Introduction to UWB

Introduction to Ultra WideBand Systems

Chia-Hsin Cheng

Wireless Access Tech. Lab.

CCU Wireless Access Tech. Lab.

Outlines

IntroductionThe history of UWBUWB Regulations (FCC Rules)UWB signalsUWB in IEEE 802 Standards The Application of UWB



Introduction

The world of ultra wideband (UWB) has changed dramatically in very recent history. In the past 20 years, UWB was used for radar, sensing, military communications and niche applications.

A substantial change occurred in February 2002, when the FCC (2002a,b) issued a ruling that UWB could be used for data communications as well as for radar and safety applications.

Recently, UWB technology has been focused on consumer electronics and communications.

Ideal targets for UWB systems are low power, low cost, high data rates, precise positioning capability and extremely low interference.



UWB transmitter signal BW:

Or, BW 500 MHz regardless of fractional BW

UWB Transmitter Defined

fu-fl

fu+fl2 0.20

Where: fu= upper 10 dB down point fl = lower 10 dB down point

Source: US 47 CFR Part15 Ultra-Wideband Operations FCC Report and Order, 22 April 2002:http://www.fcc.gov/Bureaus/Engineering_Technology/Orders/2002/fcc02048.pdf



UWB: Large Fractional Bandwidth

Po

wer

Sp

ect

ral

Den

sit

y (

dB

)

one “chip”one “chip”CDMA: 1.288Mcps/1.8 GHz 0.07% bandwidth

6% bandwidth

-80

-40

0

Frequency (GHz)

3 6 9 12 15

Random noise signal

100% bandwidth

UWBUWB

NBNB

20% bandwidth



Large Relative (and Absolute) Bandwidth

UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum Wider than any narrowband system by orders of magnitude Power seen by a narrowband system is a fraction of the

total UWB signals can be designed to look like imperceptible

random noise to conventional radios

Narrowband (30kHz)

Wideband CDMA (5 MHz)

UWB (Several GHz)

Frequency

Part 15 Limit( -41.3dBm/Hz )



Why is Ultra Wideband So Effective?

Shannon showed that the system capacity, C, of a channel perturbed by AWGN ---

)1(log 2 N

SBC

Where: C = Max Channel Capacity (bits/sec) B = Channel Bandwidth (Hz) S = Signal Power (watts) N = Noise Power (watts)

Capacity per channel (bps) BCapacity per channel (bps) log(1+S/N)

1. Increase B2. Increase S/N, use higher order modulation3. Increase number of channels using spatial separation (e.g., MIMO)



Throughput

Low Power UWB Comparable to High Power Wireless Systems

UWB throughput between 802.11a and b



UWB Properties

Extremely difficult to detect by unintended users Highly Secured

Non-interfering to other communication systems It appears like noise for other systems

Both Line of Sight and non-Line of Sight operation Can pass through walls and doors

High multipath immunityCommon architecture for communications, radar & posit

ioning (software re-definable)Low cost, low power, nearly all-digital and single chip ar

chitecture



Outlines

IntroductionThe history of UWBUWB Regulations (FCC Rules)UWB signalsUWB in IEEE 802 StandardsThe Application of UWB



The history of UWB Technology

Before 1900: Wireless Began as UWB Large RF bandwidths, but did not take advantage of large spreading gain

1900-40s: Wireless goes ‘tuned’ Analog processing: filters, resonators ‘Separation of services by wavelength’ Era of wireless telephony begins: AM / SSB / FM Commercial broadcasting matures, radar and signal processing

1970-90s: Digital techniques applied to UWB Wide band impulse radar Allows for realization of the HUGE available spreading gain

Now: UWB approved by FCC for commercialization

For further details, refer to ref.[1]



What UWB is Today

7,500 MHz available spectrum for unlicensed useUS operating frequency: 3,100 – 10,600 MHz Emission limit: -41.3dBm/MHz EIRPIndoor and handheld systemsOther restrictions and measurement procedures in Report and Orde

r

UWB transmitter defined as having the lesser ofFractional bandwidth greater than 20%Occupies more than 500 MHz

UWB is NOT defined in terms of Modulation or Carrierless or Impulse radio



Outlines




Summary of the FCC Rules

Significant protection provided for sensitive systems GPS, Federal aviation systems, etc.

Lowest emission limits ever by FCCIncorporates NTIA (National Telecomm. and Info.

Administration) recommendationsAllows UWB technology to coexist with existing radio

services without causing interferenceFCC opened up new spectrum for UWB transmissions

One of the bands is from 3.1GHz to 10.6GHz Maximum power emission limit is - 41.3dBm/MHz



FCC UWB Device Classifications

Report and Order authorizes 5 classes of devices with different limits for each: Imaging Systems

Ground penetrating radars, wall imaging, medical imaging Thru-wall Imaging & Surveillance Systems

Communication and Measurement Systems Indoor Systems Hand-held Systems

Vehicular Radar Systems collision avoidance, improved airbag activation, suspension systems, etc.



FCC First Report and Order Authorizes Five Types of Devices

Class / Application Frequency Band for Operation at Part 15 Limits

User Limitations

Communications and Measurement Systems

3.1 to 10.6 GHz(different “out-of-band” emission limits for indoor a

nd hand-held devices)No

Imaging: Ground Penetrating Radar, Wall, Medical Imaging

<960 MHz or 3.1 to 10.6 GHz Yes

Imaging: Through-wall <960 MHz or 1.99 to 10.6 GHz Yes

Imaging: Surveillance 1.99 to 10.6 GHz Yes

Vehicular 22 to 29 GHz No



UWB Emission Limits for GPRs, Wall Imaging, & Medical Imaging Systems

Operation is limited to law enforcement, fire and rescue organizations, scientific research institutions, commercial mining companies, and construction companies.

0.96 1.61

1.993.1 10.6

GPS Band

Source: www.fcc.gov



UWB Emission Limits for Thru-wall Imaging & Surveillance Systems

Operation is limited to law enforcement, fire and rescue organizations. Surveillance systems may also be operated by public utilities and industrial entities.

0.96 1.61

1.99 10.6GPS Band

Source: www.fcc.gov



UWB Emission Limit for Indoor Systems

0.96 1.61

1.99

3.1 10.6

GPS Band

Source: www.fcc.gov



0.96 1.61

1.99

3.1 10.6

GPS Band

Source: www.fcc.gov

Proposed UWB Emission Limit for “Outdoor” Systems

Proposed in preliminary Report and Order, Feb. 14, 2002.



0.01 0.1 1 10 100-80

-70

-60

-50

Frequency, GHz

-40EIRP, dBm/MHz

First Report and Order, April 22, 2002.

UWB Band-width must be contained here

Actual UWB Emission Limit for Hand-held Systems



Outlines




UWB Signals

Monocycle Shapes for UWBData ModulationModulation Schemes



Monocycle Shapes for UWB

Monocycle shapes will affect the performanceListed monocycles’ duration is 0.5ns

Gaussian pulse Gaussian Monocycle Scholtz’s Monocycle Manchester Monocycle RZ- Manchester Monocycle Sine Monocycle Rectangle Monocycle

For further details, refer to ref.[4]



Monocycle Shapes for UWB (cont.)

Gaussian Pulse




Gaussian monocycle Similar to the first derivative of Gaussian pulse




Scholtz’s monocycle Similar to the second derivative of Gaussian pulse




Manchester Monocycle It has amplitude A during half of the monocycle width and has

amplitude –A during the other half.




RZ- Manchester Monocycle It has amplitude A and –A only a portion of each half monocycle

width.




Sine Monocycle Just a period of sine wave




Rectangle Monocycle It has uniform amplitude A during the whole pulse width.



Data Modulation

A number of modulation schemes may be used with UWB systems. The potential modulation schemes include both orthogonal and antipodal schemes.

Pulse Position Modulation (PPM)

Pulse Amplitude Modulation (PAM)

On-Off Keying (OOK)

Bi-Phase Modulation (BPSK)



Modulation Schemes

Many different pulse generation techniques may be used to satisfy the requirements of an UWB signal.

The FCC requires that the fractional bandwidth is greater than 20 %, or that the bandwidth of the transmitted signal is more than 500MHz, whichever is less.

The most common UWB concepts Time-hopping (TH) technique Direct-Sequence (DS) technique Multi-band (MB) technique



TH-UWB

TH-PPM1. transmitting 0

Tf

Ts : data symbol time

Tc t

pulse wtr(t)Str(t)

cfchf

s

fsfss

p

h

TTeiTNT

N

TTeiTNT

N

NC

3..

symbol dataper pulses ofnumber :

4..

4 periodcode

2 , ]2001[ codeword

1

0

s

Ns

tr tr s f iN j c ii j

S t w t iT jT c T d

=0id



TH-UWB

TH-PPM2 . transmitting 1

Tf

Ts

Tc t

Str(t)

cfchf

s

fsfss

p

h

TTeiTNT

N

TTeiTNT

N

NC

3..

symbol dataper pulses ofnumber :

4..

4 periodcode

2 , ]2001[ codeword

1

0

s

Ns

tr tr s f iN j c ii j

S t w t iT jT c T d

=1id



DS-UWB

DS-UWB1

0

( ) ( )cN

tr i n b ci n

s t d a w t iT nT

=1id

= -1id



Multiband UWB

Refer to OFDM course



Outlines




UWB in IEEE 802 Standards

IEEE 802 Organization IEEE 802.15.3a IEEE 802.15.4a



WLAN™IEEE 802.11

WPAN™IEEE 802.15

WMAN™IEEE 802.16

802.15.1“Bluetooth”

802.15.3“High Data Rate” MAC &

2.4 GHz PHY

Task Group 3aAlt PHY (UWB)

802.15.4“Zigbee” 2.4 GHz

LAN/MAN Standards Committee (Wireless Areas)

802.15.2Coexistence

IEEE 802 Organization

MBWAIEEE 802.20

Regulatory TAGIEEE 802.18

Coexistence TAGIEEE 802.19

Based on: “Overview of 802.15.3 and 3a,” R. F. Heile, Workshop on Current Developments in UWB, Institute for Infocomm Research, Singapore

Study Group 4a(UWB?)

Mini-Glossary: WLAN-wireless Local Area Network; MAN-Metropolitan Area Network; TAG-Technical Advisory Group;-MBWA-Mobile Broadband Wireless Access



IEEE Project 802 Local and Metropolitan Area Network Standards Committee

Accredited by ANSI, Sponsored by IEEE Computer Society Ethernet, Token Ring, Wireless, Cable Modem Standards Bridging, VLAN, Security Standards

Meets three times per year (400-600 individuals, 15% non-US)

Develops equivalent IEC/ISO JTC 1 standardsJTC 1 series of equivalent standards are ISO 8802-nnn

IEEE URLs 802 http://grouper.ieee.org/groups/802/ 802.15 http://grouper.ieee.org/groups/802/15/



Standards : Range and Data Rate



UWB Technique

OFDM TDMS/FDMA Pulses DSSS/CDMA

Bands 3 to 13 3 to 13 2

Bandwidths 528 MHz 550 MHz 1.368 GHz, 2.736 GHz

Frequency ranges

3.168 GHz – 4.752 GHz 4.752 – 10.296

3.325 GHz – 4.975 GHz, 4.975 GHz – 10.475 GHz

3.1 GHz – 5.15 GHz 5.825 GHz – 10.6 GHz

Modulation Scheme

OFDM, QPSK M-ary Bi-Orthogonal Keying (M-BOK), QPSK

BPSK, QPSK, M-BOK

Error correction

Convolutional code Convolutional code, Reed-Solomon code

Convolutional code, Reed-Solomon code

Code rates 11/32 rate at 110 Mbps, 5/8 rate at 200 Mbps, ¾ rate at 480 Mbps

6/32 rate at 110 Mbps, 5/16 rate at 200 Mbps, ¾ rate at 480 Mbps

½ rate at 110 Mbps, RS(255,223) at 200 Mbps, RS(255,223) t 480 Mbps

Link margin 5.3/6 dB at 10 m / 110 Mbps, 10.7 dB at 4 m / 200 Mbps, 6.2 dB at 4 m / 480 Mbps

6.3 dB at 10 m / 108 Mbps, 8.0 dB at 4 m / 288 Mbps, 4.0 dB at 4 m / 577 Mbps

6.1 dB at 10 m / 110 Mbps, 11.1 dB at 4 m / 200 Mbps, 6.1 dB at 4 m / 600 Mbps

Symbol period

312.5 ns OFDM symbol 3 ns 23 or 17.5 ns (Low band), 11.7 or 8.9 ns (High band)

Multipath mitigation method

1-tap (robust to 60.6 ns delay spread)

frequency interleaving of MBOK chips; time frequency codes; feed forward filter

Decision feedback equalizer

Candidate UWB Systems



802.15.3a – high data rate WPAN standard

Direct sequence (DS-UWB) Championed by Motorola/XtremeSpectrum Classic UWB, simple pulses, 2 frequency bands: 3.1-4.85GHz, 6.2-9.7GHz CDMA has been proposed at the encoding layer Spectrum dependent on the shaping filter – possible differing de

vices worldwideMultiband Orthogonal Frequency Division Multiplexing

(MB-OFDM) Intel/TI/many others Similar in nature to 802.11a/g 14 528MHz bands (simplest devices need to support 3 lowest ba

nds, 3.1GHz – 4.7 GHz) Spectrum shaping flexibility for international use



Detail of DS-CDMA Candidate for 802.15.3a

Multi-band DS-CDMA Physical Layer Proposal

Summary from IEEE document 15-03-0334-02-003a-Merger-2-CFP-Presentation.ppt



3 4 5 6 7 8 9 10 11

High Band

3 4 5 6 7 8 9 10 11

Low Band

3 4 5 6 7 8 9 10 11

Multi-Band

With an appropriate diplexer, the multi-band mode will support full-duplex operation (RX in one band while TX in the other)

Low Band (3.1 to 5.15 GHz) 25 Mbps to 450 Mbps

High Band (5.825 to 10.6 GHz) 25 Mbps to 900 Mbps

Multi-Band (3.1 to 5.15 GHz plus 5.825 GHz to 10.6 GHz) Up to 1.35 Gbps

Two BandDS-CDMA

3 Spectral Modes of Operat

ion



Joint Time Frequency Wavelet Family

ExampleDuplexWavelet

MidWavelet

LongWavelet

3 4 5 6 7 8 9 10 11-40-35-30-25-20-15-10-50

GHz

dB

3 4 5 6 7 8 9 10 11-40-35-30-25-20-15-10-50

GHz

dB

3 4 5 6 7 8 9 10 11-40-35-30-25-20-15-10-50

GHz

dB

-1 0 1-1

-0.5

0

0.5

1

-1 0 1-1

-0.5

0

0.5

1

-1 0 1-1

-0.5

0

0.5

1



• PHY Proposal accommodates alternate spectral allocations

• Center frequency and bandwidth are adjustable

• Supports future spectral allocations

• Maintains UWB advantages (i.e. wide bandwidth for multipath resolution)

• No changes to silicon

Example 1: Modified Low Band to include protection for 4.9-5.0 GHz WLAN Band

3 4 5 6 3 4 5 6

3 4 5 6 7 8 9 10 11

Example 2: Support for hypothetical “above 6 GHz” UWB definition

Note 1: Reference doc IEEE802.15-03/211

Spectral Flexibility and Scalability



Detail of OFDM Candidate for 802.15.3a

Multi-band OFDM Physical Layer Proposal

Summary from IEEE document 03267r1P802-15_TG3a-Multi-band-OFDM-CFP-Presentation.ppt



Overview of Multi-band OFDM

Basic idea: divide spectrum into several 528 MHz bands.

Information is transmitted using OFDM modulation on each band. OFDM carriers are efficiently generated using an 128-point IFFT/FFT. Internal precision is reduced by limiting the constellation size to

QPSK.

Information bits are interleaved across all bands to exploit frequency diversity and provide robustness against multi-path and interference.

60.6 ns cyclic prefix provides robustness against multi-path even in the worst channel environments.

9.5 ns guard interval provides sufficient time for switching between bands.



Multi-band OFDM: TX Architecture Block diagram of an example TX architecture:

Architecture is similar to that of a conventional and proven OFDM system. Can leverage existing OFDM solutions for the development of the Multi-band OFDM physical layer.

For a given superframe, the time-frequency code is specified in the beacon by the PNC (PicoNet Controller). The time-frequency code is changed from one superframe to another in order to randomize multi-piconet interference.

DACScramblerConvolutional

EncoderPuncturer

BitInterleaver

ConstellationMapping

IFFTInsert Pilots

Add CP & GI

Time-Frequency Code

exp(j2fct)

InputData



Band Plan Group the 528 MHz bands into 4 distinct groups

Group A: Intended for 1st generation devices (3.1 – 4.9 GHz) Group B: Reserved for future use (4.9 – 6.0 GHz) Group C: Intended for devices with improved SOP performance (6.0 – 8.1 GHz) Group D: Reserved for future use (8.1 – 10.6 GHz)

f3432MHz

3960MHz

4488MHz

5016MHz

5808MHz

6336MHz

6864MHz

7392MHz

7920MHz

8448MHz

8976MHz

9504MHz

10032MHz

Band#1

Band#2

Band#3

Band#4

Band#5

Band#6

Band#7

Band#8

Band#9

Band#10

Band#11

Band#12

Band#13

GROUP A GROUP B GROUP C GROUP D



802.15.4a – alternate PHY for 802.15.4

Addresses the followingGlobally deployableCompatible / interoperable with 802.15.4Longer rangeHigher reliabilityRanging/localization supportLower latency & support for mobilityLow cost

Current UWB systems not quite suitable90 nm CMOS is expensive, 200 mW is a lot of power

Still in early stagesProposals due Jan. 2005!DS-UWB a major contender (Motorola)Chirp Spread Spectrum another cool tech (Nanotron)Many axes for diversity: Basic tech (2.4 v. UWB), ranging (UWB v.

CSS v. Phase-based ranging), pulse shapes, channel arbitration (CSMA v. CDMA)



Outlines

IntroductionThe history of UWBUWB Regulations (FCC Rules)UWB signalsStandards of IEEE 802The Application of UWB



The Application of UWB

Ultra-wideband is the contortionist of the wireless world – it is flexible enough to work in many different ways while still maintaining its character.

These applications are distributed amongst three categories: Communications and sensors Position location and tracking Radar



The Application of UWB

Single and multi-family dwelling residents who have at least one of the following configurations in their dwellings:

Source: doc.: IEEE 802.15-01/036r0

– Remote control for:

• Multimedia PC with interactive gaming options

• Consumer devices like,TV (w internet access),Home Theatre, video gaming console, DVD player,STB, DVCR, Home Stereo, TiVo

– Interconnectivity between devices (Tomoguchis, Gameboys, etc.)

– Home security, home automation or HVAC systems (sensors, control units)

– Illumination control (light switches, spot light control)

– Small Office/Home Office (SOHO) control of:

• multimedia presentations

• conference rooms

• training rooms

• automation or control functions

– Industry applications for control and surveillance

– Healthcare industry for monitoring and wearable sensors, patient monitoring



Source: Walter Hirt, Dennis L. Moeller, "The Global View of a Wireless System Integrator," International Symposium on Advanced Radio Technologies (ISART), Boulder, CO, USA, 4-6 March 2002



4G

POTENTIAL FOR UWB

3G and beyond



Wide AreaCellular Network

InternetPDA

Camcorder

DVDDesktopComputer

Printer

DigitalCamera

LaptopComputerTV

Monitor

Audio

WirelessBridge

Gateway


InternetPDA

Camcorder

DVDDesktopComputer

Printer

DigitalCamera

LaptopComputerTV

Monitor

Audio

WirelessBridge

Gateway

MotionSensor

TemperatureSensor

LightSensor

Position Sensor

PositionSensor

PositionSensor

Position Sensor

PositionSensor

Wireless Bridge

HomeController


(Alarms, Remote Control

MotionSensor

TemperatureSensor

LightSensor

Position Sensor

PositionSensor

PositionSensor

Position Sensor

PositionSensor

Wireless Bridge

HomeController


(Alarms, Remote Control

Internet AccessFix line

3G corenetwork

Ad hocconnection option

High Data RateData Exchange (Gaming)

PDA

PDA PDA

PDA

UWB connection

Opt.

Opt.

Access Box

▲Hot-spot Wireless PersonalArea Network (WPAN)

Intelligent WirelessArea Network (IWAN) ►

Sensor, Positioning, and Identification Network (SPIN)▼

Wireless Body AreaNetwork (WBAN)▼

Outdoor Peer-to-PeerNetworking (OPPN)◄

Potential Application Scenarios



UWB Consumer Applications

Home EntertainmentHome Entertainment

Mobile DevicesMobile DevicesComputingComputing

AutomotiveAutomotive

Freescale Semi.Freescale Semi.



Entertainment Applications

Connect between sources and displays Drivers are wire elimination for install

and freedom of component placement Requirements

Bandwidth Each MPEG2 HD Stream 20-29 Mbps Two full rate streams required for PIP Handheld can be used for PIP viewing

or channel surfing (SD stream)

Range Media center to display or handheld Anywhere in the room (<10m)

QoS with low latency Channel change, typing, gamers

Available Now: both SD and HD



Content Transfer: Mobile Devices

Applications Smartphone/PDA, MP3, DSC Media Player, Storage, display

Requirements Mobile device storage sizes

Flash 5, 32, 512, 2048 … MB HD 4, …, 60+ GB

Range is near device (< 2m) User requires xfer time < 10s

Print from handheld

Images from camera to storage/network

MP3 titles to music player

MPEG4 movie(512 MB) to player

Mount portable HD

Exchange your music & data

Low Power Use Cases

Low Power & High Data Rate Use



Content Streaming Applications

Digital video camcorder (DVC) Smartphone/PDS, Media player

Requirements Range is in view of display (< 5m) DV Format 30 Mbps with QoS MPEG 2 at 12-20Mbps Power budget < 500 mW

Stream DV or MPEGDS-UWB is just a shift register

Stream presentationfrom Smartphone/PDA to projector

Channel surf and PIPto handheld

Use Cases



References

[1] K. Siwiak and D. McKeown, Ultra-Wideband Radio Technology, Wiley: UK, 2004.

[2] Mohammad Ghavami, Lachlan Michael, Ryuji Kohno. Ultra-Wideband Signals and Systems in Communication Engineering, John Wiley & Sons, Ltd, 2004.

[3]M.-G. Di Benedetto and G. Giancola, UnderstandingUltra Wide Band radio Fundamentals, Prentice Hall, 2004.

Ian Oppermann. UWB: Theory and Applications. John Wiley & Sons, Ltd., 2005.

[4] Xiaomin Chen and Sayfe Kiaei, "Monocycle Shapes for Ultra Wideband System,“ IEEE International Symposium on Circuits and Systems, vol. 1, pp. 597-600,May 2002.

Introduction to UWB

Documents