO)

Agilent(HP + SAFCO)

BerkeleyVaritronics

Grayson Qualcomm

DTI Willtech


Grayson’s Invex3G Tool

100 MB ethernet connection to PCthe eight card slots can hold receivers or dual-phone cardsthere’s also room for two internal PN scannersMultiple Invex units can be cascaded for multi-phone load-test applicationsCards are field-swappable -Users can reconfigure the unit in the field for different tasks without factory assistance


This mobile is in a 2-way soft handoff (two green FCH walsh codes assigned) in the middle of a downlink SCH burst. Notice walsh code #3, 4 chips long, is assigned as an SCH but only on one sector, and the downlink data speed is 153.6kb/s.

153.6kb/s

Grayson Invex 1x Data Example

July, 2008Introduction to Wireless & CDMA -- RF100 v3.0 - (c) 2008 Scott BaxterTechnical Introduction to Wireless -- ©1997 Scott Baxter - V0.0249

F-SCH rates 153.6 kbps; R-SCH 76.8kbps

PN Scanner Data

Grayson Invex 1xData Example

Current Data Task StatusLayer-3 Messages

CDMA Status


WillTech Tools

Blue Rose platform can manage multiple phones and collect data

• Internal processor manages test operations independently for stand-alone operation

• Internal PCMCIA flash card provides storage

• An external PC can display collected data during or after data collection


Agilent Drive-Test Tools

Agilent offers Drive-Test tools• Serial interfaces for up to four

CDMA phones• A very flexible digital receiver

with several modesPN Scanner

• Fast, GPS-locked, can scan two carrier frequencies

Spectrum Analyzer• Can scan entire 800 or 1900

mHz. BandsBase-Station Over-Air Tester (BOAT)

• Can display all walsh channel activity on a specific sector

• Useful for identifying hardware problems, monitoring instantaneous traffic levels, etc.

Post-Processing tool: OPAS32


Comarco Mobile Tools

X-Series Units for more data-intensive collection activities

• Multiple handsets can be collected

• Data is displayed and collected on PC

LT-Series provides integrated display and logging"Workbench" Post-Processing tool analyzes drive-test files


PN Scanners

Why PN scanners? Because phones can’t scan remaining set fast enough, miss transient interfering signalsBerkeley Varitronics

• high-resolution, GPS-locked– full-PN scan speed 26-2/3 ms.

• 2048 parallel processors for very fast detection of transient interferors

Agilent (formerly Hewlett-Packard)• high resolution, GPS-locked

– full-PN scan speed 1.2 sec.• Integrated with spectrum analyzer and

phone call-processing toolGrayson Wireless

• New digital receiver provides CDMA PN searcher and and sector walsh domain displays


Post-Processing ToolsPost-Processing tools display drive-test files

for detailed analysis - Faster, more effective than studying data playback with collection tools aloneActix Analyzer

• Imports/analyzes data from almost every brand of drive-test collection tool

Grayson Interpreter• Imports/analyzes data from Grayson

Wireless Inspector, Illuminator, and Invex3G

Agilent OPAS32• Imports/analyzes a variety of data

Nortel RF Optimizer• Can merge/analyze drive-test and

Nortel CDMA system dataWavelinkComarco "Workbench" ToolVerizon/Airtouch internal tool “DataPro”

OPAS32

COMARCO


The Key Features and Structure of 1xEV-DO

The Key Features and Structure of 1xEV-DO


Channel Structure of 1xEV-DO vs. 1xRTTCHANNEL STRUCTURE

IS-95 and 1xRTT• many simultaneous users, each

with steady forward and reverse traffic channels

• transmissions arranged, requested, confirmed by layer-3 messages – with some delay……

1xEV-DO -- Very Different:• Forward Link goes to one user at a

time – like TDMA!• users are rapidly time-multiplexed,

each receives fair share of available sector time

• instant preference given to user with ideal receiving conditions, to maximize average throughput

• transmissions arranged and requested via steady MAC-layer walsh streams – very immediate!

BTS

IS-95 AND 1xRTTMany users’ simultaneous forward

and reverse traffic channelsW0W32W1W17W25W41

W3

W53

PILOTSYNC

PAGINGF-FCH1F-FCH2F-FCH3

F-SCH

F-FCH4

AP

1xEV-DO AP (Access Point)

ATs (Access Terminals)

1xEV-DO Forward Link


Power Management of 1xEV-DO vs. 1xRTT

POWER MANAGEMENTIS-95 and 1xRTT:

• sectors adjust each user’s channel power to maintain a preset target FER

1xEV-DO IS-856:• sectors always operate at

maximum power• sector output is time-

multiplexed, with only one user served at any instant

• The transmission data rate is set to the maximum speed the user can receive at that moment

PILOT

PAGINGSYNC

Maximum Sector Transmit Power

User 123

45 5 5678

time

pow

er

IS-95: VARIABLE POWER TO MAINTAIN USER FER

time

pow

er

1xEV-DO: MAX POWER ALWAYS,DATA RATE OPTIMIZED


Some EV-DO Terminology

Phone, Mobile,

Handset, or Subscriber Terminal

ATAccess

Terminal

Base Station,BTS,

Cell Site

APAccess Point

IS-95, IS-2000, 1xRTT EV-DO


1xEV-DO Technical DetailsData Flow and Channels

1xEV-DO Technical DetailsData Flow and Channels


1xEV-DO Transmission TimingForward Link

All members of the CDMA family - IS-95, IS-95B, 1xRTT, 1xEV-DO and 1xEV-DV transmit “Frames”

• IS-95, IS-95B, 1xRTT frames are usually 20 ms. long

• 1xEV-DO frames are 26-2/3 ms. long– same length as the short PN code– each 1xEV-DO frame is divided into

1/16ths, called “slots”The Slot is the basic timing unit of 1xEV-DO transmission

• Each slot is directed toward somebody and holds a subpacket of information for them

• Some slots are used to carry the control channel for everyone to hear; most slots are intended for individual users or private groups

Users don’t “own” long continuing series of slots like in TDMA or GSM; instead, each slot or small string of slots is dynamically addressed to whoever needs it at the moment

One 1xEV-DO Frame

One Slot

One Cycle of PN Short Code


What’s In a Slot?

The main “cargo” in a slot is the DATA being sent to a userBut all users need to get continuous timing and administrative information, even when all the slots are going to somebody elseTwice in every slot there is regularly-scheduled burst of timing and administrative information for everyone to use

• MAC (Media Access Control) information such as power control bits

• a burst of pure Pilot– allows new mobiles to acquire the cell and decide to use it– keeps existing user mobiles exactly on sector time– mobiles use it to decide which sector should send them

their next forward link packet

SLOT DATA

MA

CPI

LOT

MA

C

DATA DATA

MA

CPI

LOT

MA

C

DATA

400 chips 64 96 64 400 chips 400 chips 64 96 64 400 chips

½ Slot – 1024 chips ½ Slot – 1024 chips


empty empty empty empty

What if there’s No Data to Send?

Sometimes there may be no data waiting to be sent on a sector’s forward link

• When there’s no data to transmit on a slot, transmitting can be suspended during the data portions of that slot

• But---the MAC and PILOT must be transmitted!!• New and existing mobiles on this sector and surrounding

sectors need to monitor the relative strength of all the sectorsand decide which one to use next, so they need the pilot

• Mobiles TRANSMITTING data to the sector on the reverse link need power control bits

• So MAC and PILOT are always transmitted, even in an empty slot

SLOT

MA

CPI

LOT

MA

C

MA

CPI

LOT

MA

C




Slot

Slots and Frames

SLOT

FRAME1 Frame = 16 slots – 32k chips – 26-2/3 ms

DATA

MA

CPI

LOT

MA

C

DATA DATA

MA

CPI

LOT

MA

C

DATA



Two Half-Slots make a Slot16 Slots make a frame


Frames and Control Channel Cycles

A Control Channel Cycle is 16 frames (that’s 426-2/3 ms, about 1/2 second)The first half of the first frame has all of its slots reserved for possible use carrying Control Channel packetsThe last half of the first frame, and all of the remaining 15 frames, have their slots available for ordinary use transmitting subpackets to users


16 Frames – 524k chips – 426-2/3 ms

CONTROLCHANNEL USER(S) DATA CHANNEL

16-FRAMECONTROL CHANNEL

CYCLE

Slot

That’s a lot of slots!16 x 16 = 256


Forward Link Frame and Slot Structure:“Big Picture” Summary

Slots make Frames and Frames make Control Channel Cycles!

SLOT


16 Frames – 524k chips – 426-2/3 ms

CONTROLCHANNEL USER(S) DATA CHANNEL

16-FRAMECONTROL CHANNEL

CYCLE

DATA

MA

CPI

LOT

MA

C

DATA DATA

MA

CPI

LOT

MA

C

DATA




The 1xEV-DO Channels

These channels are NOT CONTINUOUS like IS-95 or 1xRTT!• They are made up of SLOTS carrying data subpackets to individual

users or control channel subpackets for everyone to monitor• Regardless of who “owns” a SLOT, the slot also carries two small

generic bursts containing PILOT and MAC information everyone canmonitor

IN THE WORLD OF CODES

Sect

or h

as a

Sho

rt P

N O

ffset

just

like

IS-9

5A

ccessLong PN

offsetPublic or Private

Long PN offset

ACCESS

FORWARD CHANNELS

AccessPoint(AP)

REVERSE CHANNELS

TRAFFIC

Pilot

Data

Pilot

DataACK

Pilot

ControlTraffic

MAC

MAC FORWARD

Rev ActivityDRCLockRPC

DRC

RRI

W 64

W264

W064

Wx16

Wx16

W48

W24

W816

W016

W24

W016

MA

C

W0 W4W1 W5W2 W6W3 W7

AccessTerminal

(UserTerminal)

Walshcode

Walshcode

Access Channelfor session setup

from Idle Mode

Traffic Channelas used duringa data session


Information Flow Over 1xEV-DO

The system notifies a mobile when data for it is waiting to be sentThe mobile chooses which sector it hears best at that instant, and requests the sector to send it a packetthere are 16 possible transmission formats the mobile may request, called “DRC Indices”. Each DRC Index value is really a combined specification including specific values for:

• what data speed will be transmitted• how big a “chunk” of waiting data will be sent (that amount of data will be

cut of the front of the waiting data stream and will be the “Packet”transmitted)

• what kind of encoding will be done to protect the data (3x Turbo, 5x Turbo, etc.) and the symbol repetition, if any

• after the symbols are formed, how many SUBpackets they will be divided into

Then, the sector starts transmitting the SUBpackets in SLOTS on the forward linkThe first slot will begin with a header that the mobile will recognize so it can begin the receiving process

AP

Data Ready

DRC: 5

Data from PDSN for the Mobile

MP3, web page, or other content


Transmission of a Packet over EV-DO

AP

Data Ready

A user has initiated a1xEV-DO data session on their AT, accessing a favorite website.The requested page has just been received by the PDSN.The PDSN and Radio Network Controller send a “Data Ready” message to let the AT know it has data waiting.




Transmission of a Packet over EV-DO

AP

Data Ready

A user has initiated a1xEV-DO data session on their AT, accessing a favorite website.The requested page has just been received by the PDSN.The PDSN and Radio Network Controller send a “Data Ready” message to let the AT know it has data waiting.

The AT quickly determines which of its active sectors is the strongest. On the AT’s DRC channel it asks that sector to send it a packet at speed “DRC Index 5”.

The mobile’s choice, DRC Index 5, determines everything:The raw bit speed is 307.2 kb/s.The packet will have 2048 bits.There will be 4 subpackets (in slots 4 apart).The first subpacket will begin with a 128 chip preamble.

DRC: 5

DRCIndex Slots Preamble

ChipsPayload

BitsRawkb/s

0x0 n/a n/a 0 null rate0x1 16 1024 1024 38.40x2 8 512 1024 76.80x3 4 256 1024 153.60x4 2 128 1024 307.20x5 4 128 2048 307.20x6 1 64 1024 614.40x7 2 64 2048 614.40x8 2 64 3072 921.60x9 1 64 2048 1,228.80xa 2 64 4096 1,228.80xb 1 64 3072 1,843.20xc 1 64 4096 2,457.60xd 2 64 5120 1,536.00xe 1 64 5120 3,072.0

C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A

Modu-lationQPSKQPSKQPSKQPSKQPSKQPSKQPSKQPSKQPSKQPSK

16QAM8PSK

16QAM16QAM16QAM




Transmission of a Packet over EV-DOData from PDSN for the Mobile

MP3, web page, or other content AP

Data Ready

DRC: 5

2048 bits

Interleaver

+ D+

+D D

++ +

+

+ D+

+D D

++ +

+

Turbo Coder

PACKET

Symbols

Using the specifications for the mobile’s requested DRC index, the correct-size packet of bits is fed into the turbo coder and the right number of symbols are created.


ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A


16QAM8PSK

16QAM16QAM16QAM




Data Ready

DRC: 5

2048 bits

Interleaver

+ D+

+D D

++ +

+

+ D+

+D D

++ +

+

Turbo Coder

Block Interleaver

PACKET

Symbols


To guard against bursty errors in transmission, the symbols are completely “stirred up” in a block interleaver.


ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A


16QAM8PSK

16QAM16QAM16QAM




Data Ready

DRC: 5

2048 bits

Interleaver

+ D+

+D D

++ +

+

+ D+

+D D

++ +

+

Turbo Coder

Block Interleaver

PACKET

Symbols

Interleaved Symbols


To guard against bursty errors in transmission, the symbols are completely “stirred up” in a block interleaver.

The re-ordered stream of symbols is now ready to transmit.


ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A


16QAM8PSK

16QAM16QAM16QAM




Data Ready

DRC: 5

2048 bits

Interleaver

+ D+

+D D

++ +

+

+ D+

+D D

++ +

+

Turbo Coder

Block Interleaver

PACKET

Symbols

Interleaved Symbols

Using the specifications for the mobile’s requested DRC index, the correct-size packet of bits is fed into the turbo coder and the right number of symbols are created.To guard against bursty errors in transmission, the symbols are completely “stirred up” in a block interleaver.The re-ordered stream of symbols is now ready to transmit. The symbols are divided into the correct number of subpackets, which will occupy the same number of transmission slots, spaced four apart.It’s up to the AP to decide when it will start transmitting the stream, taking into account any other pending subpackets for other users, and “proportional fairness”. Su

bpac

ket

1

Subp

acke

t 2

Subp

acke

t 3

Subp

acke

t 4


ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A


16QAM8PSK

16QAM16QAM16QAM




Data Ready

DRC: 5

2048 bits

1 2 3 4

Interleaver

+ D+

+D D

++ +

+

+ D+

+D D

++ +

+

Turbo Coder

Block Interleaver

PACKET

SLOTS

Symbols

Interleaved Symbols

When the AP is ready, the first subpacket is actually transmitted in a slot.

The first subpacket begins with a preamble carrying the user’s MAC index, so the user knows this is the start of its sequence of subpackets, and how many subpackets are in the sequence..

The user keeps collecting subpackets until either:

1) it has been able to reverse-turbo decode the packet contents early, or

2) the whole schedule of subpackets has been transmitted.

Subpackets


ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3

in Rev. Ain Rev. A


16QAM8PSK

16QAM16QAM16QAM


1xEV-DO Rev. A1xEV-DO Rev. A


1xEV-DO Rev. A Design Objectives

To enable multimedia services• high-speed upload of multimedia files and attachments • interactive gaming• IP-based services such as Voice over Internet Protocol (VoIP).

To allow real-time conversational services• push to talk, • video telephony • instant multimedia -- an extension of push to talk that combines

immediate voice with simultaneous delivery of video and pictures. multimedia multicasting using QUALCOMM's “Platinum Multicast”

• enables high-quality video/audio to many users simultaneously.Peak forward link data rates of 3.1 Mbps Peak reverse link data rates of 1.8 Mbps Optimized packet data service

• one of lowest costs per bit compared to other wireless technologies.


1xEV-DO Rev. A Differences

Everything we’ve seen thus far applies to 1xEV-DO Revision 0.1xEV-DO Rev. A is now officially standardized and ready for commercial deployment


Forward Link Enhancements in 1xEV-DO Rev. A

Forward Link Enhancements• Peak rates increased from 2.4 Mbps to 3.1 Mbps• Multi-user packet support• Small payload sizes (128, 256, 512 bits) improve frame fill efficiency• The DRC channel functions are broken out into two channels

– DRC retains rate control indication– new Data Source Control (DSC) Channel shows desired serving cell

• Minimizes interruptions due to server switching on FL


Reverse Link Enhancements in 1xEV-DO Rev. A

Reverse Link Enhancements• Higher data rates and finer quantization

• Data rates from 4.8 kbps to 1.8 Mbps with 48 payload sizes• 4 slots/sub-packets regardless of payload size (6.66 ms)• Modulation:

– Low rates: 1 walsh channel, BPSK modulation– Medium rates: 1 walsh channel, QPSK modulation– High Rates: 2 walsh channels, QPSK modulation– Highest Rate: 2 walsh channels, 8PSK modulation

• Hybrid ARQ using fast re-transmission (re-tx) and early termination• Flexible rate allocation: each AT has autonomous and scheduled mode• Efficient VOIP support• 3-channel synchronous stop-and-wait protocol• The mobile can use higher power and finish earlier when transmitting

packets of applications requiring minimum latency


Available Link Rates in 1xEV-DO Rev. A

The 1xEV-DO Rev. A reverse link has seven available modes offering higher speeds than available in Rev. 0

• Modulation formats are hybrids defined in the standardThe 1xEV-DO Rev. A forward has two available modes offering higher speeds than available in Rev. 0.

FORWARD LINK REVERSE LINKDRCIndex Slots Preamble

ChipsPayload

BitsRawkb/s


C/Idbn/a

-11.5-9.2-6.5-3.5-3.5-0.6-0.5+2.2+3.9+4.0+8.0+10.3+8.3+11.3


16QAM8PSK

16QAM16QAM16QAM

PayloadBits128256512768102415362048307240966144819212288

Modu-lation

B4B4B4B4B4Q4Q4Q2Q2

Q4Q2Q4Q2E4E2

Effective Rate kbps after:4 slots

184312289216144613072301531157638

19.28 slots

92161446130723015311576.857.638.419.29.6

12 slots

614409307

204.8153.6102.476.851.238.425.612.86.4

16 slots

460.8307.2230.4153.6115.276.857.638.428.819.29.64.8

Code Rate (repetition) after4 slots 8 slots 12 slots16 slots

1/5 1/5 1/5 1/51/5 1/5 1/5 1/51/4 1/5 1/5 1/53/8 1/5 1/5 1/51/2 1/4 1/5 1/53/8 1/5 1/5 1/51/2 1/4 1/5 1/53/8 1/5 1/5 1/51/2 1/4 1/5 1/51/2 1/4 1/5 1/52/3 1/3 2/9 1/52/3 1/3 1/3 1/3


What’s Next? 1xEV-DO Rev. B

CDG says 1Q06 for Rev. BTelecoms.com News17 November 2005Rufus Jay, [email protected]

The CDMA Development Group (CDG) has announced that the EV-DO Revision B standard is pencilled in for release in 1Q06. Rev. B increases data throughput to 73.5Mbps in the forward linkand 27Mbps in the reverse link. As well as supporting mobile broadband data and OFDM based multicasting, Rev. B's lower latency rates will improve the performance of VoIP, push to talkover cellular, video calling, concurrent voice and multimedia and multiplayer online gaming. The CDG also plans to expand cdma2000 by improved roaming and a sub US$40 handset push, similar to the GSMA's emerging markets initiative.


1xEV-DO Network Architecture1xEV-DO Network Architecture


CDMA Network for Circuit-Switched Voice Calls

The first commercial IS-95 CDMA systems provided only circuit-switched voice calls

t1t1 v CESEL

t1PSTN

BTS



CDMA 1xRTT Voice and Data Network

CDMA2000 1xRTT networks added two new capabilities:• channel elements able to generate and carry independent streams of

symbols on the I and Q channels of the QPSK RF signal– this roughly doubles capacity compared to IS-95

• a separate IP network implementing packet connections from the mobile through to the outside internet

– including Packet Data Serving Nodes (PDSNs) and a dedicated direct data connection (the Packet-Radio Interface) to the heart of the BSC

The overall connection speed was still limited by the 1xRTT air interface

t1t1 v CESEL

t1

PDSNForeign Agent

PDSNHome Agent


VPNs

PSTN


AccountingAAA

BTS



1xEV-DO Overlaid On Existing 1xRTT Network

1xEV-DO requires faster resource management than 1x BSCs can give• this is provided by the new Data Only Radio Network Controller (DO-RNC)

A new controller and packet controller software are needed in the BTS to manage the radio resources for EV sessions

• in some cases dedicated channel elements and even dedicated backhaul is used for the EV-DO traffic

The new DO-OMC administers the DO-RNC and BTS PCF additionExisting PDSNs and backbone network are used with minor upgradingThe following sections show Lucent, Motorola, and Nortel’s specific solutions

t1t1 v CESEL

t1

PDSNForeign Agent

PDSNHome Agent


VPNs

PSTN


AccountingAAA

BTS

(C)BSC/Access ManagerSwitch CE

DORadio

NetworkController

DO-OMC


1xEV-DO / 1xRTT Interoperability

1xEV-DO / 1xRTT Interoperability


1xEV-DO/1xRTT Interoperability

The CDMA2000 1xEV-DO Standard IS-856 makes no provision for any kind of handoff to or from any other technologyDriven by Operator interest, a “Hybrid” mode has been developed to provide some types of handoff functions to the best extent possibleHybrid Mode

• is a mobile only function – neither the EV nor 1xRTT network knows anything about it

• is a proprietary feature with vendor-specific implementation• has no standard-defined RF “triggers”; no “hooks”

In the 1xEV rev. A standard, some new features will be provided• the 1xEV control channel will be able to carry 1xRTT pages too• this and other changes may make the “hybrid” mode

unnecessary and obsolete


What Handoffs are Possible in Hybrid Mode?

All switching between systems occurs in Idle Mode• there are no “handoffs” in active traffic state in either mode

Sessions can be transferred from one system to the other, but NOT in active traffic state

• If there is a connection, it can be closed and then re-originated on the other system

• In some cases this can be accomplished automatically without the end-user’s awareness – in other cases, this is not possible


Hybrid Mode Transition Scenarios

DO systems will be Implemented in Several Configurations• 1:1 overlays in busy core areas• 1:1 or 1:N overlays in less dense areas

Many EV>1x and 1x>EV transition events may occur as a user transitions from area to areaInitial system acquisition is also involved as a user activates their AT in different locationsThese transitions are dependent on the Hybrid mode implementation in the ATThe following pages show some possible transitions assuming Mobile IP and AT Hybrid Mode are implemented

EV-DO, F21xRTT, F1

1:2 Deployment 1:1 Deployment1:1 Deployment


1xRTT / 1xEV-DO Hybrid Idle Mode

1xRTT/1xEV-DO Hybrid Mode• depends on being able to hear pages on both

systems – 1xRTT and 1xEV-DO• is possible because of slotted mode paging• 1xRTT and 1xEV-DO paging slots do not occur

simultaneously• mobile can monitor both

During 1xEV-DO traffic operation, the hybrid-aware mobile can still keep monitoring 1xRTT paging channelDuring 1xRTT traffic operation, the hybrid-aware mobile is unable to break away; 1xRTT traffic operation is continuous

• no opportunity to see 1xEV-DO signalThis hybrid Idle mode capability is the foundation for all 1xRTT/1xEV mode transfers

• the network does not trigger any transfers

1xR

TT

Act

ive

1xR

TT

Idle

1xEV

-DO

Idle

1xEV

-DO

A

ctiv

e

IdleMode

IdleMode

HybridMode


Hybrid Dual-Mode Idle Operation1xRTT / 1xEV-DO Paging Interoperability

A dual-mode 1xRTT/1xEV-DO mobile using slotted-mode paging can effectively watch the paging channels of both 1xRTT and 1xEV-DO at the same timeHow is it possible for the mobile to monitor both at the same time?

• The paging timeslots of the two technologies are staggeredThree of the 16 timeslots in 1xRTT conflict with the control channel slots of 1xEV-DO

• However, conflicts can be avoided by page repetition, a standardfeature in systems of both technologies

16-frame Control Channel Cycle16 slots of 26-2/3 ms = 426-2/3 ms

1xRTT Minimum Slot Cycle Index: 16 slots of 80 ms each = 48 26-2./3 ms frames1xRTT Minimum Slot Cycle Index: 16 slots of 80 ms each = 48 26-2./3 ms frames

16-frame Control Channel Cycle16 slots of 26-2/3 ms = 426-2/3 ms

LONGEST POSSIBLEPACKET

DRC 16 Subpackets


1xR

TT

Act

ive

1xR

TT

Idle

1xEV

-DO

Idle

1xEV

-DO

A

ctiv

eInitial System Acquisition by Hybrid Mobile

IdleMode

Acquire1xRTTSystem

driven byPRL

Registerwith

1xRTTNetwork

Acquire1xEV-DOSystem

driven byPRL

Classical 1xRTTIdle Mode

no, can’t see EV

VoicePage!

1xRTTVoiceCall

IdleMode

Release

when 1xEV-DO is NOT Available

After entering this state, the mobile will not search for

1xEV service again


1xR

TT

Act

ive

1xR

TT

Idle

1xEV

-DO

Idle

1xEV

-DO

A

ctiv

eInitial System Acquisition by Hybrid Mobile

IdleMode

Acquire1xRTTSystem

driven byPRL

Registerwith

1xRTTNetwork

Acquire1xEV-DOSystem

driven byPRL

Set Up orRe-establish

1xEVDOData

Session

yes, found EV

IdleMode

IdleMode

HybridMode

1xEVTraffic

AT DataReady!

AN DataPage!

DataConnectionClosed

VoicePage!

1xEVTraffic

1xRTTVoiceCall

IdleMode

HybridMode

IdleMode

IdleMode

HybridMode

Release

when 1xEV-DO is Available

interruptedduring1xRTT

voice call

Triggers:


In-Traffic: EV-DO Fade with 1xRTT Available1x

RTT

A

ctiv

e1x

RTT

Id

le1x

EV-D

OId

le1x

EV-D

O

Act

ive

Traffic Mode,Data Transfer

IdleMode

Fade

Fade

CloseConnection

ReestablishCall

PPPResync

MIPRegistr.

ResumeData Transfer

TransferFinished

Dormant/Idle

Dormant/Idle

DOSystem

Acquired SameDO

Subnet?

Get NewUATI

no

PPPResync

MIPRegistr.


AT data ready

AN data ready


1xR

TT

Act

ive

1xR

TT

Idle

1xEV

-DO

Idle

1xEV

-DO

A

ctiv

eTransition In-Traffic: Lost EV-DO and 1xRTT

Fade

IdleMode

Fade

Fade

CloseConnection

LostSignal!!

Use 1x PRL,Search for

1xRTTNo

SignalFound!!


DO PRL,Search for

DO

FoundNew DOSignal!!

IdleMode

Same DOSubnet?

Get NewUATI

No

IdleModeYes

Use 1x PRL,Search for

1xRTT

No Signal Found!!

IdleMode

HybridMode

No 1x Signal,Continue EV

Operation

Set Up orRe-establish

1xEVDOData

Session

1xEVTraffic

AT DataReady!

AN DataPage!

Triggers:

IdleMode


Dormant Session, EV-DO Lost > 1xRTT > 1xEV-DO1x

RTT

A

ctiv

e1x

RTT

Id

le1x

EV-D

OId

le1x

EV-D

O

Act

ive

IdleMode

Fade

Fade


DO PRL,Search for

DO

FoundNew DOSignal!!

Same DOSubnet?

Get NewUATI

No

IdleModeYes

IdleMode

HybridMode

IdleMode

Data Finished,Call Dormant

CoverageEdge

NoSignal

Found!!

PPPResync

MIPRegistr.

IdleMode

DO PRL,DO

Available?

PPPResync

MIPRegistr.

DO PRL,DO

Available?No

SignalFound!!

NoSignal

Found!!

DO PRL,DO

Available?

rf100

Documents

wireless cdma

wireless radio telegraph

rf100 v3

scott baxter rf100

radio frequencies

portable radio

public marriage of radio

radio guglielmo marconi