WIMAX © 2005 H. H’mimyLecture 11, Slide 1SMU EE 8315 Advanced Topics in Wireless Communications - Spring’05 Southern Methodist University EETS 8315 / TC752-N.

WIMAX

© 2005 H. H’mimy Lecture 11, Slide 1SMU EE 8315 Advanced Topics in Wireless Communications - Spring’05

Southern Methodist University

EETS 8315 / TC752-N

Advanced Topics in Wireless Communications

Spring2005

http://engr.smu.edu/eets/8315

Lecture 11: WIMAX

Instructor: Dr. Hossam H’mimy, Ericsson [email protected]

(972) 583-0155

WIMAX


Announcement

WIMAX


WiMAX forum

• The WiMAX mission is to make the 802.16 interoperable. Just like WiFi did for 802.11.

• No WiMAX compliant products today, foreseen during 2005. The first WiMAX products will be based on 802.16d.

• Intel is the most powerful player in WiMAX forum• Architecture specification work initiated in a new sub-

group

WIMAX


WiMAX forum ..

• FDD as well as TDD

• Licensed as well as unlicensed spectrum – Licensed needed to guarantee wide area service

• No single global spectrum assigned, possibilites:– 5.8 GHz

– 3.5 GHz

– 2.5 GHz, (IMT-2000 more likely in this band)

– 2.3 GHz

WIMAX


38% of US households are interested in a Portable Broadband Service...

7%9% 8%

37%

20%

13%

5%

0%

10%

20%

30%

40%

50%

Definitely

would

not

2 3 Neutral 5 6 Definitely

would

Interest in Portable Broadband Services(n = 3,370 U.S. Broadband Households)

Source: Unlicensed Broadband Wireless: Solutions and Applications© 2004 Parks Associates

38%

WIMAX


Broadband Technologies

3G Evolved802.16DSL/Fiber

• Fixed

• Triple Play (Video)• IP Telephony• Internet

• Fixed• Nomadic

• IP Telephony• Internet

• Full mobility• Full roaming• All over the world• POMS• IP Telephony• Internet

WIMAX


WiMAX Standards Roadmap

10 – 66 GHzLOS

Sep 2000

802.16

Some Mobility 2005 ?

802.16e

NOTE: IEEE 802.16 specifies only layer 1 & 2

2 – 11 GHzNLOS

Jan 2003

802.16a

WiMAX = interoperable subset of this (< 6 GHz)

Similar to .16aErrata

Jul 2004

802.16d

WIMAX


WIMAX


• DSL complement DSL is not available, e.g. poor copper infrastructure DSL OPEX too high, e.g. low population density Central Office is too far away for DSL CLEC bypassing incumbent

• DSL competition If DSL is available, hard to beat

•

802.16

802.16 for Broadband Wireless Access

WIMAX


WiMAX segments, High level pros and cons

• Backhaul, Fixed, point to point – LOS– High Bitrate

– Low Interference

– Clear Signal – No multipath fading

– Relatively Low Cost

• DSL, Fixed up to portable, Point to point, point to multipoint – NLOS– Relative high bitrate, but lower

– One cell

– Still relative cheap

– Low to moderate interference-> Static radio environment • WAN and Mobile environment

– Significantly lower bitrate– High interference. More multipath fading and dopplershift effects

WIMAX


IEEE 802.16 Standard

802.16 802.16d/HiperMAN 802.16e

Completed December 2001 June 2004 (802.16d) Estimate 2005

Spectrum 10 - 66 GHz < 11 GHz < 6 GHz

Channel Conditions

Line of Sight Only Non Line of Sight Non Line of Sight

Bit Rate 32 – 134 Mbps in 28MHz channel bandwidth

Up to 75 Mbps in 20MHz channel bandwidth

Up to 15 Mbps in 5MHz channel bandwidth

Modulation QPSK, 16QAM and 64QAM

OFDM 256 FFT

QPSK, 16QAM, 64QAM

Scalable OFDMA

128 to 2048 FFT

Mobility Fixed Fixed Portable

Channel Bandwidths

20, 25 and 28 MHz 1.75 to 20 MHz 1.75 to 20 MHz

WiMAX

WIMAX


WIMAX Features

Feature Benefit

256 point FFT OFDM waveform

Built in support for addressing multipath in outdoor LOS and NLOS environments

Adaptive Modulation and variable error correction encoding per RF burst

Ensures a robust RF link while maximizing the number of bits/second for each subscriber unit

TDD and FDD duplexing support

Address varying worldwide regulations where one or both may be allowed

Flexible Channel sizes (such as 3.5 MHz, 5 MHz, 10 MHz, and so on)

Provides the flexibility necessary to operate in many different frequency bands with varying channel requirements around the world

Designed to support smart antenna systems

Smart antennas are fast becoming more affordable, and as these costs come down their ability to suppress interference and increase system gain will become important to BWA deployments

WIMAX


WiMAX Modulation and Coding

The further the subscriber is from the base station, the greater the likelihood of a lower form of modulation and a higher amount of coding and thus a lower bit-rate

WIMAX


Fit with Other Technologies

• Whether 802.16a will complement or clash with certain other technologies remains to be seen. For a while, at least, it will certainly be complementary to 802.11a, enabling Wi-Fi users to dramatically extend their distance from wired networks.

WIMAX


Theoretical WiMAX Raw Bandwidth (Mbit/s)*

Modulation /Code rate

1,75 MHz

3,5 MHz

7,0MHz

14,0 MHz

20,0 MHz

1.45

2.91

5.82

11.64

16.26

QPSK 1/2 QPSK 3/4

2.18

4.36

8.73

17.45

24.40

4.36

8.73

17.45

34.91

48.79

16 QAM 3/416 QAM 1/2

2.91

5.82

11.64

23.27

32.53

64 QAM 2/3 64 QAM 3/4

5.82

11.64

23.27

46.55

65.05

6.55

13.09

26.18

52.36

73.19

*OFDM 256 FFT. Includes MAC and preamble overhead

WIMAX


Theoretical Coverage (Km)*

Type of Area

Rural

Suburban

Urban

N/A

N/A

Rooftop Antenna

Window/FixedAntenna

<8 Km

Indoor/PortableAntenna

*Approximate distances only, depends heavily on geographical area

<4 Km

<2 Km

<4 Km

<2 Km

<1 Km

<20 Km usingNLOS**

**<50 Km is the theoretical maximum for LOS. Assumption is a NLOS base station and a rooftop antenna for better reception and maximum uplink power

WIMAX


Portability (Mobility) in 802.16e

• New network reference model– New BS-BS interface (IB) and BS-server interface (A) defined– Authentication and service authorization (ASA) servers provide

authorization, authentication, billing, management, provisioning and other services. EAP is defined for SIM cards, and other means of Authentication.

WIMAX


Enhancements for mobility in 802.16e – Layer 2

• Handover (HO) process defined in MAC including – cell reselection– target BS scanning– network re-entry– HO decision and initiation and HO cancellation.

• MAC messages for each of the handover functions defined.• Broadcast paging message defined.• Neighbor topology advertisement messages defined.• Option of using mobile IP provided. To be defined in May-05. WG

active.• Full QoS supported. All four GSM/WCDMA classes.

WIMAX


Enhancements for mobility in 802.16e – Layer 1

• Sleep mode, paging enabled.• Fast time alignment (ranging) mechanism• Flexible FFT sizes depending on channel bandwidth to ensure

OFDM symbol duration is compatible with mobility requirements• Soft handover, i.e., transmit/receive from multiple BS• Fast channel feedback• Fast BSS handover involving maintenance of sync to multiple

BS’ while transmitting/receiving from anchor BS• New MIMO, STC modes

– MIMO soft-handoff based macro-diversity transmission– Space-time codes for 3 antenna configurations. Fixed version has

2 and 4 antenna modes.

WIMAX


some differences

• MAC– 802.11: Contention-based MAC (CSMA/CA), basically

wireless Ethernet.– 802.16: Dynamic TDMA-based MAC with on-demand

bandwidth allocation.• OFDM

– 802.11a: 64 FTTs– 802.16d: 256 FFTs

• Spectrum– 802.11: limited channels in Un-license spectrum– 802.16: multiple channels in licensed & Un-license spectrum

WIMAX


Comparison 802.11 and 802.16

802.11

< 300 feet

Optimized for indoor short range2.7 bps/Hz peak. <= 54Mbps in 20MHz

1-10 CPE CSMA/CA

No QOS

Technology

Range

Coverage

Data rate

Scalability

QOS

802.16

< 30 Mile ( typical 3~4)

Outdoor LOS & NLOS

5bps/Hz peak, <100Mbps in 20 MHz

1- hundreds CPE TDMA

On demand BW voiceVideo, data

WIMAX


WiMAX• Wireless Broadband• Laptop centric• Fixed Portability• Line-of-Sight & Non Line-of-Sight• IEEE Layer 1 & 2 standard• Data optimized• Optimized for Fixed High data rate• Evolution towards mobility

Drivers: • Data optimized network (simple)• DSL complement

Broadband Wireless systems

3G Evolved• Mobile Broadband• Phone & laptop• Full mobility• Non line-of-sight• 3GPP and 3GPP2 standard• Voice/data optimized• Optimized for Mobility• Evolution towards Higher Data

Drivers: • Mobile Broadband for incremental

investment• National & global roaming networks

WIMAX


1xEV-DV

1xEV-DO

HSDPA

EDGE

GSM/GPRS

WCDMA

CDMA2000 1x

Flarion

IEEE 802.16d

Ch

ann

el

Ban

dw

idth

200KHz

5Mhz

1.25 MHz

1.25 MHz

Pea

kb

it-rateD

L

160 kbps

Pea

kB

it-rateU

L

FD

D/T

DD

-20 MHz

480 kbps

2 Mbps

14.4 Mbps

640 kbps

3.1 Mbps

3.1 Mbps

- 75 Mbps

3.2 Mbps

160 kbps

480 kbps

2 Mbps

7.68 Mbps

450 kbps

1.8 Mbps

1.8 Mbps

- 75 Mbps

900 kbps

FDD

FDD/TDD

FDD

FDD

FDD

FDD

FDD/TDD

FDD

FDD

Stan

dard

sco

mp

liant

3GPP

_

Peak Bit Rates Comparison

3GPP

3GPP

3GPP

3GPP2

3GPP2

3GPP2

IEEE

WIMAX


• Propagation difference between 1900MHz and other frequencies ( H-O Model)

• 2100MHz ( Delta = 1.1dB)• 2400MHz ( Delta = 2.6dB)• 3500MHz ( Delta = 7dB)• 850 MHz ( Delta = -12 dB)

WIMAX


WiMax IEEE802.16a, e

• Understanding WiMax – http://www.intel.com/netcomms/technologies/downloads/305150.pdf– http://www.intel.com/netcomms/technologies/wimax/304471.pdf– http://www.wimaxforum.org/certification/White_Papers/

• OFDM– http://www.intel.com/netcomms/technologies/wimax/303787.pdf

• Adaptive modulation– http://www.intel.com/netcomms/technologies/wimax/303788.pdf

WIMAX © 2005 H. H’mimyLecture 11, Slide 1SMU EE 8315 Advanced Topics in Wireless Communications - Spring’05 Southern Methodist University EETS 8315 / TC752-N.

Documents

wimax products

d slide

wimax instructor

wimax mission

smu ee

wimax compliant products

unlicensed broadband

tc752n advanced topics