Cdma2000 Wcdma Comparison

CDMA2000 & W-CDMA "A Comparison Study"

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Advanced Technologies Group

CDMA2000 & W-CDMA

"A Comparison Study"

Prepared by:

Hedayat Azad

Roger Cheung


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Table of Contents

1. Introduction 5

2. Evolution of cellular systems 7

3. CDMA: Past, Present and Future 11

4. Standardization Process of 3G Systems 13

5. cdma2000 215.1 cdma2000 Standard 21

5.1.1 Phase 1: cdma2000 1xRTT 24

5.1.2 Phase 2: cdma2000 3xRTT 25

5.1.3 cdma2000 Packet Core Network 26

5.2 cdmaOne Evolution Path to 3G CDMA 27

5.3 cdma2000 Attributes 28

5.4 cdma2000 Key Parameters Summary 31

5.5 cdma2000 Downlink 32

5.5.1 cdma2000 Downlink Multicarrier Scenario 33

5.5.2 cdma2000 Downlink Channel Structure 33

5.6 cdma2000 Uplink 35

5.6.1 cdma2000 Uplink Scenario 35

5.6.2 cdma2000 Uplink Channel Structure 36

5.7 More on cdma2000 Technology 38

5.7.1 Spreading 38

5.7.2 Multirate 38

5.7.3 Packet Data 39

5.7.4 Handover 39

5.7.5 Transmit Diversity 40


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6. Wide-band CDMA (W-CDMA) 416.1 UTRAN (UMTS Terrestrial Radio Access Network) Logical Architecture 45

6.2 Carrier Spacing and Deployment Scenarios 46

6.3 W-CDMA FDD Logical and Physical Channels 46

6.3.1 Uplink Physical Channels 47

6.3.2 Downlink Physical Channels 52

6.4 More on W-CDMA Technology 55

6.4.1 Spreading 55

6.4.2 Multirate 57

6.4.3 Packet Data 59

6.4.4 Soft Handover 59

6.4.5 Interfrequency Handovers 60

6.4.6 Inter-Operability Between GSM and W-CDMA 61

6.5 UTRA TDD 63

6.5.1 Transport Channels 63

6.5.2 Physical Channels 64

6.5.3 Multiplexing, Channel Coding and Interleaving 68

6.5.4 Spreading and Modulation 70

6.5.5 Radio Transmission and Reception 71

6.5.6 Physical Layer Procedures 72

6.5.7 Additional Features and Options 74

7. Comparison of CDMA2000 with UTRA (FDD & TDD) 757.1 Major Technical Differerences between cdma2000 and W-CDMA 75

7.1.1 The Chip Rate 75

7.1.2 Base Station Synchronization 76

7.1.3 Compatibiliy with Different Core Networks 76

7.1.4 Multi-Carrierd vs. Direct Sequence 77

7.1.5 Pilot Channel Functionality 77

7.2 cdma2000 and UTRA (FDD, TDD) Specifications Comparison 78


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7.3 Comparison of cdma2000 and UTRA Evaluation Reports 80

8. Other Relevant Technologies 998.1 1xEV-DO Standard 99

8.1.1 1xEV-DO Protocol Architecture 100

8.1.2 Physical Layer Link Structures 100

8.1.3 1xEV’s Reverse Channel Structure 101

8.1.4 Reverse Link Modulation Parameters 106

8.1.5 Reverse Link Other Parameters 107

8.1.6 1xEv’s Forward Channel Structure 109

8.1.7 Forward Link Other Parameters 115

8.2 1xTREME 118

8.2.1 Evolutions from IS-2000 1X 118

8.2.2 Key Concept of 1xTREME 120

8.2.3 Adaptive Modulation and Coding 122

9. References 125


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1. Introduction

The explosive growth of the Internet is expected to produce a tremendous increase in the demand

for wireless multimedia services. First and second generation wireless networks have proven

capable of providing voice and low-rate data services; however, their current air interfaces are

inadequate for satisfying the higher data rates that have been specified by the ITU for IMT-2000.

In order to satisfy so-called third generation requirements, GSM networks will evolve to

GPRS/EDGE technology and ultimately utilize a new air interface based on wideband CDMA.

Is-136 TDMA networks will most likely follow the same path as of GSM by evolving to GPRS-

136 and eventually to 136 HS or W-CDMA. Finally, cdma2000 will provide the migration path

for existing IS-95 networks based on code division multiple access.

Third-generation mobile radio networks, often dubbed as 3G, have been under intense research

and discussion recently and will emerge around the year 2000. In the International

Telecommunications Union (ITU), third generation networks are called International Mobile

Telecommunications-2000 (IMT-2000), and in Europe, Universal Mobile Telecommunications

System (UMTS). IMT-2000 will provide a multitude of services, especially multimedia and high-

bit-rate packet data. Wideband code division multiple access (CDMA) has emerged as the

mainstream air interface solution for the third-generation networks. In Europe, Japan, Korea, and

the United States, wideband CDMA systems are currently being standarized.

The preferred technology for third-generation systems depends on technical, political, and

business factors. Technical factors include issues such as provision of required data rates, and

performance. Political factors involve reaching agreement between standards bodies and taking

into account the different starting points of different countries and regions. On one hand, the

investments into the existing systems motivate a backward compatibility approach. On the other,

new business opportunities or the possibility of changing the current situation might motivate a

new approach.


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This document provides a complete review of the accepted CDMA air interface proposals which

are the European WCDMA and cdma2000 in the United States. The document is organized as

follows. The evolution of cellular systems is presented in section-2. In section-3, the past,

present, and future of CDMA technology are presented. A brief summary of the 3G

standardization is described in section-4. American cdma2000 standard and its different phases

has been explained in section-5. Technical specifications of European W-CDMA standard are

introduced in section-6. A comparison between cdma2000 and W-CDMA has been carried out in

section-7. Some other relevant 2.5/3rd generation technologies are described in section-8. Section-

9 is a brief conclusion and finally, the references are given in section-10.


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2. Evolution of Cellular Systems

The evolution of the Cellular Systems can be summarized as the following steps ( see also Table-

1).

• Precellular Systems

• First Generation

» Analog Voice with No Coding

» Few Services and Features

» Almost No Message Security

» Low Capacity

•• Second Generation

» Digital Compressed Voice

» Channel Coding Encryption and Security

» Enhanced Features and Services

• Third Generation

» High Speed Data Capability

» Multimedia Services

» Global Harmonization and Roaming

» Intelligent Networking

Capacity (SpectralEfficiency) & Coverage

Capacity, Security &Unification of VariousStandards

HSD, MutimediaServices, IN,more Unification


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Table-1 : 2G vs. 3G Systems

2G System 3G System

Digital Technology Use digital technologies formodulation, speech, andchannel coding.

Increased use of digitaltechnologies, includingsoftware.

Commonality for DifferentOperating Environments

Optimized for specificenvironment

Maximizing commonality andoptimization of radiointerface.

Frequency Band 800 MHz, 900 MHz, and 1.5and 1.8 GHz

Use of common globalfrequency band for bothterrestrial and satellitecomponents.

Data Services Data services less than orequal to 32kbps

Higher transmission speedcapabilities with circuit andpacket switch as well asmultimedia services.

Roaming Generally limited to specificregion

Improved global roaming dueto global frequencycoordination, increased use ofSIM, availability of globalsatellite coverage.

Technology Spectrum efficiency, overallcost, and flexibility are limitedby system design objectivesand technologies existing atdesign inception andimplementation.

Spectrum efficiency,flexibility, and overall costswill be improved as a result ofbuilding upon 2G Wirelesssystem design experience andutilization of year 2000technologies.


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First and second generation wireless networks currently provide support for circuit-switched

voice services as well as low-rate circuit-switched and packet-switched data services. The most

widely deployed first generation analog mobile phone systems are Advanced Mobile Phone

System (AMPS), Nordic Mobile Telephone (NMT), and Total Access Communications System

(TACS). AMPS has major network deployments in North America, the Asia / Pacific region, and

Central and Latin America. NMT and TACS first deployments were primarily in Europe – NMT

in Scandanavia and TACS in the United Kingdom, with other substantial network operations in

the Asia / Pacific region. Second generation (2G) systems consist of Global System for Mobile

Communications (GSM), IS-136 or Digital AMPS (DAMPS), IS-95 or cdmaOne™, and

Personal Digital Cellular (PDC). GSM, IS-136, and PDC are time-division multiple access

(TDMA) based systems; whereas, IS-95 relies on code division multiple access (CDMA) as its

air interface. GSM is widely deployed throughout the world and is the predominant standard in

Europe. GSM is also recognized as the world leader in terms of number of subscribers. IS-136

and IS-95 are the main 2G standards in operation in the North America, with other major

installations throughout Central and South America and the Asia / Pacific region. Although it

supports a substantial digital subscriber base, PDC is currently only in operation in Japan.

The primary focus of third generation architectures will be to attempt to seamlessly evolve second

generation systems to provide high-speed data services to support multimedia applications such

as web browsing. The key word is "evolve" - as the challenge to wireless equipment

manufacturers is to provide existing customers, namely, service providers, with a migration path

that simultaneously satisfies the requirements set forth by the International Telecommunications

Union (ITU) for 3G wireless services while preserving customer investment in existing wireless

infrastructure. Emerging requirements for higher rate data services and better spectrum efficiency

are the main drivers identified for the third-generation mobile radio systems.


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The main objectives for the IMT-2000 air interface (Figure. 1) can be summarized as:-

• Full coverage and mobility for 144 Kb/s, preferably 384 Kb/s

• Limited coverage and mobility for 2 Mb/s

• High spectrum efficiency compared to existing systems

• High flexibility to introduce new service

Figure 1: IMT-2000 User Bit Rate vs. Coverage and Mobility

The bit rate targets have been specified according to the Integrated Services Digital Network

(ISDN) rates. The 144-Kb/s data rate provides the ISDN 2B+D channel, 384 Kb/s provides the

ISDN H0 channel, and 1920 Kb/s provides the ISDN H12 channel. However, it may be that the

main IMT-2000 services are not ISDN-based services. It has to be noted that these figures have

been subject to considerable debate. Ultimately, market demand will determine what data rates

will be offered in commercial systems.

EDGE

IMT-2000/UMTSCDMA2000,WCDMA

GSM, IS-95A, IS-136, PDC (Basic 2G)

Evolved 2G (GSM HSCSD and GPRS, IS-95B)

Fixed/lowmobility

Wide area/high mobility

10Kbps

64Kbps

384Kbps

2Mbps

User Bit Rate


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3. CDMA: Past, Present, and Future

The origins of spread spectrum are in military field and navigation systems. Techniques

developed to counteract intentional jamming have also proved suitable for communication

through dispersive channels in cellular applications. In this section we highlight the milestones

for CDMA development starting from the 1950s after the invention of the Shannon theorem.

In 1949, John Pierce wrote a technical memorandum where he described a multiplexing system in

which a common medium carries coded signals that need not be synchronized. This system can

be classified as a time hopping spread spectrum multiple access system [1]. Claude Shannon and

Robert Pierce introduced the basic ideas of CDMA in 1949 by describing the interference

averaging effect and the graceful degradation of CDMA [2]. In 1950, De Rosa-Rogoff proposed a

direct sequence spread spectrum system and introduced the processing gain equation and noise

multiplexing idea [1]. In 1956, Price and Green filed for the anti-multipath "RAKE" patent [1].

Signals arriving over different propagation paths can be resolved by a wideband spread spectrum

signal and combined by the RAKE receiver. The near-far problem (i.e., a high interference

overwhelming a weaker spread spectrum signal) was first mentioned in 1961 by Magnuski [1].

For cellular application spread spectrum was suggested by Cooper and Nettleton in 1978 [3].

During the 1980s Qualcomm investigated DS-CDMA techniques, which finally led to the

commercialization of cellular spread spectrum communications in the form of the narrowband

CDMA IS-95 standard in July 1993. Commercial operation of IS-95 systems started in 1996.

Multiuser detection (MUD) has been subject to extensive research since 1986 when Verdu

formulated an optimum multiuser detection for the additive white Gaussian noise (AWGN)

channel, maximum likelihood sequence estimator (MLSE) [4].

During the 1990s wideband CDMA techniques with a bandwidth of 5 MHz or more have been

studied intensively throughout the world, and several trial systems have been built and tested [5].

These include FRAMES Multiple Access (FRAMES FMA2) in Europe, Core-A in Japan, the


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European/Japanese harmonized WCDMA scheme, cdma2000 in the United States, and the

Telecommunication Technology Association I and II (TTA I and TTA II) schemes in Korea.

Introduction of third-generation wireless communication systems using wideband CDMA is

expected around the year 2000.

Based on the above description, the CDMA era can be summarized into three periods: the pioneer

CDMA era, the narrowband CDMA era, and the wideband CDMA era, as shown in Table 2.

Table 2: CDMA era

Pioneer Era1949 John Pierce: time hopping spread spectrum

1949 Claude Shannon and Robert Pierce: basic ideas of CDMA

1950 De Rosa-Rogoff: direct sequence spread spectrum

1956 Price and Green: antimultipath "RAKE" patent

1961 Magnuski: near-far problem

1970sSeveral developments for military field and navigationsystems

Narrowband CDMA Era1978 Cooper and Nettleton: cellular application of spread spectrum

1980sInvestigation of narrowband CDMA techniques for cellularapplications

1986 Formulation of optimum multiuser detection by Verdu

1993 IS-95 standard

Wideband CDMA EraEurope:FRAMES FMA2

Japan: Core-AWCDMA

USA :cdma20001995

Korea :TTA I TTA II

2000s Commercialization of wideband CDMA systems


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4. Standardization Process of 3G Systems

In 1998, the International Telecommunications Union (ITU) (www.itu.int) called for Radio

Transmission Technology (RTT) proposals for IMT-2000 (originally called Future Public Land

Mobile Telecommunications Systems, FPLMTS), the formal name for the Third Generation

standard. Many different proposals were submitted: the DECT and TDMA/Universal Wireless

Communications proposals for the RTT (Radio Transmission Techonology) were TDMA-based,

whilst all other proposals for non-satellite based solutions were based on wideband CDMA - the

main submissions were called Wideband CDMA (WCDMA) and cdma2000. The ETSI/GSM

players including infrastructure vendors such as Nokia and Ericsson backed WCDMA. The North

American CDMA community, led by CDMA Development Group (CDG) including infrastructure

vendors such as Qualcomm and Lucent Technologies, backed cdma2000. Figure-2 details the

main Participants for the IMT-2000.

3GPP (Third Generation Partnership Project)

In December 1998, the Third Generation Partnership Project (3GPP) was created following an

agreement between six standards setting bodies around the world including ETSI, ARIB and TIC

of Japan, ANSI of the USA and the TTA of Korea. This unprecedented cooperation into

standards setting made 3GPP responsible for preparing, approving and maintaining the Technical

Specifications and Reports for a Third Generation mobile system based on evolved GSM core

networks and the Frequency Division Duplex (FDD) and Time Division Duplex (TDD) radio

access technology. For example, ETSI SMG2 activities on UMTS have been fully transferred to

3GPP. The Chinese and the CDMA Development Group were not the original members of the

3GPP.


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Figure 2: IMT2000 Main Participants

3GPP2 (Third Generation Partnership Project 2)

The Third-Generation Partnership Project 2 (3GPP2) is an effort spearheaded by the International

Committee of the American National Standards Institute's (ANSI) board of directors to establish a

3G Partnership Project for evolved ANSI/TIA/EIA-41, "Cellular Radiotelecommunication

Intersystem Operations" networks and related RTTs. 3GPP2 members are TIA (USA),

ARIB/TTC (Japan), TTA (Korea), CWTS (China). 3GPP2 is focused on cdma2000 (1x and 3x)

Access Network and Evolved IS-41& All-IP Core network.

ARIB - Association of Radio Industries and Business (Japan)ETSI - European Telecommunications Standards Institute (Europe)ITU - International Telecommunications UnionTIA - Telecommunications Industry Association (USA)TTA - Telephone and Telegraph Association (S.Korea)

KKoorree aa

ETSI

WCDMA &

TD-CDMA

EEuurrooppee

ARIB

ITU-R

TIATR45.5 &

TR45.3

TTA (I & II)

JJaappaannUU..SS..

CDMA2000 &

UWC-136

EDGE


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In the first half of 1999, much progress was made in agreeing a global IMT-2000 standard that

met the political and commercial requirements of the various technology protagonists- GSM,

CDMA and TDMA. In late March 1999, Ericsson purchased Qualcomm’s CDMA infrastructure

division and Ericsson and Qualcomm licensed each other’s key Intellectual Property Rights and

agreed to the ITU’s “family of networks” (Figure 3) compromise to the various standards

proposals.

Figure 3: IMT-2000 “Family of Systems”

Cdma2000 & DoCoMo WCDMA

ARIB & TTC

ANSI-41 / WIN &GSM-MAP/CAMEL

Asia/Pacific

Cdma2000 & UWC-136

ANSI-41/ WIN

TIA TR 45

North America

UTRA

GSM-MAP / CAMELEurope

ETSI

A “Family ofSystems” for IMT-2000 services,ensuring networkstandardsinteroperability.


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A summary of IMT-2000 goals and requirements is given in Table 3.

Table 3: Summary of IMT-2000 Objectives

IMT- 2000 Goals

• Global system for wireless communications• Multi-environment operation

– Vehicular– Pedestrian and Outdoor-to-Indoor– Indoor Office– Satellite

• Support for packet data and circuit-switched services• Multimedia services support• Expected data rates:

– 144 kbps in vehicular– 384 kbps in pedestrian– 2 Mbps in indoor office environment

• IMT- 2000 spectrum allocated at WARC 1992 in the 2 GHz band• Year 2000+ services (subject to market considerations)

IMT-2000 End User Terminal Requirements

• Low cost• Light weight• Low power drain / long talk time• Toll-quality voice• High security• Use multiple devices with the same User ID

– Services, routing and charging by personal ID/subscription• International roaming• Broad range of services

– Fixed and mobile– Voice, data, multimedia

IMT- 2000 Key Architectural Requirements

• Broadband Radio Access– Data Rates: 144, 384, 2000 kbps– Evolution from 2G (CDMA, TDMA, GSM, PHS, etc.)– Mobility vs. Fixed Wireless Access


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– Harmonized Spectrum Allocations• Broadband Backbone Infrastructure

– Integrated Voice, Data, Image• Network Architecture

– Functional Distribution– WIN, GSM MAP, INAP

The proposed IMT-2000 standard for Third Generation mobile networks globally is a CDMA-

based standard that encompasses THREE OPTIONAL modes of operation, each of which should

be able to work over both GSM MAP and IS-41 network architectures. The three modes are

shown in Table 4 and Figure 4.

Table 4: Three Operational Modes of IMT-2000

Mode Title Origin Supporters

1 IMT DSWCDMADirect Spread FDD(Frequency DivisionDuplex)

Based on the first operational modeof ETSI’s UTRA (3G TerrestrialRadio Access) RTT proposal.

Japan’s ARIB (Association of RadioIndustries and Businesses, the Japanesestandards setting body) and GSMnetwork operators and vendors.To be deployed in Japan and Europe.

2 IMT MCcdma2000Multi-Carrier FDD(Frequency DivisionDuplex)

Based on the cdma2000 RTTproposal from the USTelecommunications IndustryAssociation (TIA). Consists of the1XRTT and 3XRTT components

cdmaOne operators and members of theCDMA Development Group (CDG).Likely to be deployed in the USA.

3 IMT TCUTRA TDD (TimeDivision Duplex)

The second operational mode ofETSI’s UTRA (3G Terrestrial RadioAccess) RTT proposal. An unpairedband solution to better facilitateindoor cordless communications.

Harmonized with China’s TD-SCDMARTT proposal. Probably will bedeployed in China.


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Figure 4: Family of 3G: Radio Access and Core Network

One goal of the harmonization effort is to provide seamless global roaming between the different

modes of CDMA 3G, cdma2000 and WCDMA.

Table 5 shows some of the contracts already awarded to equipment manufacturers by differentservice providers around the globe.

Table 5: 3G Contracts Awarded

Country Network Operator Date announced 3G Supplier

Australia Telstra(WCMA)

23MAY99 Lucent

Australia One.Tel 23NOV99 LucentCanada EricssonCanada Microcell/ GSM Allianc

(WCDMA)Nortel

France France Telecom(WCDMA)

Alcatel and Ericsson switches,Alcatel and Nortel base stations

Nortel

France Cegetel Nortel


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(WCDMA)Germany Mannesmann D2 01JUL98 EricssonGermany T-Mobil D1 01JUL98 EricssonHong Kong SmarTone

(WCDMA)Ericsson

Hong Kong Hong Kong Telecom(WCDMA)

Nokia

Italy Telecom Italia Mobile EricssonJapan NTT DoCoMo (supply of WDMA

terminals)Nokia

Japan NTT DoCoMo(WCMA TERMINALS)

Motorola

Japan DDI/ IDO(WCDMA)

Motorola

Japan NTT DoCoMo (WCDMA) SiemensJapan NTT DoCoMo

(WCDMA)Nortel

Japan DDI/ ICO(cdma2000)

Lucent

Japan NTT DoCoMo 28APR99 EricssonJapan NT DoCoMo

(WCDMA)26APR99 Lucent

Korea SK Telecom(WCDMA)

Nokia

Sweden Telia EricssonUSA AT&T Wireless

(UWC 136)Lucent

USA Bell Atlantic(cdma2000)

Lucent

USA Sprint PCS(cdma2000)

Lucent

UK Vodafone(WCDMA)

23FEB99 Motorola

UK Vodafone(WCDMA)

15OCT98 Lucent

UK Orange(WCDMA)

10FEB99 Lucent

UK Vodafone(WCDMA)

Ericsson Nortel

UK BT Ericsson Nortel


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(WCDMA)UK Vodafone 22APR99 EricssonUSA Sprint PCS

(cdma2000)Motorola

USA Sprint PCS(cdma2000)

Nortel

USA EricssonUSA AirTouch

(cdma2000)Nortel

Venezuela Movilnet (TDMA) 13DEC99 Ericsson


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5. cdma2000

Currently, mobile data rates are low on both GSM at 9.6 kbps with Circuit Switched Data and

cdmaOne 95A networks at 14.4 kbps in either circuit or packet switched modes. These speeds are

far lower than those available to a typical user of a PSTN wire-line network. However, we are

now entering a period that will see new and faster non-voice mobile services. For example,

anticipating an increased demand for data services, Korean and Japanese operators SK Telecom,

Hansol, DDI and IDO have already implemented commercial cdmaOne 95B packet data at speeds

of 64 kbps.

5.1 cdma2000 Standard

cdma2000 is the 3rd Generation solution based on IS-95. It is an evolution of an existing wireless

standard. cdma2000 supports 3G services as defined by the International Telecommunications

Union (ITU) for IMT-2000. 3G networks will deliver wireless services with better performance,

greater cost-effectiveness and significantly more content. The goal is access to any service,

anywhere, anytime from one terminal - true converged, mobile services.

cdma2000 is one solution for wireless operators who want to take advantage of the new market

dynamics created by mobility and the Internet. cdma2000 is both an air interface and a core

network solution for delivering the services that customers are demanding today. These services

are sometimes referred to as 3G. cdma2000 and 3G are synonymous.

cdma2000 is one mode of the Radio Access "Family" of Air interfaces agreed upon by the

Operators Harmonization Group (OHG) for promoting and facilitating convergence of third

generation (3G) networks. The CDMA2000 specification defines two modes (Figure 5 and

Figure 6) of spreading and modulations.


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•••• DDiirreecctt SSpprreeaadd

» the high rate baseband signal is directly spread over the entire available spectrum.

Figure 5: Direct Sequence cdma2000

•••• MMuullttiiccaarrrriieerr

» the spectrum is divided into multiple 1.25MHZ channels.

» the information bit stream is multiplexed into different lower rate data streams, eachspread and modulated over a 1.25MHz wide carrier.

» Multiple carriers are transmitted and received in parallel, and data bits aredemultiplexed at the receiver.

» Figure 6: Multi-carrier cdma2000

abc

S/Pabc

a b c


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The cdma2000 standard is divided into two phases commonly known as 1X and 3X. Phase one

provides support for the cdma2000 1X air interface - providing average data rates of 144 kbps.

Phase two incorporates additional support for 3X systems - providing for data rates upto 2Mbps.

The approximate voice capacity and peak data rates of cdma2000's both phases, 1x and 3x RTTs,

are shown in Figure 7.

Figure 7- cdma2000 Today and Beyond

And finally, the timeline for market trial and commercial availability of 1x and 3x solutions arepresented in Figure 8.

Figure 8- cdma2000 Timeline

2000 2001 2002 2003 2004 2005

22000000MMCC11xx

MMCC33xx

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CCuurrrreennttCCaappaacciittyy

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MMCC11XX((IISS--22000000 rreell..00))

MMCC 33xx

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11xxRRTTTT

33xxRRTTTT

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CCoommmmeerrcciiaallllyyAAvvaaiillaabbllee

MMaarrkkeett TTrriiaall

CCoommmmeerrcciiaallllyy AAvvaaiillaabbllee


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55..11..11 PP hhaassee 11:: ccddmmaa22000000 11XX

The IS-2000 standard (cdma2000 1X) has been completed and published by the

Telecommunications Industry Association (TIA). 1X offers approximately twice the voice

capacity of cdmaOne, average data rates of 144 kbps, backward compatibility with cdmaOne

networks, and other performance improvements.

1X refers to cdma2000 implementation within existing spectrum allocations for cdmaOne - 1.25

MHz carriers. The technical term is derived from N = 1 (i.e. use of the same 1.25 MHz carrier as

in cdmaOne) and the 1X means one times 1.25 MHz (RTT refers to Radio Transmission

Technology). 1X can be implemented (Figure 9) in existing spectrum or in new spectrum

allocations.

Figure 9: cdma2000 1X

A cdma2000 - 1X network will also introduce simultaneous voice and data services, low latency

data support and other performance improvements. The backward compatibility with cdmaOne,

further ensures investment protection.


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55..11..22 PP hhaassee 22 :: ccddmmaa22000000 -- 33XX

The IS-2000-A standard (cdma2000-3X) offers even higher capacity than 1X, data rates of up to

2 Mbps, backward compatibility with both 1X and cdmaOne deployments, and other performance

enhancements.

3X can also be implemented in existing or new spectrum allocations, but it utilizes a broader band

of spectrum. The term 3X refers to N = 3 (i.e. use of three 1.25 MHz carriers). There are currently

two implementations (Figure 10) of 3X identified in the standard. The Multi-Carrier mode

utilizes three 1.25 MHz carriers to deliver 3G services, while the Direct Sequence mode utilizes

one 3.75 MHz carrier to deliver the same services. The mode implemented would largely depend

on the operator's existing spectrum allocations and usage.

Figure 10: cdma2000 3X

With cdma2000 3X operators will be able to offer even higher average and peak data rates from

their networks - upto 2Mbps. Quality of service for delivering multimedia applications will also

be improved. cdma2000 3X offers simultaneous support and roaming for cdmaOne, 1X and 3X

users and improves the voice capacity even more - adding value and lowering cost for wireless

operators.


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55..11..33 ccddmmaa22000000 PPaacckkeett CCoorree NNeettwwoorrkk

The standards for a CDMA packet core network (Figure 11) are being developed by the

TR45.6 working group of the TIA. These standards are being developed by using

existing standards from the IEFT (Internet Engineering Task Force) on Mobile IP.

To provide secure and efficient transport for wireless data, a data delivery mechanism

should be introduced. One example is using a PCN (Packet Core Network) which is

comprised of the PDSN (Packet Data Serving Node) and AAA (Authentication,

Authorization and Accounting). The HA (Home Agent) can be added to provide Mobile

IP based packet data services.

Figure 11: CDMA Packet Core Network


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5.2 cdmaOne Evolution Path to 3G CDMA

Figure 12: Evolution Path for cdmaOne to cdma2000

• From IS-95A to IS-95B (Figure 12 and Table 6)

Same Physical and Radio Channelization

Added Supplemental Channel for Multi-code Operation

• From IS-95A / B to cdma2000 (see Figure 12 and Table 6)

Same Radio Channelization for 1X, Wider channels for nX deployments

Multi-Carrier / Direct Spread Options

Multi-Rate Physical Channels

Many new common channels, broadcast and dedicated in support of packet data and

high data rates.

• Migration from cdmaOne to 1x

Main unit and software upgrade only

No modiffication to remote units or antennas

Upgrade only portions of network that demand capacity or higher data rates

• Migration to 3x with channel card and software upgarde only

Operate 1X and 3X on the same base station

Remote units designed with wideband receive chain for 3X reverse link

No changes required to antenna configuration

Optional support for transmit diversity


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Table 6: Packet Data Equipment Requirments for cdma2000 evoluation from cdmaOne

Packet DataEquipmentrequirements

95A 95BIMT-2000 CDMAMulti-carrier1X(MC 1X)

IMT-2000 CDMAMulti-carrier3X(MC 3X)

Handset

Standard95A handsets willwork on all futurenetworks: 95B, 1Xand 3Xat 14.4Kbps-Single-Mode phone*

Standard inchipsets199995B handsets willwork on 95Anetworks at14.4Kbps and 95B,1X and 3X systemsat speeds up to 114Kbps-Single-Modephone

1X standard inchipsets in 20011X handsets willwork on 95Anetworks at14.4Kbps, 95BNetworks at speedsup to 114 Kbps and1X and 3X networksat speeds up to307Kbps-Single-Mode phone

New handsets3X handsets willwork on 95Anetworks at14.4Kbps, 95Bnetworks at speedsup to 114Kbps and1X networks atspeeds up to 307Kbps and 3Xnetworks at 2Mbps-Single-Mode phone

Infrastructure StandardNew software inBSC (Base StationController)

1X requires newsoftware in backboneand new channelcards at base station

BackbonemodificationsNewchannel cards at basestations

TechnologyPlatform CDMA CDMA CDMA CDMA

5.3 cdma2000 Attributes

• Voice Capacity Improvement− Doubling the available voice capacity in the existing 1.25 MHz cdmaOne carrier− Improved Grade of Service (GoS) and Customer satisfaction with service− More revenue with less investment

• Voice Quality Improvement and QoS− Offering premium voice quality to certain users at a premium price− Also called V2 Voice Mode (V1 is a standard voice quality)− Multimedia Applications

→ Low Delay Tolerance− Priority Service Access− Data Rate Guarantee


Page: 29


• Backward Compatibility (Figure 13)− Simultaneous support for both cdmaOne and 1X users in the same cell

Figure 13: cdma2000 1X Backward Compatibility with cdmaOne

• Handoff and Roaming (Figure 14)

Figure 14: Roaming and Handoff between cdmaOne and 1X networks

cdma2000 - 1xRTTNetwork

Neighboring cdmaOneNetwork

1xRTT Coverage

cdmaOne Traffic

cdmaOne Phone

cdma2000 Traffic

cdma2000 - 1XPhone


Page: 30


• High Speed Wireless Data Services− Average data rates of 144 kbps− Improved data throughput for packet and circuit data applications

→ Internet, File Transfer, Streaming data, e-commerce− Provides low latency data throughput for delay-sensitive applications− Credit card transaction, telematics, VoIP (Voice Over IP), streaming audio and video− Offering side range of data speeds and data services− Various Data Speeds

→ 144 kbps average with 1X→ 2 Mbps peak with 3X

− Various Data Services→ Telematics Services→ Horizontal Services→ Vertical Services

• Simultaneous Voice / Data Services− Concurrent Services− Circuit-switched voice / data and packet data simultaneously

→ Talking over the phone while sending fax and surfing Internet, etc.

• Hot Spot Coverage and Smart Antenna Tracking (Figure 15)− Increasing coverage, capacity, or data rate− Hot spots coverage in convention centers, stadiums, malls and campuses− Dedicated data rates and coverage to group of users

Figure 15: Hot Spot Coverage for different data rate requirements

Auxiliary Sectorsserving highspeed data

Normal sectors servingvoice and low speed

data users

ββ

γγ

αα

S

Sector αα

High Speed Data Users

C

Auxiliary Sectorsdedicated to high

speed data

Sector γγ

Sector ββ


Page: 31


• Access Reliability− Improving Acccess reliability when…..

→ High data pipes for multiple data rate applications leave big gap in Walsh space assigned to users

→ Run out of Walsh functions in sector− Sport beam and Smart antenna application

• Extends battery life / talk time of the mobile unit

5.4 cdma2000 Key Parameters Summary

Within standardization committee TIA TR45.5, the subcommittee TR45.5.4 was responsible for

the selection of the basic cdma2000 concept. Like for all the other wideband CDMA schemes, the

goal has been to provide data rates that meet the IMT-2000 performance requirements of at least

144 Kb/s in a vehicular environment, 384 Kb/s in a pedestrian environment, and 2048 Kb/s in an

indoor office environment. The main focus of standardization has been providing 144 Kb/s and

384 Kb/s with approximately 5-MHz bandwidth. The main parameters of cdma2000 are listed in

the Table 7 for reference.

Table 7: Cdma2000 Key Parameters List

Channel bandwidth 1.25, 5, 10, 15, 20 MHz

Downlink RF channel structure Direct spread or multicarrier

1.2288/3.6864/7.3728/11.0593/14.7456 Mc/s for direct spreadChip rate

n x 1.2288 Mc/s (n = 1, 3, 6, 9, 12) for multicarrier

Roll-off factor Similar to IS-95

Frame length20 ms for data and control/5 ms for control information on the

fundamental and dedicated control channel

Balanced QPSK (downlink)

Dual-channel QPSK (uplink)Spreading modulation

Complex spreading circuit


Page: 32


QPSK (downlink)Data modulation

BPSK (uplink)

Pilot time multiplexed with PC and EIB (uplink)Coherent detection

Common continuous pilot channel and auxiliary pilot (downlink)

Control, pilot, fundamental, and supplemental code multiplexedChannel multiplexing in uplink

I&Q multiplexing for data and control channels

Multirate Variable spreading and multicode

Spreading factors 4256

Power control Open loop and fast closed loop (800 Hz, higher rates under study)

Spreading (downlink)

Variable length Walsh sequences for channel separation, M-sequence 215

(same sequence with time shift utilized in different cells, different

sequence in I&Q channel)

Spreading (uplink)

Variable length orthogonal sequences for channel separation, M-sequence

215 (same sequence for all users, different sequences in I&Q channels);

M-sequence 2411 for user separation (different time shifts for different

users)

Soft handoverHandover

Interfrequency handover

5.5 cdma2000 Downlink

cdma2000 Multi- Carrier (MC) demultiplexes modulated symbols into N separate 1.25 MHz

carriers resulting in a chip rate of 1.2288 Mcps per carrier. cdma2000 Direct Spread (DS) spreads

the modulation symbols to N x 1.2288 Mcps resulting in one N X 1.25 MHz carrier. Both

methods offer comparable link performance and capacity. As was mentioned before, cdma2000

multi-carrier has been chosen as one of the modes of IMT-2000 family of systems concept.


Page: 33


55..55..11 ccddmmaa22000000 DDoowwnnlliinnkk mmuulltt iiccaarrrriieerr sscceennaarriioo

Figure 16: Downlink Scenario for multi-carrier cdma2000 (N = 3)

where F1, F2 & F3 carry the Fundamental Channel Spread using a single Walsh Code over all

three 1.25 MHz channels (transmitted separately) and S1, S2 & S3 carry the supplemental

channel spread using a single Walsh Code over all three 1.25 MHz channels (transmitted

separately).

55..55..22 ccddmmaa22000000 DDoowwnnlliinnkk CChhaannnneell SSttrruuccttuurree

cdma2000 multi-carrier downlink channel structure is shown in Figure 17. The Fundamental and

Supplemental Channels carry user data and the dedicated control channel control messages. The

dedicated control channel contains power control bits and rate information. The synchronization

channel is used by the mobile stations to acquire initial time synchronization. One or more paging

channels are used for paging the mobiles. The pilot channel provides a reference signal for

coherent detection, cell acquisition, and handover.

In the downlink, cdma2000 has a common pilot channel, which is used as a reference signal for

coherent detection when adaptive antennas are not employed. The pilot channel is similar to IS-

95 (i.e., it is comprised of a long PN-code and Walsh sequence number 0).


Page: 34


Figure 17: cdma2000 Multicarrier downlink channel structure

When adaptive antennas are used, auxiliary pilot is used as a reference signal for coherent

detection. Code multiplexed auxiliary pilots are generated by assigning a different orthogonal

code to each auxiliary pilot. This approach reduces the number of orthogonal codes available for

the traffic channels. This limitation is alleviated by expanding the size of the orthogonal code set

used for the auxiliary pilots. Since a pilot signal is not modulated by data, the pilot orthogonal

code length can be extended, thereby yielding an increased number of available codes, which can

be used as additional pilots

The multicarrier transmission principle is illustrated in Figure 18.

FORWARD CDMA CHANNEL

for Spreading Rates 1 and 3

(SR1 and SR3)

PilotChannels

SyncChannel

PagingChannels

(SR1)

CommonControl

Channels

TrafficChannels

0-1 FundamentalChannel

Mobile StationPower ControlSubchannel

0-7 SupplementalCode Channels (Radio

Configurations 1-2)

0-2 SupplementalChannels (Radio

Configurations 3-9)

BroadcastChannels

QuickPaging

Channels

CommonPower Control

Channels

CommonAssignmentChannels

ForwardPilot

Channel

TransmitDiversity Pilot

Channel

AuxiliaryPilot

Channels

Auxiliary TransmitDiversity Pilot

Channels

0-1 DedicatedControlChannel


Page: 35


Figure 18: Multicarrier Downlink

5.6 cdma2000 Uplink

55..66..11 ccddmmaa22000000 UUpplliinnkk sscceennaarriioo

Figure 19: Uplink Scenario for cdma2000

F: 5Mhz fundamental channel with pilot and controlS: 5Mhz supplemental channel dynamically assigned;- Variable user data rate with 3.6864 Mcps chiprate- Multiple supplemental channels can be used for multiple services


Page: 36


55..66..22 ccddmmaa22000000 UUpplliinnkk cchhaannnneell ssttrruuccttuurree

cdma2000 uplink channel structure is shown in Fifure 20. In the uplink there are four different

dedicated channels. The fundamental and supplemental channels carry user data. A dedicated

control channel, with a frame length 5 or 20 ms, carries control information such as measurement

data, and a pilot channel is used as a reference signal for coherent detection. The pilot channel

also carries time multiplexed power control symbols.

Figure 20: cdma2000 uplink channel structure

Figure 21 illustrates the different uplink dedicated channels separated by Walsh codes.

The reverse access channel (R-ACH) and the reverse common control channel (R-CCCH) are

common channels used for communication of layer 3 and MAC layer messages. The R-ACH is

used for initial access, while the R-CCCH is used for fast packet access.

REVERSE CDMA CHANNEL(1.25 MHz or 5 MHz channel received by base station)

AccessChannel

ReverseTraffic

Channel(RC 1 or 2)

EnhancedAccess

Channel

ReverseCommonControlChannel

ReverseDedicatedChannel

(RC 3 to 6)

ReverseFundamental

Channel

ReversePilot Channel



0 to 7 ReverseSupplementalCode Channels

Enhanced AccessChannel

Reverse CommonControl Channel

0 or 1 ReverseDedicated Control

Channel

0 or 1 ReverseFundamental

Channel

0 to 2 ReverseSupplemental

Channels

Power ControlSubchannel


Page: 37


Figure 21: cdma2000 uplink dedicated channels

The fundamental channel conveys voice, signaling, and low rate data. Basically it will operate at

low FER (around 1 percent). The fundamental channel supports basic rates of 9.6 Kb/s and 14.4

Kb/s and their corresponding subrates (i.e., Rate Set 1 and 2 of IS-95). The fundamental channel

will always operate in soft handover mode. The fundamental channel does not operate in a

scheduled manner; thus permitting the mobile station to transmit acknowledgments or short

packets without scheduling. This reduces delay and the processing load due to scheduling. Its

main difference compared to the IS-95 voice channel is that discontinuous transmission is

implemented using repetition coding rather than gated transmission.

The supplemental channel provides high data rates. The uplink supports one or two supplemental

channels. If only one supplemental channel is transmitted, then the Walsh code (+) is used on the

first supplemental channel, and if two supplemental channels are transmitted then the Walsh code

(++) is used. A repetition scheme is used for variable data rates on the supplemental channel.


Page: 38


5.7 More on cdma2000 technology

55..77..11 SSpprreeaaddiinngg

On the downlink, the cell separation for cdma2000 is performed by two M-sequences of length

215, one for the I-Channel and one for the Q-Channel, which are phase shifted by PN-Offset for

different cells. Thus, during the cell search process only these sequences need to be searched.

Since there is only a limited number of PN-Offsets, they need to be planned in order to avoid PN-

Confusion. In the uplink, user separation is performed by different phase shifts of M-sequence of

length 241. The channel separation is performed using variable spreading factor Walsh sequences,

which are orthogonal to each other. Fundamental and supplemental channels are transmitted with

the multicode principle. The variable spreading factor scheme is used for higher data rates in the

supplemental channel. In the uplink, it is used with dual-channel modulation.

55..77..22 MMuullttiirraattee

The fundamental and supplemental channels can have different coding and interleaving schemes.

In the downlink, high bit rate services with different QoS requirements are code multiplexed into

supplemental channels, as illustrated Figure 22.

Figure 22: Principle of code multiplexing


Page: 39


In the uplink, one or two supplemental channels can be transmitted. The user data frame length of

cdma2000 is 20 ms. For the transmission of control information, 5- and 20-ms frames can be used

on the fundamental channel. Also on the fundamental channel a convolutional code with

constraint length of 9 is used. On supplemental channels a convolutional code is used up to 14.4

Kb/s. For higher rates Turbo codes with constraint length 4 and rate 1/4 are preferred. Rate

matching is performed by puncturing, symbol repetition, and sequence repetition.

55..77..33 PPaacckkeett DDaattaa

cdma2000 uses also the slotted Aloha principle for packet data transmission. However, instead of

fixed transmission power it increases the transmission power for the random access burst after an

unsuccessful access attempt. When the mobile station has been allocated a traffic channel, it can

transmit without scheduling up to a predefined bit rate. If the transmission rate exceeds the efined

rate, a new access request has to be made. When the mobile station stops transmitting, it releases

the traffic channel but not the dedicated control channel. After a while it also releases the

dedicated control channel but maintains the link layer and network layer connections in order to

shorten the channel setup time when new data need to be transmitted. Short data bursts can be

transmitted over a common traffic channel in which a simple ARQ is used to improve the error

rate performance.

55..77..44 HHaannddoovveerr

It is expected that soft handover of the fundamental channel will operate similarly to the soft

handover in IS-95. In IS-95, the Active Set is the set of base stations transmitting to the mobile

station. For the supplemental channel, the Active Set can be a subset of the Active Set for the

fundamental channel. This has two advantages. First, when diversity is not needed to counter

fading, it is preferable to transmit from fewer base stations. This increases the overall downlink

capacity. For stationary conditions, an optimal policy is to transmit only from one base station --

the base station that would radiate the smallest amount of downlink power. Second, for packet

operation, the control processes can also be substantially simplified if the supplemental channel is


Page: 40


not in soft handover. However, maintaining the fundamental channel in soft handover provides

the ability to reliably signal the preferred base station to transmit the supplemental channel when

channel conditions change.

55..77..55 TTrraannssmmiitt DDiivveerrssiittyy

The downlink performance can be improved by transmit diversity. For direct spread CDMA

schemes, this can be performed by splitting the data stream and spreading the two streams using

orthogonal sequences. For multicarrier CDMA, the different carriers can be mapped into different

antennas.


Page: 41


6. Wide-band CDMA (W-CDMA)

WCDMA (Wideband Code Division Multiple Access) is the radio access technology selected by

ETSI (European Telecommunications Standards Institute) in January 1998 for wideband radio

access to support third-generation multimedia services. The W-CDMA scheme has been

developed as a joint effort between ETSI and ARIB during the second half of 1997[6]. The ETSI

W-CDMA scheme has been developed from the FMA2 scheme in Europe [7 13] and the ARIB

W-CDMA from the Core-A scheme in Japan [14 19]. The uplink of the WCDMA scheme is

based mainly on the FMA2 scheme, and the downlink on the Core-A scheme.

Optimized to allow very high-speed multimedia services such as voice, Internet access and

videoconferencing, the technology will provide access speeds at up to 2Mbit/s in the local area

and 384kbit/s wide area access with full mobility. These higher data rates require a wide radio

frequency band, which is why WCDMA with 5MHz carrier has been selected; compared with

200kHz carrier for narrowband GSM.

WCDMA can be added to the existing GSM core network. This will be particularly beneficial

when large portions of new spectrum are made available, for example in the new paired 2GHz

bands in Europe and Asia. It will also minimize the investment required for WCDMA rollout – it

will, for example, be possible for existing GSM sites and equipment to be reused to a large extent.

An agreement on a globally harmonized third-generation CDMA radio standard that addresses the

needs of all current wireless communities was reached by the Operators’ Harmonization Group in

May 1999. There will be three modes in the harmonized 3G CDMA standard; a direct-sequence

mode for WCDMA, a multi-carrier mode for cdma2000 (an evolution of narrowband CDMA),

and a time division duplex (TDD) CDMA mode. Figure 23 illustrates the different schemes and

their relations to standards bodies and to each other.


Page: 42


Figure 23: Relationship between wideband CDMA schemes and standards bodies

In this section, the main technical features of the ARIB / ETSI W-CDMA scheme are presented

and the key parameters and requirements of W-CDMA are listed in Table 8 and Table 9

respectively.

Table 8: Key Parameters of WCDMA

Multiple AccessDS-CDMA (FDD Mode)TDMA / CDMA (TDD Mode)

Channel bandwidth5 / 10 / 20 MHz (FDD Mode)5 MHz (TDD Mode)

Chip rate

FDD Mode: Basice Chip Rate = 4.096 Mcps, Higher Chip Rate with 8.192 and 16.384 McpsTDD Mode: 4.096 Mcps (3.84 Mcps)

Inter BS Timing

FDD Mode: Asynchronous (Sync. Possible)TDD Mode: Synchronous

Frame length 10 ms


Page: 43


Power control Fast power control for both uplink and downlink

Spreading Techique Variable-spreading factor + multi-code

Modulation QPSK with roll-off factor α = 0.22

Detection Coherent Detection on both uplink and downlink

Channel Coding1 / 2 – 1 / 3 rate Convolutional & Turbo Coding (FDD Mode)Convolutional Codes, RS Codes, Turbo Codes (TDD Mode)

HandoverSoft-Handoff (FDD Mode)Hard-Handoff (TDD Mode)

Minimum bearer capabi l i t ies for UMTS

Real Time/Constant Delay Non Real Time/Variable DelayOperating environment Peak Bit Rate BER / Max

Transfer DelayPeak Bit Rate BER / Max Transfer

DelayRural outdoor(terminal speed up to 500 km/h)

144 kbit/s

granularity 16 kbit/s

BER 10-3 (20 ms )BER 10

-7 (300 ms)

144 kbit/s BER = 10 -5 to 10-8

Max Transfer Delay150 ms or more

Urban/ Suburban outdoor(Terminal speed up to 120 km/h)

512 kbit/s


BER 10-3 (20 ms)BER 10

-7 (300 ms)

512 kbit/s BER = 10 -5 to 10-8


Indoor/ Low range outdoor(Terminal speed up to 10 km/h)

2 Mbit/s


delay 20 - 300 msBER 10

-3 (20 ms)

BER 10-7 (300 ms)

2 Mbit/s BER = 10-5

to 10-8


Table 9:


Page: 44


UMTS Goal

"UMTS will be a mobile communications system that can offer significant user benefits including

high-quality wireless multimedia services to a convergent network of fixed, cellular and satellite

components.

It will deliver information directly to users and provide them with access to new and innovative

services and applications.

It will offer mobile personalised communications to the mass market regardless of location,

network and terminal used." From UMTS Forum 1997.

UMTS Vision

The UMTS vision of Global/Umbrella/Macro cell, Suburban/urban/Micro cell and in-

building/Pico cell in a hierarchical cell structure is shown in Figure 24.

Figure 24: UMTS Vision

Global

Suburban

Macro-Cell

Urban

Micro-Cell In- Building

Pico-Cell

Home-Cell


Page: 45


6.1 UTRAN (UMTS Terrestrial Radio Access Network) logicalArchitecture

The UTRAN consists of a set of Radio Network Subsystems (RNS) connected to the Core

Network through the Iu. An RNS consists of a Radio Network Controller (RNC) and One or more

Node B nodes. Node B is connected to the RNC through the Iub interface.

The RNC is responsible for the hand-over decisions that require signaling to the User Equipment

(UE). The RNC comprises a combining/splitting function to support macro diversity inside a

Node B. However, a Node B can comprise an optimal combining/splitting function to support

macro diversity inside a Node B.

Inside the UYRAN, the RNCs of the RNS can be interconnected together through the Iur. Iu and

Iur are logical interfaces. Iur can be conveyed over physical dorect connection between RNCs or

via any suitable transport network. The UTRAN architecture is shown in Figure 25.

Figure 25: UTRAN Architecture

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub


Page: 46


6.2 Carrier Spacing and Deployment Scenarios

The carrier spacing has a raster of 200 kHz and can vary from 4.2 to 5.4 MHz. The different

carrier spacings can be used to obtain suitable adjacent channel protections depending on the

interference scenario.

Figure 26 shows an example for the operator bandwidth of 15 MHz with three cell layers. Larger

carrier spacing can be applied between operators than within one operator's band in order to avoid

inter-operator interference. Inter-frequency measurements and hand-overs are supported by

WCDMA to utilize several cell layers and carriers.

Figure 26 - Frequency utilization with WCDMA

6.3 W-CDMA FDD Logical and Physical Channels

WCDMA basically follows the ITU Recommendation M.1035 in the definition of logical

channels. The following logical channels (Figure 27) are defined for WCDMA.


Page: 47


Figure 27: WCDMA Logical Channels

66..33..11 UUpplliinnkk PPhhyyssiiccaall CChhaannnneellss

There are two dedicated channels and one common channel on the uplink (Figure 28). User data

is transmitted on the dedicated physical data channel (DPDCH), and control information is

transmitted on the dedicated physical control channel (DPCCH). The random access channel is a

common access channel. Frame structure for W-CDMA uplink DPDCH and DPCCH is depicted

in Figure 29.

Synchronisation Control Channel (SCCH)

Broadcast Control Channel (BCCH)

Paging Control Channel (PCCH)

Dedicated Control Channel (DCCH)

Common Control Channel (CCCH)

Control Channel (CCH)

Dedicated Traffic Channel (DTCH)Traffic Channel (TCH)

ODMA Dedicated Control Channel (ODCCH)

ODMA Common Control Channel (OCCCH)

ODMA Dedicated Traffic Channel (ODTCH)

Common Traffic Channel (CTCH)

Shared Channel Control Channel (SHCCH)


Page: 48


Figure 28: WCDMA Uplink Physical Channels

Figure 29: Frame Structure for WCDMA Uplink DPDCH / DPCCH

Uplink Physical channels

Common Physical ChannelsDedicated Physical Channels

Dedicated Physical Data Channels(Uplink DPDCH)

Dedicated Physical Control Channel(Uplink DPCCH))

Physical Random Access Channel (PRACH)

Physical Common Packet Channel (PCPCH)

Pilot Npilot bits

TPC NTPC bits

DataNdata bits

Slot #0 Slot #1 Slot #i Slot #14

Tslot = 2560 chips, 10*2k bits (k=0..6)

1 radio frame: Tf = 10 ms

DPDCH

DPCCHFBI

NFBI bitsTFCI

NTFCI bits


Page: 49


Figure 29 shows the principle frame structure of the uplink DPDCH. Multiple parallel variable

rate services (= dedicated logical traffic and control channels) can be time multiplexed within

each DPDCH frame. The overall DPDCH bit rate is variable on a frame-by-frame basis.

In most cases, only one DPDCH is allocated per connection, and services are jointly interleaved

sharing the same DPDCH. However, multiple DPDCHs can also be allocated (e.g. to avoid a too

low spreading factor at high data rates).

The dedicated physical control channel (DPCCH) is needed to transmit pilot symbols for coherent

reception, power control signaling bits, and rate information for rate detection. Two basic

solutions for multiplexing physical control and data channels are time multiplexing and code

multiplexing. A combined IQ and code multiplexing solution (dual-channel QPSK) is used in

WCDMA uplink to avoid electromagnetic compatibility (EMC) problems with discontinuous

transmission (DTX).

The major drawback of the time multiplexed control channel are the EMC problems that arise

when DTX is used for user data. One example of a DTX service is speech. During silent periods

no information bits need to be transmitted, which results in pulsed transmission as control data

which must be transmitted in any case. This is illustrated in Figure 30.

Figure 30: Illustration of pulsed transmission with time multiplexed control channel


Page: 50


Because the rate of transmission of pilot and power control symbols is on the order of 1 to 2 kHz,

they cause severe EMC problems to both external equipment and terminal interiors. This EMC

problem is more difficult in the uplink direction since mobile stations can be close to other

electrical equipment, like hearing aids.

Figure 31: Illustration of parallel transmission of DPDCH andDPCCH channel when data is present/adsent

The IQ/code multiplexed control channel is shown in Figure 31. Now, since pilot and power

control are on a separate channel, no pulse-like transmission takes place. Interference to other

users and cellular capacity remains the same as in the time multiplexed solution. In addition, link-

level performance is the same in both schemes if the energy allocated to the pilot and the power

control bits is the same.

The structure of the random access burst is shown in Figure 32. The random access burst consists

of two parts, a preamble part of length 16 x 256 chips (1 ms) and a data part of variable length.

The WCDMA random access scheme is based on a slotted ALOHA technique with the random

access burst structure shown in Figure 32.


Page: 51


Figure 32: Structure of WCDMA random access burst

Before the transmission of a random access request, the mobile terminal should carry out the

following tasks:

• Achieve chip, slot, and frame synchronization to the target base station from the

synchronization channel (SCH) and obtain information about the downlink scrambling

code also from the SCH

• Retrieve information from BCCH about the random access code(s) used in the target cell

/ sector

• Estimate the downlink path loss, which is used together with a signal strength target to

calculate the required transmit power of the random access request

It is possible to transmit a short packet together with a random access burst without settting up a

scheduled packet channel. No separate access channel is used for packet traffic related random

access, but all traffic shares the same random access channel. More than one random access

channel can be used if the random access capacity requires such an arrangement.


Page: 52


66..33..22 DDoowwnnlliinnkk PPhhyyssiiccaall CChhaannnneellss

The downlink physical channels are shown in Figure 33, and Figure 34 shows the principle frame

structure of the downlink DPCH (DPDCH and DPCCH).

Figure 33: WCDMA Downlink Physical Channels

Figure 34: Frame Structure for WCDMA Downlink DPCH

Common Pilot Channel(CPICH)

Primary CPICH

Downlink Physical Channels

Common Physical ChannelsDedicated Physical Channel

Secondary CPICH

Primary Common ControlPhysical Channel

(P-CCPCH)

Secondary Common ControlPhysical Channel

(S-CCPCH)

SynchronisationChannel

(SCH)

Physical Downlink Shared Channel

(PDSCH)

Acquisition IndicationChannel(AICH)

Page IndicationChannel(PICH)

Dedicated Physical Control Channel (DPCCH)

Dedicated Physical Data Channel (DPDCH)

TMUX

One radio frame, Tf = 10 ms

TPC NTPC bits

Slot #0 Slot #1 Slot #i Slot #14

Tslot = 2560 chips, 10*2k bits (k=0..7)

Data2Ndata2 bits

DPDCH

TFCI NTFCI bits

Pilot Npilot bits

Data1Ndata1 bits

DPDCH DPCCH DPCCH


Page: 53


The dedicated channels (DPDCH and DPCCH) are time multiplexed. The EMC problem caused

by discontinuous transmission is not considered difficult in downlink since (i) there are signals to

several users transmitted in parallel and at the same time and (ii) base stations are not so close to

other electrical equipment, like hearing aids.

In the downlink, time multiplexed pilot symbols are used for coherent detection. Since the pilot

symbols are connection dedicated, they can be used for channel estimation with adaptive antennas

as well. Furthermore, the connection dedicated pilot symbols can be used to support downlink

fast power control. In addition, a common pilot time multiplexed in the BCCH channel can be

used for coherent detection.

The SCH consists of two subchannels, the primary and secondary SCHs. Figure 35 illustrates the

structure of the SCH. The SCH applies short code masking to minimize the acquisition time of

the long code [48]. The SCH is masked with two short codes (primary and secondary SCH). The

primary SCH is used to acquire the timing for the secondary SCH. The modulated secondary

SCH code carries information about the long code group to which the long code of the BS

belongs. In this way, the search of long codes can be limited to a subset of all the codes.

Figure 35: Structure of the synchronization channel (SCH)


Page: 54


The primary SCH consists of a modulated code of length 256 chips, which is transmitted once

every slot. The primary synchronization code is the same for every base station in the system and

is transmitted time aligned with the slot boundary, as illustrated in Figure 35.

The secondary SCH consists of one modulated code of length 256 chips, which is transmitted in

parallel with the primary SCH. The secondary synchronization code is chosen from a set of 16

different codes depending on to which of the 32 different code groups the base station downlink

scrambling code csc belongs. The secondary SCH is modulated with a binary sequence of length

16 bits, which is repeated for each frame. The modulation sequence, which is the same for all

base stations, has good cyclic autocorrelation properties. The multiplexing of the SCH with the

other downlink physical channels (DPDCH / DPCCH and CCPCH) is illustrated in Figure 36.

Figure 36: Multiplexing of the SCH (sp = primary spreading code; sc = secondaryspreading code; cch = orthogonal code; csc = long scrambling code).


Page: 55


The SCH is transmitted only intermittently (one code-word per slot), and it is multiplexed with the

DPDCH/DPCCH and CCPCH after long code scrambling is applied on DPDCH/DPCCH and CCPCH.

Consequently, the SCH is non-orthogonal to the other downlink physical channels.

6.4 More on W-CDMA technology

66..44..11 SSpprreeaaddiinngg

The WCDMA scheme employs long spreading codes. Different spreading codes are used for cell

separation in the downlink and user separation in the uplink. In the downlink, Gold codes of

length 218 are used, but they are truncated to form a cycle of a 10-ms frame. The total number of

available scrambling codes is 512, divided into 32 code groups with 16 codes in each group to

facilitate a fast cell search procedure. In the uplink, either short or long spreading (scrambling

codes) are used. The short codes are used to ease the implementation of advanced multiuser

receiver techniques; otherwise long spreading codes can be used.

For channelization, orthogonal codes are used. Orthogonality between the different spreading

factors can be achieved by the tree-structured orthogonal codes.

IQ/code multiplexing leads to parallel transmission of two channels, and therefore, attention must

be paid to modulated signal constellation and related peak-to-average power ratio (crest factor).

By using the complex spreading circuit shown in Figure 37, the transmitter power amplifier

efficiency remains the same as for QPSK transmission in general.

Moreover, the efficiency remains constant irrespective of the power difference G between

DPDCH and DPCCH. This can be explained with Figure 38, which shows the signal

constellation for IQ/code multiplexed control channel with complex spreading.


Page: 56


Figure 37: IQ/code multiplexing with complex spreading circuit

Figure 38: Signal constellation for IQ/code multiplexed control channel with complex spreading. G isthe power difference between DPCCH and DPDCH


Page: 57


In the middle constellation with G = 0.5 all eight constellation points are at the same distance

from the origin. The same is true for all values of G. Thus, signal envelope variations are very

similar to the QPSK transmission for all values of G. The IQ/code multiplexing solution with

complex scrambling results in power amplifier output backoff requirements that remain constant

as a function of power difference. Furthermore, the achieved output backoff is the same as for one

QPSK signal.

66..44..22 MMuullttiirraattee

Multiple services of the same connection are multiplexed on one DPDCH. Multiplexing may take

place either before or after the inner or outer coding, as illustrated in Figure 39.

Figure 39: Service multiplexing in WCDMA

After service multiplexing and channel coding, the multiservice data stream is mapped to one

DPDCH. If the total rate exceeds the upper limit for single code transmission, several DPDCHs

can be allocated.

A second alternative for service multiplexing would be to map parallel services to different

DPDCHs in a multicode fashion with separate channel coding/interleaving. With this alternative

scheme, the power, and consequently the quality of each service, can be separately and

independently controlled. The disadvantage is the need for multicode transmission, which will


Page: 58


have an impact on mobile station complexity. Multicode transmission sets higher requirements

for the power amplifier linearity in transmission, and more correlators are needed in reception.

For BER = 103 services, convolutional coding of 1/3 is used. For high bit rates a code rate of 1/2

can be applied. For higher quality service classes outer Reed-Solomon coding is used to reach the

106 BER level. Retransmissions can be utilized to guarantee service quality for non real-time

packet data services.

After channel coding and service multiplexing, the total bit rate can be almost arbitrary. The rate

matching adapts this rate to the limited set of possible bit rates of a DPDCH. Repetition or

puncturing is used to match the coded bit stream to the channel gross rate. The rate matching for

uplink and downlink are introduced below.

For the uplink, rate matching to the closest uplink DPDCH bit rate is always based on unequal

repetition (a subset of the bits repeated) or code puncturing. In general, code puncturing is chosen

for bit rates less than (20 percent above the closest lower DPDCH bit rate. For all other cases,

unequal repetition is performed to the closest higher DPDCH bit rate. The repetition/puncturing

patterns follow a regular predefined rule (i.e., only the amount of repetition/puncturing needs to

be agreed on). The correct repetition/puncturing pattern can then be directly derived by both the

transmitter and receiver side.

For the downlink, rate matching to the closest DPDCH bit rate, using either unequal repetition or

code puncturing, is only made for the highest rate (after channel coding and service multiplexing)

of a variable rate connection and for fixed-rate connections. For lower rates of a variable rate

connection, the same repetition / puncturing pattern as for the highest rate is used, and the

remaining rate matching is based on discontinuous transmission where only a part of each slot is

used for transmission. This approach is used in order to simplify the implementation of blind rate

detection in the mobile station.


Page: 59


66..44..33 PPaacckkeett DDaattaa

Figure 40 shows different types of packet data transmission possibilities.

Figure 40: WCDMA Packet Data Transmission

66..44..44 SSoofftt HHaannddoovveerr

Base stations in WCDMA need not be synchronized, and therefore, no external source of

synchronization, like GPS, is needed for the base stations. Asynchronous base stations must be

considered when designing soft handover algorithms and when implementing position location

services.

Reverse linkForward link

Medium Packets

CPCH/PCPCHN-max x 10msec Frame

150 bits @ 15kb/s (SF=256)9600 bits @ 960kb/s (SF=4)

DSCH/PDSCHN-max x 10msec Frame300 bits@ 30kb/s (SF=256)

19200 bits@ 1920kb/s (SF=4)

Short Packets

RACH/PRACH1 x 10msec Frame


FACH/SCCPCH1 x 10msec Frame

300 bits@ 30kb/s (SF=256)19080 bits @ 1920kb/s (SF=4)

Long Packets

DCH/DPCHN-max x 10msec Frame


DCH/DPCHN-max x 10msec Frame60 bits@ 15kb/s (SF=512)

18720 bits@ 1920kb/s (SF=4)


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Before entering soft handover, the mobile station measures observed timing differences of the

downlink dedicated channel of the current base station and the P-CCPCH of the target base

station. The mobile station reports the timing differences back to the serving base station. The

timing of a new downlink soft handover connection is adjusted with a resolution of one symbol

(i.e., the dedicated downlink signals from the two base stations are synchronized with an accuracy

of one symbol). That enables the mobile RAKE receiver to collect the macro diversity energy

from the two base stations. Timing adjustments of dedicated downlink channels can be carried

out with a resolution of one symbol without losing orthogonality of downlink codes.

66..44..55 IInntteerrffrreeqquueennccyy HHaannddoovveerrss

Interfrequency handovers are needed for utilization of hierarchical cell structures; macro, micro,

and indoor cells. Several carriers and interfrequency handovers may also be used for taking care

of high capacity needs in hot spots. Interfrequency handovers will be needed also for handovers

to second-generation systems, like GSM or IS-95. In order to complete interfrequency handovers,

an efficient method is needed for making measurements on other frequencies while still having

the connection running on the current frequency. Two methods are considered for interfrequency

measurements in WCDMA:

• Dual receiver

• Slotted mode

The dual receiver approach is considered suitable especially if the mobile terminal employs

antenna diversity. During the interfrequency measurements, one receiver branch is switched to

another frequency for measurements, while the other keeps receiving from the current frequency.

The loss of diversity gain during measurements needs to be compensated for with higher

downlink transmission power. The advantage of the dual receiver approach is that there is no

break in the current frequency connection. Fast closed loop power loop is running all the time.


Page: 61


Figure 41: Slotted mode structure

The slotted mode approach depicted in Figure 41 is considered attractive for the mobile station

without antenna diversity. The information normally transmitted during a 10-ms frame is

compressed time either by code puncturing or by changing the FEC rate.

66..44..66 IInntteerr--ooppeerraabbiill iittyy BBeettwweeeenn GGSSMM aanndd WWCCDDMMAA

The handover between the WCDMA system and the GSM system, offering worldwide coverage

already today, has been one of the main design criteria taken into account in the WCDMA frame

timing definition. The GSM compatible multiframe structure, with a superframe multiple of 120

ms, allows similar timing for intersystem measurements as in the GSM system itself. Apparently

the needed measurement interval does not need to be as frequent as for GSM terminal operating

in a GSM system, as intersystem handover is less critical from intra-system interference point of

view. Rather, the compatibility in timing is important that when operating in WCDMA mode, a

multimode terminal is able to catch the desired information from the synchronization bursts in the

synchronization frame on a GSM carrier with the aid of frequency correction burst. This way the

relative timing between a GSM and WCDMA carriers is maintained similar to the timing between

two asynchronous GSM carriers. The timing relation between WCDMA channels and GSM

channels is indicated in Figure 42 where the GSM traffic channel and WCDMA channels use

similar 120 ms multiframe structure.


Page: 62


Figure 42: Measurements timing relation between WCDMA and GSM frame structure

The GSM frequency correction channel (FCCH) and GSM synchronization channel (SCH) use

one slot out of the eight GSM slots in the indicated frames with the FCCH frame with one time

slot for FCCH always preceding the SCH frame with one time slot for SCH as indicated in the

Figure 42.

A WCDMA terminal can do the measurements either by requesting the measurement intervals in

a form of slotted mode where there are breaks in the downlink transmission or then it can perform

the measurements independently with a suitable measurement pattern. With independent

measurements the dual receiver approach is used instead of the slotted mode since the GSM

receiver branch can operate independently of the WCDMA receiver branch.

For smooth interoperation between the systems, information needs to be exchanged between the

systems, in order to allow WCDMA base station to notify the terminal of the existing GSM

frequencies in the area. In addition, more integrated operation is needed for the actual handover

where the current service is maintained, taking naturally into account the lower data rate

capabilities in GSM when compared to UMTS maximum data rates reaching all the way to 2

Mb/s.


Page: 63


The GSM system is likewise expected to be able to indicate also the WCDMA spreading codes in

the area to make the cell identification simpler and after that the existing measurement practises

in GSM can be used for measuring the WCDMA when operating in GSM mode.

As the WCDMA does not rely on any superframe structure as with GSM to find out

synchronization, the terminal operating in GSM mode is able to obtain the WCDMA frame

synchronization once the WCDMA base station scrambling code timing is acquired. The base

station scrambling code has 10-ms period and its frame timing is synchronized to WCDMA

common channels.

6.5 UTRA TDD

Wide-band CDMA TDD mode is one of technologies approved by the ITU to be included in theIMT-2000 family of systems concept.

66..55..11 TTrraannssppoorrtt cchhaannnneellss

A general classification of transport channels is into two groups:

• dedicated channels

• common channels

Dedicated transport channelsThe only type of dedicated transport channel is the Dedicated Channel (DCH) characterized by:

• possibility to use beam-forming,

• possibility to change rate fast (each 10ms),

• possibility to use enhanced power control and

• inherent addressing of MSs.

Common transport channelsCommon transport channels are:

1. Random Access Channel(s) (RACH)

2. Forward Access Channel(s) (FACH)

3. Broadcast Control Channel (BCCH)

4. Paging Channel (PCH)

5. Synchronization Channel (SCH)


Page: 64


66..55..22 PPhhyyssiiccaall cchhaannnneellss

A physical channel is defined as the association of one code, one time slot and one frequency.

Frame structureIn the following sections, an overview about the frame, time slot and code structure is outlined.

Time slotsThe TDMA frame has duration of 10 ms and is subdivided into 16 time slots (TS) of 625

µs duration each. A time slot corresponds to 2560 chips. The physical content of the time

slots is the bursts of corresponding

length.

TDD frameEach 10 ms frame consists of 16 time slots; each allocated to either the uplink or the

downlink (Figure 43). With such flexibility, the TDD mode can be adapted to different

environments and deployment scenarios. In any configuration at least one time slot has to

be allocated for the downlink and at least one time slot has to be allocated for the uplink.

Figure 43: The TDD frame structure

Spreading codesTwo options are being considered for the bursts that can be sent as described below. Both options

allow a highdegree of bit rate granularity and flexibility, thus allowing the implementation of the

whole service range from low to high bit rates.


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Multi-code transmission with fixed spreadingWithin each time slot of length 625 ms, an additional separation of user signals by

spreading codes is used. This means, that within one time slot of length 625 ms, more

than one burst of corresponding length can be transmitted. These multiple bursts within

the same time slot can be allocated to different users as well as partly or all to a single

user. For the multiple bursts within the same time slot, different spreading codes are used

to allow the distinction of the multiple bursts. The bursts as described in Section 0 are

designed in such a way, that up to 8 bursts could be transmitted within one time slot, if

the bursts are allocated to different users in the uplink. In the downlink or if several

bursts in the time slot are allocated to one single user in the uplink, even more than 8

bursts (e.g. 9 or 10) can be transmitted within one time slot.

Single code transmission with variable spreadingWithin each time slot of 625 ms:

• a mobile always uses single code transmission by adapting the spreading factor

as a function of the data rate. This limits the peak-to-average ratio of the

modulated signal and consequently the stress imposed to the power amplifier

resulting in an improved terminal autonomy. Several mobiles can be received in

the same time slot by the base station, they are separated by their codes and the

individual decoding can take profit of the joint detection.

• a base station should broadcast a single burst per mobile again by adapting the

spreading as a function of the data rate. High rate data transmissions, requiring

more than one timeslot per mobile, can be supported by terminals having the

processing power for joint detection on a single slot: the required throughput

occupies in a general way an integer number of slots plus a fraction of an extra

slot. Single burst transmission should occur in the integer number of slots, while

the extra slot can be occupied by a burst for the considered mobile plus extra

bursts for other mobiles, joint detection is only needed for this last time slot in

the considered mobile.


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Burst typesTwo options are being considered for the spreading.

Bursts for dedicated transport channelsTwo types of bursts for dedicated transport channels are defined: The burst type 1 and the

burst type 2. Both consist of two data symbol fields, a midamble and a guard period. The

burst type 1 has a longer midamble of 512 chips than the burst type 2 with a midamble of

256 chips. Because of the longer midamble, the burst type 1 is suited for the uplink,

where up to 8 different channel impulse responses have to be estimated. The burst type 2

can be used for the downlink and, if the bursts within a time slot are allocated to less than

four users, also for the uplink.

Thus the burst type 1 can be used for:

• uplink, independent of the number of active users in one time slot

• downlink, independent of the number of active users in one time slot

The burst type 2 can be used for

• uplink, if the bursts within a time slot are allocated to less than four users

• downlink, independent of the number of active users in one time slot

The data fields of the burst type 1 are 976 chips long, whereas the data fields length of

the burst type 2 are 1104 chips. The corresponding number of symbols depends on the

spreading factor, as indicated in Table 10 below. The guard period for the burst types

1and 2 is 96 chip periods long.

Table 10: Number of symbols per data field in bursts 1 and 2

Spreading Factor (Q) Number of symbols (N) per datafield in Burst 1

Number of symbols (N) per datafield in Burst 2

1 976 11042 488 552

4 244 2768 122 13816 61 69


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The burst type 1 and 2 are shown in Figure 44 and Figure 45 as below. The contents of

the traffic burst fields are described in Table 11 and Table 12.

Table 11: The contents of the burst type 1 fields

Chip Number(CN)

Length of fieldin chips

Length of fieldin symbols

Length of field inµµs

Contents of field

0 – 975 976 Cf. Table 7 238.3 Data symbols976-1487 512 125.0 Midamble

1488-2463 976 Cf. Table 7 238.3 Data symbols2464-2559 96 23.4 Guard period

Figure 44: Burst Structure of the burst type 1. GP denotes the guard period and CP the chipperiods.

Table 12: The contents of the burst type 2 fields

Chip Number(CN)

Length of fieldin chips

Length of fieldin symbols

Length of field inµµs

Contents of field

0 – 1103 1104 Cf. Table 7 269.55 Data symbols1104-1359 256 62.5 Midamble1360-2463 1104 Cf. Table 7 269.55 Data symbols2464-2559 96 23.4 Guard period

Figure 41: Burst structure of the burst type 2. GP denotes the guard period and CP the chip periods


Page: 68


The two different bursts defined here are well-suited for the different applications

mentioned above. It may be possible to further optimise the burst structure for specific

applications, for instance for unlicensed operation.

66..55..33 MMuullttiipp lleexxiinngg,, cchhaannnneell ccooddiinngg aanndd iinn tteerrlleeaavviinngg

In the UTRA-TDD mode, the total number of basic physical channels (a certain time slot one

spreading code on a certain carrier frequency) per frame is given by the maximum number of

time slots which is 16 and the maximum number of CDMA codes per time slot. This maximum

number of codes is 8 in case the different codes within one time slot are allocated to different

users in the uplink and is higher than 8 (e.g. 9 or 10) in the downlink or if several codes are

allocated to one single user in the uplink. The service classes given in the following represent

only a selection of all possibilities that are conceivable.

MultiplexingIn a same connection, multiple services could be treated with separate channel

coding/interleaving and mapping to different basic physical channels (slot/code), Figure 46 (a).

In this way QoS can be separately and independently controlled.

Figure 46: Service multiplexing (a)

A second alternative is time multiplexing at different points of the channel coding scheme, asshown in Figure 46 (b).


Page: 69


Figure 46: Service multiplexing (b)

After service multiplexing and channel coding, the multi-service data stream is mapped to one or,

if the total rate exceeds the upper limit for single-code transmission, several resource units.

Channel coding and interleavingIn Real Time (RT) services a FEC coding is used, instead Non Real Time (NRT) services could

be well managed with a proper combination of FEC and ARQ. For the RT services two levels of

QoS (10-3 , 10 -6 ) have been considered as examples in Figure 47.

Only convolutional coding is used in case of BER = 10-3 , while a concatenated code scheme

(Reed-Solomon, Outer Interleaving and Convolutional Coding) or Turbo Codes could be used to

achieve BER = 10 -6 .

Figure 47: FEC coding


Page: 70


Inner coding/interleavingThe convolutional coding rates change according to the rates of different services. The

convolutional coding rates from 1/4 to 1 have been chosen such that the complete system

will be able to use as much as possible the same decoding structure.

Outer coding/interleavingThe outer RS coding, on GF(28 ) has different rate for different services. An outer

interleaver to break the error burst at the output of the Viterbi decoder is needed in

addition to an inner interleaver for breaking the error bursts due to fading.

Rate matchingTo map the services on the air interface either puncturing or unequal repetition is used after

channel coding. This rate matching is performed considering both bursts:

• burst 1 (long midamble) used in uplink;

• burst 2 (short midamble) used in downlink as well as for uplink transmission in the case

of multi-code transmission.

66..55..44 SSpprreeaaddiinngg aanndd mmoodduullaattiioonn

There has been made a separation between the data modulation and the spreading modulation

(Table 13).

Table 13: Basic modulation parameters

Chip Rate Same as FDD basic chiprate:4.096 Mchip/s

Carrier Spacing 5.0 MHzData Modulation QPSKChip Modulation Same as FDD chip modulation:

Root-Raised-CosineRoll-Off α = 0.22

Spreadingn Characteristics OrthogonalQ chips/symbol, where

Q = 2p, 0 <= p <= 4


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Data modulationSymbol rateThe symbol rate and duration are indicated below.

Ts = Q ∗ Tc , where Tc = 1 / chiprate = 0.24414µs, reflecting the dependence of the

symbol time Ts upon the spreading factor Q.

Pulse shape filteringThe pulse shape filtering is applied to each chip at the transmitter. The impulse

response of the above mentioned chip impulse filter shall be a root raised cosine.

The roll-off factor shall be α = 0.22. TC is the chip duration, Tc = 1 / Chip rate =

0.24414µs.

Spreading modulationOrthogonal Variable Spreading Factor (OVSF) codes are used that allowing mixing in

the same timeslot channels with different spreading factors while preserving the

orthogonality. A code can be used in a timeslot if and only if no other code on the path

from the specific code to the root of the tree or in the sub-tree below the specific code is

used in this timeslot. This means that the number of available codes in a slot is not fixed

but depends on the rate and spreading factor of each physical channel. The spreading

factor goes up to 16.

66..55..55 RRaaddiioo ttrraannssmmiissssiioonn aanndd rreecceeppttiioonn

Proposed frequency bands for operationUTRA/TDD is designed to operate in any frequency band that will accommodate at least one

4,096 Mcps carrier.

Carrier rasterThe channel raster is 200 kHz.

Tx - Rx Frequency SeparationTx and Rx are not separated in frequency.


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Output power dynamicsThe transmitter uses fast closed-loop carrier/interference based power control and slow quality

based power control on both the up- and downlink. The step size is variable and in the range 1.5

to 3 dB with 100-800 steps/s. The power control dynamic is 80 dB on the uplink and 30 dB on the

downlink.

66..55..66 PPhhyyssiiccaall llaayyeerr pprroocceedduurreess

Synchronization of the TDD base stationsIt is required that BTS supporting the TDD mode, are operated in synchronised mode, so far the

coverage area of the cells are overlapping, i.e. we have contiguous coverage for a certain area.

The nature of the TDD operation requires BTS frame synchronisation, to achieve good spectral

efficiency. The fact that MS and BTS are receiving and transmitting on the same frequency

makes it desirable, that in the reuse cell the same TX / RX timing get used. The lack of a frame

synchronisation can cause, depending on the actual time slip, interference events that will effect

several time slots.

Channel AllocationFor the UTRA-TDD mode, a physical channel is characterised by a combination of its carrier

frequency, time slot, and spreading code. Channel allocation covers both:

• resource allocation to cells (slow DCA)

• resource allocation to bearer services (fast DCA)

Resource allocation to cells (slow DCA)Channel allocation to cells follows the rules below:

• A reuse one cluster is used in the frequency domain. In terms of an

interference-free DCA strategy a timeslot-to-cell assignment is performed,

resulting in a time slot clustering.

• Any specific time slot within the TDD frame is available either for uplink or

downlink transmission.


Page: 73


• In order to accommodate the traffic load in the various cells, the assignment of

the timeslots (both UL and DL) to the cells is dynamically (on a coarse time

scale) rearranged (slow DCA) taking into account that strongly interfering cells

use different timeslots.

Resource allocation to bearer services (fast DCA)Fast channel allocation refers to the allocation of one or multiple physical channels to any

bearer service Resource units (RUs) are acquired (and released) according to a cell-

related preference list derived from the slow DCA scheme.

Power ControlPower control is applied for UTRA/TDD to limit the interference level within the system thus

reducing the inter-cell interference level and to reduce the power consumption in the MS.

As mandatory power control scheme, a slow C-level based power control scheme (similar to

GSM) is used both for up- and downlink. Power control is made individually for each resource

unit (code) with the following characteristics as indicated in Table 14:

Table 14: Power Control characteristics

Uplink DownlinkDynamic Range 80 dB 30 dBPower Control Rate Variable; 1-800 cycles / second Variable; 1-800 cycles / secondStep Size 1.5 … 3 dB 1.5 … 3 dB

Remarks A cycle rate of 100 means that everyframe the power level is controlled

Within one timeslot the powers of allactive codes are balanced to be within arange of 20 dB


Page: 74


66..55..77 AAddddiitt iioonnaall ffeeaa ttuurreess aanndd ooppttiioonnss

Joint detectionJoint detection of simultaneously active CDMA codes in the uplink as well as the downlink will

already be performed in the introductory phase of the UTRA TDD mode.

Adaptive antennasIn the UTRA TDD-component, adaptive antennas are supported through the use of connection

dedicated midamble sequences in both uplink and downlink (optional in the downlink). Although

the UTRA TDD component does not require the use of smart antennas, the resulting signal-to-

interference-plus-noise-ratio (SINR) can significantly be improved by incorporating various

smart antenna concepts at the base station on the uplink as well as the downlink.

Downlink transmit diversityDownlink transmit diversity is supported by the UTRA TDD mode.

Positioning function supportThe fact that the base stations in a local area are synchronised facilitates the implementation of

mobile positioning algorithms in the UTRA TDD mode. Time delay or delay difference

measurements to the base stations are obtained in a very efficient fashion. They are required as

input for mobile positioning algorithm.

Relaying and ODMAThe UTRA TDD mode is a suitable platform for the support of relaying which is a widely used

technique for radio packet data transmission both in commercial and military systems.

The UTRA TDD design is sufficiently flexible to support both simple relaying and advanced

relaying protocols such as Opportunity Driven Multiple Access (ODMA) with negligible increase

to the MS complexity or cost.


Page: 75


7. Comparison of CDMA2000 with UTRA (FDD & TDD)

In the battle to set a global standard for mobile communications, there are several competing

solutions based on CDMA technology. The differences between them often have historical

origins and are intended to enable the new systems to interwork with existing systems on today's

frequency bands. The principal contenders are a direct sequence wide-band CDMA solution that

is supported by Ericsson, Nokia and several other European system suppliers and DS/multi-

carrier cdma2000, which both derive from the IS-95 world.

In principle, multi-carrier cdma2000 is identical to DS-cdma2000. The difference is that the

multi-carrier technique employs several frequencies in the downlink to the mobile terminal,

allowing a mixture of IS-95 traffic using the narrowband carrier and cdma2000 traffic using the

full multi-carrier, which improves compatibility with IS-95. The uplink, however, is wide-band,

just as in W-CDMA. The requirement that cdma2000 systems should be backward-compatible

with IS-95 dictated a number of design decisions. To be completely compatible with IS-95, DS-

cdma2000 will employ a chip rate of 3 x 1.2288, or 3.6864 Mcps.

Incidentally, the multi-carrier technique is a good solution for migration of IS-95. All traffic can

be mixed, since the signals from the base station to the mobile units can be synchronized, and so-

called orthogonal codes can be used to reduce interference within each cell. Because

synchronization is not possible on the uplink, Using a multi-carrier in that direction is therefore

pointless. Instead, both IS-95 and cdma2000 traffic are transmitted on the same 5 MHz broadband

channel.

7.1 Major Technical Differences between cdma2000 & W-CDMA

77..11..11 TThhee CChhiipp rraattee

The chip rate is closely linked to the bandwidth and is determined in principle by how tightly the

carriers are packed. W-CDMA uses 4.096 Mcps ( or the compromised 3.84 Mcps), while DS-

cdma2000 uses 3.6864 Mcps. A higher speed means that a given number of users can obtain


Page: 76


higher transfer rates or that the operator can support more users for a given level of performance,

but there are trade-offs.

High bandwidth provides higher performance, but reduces opportunities for flexible utilization of

the allocated frequency, while complicating the design and making it more dependent on faster

signal processing. Also, The closer to 5 Mcps the system operates, the greater will be the leakage

into the neighboring channel, making sharper filters necessary to eliminate interference.

77..11..22 BBaassee ssttaattiioonn ssyynncchhrroonniizzaattiioonn

WCDMA does not require GPS synchronization – it employs a technique such that different

sequences are transmitted, each one unique for a given base station, thus supporting a system

without synchronization. But this synchronization function can be added if it is required by the

operator. Eliminating the requirement for GPS synchronization is an advantage in cases where the

base station site has poor GPS coverage.

On the other hand, the IS-95 system has strict requirements for synchronization, which will also

be necessary for cdma2000. Each base station in IS-95 and cdma2000 systems is therefore

equipped with a GPS receiver. In an IS-95 system, all base stations continuously transmit the

same pre-defined sequence that enables the mobile units to locate cells, identify new base stations

and establish connections. In order to enable mobile units to identify base stations and distinguish

between cells, signals are shifted in time by a constant value. This requires strict synchronization,

which is why a GPS receiver is needed.

77..11..33 CCoommppaattiibbiilliittyy wwiitthh dd iiffffeerreenntt CCoorree NNeettwwoorrkkss

W-CDMA standard is compatible with GSM-MAP, protocol which is GSM’s core network

protocol, and Evolved GSM-MAP. It will eventually be compatible with GPRS/All IP core

network. On the other hand, cdma2000 standard is compatible with ANSI-41 and Evolved ANSI-

41. However, compatibility with both core network protocols has been required by Family of

Systems concept approved by ITU


Page: 77


77..11..44 MMuullttii --ccaarrrriieerr vvss DDiirreecctt SSeeqquueennccee

cdma2000 uses a multi-carrier scheme for downlink which was described in previous chapters.

W-CDMA uses a single carrier direct sequence technique for downlink. Although different in

some parameters, both standards use direct sequence technique for uplink.

The advantage of multi-carrier scheme is the backward compatibility with existing CDMA

system, IS-95. While it has been claimed that the direct sequence wide-band scheme is more

spectrally efficient. Different investigations have indicated that the performance of the two systems are

quite similar.

77..11..55 PPiilloott cchhaannnneell ffuunncctt iioonnaalliittyy

This information is used to measure the radio link characteristics, multi-path dispersion, etc. The

W-CDMA system is based on a dedicated pilot, which uses a different sequence for each mobile

unit, while cdma2000, like IS-95, is based on a common pilot.

W-CDMA uses a time-multiplexed pilot signal, in which the pilot is transmitted first, followed by

the data, while cdma2000 transmits two different codes simultaneously. Both techniques offer

roughly equal performance.


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7.2 cdma2000 and UTRA (FDD, TDD) specificationscomparison

Some key technical differences between UTRA FDD and TDD modes with cdma2000 is

presented in Tables 15 and 16.

Table 15: Key Technical Differences between ETSI UTRA W-CDMA (FDD Mode) and cdma2000

W-CDMA (FDD Mode) cdma2000Multiple Access DS-CDMA DS-CDMA or multi-carrier CDMA

BandWidth 5MHz(10/20)

3.75MHz (1.25 x N times, N=3)Other bandwidth (1.25 x N, N=1, 6, 9,12)

Chip Rate 4.096Mcps(8.192/16.384)

3.6864Mcps (1.2288 x N, N=3)(Other chip rates: N x 1.2288, N=1, 6,9, 12)

Inter BS timing Asynchronous(Sync. Possible)

Synchronous

Frame Length 10ms Dedicated control channel andfundamental channel: 5, 20msCommon control channel: 5, 10, 20msSupplemental channel: 20ms

Handoff Soft-Handoff Soft-Handoff

Data Mod. QPSK QPSK

Spreading Mod. QPSK QPSKTCH dedicated Pilot Symbol Common Pilot Symbols / Auxiliary PLPilot StructureTime multiplexed Code Multiplexed

DL

Power Control Closed-loop based on dedicated CHSIR: 1.6kbps

Closed-loop based on fundamental CHor DCCH SIR: 0.8kbps

Data Mod. BPSK BPSK

Spreading Mod. QPSK QPSK

Pilot Structure IQ Multiplexed IQ / Code Multiplexed

Detection Pilot based Coherent Pilot Based CoherentUL

Power Control Open-loop (initial, RACH), Closed-loop (1.6kbps DCH SIR based)

Open-loop + Closed-loop(0.8kbps Pilot CH SIR based)

Channel Coding Convolutional CodesRS CodesTurbo Codes

Convolutional CodesTurbo Codes

Interleaving Periods 10/20/40/80ms 5/20ms


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Table 16: Key Technical Differences between ETSI UTRA W-CDMA (TDD Mode) and cdma2000

W-CDMA (TDD Mode) cdma2000Multiple Access TDMA/CDMA DS-CDMA or multi-carrier CDMA

BandWidth 5MHz 3.75MHz (1.25 x N times, N=3)Other bandwidth (1.25 x N, N=1, 6, 9,12)

Chip Rate 4.096Mcps 3.6864Mcps (1.2288 x N, N=3)(Other chip rates: N x 1.2288, N=1, 6,9, 12)

Inter BS Sync. Synchronous Synchronous

Cell Search Scheme SCH in Beacon Slot(1 slot per 240ms)

Pilot Channel

Frame Length 10ms Dedicated control channel andfundamental channel: 5, 20msCommon control channel: 5, 10, 20msSupplemental channel: 20ms

VSF (SpreadingCode)

2-16 For N=3DL: 4-128 depending on channel type(Fund, Suppl), Rate set (RS-1, RS-2)and bit rateUL: 2, 4 or 8 + repetition (SF dependson channel type and number ofsupplemental channels butindependent of chip rate and bit rate)

For other NDL: 4-256 (N=6), 4-512 (N=9), 4-512(N=12)UL: same as for N=3

Handoff Hard-Handoff Soft-Handoff

Data Mod. QPSK QPSK

Spreading Mod. QPSK QPSK

Spreading Code 1 Symbol Length 1 Symbol Length

ScramblingCode

1 Symbol Length 215 x N chips (26.6ms)

TCH dedicated Pilot Symbol Common Pilot Symbols / Auxiliary PLPilot StructureTime multiplexed Code Multiplexed

Detection Coherent based on MidambleSymbols

Coherent based on Pilot Channel

Power Control Closed-loop (0.1-0.02k cycles/sec) Closed-loop (0.8kbps Fund. CH SIRbased)

DL

Variable rateconcept

Orthogonal VSF + VTS + VMC +DTX

Orthogonal VSF + Repetition


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Data Mod. QPSK BPSK

Spreading Mod. QPSK OQPSK

Spreading Code 1 symbol length 1 symbol length

ScramblingCode

1 symbol length (Cell Specific) 242 – 1 chips

Pilot Structure Time multiplexed (Midamble forJoint Detection)

IQ / Code Multiplexed

Detection Coherent based on MidambleSymbols

Pilot Based Coherent

Power Control Open-loop (initial),Closed-loop (0.1-0.02k cycles/sec)

Open-loop + Closed-loop(0.8kbps Pilot code SIR based)

UL

Variable RateConcept

VSF + VTS (Time Slot) + VMC Rate Matching(Repetition/Puncturing)

Channel Coding Convolutional CodesRS CodesTurbo Codes

Convolutional CodesTurbo Codes

Interleaving Periods 10/20/40/80ms 5/20ms

Rate Detection Not clearly defined in the UTRAproposal (Negotiation by MACLayer)

Fundamental CH: BlindSupplemental CH: No BlindDetection for rate > 14.4kbps

Other Features Joint Detection is requiredDCA is required

Multi-Carrier (DL)Auxiliary Pilots (DL)Orthogonal Tx diversity (OTD)

Random Access RACH specific slot Preamble (N x 1.25ms) + Message (Nx 5 (10, 20)ms)

Super Frame Length 240ms (multi-frame) N/A

7.3 Comparison of cdma2000 and UTRA Evaluation Reports

Table 17 presents a comparison of cdma2000 and W-CDMA Evaluation Reports published by thestandard organizations and proponents of the relevant proposals [29], [30].


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Table 17: cdma2000 and W-CDMA Evaluation Reports’ comparison

COMMENTSISSUES OF INTERESTS

W-CDMA (ETSI UTRA) Cdma2000

SPECTRUM EFFICIENCY:

VOICE TRAFFIC CAPACITY

(Erlangs/MHz/cell) in a totalavailable assigned non-contiguousbandwidth of 30 MHz (15 MHzforward/15 MHz reverse) for FDDmode or contiguous bandwidth of30 MHz for TDD mode.

Key assumptions:(i) GoS: 1% blocking(ii) a common generic continuousvoice bearer with characteristics 8kbit/s data rate and an averageBER 1 x 10 –3

Simulation Results for FDD Mode

Indoor EnvironmentUplink: 33.8 Erlangs/MHz/cellDownlink: 18.4 Erlangs/MHz/cell

Pedestrian EnvironmentUplink: 30.8 Erlangs/MHz/cellDownlink: 31.4 Erlangs/MHz/cell

Vehicular EnvironmentUplink: 22.4 Erlangs/MHz/cellDownlink: 17.8 Erlangs/MHz/cell

Voice traffic capacity (at 9.6 Kbps)[Erlangs/MHz/cell]

Indoor EnvironmentUplink: 34.2 (Omni-cell), 82.1 (3-Sector)Downlink: 32.3 (Omni-cell), 79.7 (3-Sector)

Pedestrian EnvironmentUplink: 33.5 (Omni-cell), 80.4 (3-Sector)Downlink: 34.7 (Omni-cell), 83.3 (3-Sector)

Vehicular EnvironmentUplink: 29 (Omni-cell), 69.6 (3-Sector)Downlink: 36.7 (Omni-cell), 88.1 (3-Sector)

INFORMATION CAPACITY Simulation Results for FDD Mode[Mbits/MHz/cell]

Vehicular Environment 76.8kbps LONG DELAY DATA


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(Mbit/s/MHz/cell) in a totalavailable assigned non-contiguousbandwidth of 30MHz (15 MHzforward / 15 MHz reverse) forFDD mode or contiguousbandwidth of 30 MHz for TDDmode.

The information capacity is to becalculated for each test service ortraffic mix for the appropriate testenvironments. This is the onlymeasure that would be used in thecase of multimedia, or for classesof services using multiple speechcoding bit rates. Informationcapacity is the instantaneousaggregate user bit rate of all activeusers over all channels within thesystem on a per cell basis.

(N.B. for cdma2000 informationcapacity evaluation, the followingFER targets were used for thevarious simulated data rates: )

SPEECH SERVICE Indoor Environment (3km/h) Uplink: 0.135 Downlink: 0.074 Pedestrian Environment Uplink: 0.123 Downlink: 0.125 Vehicular Environment Uplink: 0.090 Downlink: 0.071

LCD SERVICE Indoor Evironment (3km/h): 2048kbps Uplink: 0.176 Downlink: 0.047 Pedestrian Environment: 384kbps, using 4 code sets Uplink: 0.269 Downlink: 0.461 Vehicular Environment : 144kbps, uing 2 code sets Uplink: 0.208 Downlink: 0.210

UDD SERVICE Indoor Environment(3km/h): 2048kbps, using 2 code sets Uplink: 0.273 Downlink: 0.453 Pedestrian Environment: 384kbps, using 2 code sets Uplink: 0.449 Downlink: 0.668 Vehicular Environment: 144kbps Uplink: 0.202

Uplink: 0.212 (Omni-cell), 0.509 (3-Sector) Downlink: 0.134 (Omni-cell), 0.322 (3-Sector)

153.6kbps LONG DELAY DATA Uplink: 0.197 (Omni-cell), 0.473 (3-Sector) Downlink: 0.078 (Omni-cell), 0.187 (3-Sector)

Pedestrian Environment 76.8kbps LONG DELAY DATA Uplink: 0.264 (Omni-cell), 0.634 (3-Sector) Downlink: 0.140 (Omni-cell), 0.336 (3-Sector)

460.8kbps LONG DELAY DATA Uplink: 0.215 (Omni-cell), 0.516 (3-Sector) Downlink: 0.055 (Omni-cell), 0.132 (3-Sector)

Indoor Environment 76.8kbps LOW DELAY DATA Uplink: 0.226 (Omni-cell), 0.542 (3-Sector) Downlink: 0.73 (Omni-cell), 0.175 (3-Sector)

(N.B. Capacity estimates for long delay data assume soft-handoff.)


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Downlink: 0.290

Simulation Results for TDD Mode[Mbits/s/MHz/cell]

SPEECH SERVICE Indoor Office: 0.073 Outdoor to Indoor, Pedestrian: 0.148 Vehicular: 0.070

LCD SERVICE (with Antenna Diversity) Indoor Office(2048kbps): 0.062 Outdoor to Indoor, Pedestrian (384kbps): 0.330 Vehicular (144kbps): 0.201

UDD SERVICE (with Antenna Diversity) Indoor Office(2048kbps): 0.400 Outdoor to Indoor, Pedestrian (384kbps): 0.642 Vehicular (144kbps): 0.320

(N.B. Since it has been found that the system capacity islimited by the downlink case, only the downlink directionis considered.)

NEED FOR ECHO CONTROL

The need for echo control isaffected by the round trip delay.

(N.B. The delay of the codecshould be that specified by ITU-T

Echo Control is required in the Mobile Station.

It is not necessarilly required in the fixed network.

It is required towards the PSTN.

This delay varies depending on vocoder used. Thefollowing delay budget assumes EVRC is used. Typical upreverse/uplink delays are shown (forward/downlink resultsare comparable)

Delay (ms)Mobile Station


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for the common generic voicebearer and if there are anyproposals for optional codecs,include the information about thosealso.)

Vocoder delay 33.0 Vocoder processing 10.0 Channel processing 2.0

Air Transission Frame Trans. Time 20.0

Base Station Channel processing 2.0 Viterbi decoding 1.6 Vocoder Speech Generation 1.0Total Delay 69.6ms

Delay without Vocoder is 25.6 ms.

Delay specified above is one way delay.

Approximate round trip delays can be estimated bydoubling the numbers provided. Echo control is needed forvoice services.


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PEAK TRANSMITTED /CARRIER(Pb) POWER

Peak transmitter power for the BSshould be considered becauselower peak power contributes tolower cost. Note that Pb may varywith test environment application.

The RTT itself does not impose any constraints on the peaktransmitter / carrier power.

Limitations may come from Regulation

The RTT itself doesn not impose any constraints on thepeak transmitter / carrier power.

BS power levels are subject to radio regulatory agencies(e.g., the FCC in the Unite States)

There are expected to be less than a total EIRP of 1640 Win transmit bandwidth and a maximum total power of100W.

The maximum total transmitter power at the BS used in thelink budget calculation is 47 dBm.

MS are expected to be of five power classes: Class I: 28 dBm < EIRP < 33 dBm Class II: 23 dBm < EIRP < 30 dBm Class III: 18 dBm < EIRP < 27 dBm Class IV: 13 dBm < EIRP < 24 dBm Class V: 8 dBm < EIRP < 21 dBm

CHANNEL CODING / ERRORHANDLING FOR BOTH FORWARD

AND REVERSE LINKS

Default: Convolutional inner code (rate 1/3 or rate 1/2, constraint length K = 9)

Optional outer Reed-Solomon code for BER = 1 x 10-6

Circuit-Switch Services.

The use of Turbo Codes for high-rate services is underconsideration and will most likely be adopted.

Forward Link (Downlink)

–– 6-bit, 8-bit, 10-bit, 12-bit, or 16-bit CRC frame error checking;

–– 9/16, 1/2, 1/3, 1/4 rate, K = 9 convolutional coding (other derived rates obtained via puncturing)


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Special FEC schemes, e.g. unequal error protection can beapplied.

–– Equivalent rate Turbo Codes with K = 4 for Supplemental Channels; 20ms and 5ms interleaving

Reverse Link (Uplink)

–– 6-bit, 8-bit, 10-bit, 12-bit, or 16-bit CRC frame error checking;

–– 9/16, 1/2, 1/3, 1/4 rate, K = 9 convolutional coding

–– Equivalent rate Turbo Codes with K = 4 for Supplemental Channels;

–– 20ms and 5ms interleaving;

Each Supplemental Channel may use different codingschemes.

DIVERSITY SCHEMES

(e.g. micro and macro diversityschemes)

Time DiversityChannel coding and interleaving in both uplink anddownlink.

Multipath DiversityRAKE receiver, Joint Detection or similar receiverstructures with, typically, maximum ratio combining is usedin both BS and MS (implementation dependent).

Space DiversityReceive antenna diversity with, typically, maximum ratiocombining can be used in both uplink and downlink.Transmit antenna diversity is under consideration for

Time DiversitySymbol interleaving and error coding and correction.

Multipath DiversityRAKE receiver

Space DiversityBS uses 2 antennas;MS antenna diversity is optional

Orthogonal Transmit DiversityCan be used on the forward link


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downlink.

Macro DiversitySoft (inter-site) handover with, typically, maximum rationcombining in downlink, selection combining in uplink.Softer (inter-sector) handover with, typically, maximumratio combining in both uplink and downlink.

Frequency DiversityWideband Carrier (equivalent to multi-path diversity)

Improvement due to DiversityFor receiver antenna diversity, the diversity gain is 2.5-3.5dB in required Eb/No for BER = 10-3. If power controlis disabled, the gain is much higher for the low speed cases.On top of the gain in reduced Eb/No there is a gain indecreased transmitted power. This gain can be up to 2.5dB,depending on the environment.

Transmit Diversity can also be employed, especially in thedownlink. A gain similar to the gain with receiver antennadiversity is expected.

All other diversity methods are inherent parts of the RTTconcept and therefore it is difficult to specify an explicitdiversity gain figure in dB.

Frequency Diversity1.2288, 3.686, 7.3728, 11.0592, or 14.7456 MHz spreading

Delay Transmit DiversityMay be employed for both Multi-carrier and Direct Spreaddeployments.

Diversity combiningEither maximum ratio or equal gain combining may be usedwith multiple RAKE fingers.

Minimum number of demodulators / receivers1 per MS2 per BS

Minimum number of antennas1 per MS (antenna diversity is optional)2 per BS

Overall Performance Improvement due to DiversityA function of situation, typically up to 10dB for 1% FER.

BS FREQUENCYSYNCHRONIZATION/TIME

ALIGNMENT REQUIREMENTS

FDD ModeBS-BS synchronization is not required.

TDD Mode

BS-to-BS synchronization is required.

The synchronization requirements are:–– Short-term timing accuracy = ± 10us


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Time slot synchronization is recommended to decrease theeffort for neighbour cell interference suppression. Framesynchronization is recommended to speed up listening ofneighbour cell beacon information.

–– Short-term frequency accuracy = 0.05ppm–– Base-to-Base bit time alignment over a 24 hour period = ±10us

The mobile station corrects its reference frequency andadjusts it to that of the BS during acquisition and operationby using the continuous common pilot.

The BS-to-BS Synchronization allows:–– Fast acquisition;–– Simplified, faster and more reliable hand off procedures;–– Improved emergency position localization;–– Increased capacity and reliability by allowing common channels to be in soft handoff;–– Use of a poorly synchronized network (developping coutries, etc.);

The number of users per RFcarrier/frequency channel

supported by the RTT

(This can affects overall cost –especially as bearer trafficrequirements increase orgeographic traffic density varieswidely with time.)

FDD Mode

There are a maximum of 256 orthogonal downlink channelsavailable, some of which must be allocated for downlinkcommon transport channels. This leaves approximately 250orthogonal channels for user traffic, such as voice.Normally, the cell capacity is interference limited, i.e. theactual number of voice channels is lower than this number(exact number of voice channels depends on operationalconditions). Uplink is never limited by the number oforthogonal code channels, as the orthogonal code tree usedis user-specific in the uplink. In some cases, e.g. for thecase when adaptive antennas are used, the number of voice

For a 5MHz deployment, 253 Walsh codes (and thus anequal number of channels) are available for voice per BSsector. This result can be scaled accordingly for the numberof sectors used for a particular BS.

The maximum number of user channels for voice traffic indifferent environments are:–– Vehicular : 109–– Pedestrian : 118–– Indoor : 112

(N.B. Worst case numbers between channel-A and channel-B are chosen as required per ITU-R M.1225.)


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channels per cell can be increased above 250 by applyingmultiple non-orthogonal code sets on the downlink.

The simulation results are:–– Vehicular A : 85–– Pedestrian A: 154 (2 code sets are considered)–– Indoor A : 85

TDD Mode

There are a maximum of 128 orthogonal downlink channelsavailable, some of which are allocated for downlinkcommon transport channels. This leaves approximately 120orthogonal channels for user traffic. The reason why themaximum number of channels in TDD is only 50% of thatin FDD is the Uplink/Downlink sharing of one 5MHzcarrier in TDD mode.

HANDOVER COMPLEXITY FDD Mode

The handover scheme is based on a mobile assistedsoft/softer handover mechaniksm and hard handover.

The mobile station (MS) monitors the pilot signal levelsreceived from neighbouring base stations and reports to thenetwork those pilots crossing or above a given set ofdynamic thresholds. Based on this information the networkorders the MS to add or remove pilots from its Active Set.The Active Set is defined as the set of base stations forwhich user signal is simultaneously demodulated and

Various types of handover are supported

–– Soft Handover between neighboring CDMA base stations on the same frequency.

Soft handover results in increased coverage range on thereverse link (uplink). This soft handover mechanism resultsin seamless handover without any disruption of service.

The spatial diversity obtained reduces the frame error ratein the handover regions and allows for improvedperformance in a difficult radio environment.


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coherently combined.

The same user information modulated by the appropriatebase station code is sent from multiple base stations.Coherent combining of the differernt signals from differentsectored antennas, from different base stations, or from thesame antenna but on different multiple path components isperformed in the MS by the usage of RAKE receivers.

Base stations with which the mobile station is in softhandover, process the signal transmitted by a mobilestation. The received signal from different sectors of a basestation (cell) can be combined in the base station, and thereceived signal from different base stations (cells) can becombined at the radio network controller. Soft handoverresults in increased coverage range on the uplink. This softhandover mechanism results in truly seamless handoverwithout any disruption of service.

The obtained spatial diversity reduces the frame error ratein the handover regions and allows for improvedperformance in difficult radio environment.

Furthermore, the RTT supports various types of hardhandover, e.g. inter-frequency handover. The measurementsto detect other available carriers are made possible throughthe use of measruement slots.

TDD Mode

TDD provides two different handover mechanismsdepending on the service type: connection oriented or

–– Hard Handover between CDMA base stations on different frequencies.–– Hard Handover CDMA to other bandwidths or technologies.–– Mobile Assisted Handover (MAHO) is supported.

The Supplemental Channel Handover does not necessarilyuse the complete Active Set of the Fundamental Channel.The optimal policy varies with channel conditions.


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packet services.

For connection oriented services, the basic HO scheme is amobile assisted, network evaluated and decided hardhandover using backward signalling. Appropriate measuresare provided to accelerate the HO procedure, e.g. in case ofa corner effect. Furthermore, the proposed RTT does notprevent the introduction of soft handover, which is forfurther study.

For packet services, the basic HO scheme is a mobileevaluated and decided hard handover with backgroundnetwork control using forward signalling (cell reselection).

Potential advantages:–– Seamless HO for connection oriented, loss-less HL for packet bearer services–– Mobile assisted network evaluated and decided handover scheme is most appropriate for RT services since it allows for both high flexibility in HO-algorithm design and implementation, e.g. to meet operator specific requirements in various deployment scenarios and system stability at high capacity.–– Mobile evaluated and decided handover with network background control is most appropriate for packet services since it allows for both resource savings on the air interface by decentralised decision making and system integrity at high capacity by network co- ordinating measures.

SYSTEM OVERLOAD FDD Mode System overload causes graceful degradation of the system.


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PERFORMANCE

(Evaluate the effect on systemblocking and quality performanceon both the primary and adjacentcells during an overload condition,at e.g. 125%, 150%, 175%, 200%and also any other effects of anoverload condition.)

Overload causes graceful degradation of systemperformance, e.g. by decreasing the speech codec bit rate orincreasing the BER.

An additional mechanism of handling overload conditionsis Cell-Breathing . Under overload conditions, theincreased interference will lead to a smaller boundary.Users near the boundary area will be handled over theadjacent, hopefully less loaded cells.

TDD ModeUnder overload conditions, DCA (Dynamic ChannelAllocation) can be used to increase the allocated resourcesto the overloaded cell at the expense of capacity loss in the neighbouring cells.

The technique called “Cell-Breathing” can be applied toreduce blocking on the overloaded cell and to minimize itsimpact on the system. When a particular cell is overloadedits reverse link interference level increases. The effectivereverse link range of the cell is reduced due to powerconstraints in the mobile station. By adjusting the forwardlink power accordingly, a mobile station at the border of theoverloaded cell will naturally and gracefully handoff toadjacent cells. This will reduce the effective coverage of theoverloaded cell and reduce its interference.

An additional feature for managing and improving the QoSfor high load conditions is the variable rate voice codec.The codec bit rate will drop to improve the coverage orrange as necessary during high loading conditions.

HANDPORTABLE PERFORMANCE:

ISOLATION BETWEENTRANSMITTER AND RECEIVER

(This has an impact on the size andweight of the handportable)

FDD ModeA duplexer is required. Required transmitter / receiverisolation is 50 dB.

TDD ModeNo duplexer is required.

� FDD: duplexer required in MS.

� TDD: no duplexer required.

Different requirements may apply for different MS classes.A typical Class II MS will require about 55dB of Tx to Rxisolation to be provided by the Rx Duplexer Filter.

A BS will require about 90 dB of Tx to Rx isolation. Thisincreased requirement is due to high effective BS powerand about 5 dB better noice figure in the receiver. This


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isolation could be provided from a combination of antennaspacing and Rx filtering.

AVERAGE TERMINAL POWEROUTPUT Po (mW)

(Lower power gives longer batterylife and greater operating time.)

FDD ModeActivity is 100% if a mobile operates a dedicated channel.For packet transmission on the common channels, smallerTX active cycles possible.

Average power outputs depend on the environment.Simulations where based in the following values:

� Indoor: 2.5 mW (4 dBm)� Pedestrian : 25 mW (14 dBm)� Vehicular : 250 mW (24 dBm)

TDD Mode:• 1 code (peak/average ratio 3.2 dB): Min. 14.8 dBm (1 timeslot), Max. 26.5 dBm (15 timeslots).• 8 codes (peak/average ratio 8.7 dB): Min. 9.2 dBm (1 timeslot used), Max. 21 dBm (15 timeslots used).

Calculation:Time average power = 30dBm – peak/average ratio + 10 * log10(used timeslots/frames/16)

In the active state, the time-averaged maximum outputpower levels are the same as the maximum EIRPs.

However the exact transmitted average is less and is servicedependent (e.g. for voice services the voice activity factorsignificantly reduces the transmitted power0

Values used in the link budget calculation:• 24 dBm for vehicular• 14 dBm for pedestrian• 4 dBm for indoor

Peak Transmission Power Three types of power control strategies are employed.

One is the ‘fast closed loop power control’ (FDD mode

The RTT itself does not impose an constraint on the peaktransmitter / carrier power.


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only) which counteracts fading on a slot basis (0.625 ms). Itis based on measurements on SIR.

The second one is ‘open loop power control’. It is used onlyfor the initial power setting.

The third one is the ‘outer loop power control’. It is basedon BER and FER measurements. It has the role to changethe target C/I, when the situation of the mobile is changingor for power control planning. It is done on a longer periodbasis.

The use of fast power control significantly improves thelink-performance (BER as a function of Eb/No) especiallyin the case of slow-moving mobile stations. For fast movingmobile stations (>100km/hr), there is less performanceimprovement due to fast power control.

Class I : 28 dBm < EIRP < 33 dBm

Class II : 23 dBm < EIRP < 30 dBm

Class III: 18 dBm < EIRP < 27 dBm

Class IV: 13 dBm < EIRP < 24 dBm

Class V : 8 dBm < EIRP < 21 dBm

POWER CONTROL DYNAMICRANGE

(Larger power control dynamicrange gives longer battery life andgreater operating time)

Uplink: 80 dB

Downlink: 30 dB

The power control dynamic range for the open and closedloops are:

Open loop: +/- 40dB

Closed loop: +/- 24 dB

POWER CONTROL STEP SIZE,ACCURACY AND SPEED

FDD ModeUplink: Variable on a cell basis in the range 0.25 – 1.5 dBDownlink: Variable on a cell basis in the range 0.25 – 1.5 dB.

Power Control Step Size:1.0 dB nominal on Uplink0.5 dB nominal on Downlink0.25 dB, 0.5 dB and 1.0 dB are available as options.


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Speed: 1600 control cycles per second.

TDD ModeThe power control step size is variable, ranging from 0.5 to3 dB.

Speed: 100 to 800 control cycles per second, depending onthe exact UL/DL time slot allocatioin.

Residual power variation after power control:Power Control Error is typically below 1.3 dB (lowmobility case) to 2.7 dB (high speed vehicular case)

Power Control Speed:800 Hz normal

DIVERSITY SCHEMES

(Diversity has an impact onhandportable complexity and size )

Diversity in the Mobile Station is possible but notmandatory.

• Time Diversity: symbol interleaving and error coding and correction.• Path diversity: RAKE receiver• Space Diversity: BS uses 2 antenna; MS antenna diversity is optional• Orthogonal Transmit Diversity: can be used on the forward link• Frequency Diversity: 1.2288, 3.686, 7.3728, 11.0592, or 14.7456 MHz spreading• Diversity Combining: either maximal-ratio or equal gain combining may be used with multiple RAKE fingers.

THE NUMBER OF ANTENNAS The Mobile Station requires a single antenna.Implementations using more than one antenna are possible.

Minimum number of antennas :

• 1 per MS (antenna diversity optional)• 2 per BS


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The Number of RECEIVERS The Mobile Stationn requires a single receiver.Implementations including more than one receiver willprovide additional advantages, for example, in theapplication of FDD mode inter-frequency handover.

Minimum number of demodulators / receivers:

• 1 per MS• 2 per BS

COVERAGE / POWER EFFICIENCY

BASE SITE COVERAGEEFFICIENCY

(The number of base sites requiredto provide coverage at system start-up and ongoing traffic growthsignificantly impacts cost.)

All the following results are expressed in km2 /cell,[Downlink / Uplink]

FDD MODESpeechIndoors: 2.6 / 3.3Pedestrian: 2.7 / 3.3Vehicular: 35.5 / 22.6

LCDIndoors (2048): 0.40 / 0.32Pedestrian (384): 0.9 / 0.7Vehicular (144): 18.9 / 8.3

UDDIndoors (2048): 0.40 / 0.32Pedestrian (384): 0.88 / 0.80Vehicular (144): 27.43 / 12.99

Coverage Efficiency in km2 / site, [Downlink / Uplink]

Voice Traffic (9.6 kbps)

Indoor Environment: 0.01 / 0.01

Pedestrian Environment: 0.375 / 0.391

Vehicular Environment: 113.6 / 72.1


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TDD MODESpeechIndoors: 2.9 / 2.6Pedestrian: 2.9 / 2.1Vehicular: 28.7 / 8.9

LCDIndoors (2048): 0.1 / 0.1Pedestrian (384): 0.8 / 0.5Vehicular (144): 53.4 / 12.2

UDD

(N.B. These results are based on the followingassumptions:• Vehicular Environment: BS with 3-sector antenna. Gain: 17 dBi• MS antenna gain: 2dBi• TX Powers (Downlind / Uplink) [dBm] )

Indoor Office (A): 13 / 10Outdoor to Indoor: 23 / 20Pedestrian: 23 / 20Vehicular (A): 30 / 24

The proposed Type II Hybrid ARQ Scheme allows forretransmission in case of unsuccessful data detection.Therefore, no fixed Eb/No or C/I values required to achievethe QoS at the cell border can be defined. However, due toARQ retransmission, the range of UDD services is largerthan the range of the corresponding LCD service.


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Method to INCREASE theCoverage Efficiency

Both FDD and TDD operating modes of UTRA are able touse all the standard types of Base Station antennas. Thisincludes those that provide omni-directional, sectored, fixedor variable patterns.

Directive Antennas decrease the interference, leading to anincrease in system capacity.

Both FDD and TDD mode support remote, distributed, andsmart antenna systems.

Signal-to-interference-plus-noise-ration (SINR) can besignificantly improved by incorporating various smartantenna concepts in the uplink as well as in the downlink.

These SINR gains may be exploited:• to increase the capacity (mainly in urban areas), e.g. by reducing the interference.• to increase the coverage (mainly in rural areas), e.g., by increasing the cell size (range extension) or by improving the edge coverage.• to increase the link quality.• to decrease the delay spread.• to reduce the transmission power, or a combination thereof.

Repeaters can be used. In addition, ODMA supports datatransfer via a network of intermediate relaying nodes(dedicated fixed relays or relaying enable mobiles).

Distribued antennas can be used in microcellularenvironments to extend coverage.

Similarly, spot antennas can be used to direct a beam to agroup of mobiles to extend coverage. A spot beam can bestatic or can follow a group of mobiles.

The degree to which the above techniques can be used toextend coverage is dependent on implementation anddeployment scenarios.


Page: 99


8. Other Relevant Technologies

There are two other relevant technologies which will be discussed in this section. The first is

High Data Rate (HDR) which has been developed and proposed by Qualcomm Inc. and the

second is a technology called 1xtreme developed and proposed jointly by Motorola and Nokia.

These technologies have been proposed, and agreed by TIA, to be incorporated and integrated

into the standardization process of cdma2000 as evolutions of 1x RTT.

Some of HDR’s attributes are given below:

- Spectrally efficient TDM/CDMA technology optimized for packet data services

- Separate 1.25 MHz carrier dedicated to HDR

- 2.4 Mbps forward peak sector throughput with a single CDMA 1.25 MHz bandwidth carrier

- Asymetric forward and reverse links

- Forward link: 2.0 Mbps/cell average throughput (3 sector)

- Reverse link: 660 Kbps/cell average throughput (3 sector)

- Identical RF characteristics as IS-95/1xRTT

- Same chip rate, link budget and coverage area

- HDR carrier looks like an IS-95/1xRTT carrier to the rest of the network

- HDR system supports mobility

- Packetized air link leverages Internet Protocol (IP)

- Packet data’s bursty nature allows the user to have quick bursts of High Data Rate

- 1x EV DO is the standard for HDR technology

8.1 1xEV DO Standard

1x EV DO is the name of the HDR’s technology which is being discussed, and further developed,as an evolution of 1x RTT.


Page: 100


88..11..11 11xxEEVV--DDOO PPrroottooccooll AArrcchhiitteeccttuurree

The 1xEV-DO interface has been layered, with clean interfaces defined for each layer (and each

protocol within each layer). This allows future modifications to a layer or to a protocol to be

isolated. Figure 48 describes the layering architecture for the 1xEV-DO Air-Interface. Each layer

consists of one or more protocols that perform the layer’s functionality. Each of these protocols

can be individually negotiated.

Stream Layer

Session Layer

Connection Layer

Security Layer

MAC Layer

Physical Layer

Application Layer

Figure 48: 1xEV-DO Air Interface Layering Architecture

88..11..22 PPhhyyssiiccaall LLaayyeerr lliinnkk ssttrruuccttuurreess

Forward and reverse link structures are shown in Figure 49 and Figure 50.

MediumAccessControl

Pilot Traffic

ReverseActivity

ReversePower

Control

Forward

Control

Figure 49: 1xEV-DO Forward link Structure


Page: 101


Access Traffic

Reverse

Pilot Data AckMediumAccessControl

Pilot Data

ReverseRate

Indicator

DataRate

Control

Figure 50: 1xEV-DO Reverse link Structure

88..11..33 11xx EEVV’’ss RReevveerrssee CChhaannnneell SSttrruuccttuurree

The Reverse HDR Channel consists of the Access Channel and the Reverse Traffic Channel. The

Access Channel shall consist of a Pilot Channel and a Data Channel. The Reverse Traffic

Channel shall consist of a Pilot Channel, a Reverse Rate Indicator (RRI) Channel, a Data Rate

Control (DRC) Channel, an Acknowledgement (ACK) Channel and a Data Channel. The RRI

Channel is used to indicate whether or not the Data Channel is being transmitted on the Reverse

Traffic Channel and if it is being transmitted, its data rate. The DRC Channel is used by the

access terminal to indicate to the access network the supportable Forward Traffic Channel data

rate and the best serving sector on the Forward HDR Channel. The ACK Channel is used by the

access terminal to inform the access network whether or not the data packet transmitted on the

Forward Traffic Channel has been received successfully.


Page: 102


The structure of the reverse link channels for the Access Channel shall be as shown in Figure 51,

and the structure of the reverse link channels for the Reverse Traffic Channel shall be as shown in

Figure 52 and Figure 53. For the Reverse Traffic Channel, the encoded RRI Channel symbols

shall be time-division multiplexed with the Pilot Channel. This time-division-multiplexed channel

is still referred to as the Pilot Channel. For the Access Channel, the RRI symbols shall not be

transmitted and the Pilot Channel shall not be time-division multiplexed. The Pilot Channel, the

DRC Channel, the ACK Channel, and the Data Channel shall be orthogonally spread by Walsh

functions of length 4, 8, or 16. Each Reverse Traffic Channel shall be identified by a distinct user

long code. The Access Channel for each sector shall be identified by a distinct Access Channel

long code.

The Access Channel frame and Reverse Traffic Channel frame shall be 26.66… ms in duration

and the frame boundary shall be aligned to the rollover of the short PN codes. Each frame shall

consist of 16 slots, with each slot 1.66… ms in duration. Each slot contains 2048 PN chips.


Page: 103


Figure 51: Reverse HDR Channel Structure for the Access Channel

Pilot Channel(All 0's)

Signal PointMapping0 → +11 → –1

( )160W = + + + + + + + + + + + + + + + +

128 BinarySymbolsper Slot


( )−−++=42W

Encoder(Code Rate =

1/4)

ChannelInterleaver

InterleavedPacket

Repetition

Data ChannelPhysical Layer

Packets

256 Bits9.6 kbps

1,024Symbols

38.4 ksps 307.2 ksps

1.2288 Mcps

QuadratureSpreading

(Complex Multiply)I = I ′ PNI – Q ′ PNQQ = I′ PNQ + Q ′ PNIData

ChannelRelative

Gain

PNI PNQ

Decimatorby Factor

of 2

PQQ-Channel

ShortPN Sequence

Walsh Cover(+ – )

UQQ-Channel

User Long-CodePN Sequence

UII-Channel


PII-Channel

ShortPN Sequence

Q ′ BasebandFilter

Q

sin(2πfCt)

s(t)∑

BasebandFilter

I

cos(2πfCt)

I′


Page: 104


Figure 52: Reverse HDR Channel Structure for the Reverse Traffic Channel

EncoderChannel

Interleaver

InterleavedPacket

Repetition

Data ChannelPhysical Layer

Packets

Physical Layer Packets CodeBits Rate (kbps) Rate Symbols Rate (ksps) Rate (ksps)256 9.6 1/4 1,024 38.4 307.2512 19.2 1/4 2,048 76.8 307.2

1,024 38.4 1/4 4,096 153.6 307.22,048 76.8 1/4 8,192 307.2 307.24,096 153.6 1/2 8,192 307.2 307.2

Pilot Channel(All 0's)

DRC SymbolsOne 4-Bit Symbol

per Active Slot

DRCCoverSymbols

One 3-Bit Symbolper Active Slot

Bi-Orthogonal

Encoder

CodewordRepetition

(Factor = 2)

8 BinarySymbols

per Active Slot

7 0,..., i ,W

Cover Walsh8i =

16 BinarySymbols

per Active Slot

7 BinarySymbols

per PhysicalLayer Packet

SimplexEncoder

RRI SymbolsOne 3-Bit Symbol

per 16-Slot PhysicalLayer Packet

CodewordRepetition

(Factor = 37


ACK Channel1 Bit per Slot

BitRepetition(Factor =

128)

TDM7:1

PunctureLast 3

Symbols

259 BinarySymbols


256 BinarySymbols


1.2288 Mcps

B

( )168W = + + + + + + + + − − − − − − − −


( )160W = + + + + + + + + + + + + + + + +

128 BinarySymbolsper Slot

A

1.2288 Mcps

( )−−−−++++=84W

1.2288 Mcps

C

128 BinarySymbols per Slot

(Transmittedin 1/2 Slot)



( )−−++=42W

1.2288 Mcps

D


Page: 105


Figure 53: Reverse HDR Channel Structure for the Reverse Traffic Channel

QuadratureSpreading

(Complex Multiply)I = I′ PNI – Q ′ PNQQ = I′ PNQ + Q′ PNI

∑

A

ACKChannelRelative

Gain

B

∑

DRCChannelRelative

Gain

DataChannelRelative

Gain

D

C

PNI PNQ

Decimatorby Factor

of 2

PQQ-Channel

ShortPN Sequence

Walsh Cover(+ – )

UQQ-Channel


UII-Channel


PII-Channel

ShortPN Sequence

Q′

I′ BasebandFilter

I

s(t)∑

cos(2πfCt)

BasebandFilter

Q

sin(2πfCt)


Page: 106


88..11..44 RReevveerrssee LLiinnkk MMoodduullaattiioonn PPaarraammeetteerrss

The modulation parameters for the Access Channel and the Reverse Traffic Channel shall be as

specified in Table 18.

Table 18: Modulation Parameters for the Access Channel and the Reverse Traffic Channel

Data Rate (kbps)

Parameter 9.6 19.2 38.4 76.8 153.6

Reverse Rate Index 1 2 3 4 5

Bits per PhysicalLayer Packet

256 512 1,024 2,048 4,096

Physical Layer

Packet Duration(ms)

26.66… 26.66… 26.66… 26.66… 26.66…

Code Rate 1/4 1/4 1/4 1/4 1/2

Code Symbols per

Physical LayerPacket

1,024 2,048 4,096 8,192 8,192

Code Symbol Rate(ksps)

38.4 76.8 153.6 307.2 307.2

Interleaved PacketRepeats

8 4 2 1 1

Modulation SymbolRate (ksps)

307.2 307.2 307.2 307.2 307.2

Modulation Type BPSK BPSK BPSK BPSK BPSK

PN Chips per

Physical LayerPacket Bit

128 64 32 16 8

The access terminal shall transmit information on the Access Channel at a fixed data rate of 9.6

kbps. The access terminal shall transmit information on the Reverse Traffic Channel at a variable

data rate of 9.6, 19.2, 38.4, 76.8, or 153.6 kbps, according to the Reverse Traffic Channel MAC

Protocol.


Page: 107


88..11..55 RReevveerrssee LLiinnkk ootthheerr PPaarraammeetteerrss

Channel coding parametersThe Reverse Traffic Channel and Access Channel physical layer packets shall be encoded with

code rates of 1/2 or 1/4, depending on the data rate. First, the encoder shall discard the last six bits

of the TAIL field in the physical layer packet inputs (i.e., it shall discard the last six bits in the

input physical layer packets). Then, it shall encode the remaining bits with a turbo encoder. The

turbo encoder will add an internally generated tail. The encoder parameters shall be as specified

in Table 19.

Table 19: Parameters for the Reverse Link Encoder

Data Rate(kbps)

9.6 19.2 38.4 76.8 153.6

Reverse Rate Index 1 2 3 4 5

Code Rate 1/4 1/4 1/4 1/4 1/2

Bits per

Physical LayerPacket

256 512 1,024 2,048 4,096

Number of Turbo

Encoder InputSymbols

250 506 1,018 2,042 4,090

Turbo EncoderCode Rate

1/4 1/4 1/4 1/4 1/2

Encoder OutputBlock Length

(Code Symbols)

1,024 2,048 4,096 8,192 8,192

Channel InterleavingThe sequence of binary symbols at the output of the encoder shall be interleaved with a bit-

reversal channel interleaver. The bit-reversal channel interleaver shall be functionally equivalent

to an approach where the entire sequence of symbols to be interleaved is written into a linear


Page: 108


sequential array with addresses from 0 to 2L – 1 and they are read out from a sequence of

addresses based on a particular procedure .

Sequence RepetitionIf the data rate is lower than 76.8 kbps, the sequence of interleaved code symbols shall be

repeated before being modulated. The number of repeats varies for each data rate and shall be as

specified in Table 18. The repetition shall be functionally equivalent to sequentially reading out

all the symbols from the interleaver memory as many times as necessary to achieve the fixed

307.2-ksps modulation symbol rate.

Orthogonal CoversThe Pilot Channel, consisting of the time-division-multiplexed Pilot and RRI Channels, the DRC

Channel, the ACK Channel, and the Data Channel shall be spread with Walsh functions, also

called Walsh covers, at a fixed chip rate of 1.2288 Mcps. Walsh function time alignment shall be

such that the first Walsh chip begins at a slot boundary referenced to the access terminal

transmission time.

Quadrature SpreadingFollowing the orthogonal spreading, the ACK, DRC, and Data Channel chip sequences shall be

scaled by a gain factor that gives the gain of each of these channels relative to that of the Pilot

Channel gain. The relative gain values for the ACK and DRC Channels are specified by the

parameters AckChannelGain and DRCChannelGain , which are public data of the Route Update

Protocol. For the Reverse Traffic Channel, the relative gain of the Data Channel is specified by

parameters that are public data of the Reverse Traffic Channel MAC Protocol. For the Access

Channel, the relative gain of the Data Channel is specified by parameters that are public data of

the Access Channel MAC Protocol.

After the scaling, the Pilot and scaled ACK, DRC, and Data Channel sequences are combined to

form resultant I-Channel and Q-Channel sequences, and these sequences are quadrature. The

quadrature spreading shall occur at the chip rate of 1.2288 Mcps, and it shall be used for the


Page: 109


Reverse Traffic Channel and the Access Channel. The Pilot and scaled ACK Channel sequences

shall be added to form the resultant I-Channel sequence, and the scaled DRC and Data Channel

sequences shall be added to form the resultant Q-Channel sequence. The quadrature spreading

operation shall be equivalent to a complex multiply operation of the resultant I-Channel and

resultant Q-Channel sequences by the PNI and PNQ PN sequences, as shown in Figure 53.

88..11..66 11xx EEVV’’ss FFoorrwwaarrdd CChhaannnneell SSttrruuccttuurree

The HDR Forward Channel shall have the overall structure shown in Figure 54. The HDR

Forward Channel shall consist of the following time-multiplexed channels: the Pilot Channel, the

Forward Medium Access Control (MAC) Channel, and the Forward Traffic Channel or the

Control Channel. The Traffic Channel carries user data packets. The Control Channel carries

control messages, and it may also carry user traffic. Each channel is further decomposed into

code-division-multiplexed quadrature Walsh channels.

The forward link shall consist of slots of length 2048 chips (1.66… ms). Groups of 16 slots shall

be aligned to the PN rolls of the zero-offset PN sequences and shall align to system time on even-

second ticks.


Page: 110


Figure 54: HDR Forward Channel Structure

SequenceRepetition/

SymbolPuncturing

16-aryWalshCovers

WalshChannelGain =1/4

WalshChip LevelSummer

SymbolDEMUX1 to 16Q

I

Q

I

Q

I

Q

I

Q

I

Q

IC

D

16 ChannelsScrambler

Forward TrafficChannel or

Control ChannelPhysical Layer

Packets

BasebandFilter

∑

BasebandFilter

Q

I

BQ′

AI′

ForwardModulatedWaveform

32-Symbol Bi-Orthogonal Coverwith MACIndex i

EncoderR = 1/3or 1/5

ChannelInterleaver


0Q

IPreamble(All 0's)


RPC WalshChannelGainsG(i)

MAC ChannelRPC Bits forMACIndex i

1 Bit per Slot(600 bps)


BitRepetition(Factor =

RABLength)

MAC ChannelRA Bits1 Bit per

RABLength Slots(600/RABLength

bps)


I

Q0

Pilot Channel(All 0’s)

192 PNChips

per Slotfor Pilot

WalshChip LevelSummer

SequenceRepetition(Factor = 4)

Walsh Cover 0

TDM

A

B

I WalshChannels

Q WalshChannels

644Walsh Cover W

PNQ

Q-ChannelPN Sequence1.2288 Mcps

PNI

I-ChannelPN Sequence1.2288 Mcps

cos(2πfCt)

sin(2πfCt)

Quadrature Spreading(Complex Multiply)I = I' PNI − Q' PNQQ = I' PNQ + Q' PNI

QPSK/8-PSK/16-QAM

Modulator

I

Q

C

D

256 PNChips

per Slotfor MAC

64 to 1,024 PN Chips

per PhysicalLayer Packetfor Preamble

RAChannel

Gain

SequenceRepetition

I

Q

I

Q

I

64-ary Walsh Coverfor MACIndex i

I Channel forEven MACIndexQ Channel forOdd MACIndex


Page: 111


Within each slot, the Pilot, MAC, and Traffic or Control Channels shall be time-division

multiplexed as shown in Figure 55. All time-division-multiplexed channels shall be transmitted at

the maximum power of the sector.

Figure 55: Forward Link Slot Structure

Active Slot

Idle Slot

Data400

Chips

Data400

Chips

Data400

Chips

Data400

Chips

1/2 Slot1,024 Chips

1/2 Slot1,024 Chips

Pilot96

Chips

MAC64

Chips

MAC64

Chips

Pilot96

Chips

MAC64

Chips

MAC64

Chips

Pilot96

Chips

MAC64

Chips

MAC64

Chips

Pilot96

Chips

MAC64

Chips

MAC64

Chips

The Pilot Channel shall consist of all-‘0’ symbols transmitted on the I channel with - Walsh cover

0. Each slot shall be divided into two half slots, each of which contains a pilot burst. Each pilot

burst shall have a duration of 96 chips and be centered at the midpoint of the half slot.1

The MAC Channel shall consist of two subchannels: the Reverse Power Control (RPC) Channel

and the Reverse Activity (RA) Channel. The RA Channel transmits a reverse link activity bit

(RAB) stream.

Each MAC Channel symbol shall be BPSK modulated on one of 64 64-ary Walsh code-words

(covers). The MAC symbol Walsh covers shall be transmitted four times per slot in bursts of 64

chips each. A burst shall be transmitted immediately preceding both of the pilot bursts in a slot,

1 The pilot is used by the access terminal for initial acquisition, phase recovery, timing recovery, andmaximal-ratio combining. An additional function of the pilot is to provide the access terminal with a meansof predicting the receive C/I for the purpose of access-terminal-directed forward data rate control (DRC) ofthe Data Channel transmission.


Page: 112


and a burst shall be transmitted immediately following both of the pilot bursts in a slot. The

Walsh channel gains may vary the relative power. The Forward Traffic Channel is a packet-

based, variable-rate channel. The user data for an access terminal shall be transmitted at a data

rate that varies from 38.4 kbps to 2.4576 Mbps.2

The Forward Traffic Channel and Control Channel data shall be encoded in blocks called

physical layer packets. The output of the encoder shall be scrambled and then fed into a channel

interleaver. The output of the channel interleaver shall be fed into a QPSK/8-PSK/16-QAM

modulator. The modulated symbol sequences shall be repeated and punctured, as necessary.

Then, the resulting sequences of modulation symbols shall be demultiplexed to form 16 pairs (in-

phase and quadrature) of parallel streams. Each of the parallel streams shall be covered with a

distinct 16-ary Walsh function at a chip rate to yield Walsh symbols at 76.8 ksps. The Walsh-

coded symbols of all the streams shall be summed together to form a single in-phase stream and a

single quadrature stream at a chip rate of 1.2288 Mcps. The resulting chips are time-division

multiplexed with the preamble, Pilot Channel, and MAC Channel chips to form the resultant

sequence of chips for the quadrature spreading operation.

Forward Traffic Channel and Control Channel physical layer packets can be transmitted in 1 to

16 slots (Table 20 and Table 21). When more than one slot is allocated, the transmit slots shall

use a 4-slot interlacing. That is, the transmit slots of a packet shall be separated by three

intervening slots, and slots of other packets shall be transmitted in the slots between those

transmit slots. If a positive acknowledgement is received on the reverse link ACK Channel that

the physical layer packet has been received on the Forward Traffic Channel before all of the

allocated slots have been transmitted, the remaining untransmitted slots shall not be transmitted

and the next allocated slot shall be used for the first slot of the next physical layer packet

transmission.

2 The DRC symbol from the access terminal is based primarily on its estimate of the forward C/I for theduration of the next possible forward link packet transmission.


Page: 113


Table 20: Modulation Parameters for the Forward Traffic Channel and the Control Channel

Number of Values per Physical Layer Packet

DataRate(kbps) Slots Bits

CodeRate

ModulationType

TDM Chips(Preamble,

Pilot,MAC,Data)

38.4 16 1,024 1/5 QPSK

1,0243,072

4,09624,576

76.8 8 1,024 1/5 QPSK

512

1,5362,048

12,288

153.6 4 1,024 1/5 QPSK

256

768

1,0246,144

307.2 2 1,024 1/5 QPSK

128384

5123,072

614.4 1 1,024 1/3 QPSK

64

192256

1,536


Page: 114


Table 21: Modulation Parameters for the Forward Traffic Channel and the Control Channel

Number of Values per Physical Layer Packet

DataRate(kbps) Slots Bits

CodeRate

ModulationType

TDM Chips(Preamble,

Pilot,MAC,Data)

307.2 4 2,048 1/3 QPSK

128

768

1,0246,272

614.4 2 2,048 1/3 QPSK

64384

5123,136

1,228.8 1 2,048 1/3 QPSK

64

192256

1,536

921.6 2 3,072 1/3 8-PSK

64

384

5123,136

1,843.2 1 3,072 1/3 8-PSK

64192

2561,536

1,228.8 2 4,096 1/3 16-QAM

64

384512

3,136

2,457.6 1 4,096 1/3 16-QAM

64

192

2561,536


Page: 115


The Control Channel shall be transmitted at a data rate of 76.8 kbps or 38.4 kbps. The modulation

characteristics for the Control Channel shall be the same as those of the Forward Traffic Channel

transmitted at the corresponding rate.

The Forward Traffic Channel and Control Channel data symbols shall fill the slot as shown inFigure 5. A slot during which no traffic or control data is transmitted is referred to as an idle slot.

During an idle slot, the sector shall transmit the Pilot Channel and the MAC Channel, as

described earlier.

88..11..77 FFoorrwwaarrdd LLiinnkk ootthheerr PPaarraammeetteerrss

Modulation and data ratesThe modulation parameters for the Forward Traffic Channel and the Control Channel shall be as

shown in Table 20 and Table 21. The Control Channel shall only use the 76.8 kbps and 38.4 kbps

data rates.

The Forward Traffic Channel shall support variable-data-rate transmission at 38.4 kbps to 2.4576

Mbps, as shown in Table 20: and Table 21. The data rate of the Control Channel shall be 76.8

kbps or 38.4 kbps.

Channel coding, interleaving and multiplexingA preamble sequence shall be transmitted with each Forward Traffic Channel and Control

Channel physical layer packet in order to assist the access terminal with synchronization of each

variable-rate transmission.

The Traffic Channel physical layer packets shall be encoded with code rates of R = 1/3 or 1/5.

The encoder shall discard the 6-bit TAIL field of the physical layer packet inputs and encode the

remaining bits with a parallel turbo encoder, as specified in Figure 56. The turbo encoder will add

an internally generated tail of 6/R output code symbols, so that the total number of output

symbols is 1/R times the number of bits in the input physical layer packet.


Page: 116


Figure 56 illustrates the forward link encoding approach.

Figure 56: Forward Link Encoder

Data Total Bits Bits SymbolsRate Slots Code per per per

(kbps) Used Rate Packet Packet Packet38.4 16 1/5 1,024 1,018 5,12076.8 8 1/5 1,024 1,018 5,120153.6 4 1/5 1,024 1,018 5,120307.2 2 1/5 1,024 1,018 5,120614.4 1 1/3 1,024 1,018 3,072307.2 4 1/3 2,048 2,042 6,144614.4 2 1/3 2,048 2,042 6,144

1,228.8 1 1/3 2,048 2,042 6,144921.6 2 1/3 3,072 3,066 9,216

1,843.2 1 1/3 3,072 3,066 9,2161,228.8 2 1/3 4,096 4,090 12,2882,457.6 1 1/3 4,096 4,090 12,288

Forward Traffic Channelor

Control ChannelPhysical Layer Packets

Turbo Encoderwith an

InternallyGenerated Tail

CodeSymbols

Discard6-Bit

EncoderTail Field

The turbo encoder employs two systematic, recursive, convolutional encoders connected in

parallel, with an interleaver, the turbo interleaver, preceding the second recursive convolutional

encoder. The two recursive convolutional codes are called the constituent codes of the turbo code.

The outputs of the constituent encoders are punctured and repeated to achieve the desired number

of turbo encoder output symbols.

The turbo interleaver, which is part of the turbo encoder, shall block interleave the turbo encoder

input data that is fed to Constituent Encoder 2. The output of the encoder shall be scrambled to

randomize the data prior to modulation to limit the peak-to-average ratio of the envelope of the

modulated waveform. The channel interleaving shall consist of a symbol reordering followed by

symbol permuting.

The output of the channel interleaver shall be applied to a modulator that outputs an in-phase

stream and a quadrature stream of modulated values. The modulator generates QPSK, 8-PSK, or


Page: 117


16-QAM modulation symbols, depending on the data rate. Then the sequence repetition and

symbol puncturing would take place. The in-phase stream at the output of the sequence repetition

operation shall be demultiplexed into 16 parallel streams. The individual streams generated by the

symbol demultiplexer shall be assigned to one of 16 distinct Walsh channels. The modulated

symbols on each branch of each Walsh channel shall be scaled to maintain a constant total

transmit power independent of data rate. The scaled Walsh chips associated with the 16 Walsh

channels shall be summed on a chip-by-chip basis.

The Control Channel transmits broadcast messages and access-terminal-directed messages. The

Control Channel messages shall be transmitted at a data rate of 76.8 kbps or 38.4 kbps. The

modulation characteristics shall be the same as those of the Forward Traffic Channel at the

corresponding data rate. The Forward Traffic Channel or Control Channel data modulation chips

shall be time-division multiplexed with the preamble, Pilot Channel, and MAC Channel chips.

Following orthogonal spreading, the combined modulation sequence shall be quadrature spread as

shown in Figure 54. The spreading sequence shall be a quadrature sequence of length 215 (i.e.,

32768 PN chips in length). ). This sequence is called the pilot PN sequence. The chip rate for the

pilot PN sequence shall be 1.2288Mcps. The pilot PN sequence period is 32768/1228800 =

26.666… ms, and exactly 75 pilot PN sequence repetitions occur every 2 seconds.

Pilot Channels shall be identified by an offset index in the range from 0 through 511 inclusive.

This offset index shall specify the offset value (in units of 64 chips) of the pilot PN sequence

from the zero-offset pilot PN sequence. The zero-offset pilot PN sequence shall be such that the

start of the sequence shall be output at the beginning of every even second in time, referenced to

access network transmission time.


Page: 118


8.2 1xtreme

Why does IS- 2000 1X need to evolve?

• IS- 2000 1X supports voice and data, but is prioritized for voice

– Difficult to implement shared- channel services for multiple packet data users

• However, market may not justify investment in a system purely for best-effort data

users

– Market for real- time services (voice, video) continues to grow and will need IP to

serve all type of services in a flexible way

• Market needs one air interface which, if optimized for both real- time services and best-

effort data, can be parameterized in a flexible way, even on a per cell basis

• Therefore, comes the idea of a gracefully evolved IS- 2000 1X

• Support of both voice and data

• Evolution from existing 1X CDMA standard

• High- speed wireless Internet Access

• Performance comparable or better than 3G Standards

88..22..11 EEvvoolluuttiioonn ffrroomm IISS--22000000 11XX

• Same as 1x RTT:

– RF (1.25 MHz)

– Orthogonal Walsh- Hadamard Codes

– Long code scrambling

– Reuse existing antennas

– Uplink uses BPSK modulation with orthogonal code control channels

– Pilot, Paging, Quick Paging and Sync Channels as in IS- 2000


Page: 119


• Retain:

– QPSK as the basic modulation for downlink

– Power control

– 5 msec frame duration

– Turbo Codes

– Compatibility with IS2000 1X Mobiles

Adaptation is the Key to Improved Performance

• Dynamically adjust system and link parameters to account for traffic and link quality

variation

• Better use of radio resources to increase system capacity for multiple services

• Maximize operator revenue

1xtreme forward link and reverse link channels as compared to IS-2000

A comparison of 1xtreme's forward and reverse links with IS-2000 standard is presented in Table

22 and Table 23.

Table 22: 1XTREME Reverse Link Channel Types

Channel Type Acronym Compare to IS-2000Reverse Pilot Channel R- PICH MReverse Transmit Sector Indicator Channel R- TSICH NEnhanced Access Channel EACH UReverse Power Control Channel R- PCCH MReverse Acknowledgement Indicator Channel R- AICH NReverse Explicit Rate Indicator Channel R- ERICH NReverse Fundamental Channel R- FCH RReverse Supplemental Code Channel R- SCH M

N= new, M= modified, R= reduced, U= unchanged


Page: 120


Table 23: 1XTREME Forward Link Channel Types

Channel Type Acronym Compare to IS-2000Forward Pilot Channel F- PICH UTransmit Diversity Pilot Channel F- TDPICH USynch and Paging Channels F-SYNC

F-PCHU

Quick Paging Channel F-QPCH UCommon Power Control Channel F-CPCCH UForward Common Control Channel F-CCCH UBroadcast Channel F-BCH UForward Fundamental Channel F-FCH RForward Shared Channel F-SHCH NForward Dedicated Control Channel F-DCCH M

N= new, M= modified, R= reduced, U= unchanged

88..22..22 KKeeyy CCoonncceepptt ooff 11XXTTRREEMMEE

• Adaptive Scheduling

– Optimize scheduling to support data only or mixed services

– Trade peak data capacity in support of mixed services

• Adaptive Modulation and Coding

– High Data Rate Carrier in 1.25MHz bandwidth

• 64 QAM provides ~5 Mbps peak

• 16 QAM provides ~3.4 Mbps peak

• 8 PSK provides ~ 2.6 Mbps peak

– Turbo codes

• Error correction near theoretical limit

– Explicit Information Bit Rate Detection

• Adaptive Hybrid ARQ

– Automatically adapts to instantaneous channel conditions by adding redundancy only

when needed


Page: 121


– Enabled by Dual Channel Stop- and- Wait Hybrid ARQ

• Adaptive Multi- code Allocation

– Code Division Multiplex packets from different users within a frame

– Multiple codes for a single user within a frame supports peak data rates

• Adaptive Cell Site Selection

– Fast selection replaces forward link soft handoff for 1XTREME terminals

– Reduced interference leads to increased capacity

• Adaptive Antennas

– Downlink Tx Diversity (Space Time Block Coding)

– Uplink and Downlink Rx Antenna Diversity

The downlink peak information rate is 5.184 Mbps, with 64 QAM.

The uplink information rates are 614.4 Kbps, 460.8 Kbps, 307.2 Kbps, 153. 6 Kbps, 76. 8 Kbps,38.4Kbps, 19. 2 Kbps and 9. 6 Kbps.

1xtreme 's forward link shared channel is shown in Figure 57.

Figure 57: Forward Link Physical Layer Single User Block Diagram


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1xtreme 's forward dedicated control channel is shown in Figure 58.

Figure 58: Forward Dedicated Control Channel

88..22..33 AAddaappttiivvee MMoodduullaatt iioonn aanndd CCooddiinngg

• Modulation Coding Scheme (MCS) – Table 24

– QPSK, 8- PSK, 16- QAM, or 64- QAM and R= 3/ 4 and 1/ 2 Turbo coding

– The MCS for each IP packet is selected based on average link quality

• Reduces average delay by lowering expected retries for disadvantaged channels.

– Very similar to the rate selection process for AMR (adaptive multirate coder) or

EDGE

Table 24: Adaptive Multi-Rate Modulation and Coding Scheme

MCSs Modulation Code Rate8 64 3 / 47 64 1 / 26 16 3 / 45 16 1 / 24 8 3 / 43 8 1 / 22 4 3 / 41 4 1 / 2


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The modulation and coding parameters of 1xtreme is presented in table 25.

Info Rate(Mbps)

PacketSize

Info Rate(Mbps)

PacketSize

Code rate Modulation

5.1840 25920 0.3456 1728 3 / 4 643.4560 17280 0.2304 1152 1 / 2 643.4560 17280 0.2304 1152 3 / 4 162.3040 11520 0.1536 768 1 / 2 162.5920 12960 0.1728 864 3 / 4 81.7280 8640 0.1152 576 1 / 2 81.7280 8640 0.1152 576 3 / 4 41.1520 5760 0.0768 384 1 / 2 4

Table 25: 1xtreme: modulation and coding parameters

Adaptive Modulation and Coding with Adaptive Hybrid ARQ

• Adaptive Modulation and Coding

– Gives the flexibility to match Modulation Coding Scheme to the average channel

conditions

for each user

• Coarse data rate selection

– Drawbacks

• Sensitive to measurement error and delay

• Still need ARQ

• Adaptive Hybrid ARQ (A- HARQ)

– Independent of various thresholds

– Automatically adapts to instantaneous channel conditions

• Insensitive to measurement error and delay

• Fine data rate adjustment

• 1XTREME combines the best of both!


Page: 124


Modulation, coding and effective information bit rates with adaptive hybrid ARQ are presented in

Table 26.

Effective Information Bit Rate (Mbps)Number

ofAttempts

Mod= 64Rate=3/4Codes=15

Mod=64Rate=1/2Codes=15







1 5.184 3.456 3.456 2.304 2.592 1.728 1.728 1.1522 2.592 1.728 1.728 1.152 1.296 0.864 0.864 0.5763 1.728 1.152 1.152 0.768 0.8664 0.576 0.576 0.384

Table 26: Effective Information Bit Rate with adaptive hybrid ARQ

Transmit Diversity

• 1XTREME utilizes Forward Link Space Time Coded Transmit Diversity (STTD)

– Used for F-SHCH and its associated F-DCCH

– Robust to vehicle speeds

• Adaptive Antennas (AA)

– Application of Tx-AA is under investigation


Page: 125


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[12] Nikula, E., A. Toskala, E. Dahlman, L. Girard, and A. Klein, "FRAMES Multiple Accessfor UMTS and IMT-2000," EEE Pers. Commun., April 1998.

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[23] Roger Derrien (Managing Director, Wireless Business Development A/P, LucentTechnologies), “Migration Paths to 3G,” CDG Asia 3G Executive Briefing, March 29,2000, Bangkok, Thailand.

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