The Creation of IMT-2000

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Third Generation (3G) Wireless:

Where is it Going?

Dr. Theodore S. Rappaport

James S. Tucker Professor

Mobile and Portable Radio Research Group Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University

Blacksburg, VA 24061 http://www.mprg.ee.vt.edu

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The Creation of IMT-2000

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A decision was made at WARC-92 to identify a global spectrum in a common frequency

band around 2000 MHz

❖

Spectrum would have both terrestrial and satellite components

❖

Originally known as FPLMTS (Future Public Land Mobile Telecommunications Systems)

Source: ITU Website, http://www.itu.int/itunews/199505/radio.htm

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Key Features of IMT-2000

❖

Emphasizing worldwide commonality in design

❖

Compatibility of services within fixed networks and within IMT-2000

❖

High quality

❖

Use of small pocket-terminal worldwide

Source: Working Document of Security Principles for FPLMTS, 1994

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The Evolution of the Standard

❖

Originally, IMT-2000 was to embrace a single worldwide wireless standard.

❖

Unable to unite 2G systems under one 3G technology

❖

IMT-2000 will now be seen as a “family of standards” to ensure both current

investments and global compatibility

Source: Personal Communications Newsletter, January 12, 1998

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IMT-2000 Frequencies

Source: http://www.mpt.go.jp/pressrelease/english/telecomm/news8-9-3.html

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Key Players in the Debate

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CDMA: U.S. and Asia focused, fueled by Qualcomm, Lucent, and Motorola

¹

❖

GSM: Europe focused, fueled by Ericsson, Nokia, Nortel, Alcatel

²

❖

IS-136: proposed high speed data (HSD) interface

³

❖

As Asian subscriptions increase, CDMA could

overtake GSM as most popular cellular technology

⁴

Sources: 1, AOL Website, July 16, 1998, http://www.aol.com 2, Online Telecommunications Magazine, June 1998 3, Ojanperä, “Development of 3G Radio Technologies”

4, CDG Website, June 1998, http://www.cdg.org

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3G Technologies Around the World

Source: CDG Website, http://www.cdg.org/cdma_world.html

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The Evolution of European Wireless Systems

❖ Systems developed by the High Speed Data Group (HSD) of the Global TDMA Forum (GTF) within the Universal Wireless

Communications Consortium (UWCC).

❖ The EDGE (Enhanced Data for GSM/Global Evolution) system would enhance GSM system through higher level modulations

❖ The Double EDGE system would provide two carrier spacings, 200 kHz and 1.6 MHz, to allow for the IS-136 air interface

❖ Provides less expensive equipment in a more timely fashion and so provides economies of scale

Source: Ojanperä, T.,“Development of 3G Radio Technologies,” Nokia Research Center

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Current Status of IMT-2000

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10 terrestrial and 5 satellite proposals were received at ITU--June, 1998

❖

Proposals will be evaluated by groups

representing various countries--July 1998

❖

Accepted proposals will be announced--Fall, 1998

Source: Wireless Week, July 6, 1998

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ITU Timetable for 3G Policy

Source: ITU Website, http://www.itu.int/imt/2-radio-dev/time/index.html

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IMT-2000 Proposals:

Terrestrial (of 10 submitted)

❖ DECT, ETSI Project

(Digital Enhanced Cordless Communications)

❖ UWC-136, USA TIA TR45.3

(Universal Wireless Communications)

❖ WIMS/W-CDMA, USA TIA TR46.1

(Wireless Multimedia & Messaging Services/

Wideband CDMA)

Source: ITU Website, http://www.itu.int/imt/2-radio-dev/rtt/index.html

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IMT-2000 Proposals:

Terrestrial (of 10 submitted)

❖ TD-SCDMA, China ATT

(Time-Division Synchronous CDMA)

❖ W-CDMA, Japan ARIB

(Wideband CDMA)

❖ CDMA II, S. Korea TTA

(Asynchronous DS-CDMA)

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IMT-2000 Proposals:

Terrestrial (of 10 submitted)

❖ UTRA: W-CDMA, ETSI SMG2

(UMTS Terrestrial Radio Access: Wideband CDMA)

❖ NA: W-CDMA, USA T1P1-ATIS

(North American: Wideband CDMA)

❖ cdma2000, USA TIA TR45.5

(Wideband CDMA: IS-95)

❖ CDMA I, S. Korea TTA

(Multiband Synchronous DS-CDMA)

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IMT-2000 Proposals:

Satellite (of 5 submitted)

❖

SAT-CDMA, S. Korea Telecommunication Technologies Association (TTA)

(49 LEO sats in 7 planes at 2000 km)

❖

SW-CDMA, European Space Administration (ESA)

(Satellite Wideband CDMA)

❖

SW-CTDMA, ESA

(Satellite Wideband hybrid CDMA/TDMA)

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IMT-2000 Proposals:

Satellite (of 5 submitted)

❖

ICO RTT, ICO Global Communications (Inmarsat affiliate based in UK)

(10 MEO sats in 2 planes at 10390 km)

❖

Horizons, Inmarsat (International Marine Satellites)

(Horizons satellite system)

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DECT (Digital Enhanced

Cordless Communications)

❖

Authored by the European Telecommunications Standards Institute

❖

Interworking to connectionless networks:

Ethernet, Token Ring LANs, TCP/IP, MANs

❖

Generic data link service

❖

Multimedia messaging service

❖

Channel setup:

_< 50 ms

❖

Error rates better than 10

^-9

❖

Throughput rate of up to 552 kbit/s

(2-level modulation, higher with 4- and 8-level)

Source: http://www.itu.int/imt/2-radio-dev/rtt/ep-dect

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UWC-136 (Universal Wireless Communications)

❖

Authored by the Universal Wireless Communications Consortium)

❖

Spectrum efficiency:

at least 0.45 Mbits/s/Mhz/cell

❖

Fits into existing IS-136 RF frequency plan

❖

Microcell and macrocell performance comparable:

pedestrian (3 km/h): up to 384 kbit/s

low speed vehicular (<100 km/h): up to 384 kbit/s

high speed vehicular (100-500 km/h): up to 144 kbit/s

Source: http://www.itu.int/imt/2-radio-dev/rtt/usa/tia/uwc-136.pdf

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WIMS/W-CDMA (Wireless Multimedia and Messaging Services/Wideband CDMA)

❖

Principal author: Golden Bridge Technology

❖

Data rates

of 8 kbps, 16 kbps, 32 kbps, 64 kbps, 144 kbps, 384 kbps, T1/E1

❖

Multimedia operating system

❖

Exploits software radio technology

providing backward compatibility

❖

Usable in all environments:

WLL, indoor, pedestrian, vehicular

❖

Duplex method: FDD

❖

Multiple access method: DS-CDMA

Source: http://www.itu.int/imt/2-radio-dev/rtt/usa/tia/wims.pdf

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TD-SCDMA (Time-Division Synchronous CDMA)

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Authored by China’s Academy of Telecommunications Technology

❖

Utilizes new technologies:

synchronous CDMA, smart antennas, software radio

❖

Similar to IS-95 system

❖

Each RF channel equals:

8 TDMA time slots=16 CDMA code channels

❖

Code channel identification:

by specific Walsh code XOR a common pseudo random (PN) spreading code

Source: http://www.itu.int/imt/2-radio-dev/rtt/chn

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W-CDMA (Wideband CDMA)

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Authored by Japan’s Association of Radio Industries and Businesses (ARIB)

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CDMA II (Asynchronous DS-CDMA)

❖

Authored by S. Korea’s Telecommunication Technologies Association

❖

Adopted inter-cell asynchronous mode

❖

Multi-bandwidth spreading technique

supports multimedia services

❖

High-data-rate capabilities provided

by wide-band spreading and multi-code schemes

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Multiple access method: DS-CDMA

❖

Duplexing method: FDD

❖

Chip rate:

1.024/4.096/8.192/16.384 Mcps

Source: http://www.itu.int/imt/2-radio-dev/rtt/kor/tta2

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NA: W-CDMA (North American:

Wideband CDMA)

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Principal author: Ericsson

❖

GSM DCS-1900 variant

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4.096 Mcps spread spectrum overlap on GSM

❖

Duplex scheme: FDD/TDD

❖

Multiple access scheme: DS-CDMA

❖

Support for:

inter-frequency handover, future technologies (adaptive antennas, transmitter diversity), high-data-rate

transmission (384 kbps with wide-area coverage, 2 Mbps with local coverage)

Source: http://www.itu.int/imt/2-radio-dev/rtt/usa/t1p1/wcdma_na.pdf

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CDMA I (Multiband

Synchronous DS-CDMA)

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Authored by S. Korea’s Telecommunication Technologies Association

❖

Proposed multiband system of

0.9216/3.6864/14.7456 Mcps

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Base station coordination:

synchronous between stations with optional asynchronous mode

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Discontinuous transmission possible

with pilot channel aided coherent scheme

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Enhances power efficiency in reverse link:

BPSK data/OCQPSK (orthogonal complex QPSK) for low rate and QPSK/OCQPSK for high rate services

Source: http://www.itu.int/imt/2-radio-dev/rtt/kor/tta1/tta_rtt1.pdf

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UTRA (UMTS Terrestrial Radio Access: Wideband CDMA)

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Represents ETSI Special Mobile Group’s attempt to ensure backward compatibility for GSM

❖

Product of the harmonization of ARIB &

UTMS

❖

Duplex method: FDD and TDD

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Will operate in indoor, pedestrian,

vehicular, and mixed-cell environments

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Will most likely adopt Turbo codes for high-rate services

Source: http://www.itu.int/imt/2-radio-dev/rtt/etsi/utra.pdf

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UTRA Key Technical Characteristics

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Carrier spacing: flexible in the range 4.4-5.2 MHz (200 kHz carrier raster)

❖

Chip rate: 4.096/8.192/16.384 Mcps

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Frame length: ^{10 ms}

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Spreading modulation: balanced QPSK (forward link), dual channel QPSK (reverse link)

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Coherent detection: time multiplexed pilot

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Physical control channel: time multiplexed (forward link), I&Q multiplexed (reverse link)

Source: Ojanperä, T., “Development of 3G Radio Technologies,” Nokia Research Center

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UTRA Key Technical Characteristics

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Power control: open and closed loop (1.6 kHz)

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Multi-rate/variable-rate scheme: ^variable

spreading factor and multi-code

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Channel coding scheme: convolutional coding (rate 1/2-1/3), optional outer Reed-Solomon coding (rate 4/5)

❖

Inter-base station synchronization: FDD mode: no accurate synchronization needed, TDD mode: synchronization needed

Source: Ojanperä, T., “Development of 3G Radio Technologies,” Nokia Research Center

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cdma2000 (Wideband CDMA:

IS-95): one U.S. View of IMT-2000

Source: Tiedemann, E., The Evolution of CDMA, 8th Virginia Tech Symposium on Wireless Personal Communications

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Source: 1, Oregon State Univ. Website, http://www.ece.orst.edu/~rodrigfr/cdma/tutorial.html

The Pros and Cons of CDMA

Advantages include:

¹

❖ Voice activities cycles

❖ No hard handoff

❖ No guard time in CDMA

❖ Less fading

❖ Capacity advantage

❖ No frequency mgmt. or assignment needed

❖ Soft capacity

❖ Coexistence

Drawbacks include:

❖ Rake receiver needed in each portable receiver

❖ Island cells occur if time sync is off between base stations

❖ Not suitable for microcell and in-building systems

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J-STD-008 AND TSB74 Key Pioneering Characteristics

❖ Multiple rates (Rate Set 1 and 2)

-- Rate Set 2: 1800, 3600, 7200, 14400 bps

❖ Multiple bands (cellular and PCS)

❖ Faster Forward link power control

--Erasure indicator bit

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IS-95-B Key Characteristics

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Higher rate operation

--Up to 76.8 kbps (Rate Set 1) and 115. 2 kbps (Rate Set 2)

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Supplemental channels

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Independent soft handoff of fundamental and supplemental channels

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Searching on another frequency for hard handoff

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Soft channel assignment, access handoff, and access probe handoff

❖

Enhanced soft handoff reporting based upon total E c /I 0

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cdma2000

Key Characteristics

❖

Different RF channel bandwidths (N x 1.2288 MHz where N = 1, 3, 5, 9, 12)

– 1.2288, 3.6864, 7.3728, 11.0592, and 14.7456 Mcps

❖

Multi- carrier operation for overlays of existing systems

❖

Fast forward link power control

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Forward link transmit diversity

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Turbo coding

❖

Auxiliary pilots

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cdma2000

Key Characteristics

❖

Coherent reverse link

BPSK- like modulation Continuous transmission Peak to average reduction

❖

Enhanced channel structure

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Mixed frame lengths

❖

Advanced Medium Access Control (MAC)

Supports efficient packet operation

Supports different quality of service (Q o S)

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Forward Link Spreading

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Example Multi-Carrier Deployment in 20MHz

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cdma2000 Deployments

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Forward Link

Transmit Diversity

❖ Multi=carrier (MCTD)

--Different carriers are radiated by different antennas

❖ Orthogonal transmit diversity (OTD)

--Split forward link channel into two streams that are transmitted over each antenna

--Orthogonal forward link permits signals to be orthogonal between antennas

❖ Time-switched transmit diversity (TSTD)

--Quickly switch transmissions on a forward channel between antennas

--Orthogonal forward link permits signals to be orthogonal between antennas

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Third Generation Questions

❖

Markets

--Is there a market?

--If so, what market?

--Is this a technology push or a market pull?

❖

Technology

--What performance gains do we really get over IS-95 or GSM, particularly for voice?

❖

Standards

--Are we going to have one or two CDMA systems, or can W- CDMA (now UTRA) and cdma2000 converge?

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Acknowledgements

Professor Rappaport wishes to extend a thank you to Ms. Anne

Dean, research associate at MPRG, who conducted background research to prepare for this presentation.