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3G CDMA2000
Wireless System Engineering
For a listing of recent titles in the Artech House
Mobile Communications Library, turn to the back of this book.
3G CDMA2000
Wireless System Engineering
Samuel C. Yang
Artech House, Inc.
Boston • London
www.artechhouse.com
Library of Congress Cataloging-in-Publication Data
A catalog record for this book is available from the U.S. Library of Congress.
British Library Cataloguing in Publication Data
Yang, Samuel C.
3G CDMA2000 wireless system engineering.—(Artech House mobile communications
library)
1. Wireless communication systems. 2. Code division multiple access
I. Title
621.3'845
ISBN 1-58053-757-x
Cover design by Yekaterina Ratner
© 2004 ARTECH HOUSE, INC.
685 Canton Street
Norwood, MA 02062
All rights reserved. Printed and bound in the United States of America. No part of this book
may be reproduced or utilized in any form or by any means, electronic or mechanical, includ-
ing photocopying, recording, or by any information storage and retrieval system, without
permission in writing from the publisher.
All terms mentioned in this book that are known to be trademarks or service marks have
been appropriately capitalized. Artech House cannot attest to the accuracy of this informa-

tion. Use of a term in this book should not be regarded as affecting the validity of any trade-
mark or service mark.
International Standard Book Number: 1-58053-757-x
10987654321
To my wife Jenny and my son Daniel
.
Contents
Preface xiii
Acknowledgments xvii
CHAPTER 1
Introduction to 3G CDMA 1
1.1 Third Generation Systems 1
1.2 Protocol Architecture 2
1.3 Other Elements of Protocol Architecture 3
1.4 Spreading Rate 1 and Spreading Rate 3 5
1.5 Differences Between IS-2000 and IS-95 7
1.5.1 Signaling 7
1.5.2 Transmission 8
1.5.3 Concluding Remarks 8
References 9
CHAPTER 2
Physical Layer: Forward Link 11
2.1 Introduction 11
2.2 Radio Configurations 14
2.3 Signaling Channels 15
2.3.1 Forward Dedicated Control Channel (F-DCCH) 15
2.3.2 Quick Paging Chanel (F-QPCH) 16
2.3.3 Forward Common Control Channel (F-CCCH) 19
2.3.4 Broadcast Control Channel (F-BCCH) 20
2.3.5 Common Assignment Channel (F-CACH) 21

2.3.6 Common Power Control Channel (F-CPCCH) 22
2.3.7 Pilot Channels 24
2.4 User Channels 26
2.4.1 Forward Fundamental Channel (F-FCH) 26
2.4.2 Forward Supplemental Channel (F-SCH) 27
2.5 Channel Structure 31
2.6 Modulation 32
2.7 Capacity Gain: Forward Link 34
References 35
Selected Bibliography 35
vii
CHAPTER 3
Physical Layer: Reverse Link 37
3.1 Introduction 37
3.2 Radio Configurations 39
3.3 Signaling Channels 40
3.3.1 Reverse Dedicated Control Channel (R-DCCH) 40
3.3.2 Reverse Common Control Channel (R-CCCH) 41
3.3.3 Enhanced Access Channel (R-EACH) 42
3.3.4 Reverse Pilot Channel (R-PICH) 45
3.4 User Channels 49
3.4.1 Reverse Fundamental Channel (R-FCH) 50
3.4.2 Reverse Supplemental Channel (R-SCH) 50
3.5 Channel Structure 50
3.6 Modulation 51
3.7 Capacity Gain: Reverse Link 52
References 53
Selected Bibliography 53
CHAPTER 4
Medium Access Control 55

4.1 Introduction 55
4.2 Primitives 55
4.3 Multiplex Sublayers 57
4.4 Radio Link Protocol (RLP) 60
4.4.1 Overview of Layer 2 Protocols 60
4.4.2 llustration of the RLP 61
4.4.3 Concluding Remarks 62
4.5 Signaling Radio Burst Protocol (SRBP) 63
4.6 System Access 64
4.6.1 Basic Access Mode 65
4.6.2 Reservation Access Mode 65
4.6.3 Power Controlled Access Mode 67
4.6.4 Designated Access Mode 68
References 68
CHAPTER 5
Signaling Link Access Control 71
5.1 Introduction 71
5.2 LAC Sublayers 71
5.2.1 Authentication and Addressing Sublayers 71
5.2.2 ARQ Sublayer 73
5.2.3 Utility Sublayer 73
5.2.4 Segmentation and Reassembly Sublayer 74
5.3 Sublayer Processing 74
5.3.1 Common Signaling: Forward Link 74
5.3.2 Common Signaling: Reverse Link 76
5.3.3 Dedicated Signaling: Forward Link 77
viii Contents
5.3.4 Dedicated Signaling: Reverse Link 80
5.4 Interaction of Layer and Sublayers 80
5.4.1 Transmit Side 81

5.4.2 Receive Side 82
References 83
CHAPTER 6
Signaling: Upper Layers 85
6.1 Overview 85
6.2 State Transitions: Call Processing 87
6.2.1 Initialization State 88
6.2.2 Mobile Station Idle State 89
6.2.3 System Access State 91
6.2.4 Mobile Station Control on the Traffic Channel State 94
6.3 Mode Transitions: Packet Data Transmission 96
6.3.1 Active Mode 96
6.3.2 Control Hold Mode 96
6.3.3 Dormant Mode 96
6.3.4 Transitions 97
6.4 Channel Setup 97
6.4.1 Example 1: Base Station-Originated Voice Call 98
6.4.2 Example 2: Mobile Station-Originated Voice Call 99
6.4.3 Example 3: Mobile Station-Originated Packet Data Call 100
6.4.4 Example 4: Supplemental Channel Request During a
6.4.4 Packet Data Call 101
6.4.5 Concluding Remarks 104
References 104
CHAPTER 7
Power Control 107
7.1 Introduction 107
7.2 Power Control of the Forward Link 107
7.2.1 Inner Loop and Outer Loop 107
7.2.2 Power Control of Multiple Forward Traffic Channels 110
7.3 Power Control of the Reverse Link: Open Loop 113

7.3.1 Power Control of Multiple Reverse Channels 113
7.3.2 Summary 116
7.4 Power Control of the Reverse Link: Closed Loop 117
7.4.1 Inner Loop and Outer Loop 118
7.4.2 Power Control of Multiple Reverse Channels 119
References 121
CHAPTER 8
Handoff 123
8.1 Introduction 123
8.2 Soft Handoff 123
8.2.1 Active Set 124
Contents ix
8.2.2 Candidate Set 127
8.2.3 Neighbor Set 128
8.2.4 Remaining Set 129
8.2.5 Set Transitions 129
8.2.6 Example: Soft Handoff 129
8.3 Idle Handoff 133
8.3.1 Active Set 133
8.3.2 Neighbor Set 134
8.3.3 Private Neighbor Set 134
8.3.4 Remaining Set 134
8.3.5 Idle Handoff Process 134
8.4 Access Entry Handoff 134
8.5 Access Handoff 135
8.5.1 Active Set 136
8.5.2 Neighbor Set 136
8.5.3 Remaining Set 136
8.5.4 Access Handoff Process 136
8.6 Access Probe Handoff 138

8.7 Concluding Remarks 139
References 140
CHAPTER 9
System Performance 141
9.1 Introduction 141
9.2 Channel Supervision 141
9.2.1 Forward Link: Traffic Channel 141
9.2.2 Forward Link: Common Channel 142
9.2.3 Reverse Link 142
9.3 Code Management 142
9.3.1 Generation of Walsh Codes 143
9.3.2 Assignment of Walsh Codes: Forward Link 144
9.3.3 Quasi-Orthogonal Functions 147
9.3.4 Assignment of Walsh Codes: Reverse Link 147
9.4 Turbo Codes 150
9.5 Transmit Diversity 152
9.5.1 Orthogonal Transmit Diversity 152
9.5.2 Space Time Spreading 154
9.5.3 Concluding Remarks 156
References 156
Selected Bibliography 157
CHAPTER 10
System Design: Coverage 159
10.1 Introduction 159
10.2 Forward Pilot Channel 161
10.3 Forward Fundamental Channel 162
10.4 Forward Supplemental Channel 163
x Contents
10.5 Upper Bounds of Interference: Forward Link 165
10.6 Reverse Fundamental Channel 165

10.7 Reverse Supplemental Channel 167
10.8 Upper Bounds of Interference: Reverse Link 168
10.9 E
b
/N
0
and Receiver Sensitivity 169
10.10 Concluding Remarks 169
Reference 170
CHAPTER 11
System Design: Capacity 171
11.1 Introduction 171
11.2 Mathematical Definitions 171
11.2.1 Received Signal Power 171
11.2.2 Loading Factor 173
11.3 Reverse Link 174
11.3.1 Capacity 174
11.3.2 Capacity Improvements in IS-2000 176
11.3.3 Capacity Improvements in a System 177
11.4 Forward Link 178
11.4.1 Capacity 179
11.4.2 Capacity Improvements in IS-2000 182
11.4.3 Capacity Improvements in a System 183
References 185
CHAPTER 12
Network Architecture 187
12.1 Introduction 187
12.2 2G Network 187
12.2.1 Network Elements 187
12.2.2 Protocols 189

12.3 3G Network 189
12.3.1 Network Elements 190
12.3.2 Protocols 191
12.4 Simple IP 192
12.5 Mobile IP 193
12.6 Concluding Remarks 196
References 197
CHAPTER 13
1xEV-DO Network 199
13.1 Introduction 199
13.2 1xEV-DO Network 201
13.3 Protocol Architecture 202
13.3.1 Application Layer 204
13.3.2 Stream Layer 205
13.3.3 Session Layer 205
13.3.4 Connection Layer 206
Contents xi
13.3.5 Security Layer 210
13.3.6 Concluding Remarks 210
References 211
CHAPTER 14
1xEV-DO Radio Interface: Forward Link 213
14.1 Introduction 213
14.2 MAC Layer 213
14.2.1 Forward Traffic Channel MAC Protocol 214
14.2.2 Control Channel MAC Protocol 215
14.3 Physical Layer 215
14.3.1 Pilot Channel 215
14.3.2 Forward Traffic Channel/Control Channel 216
14.3.3 MAC Channel 219

14.3.4 Time Division Multiplexing 221
14.3.5 Modulation 225
14.4 Concluding Remarks 226
References 226
Selected Bibliography 226
CHAPTER 15
1xEV-DO Radio Interface: Reverse Link 227
15.1 Introduction 227
15.2 MAC Layer 227
15.2.1 Reverse Traffic Channel MAC Protocol 227
15.2.2 Access Channel MAC Protocol 228
15.3 Physical Layer 229
15.3.1 Reverse Traffic Channel 231
15.3.2 Access Channel 236
15.3.3 Modulation 238
15.4 Reverse Power Control 239
15.4.1 Open-Loop Power Control 239
15.4.2 Closed-Loop Power Control 240
References 240
Selected Bibliography 240
About the Author 241
Index 243
xii Contents
Preface
Over the past few years, many fundamental changes have taken place in wireless
communications that will influence the future of this dynamic field. One phenome
-
non driving these changes has been the integration of wireless communication
devices in people’s lives. While the 1990s were the years when wireless voice teleph
-

ony became popular, the 2000s should be the time when wireless data applications
are truly un-tethered from homes and offices. As more people adopt wireless com
-
munication devices and applications effected by these devices, the demand on wire
-
less networks will continue to grow.
Although code division multiple access (CDMA) has become an integral part of
the ensemble of third generation (3G) standards, many wireless network operators
have found the implementation of IS-2000 affords a good balance between cost and
performance of providing 3G services, especially if an operator evolves its network
from IS-95 to IS-2000. As such, IS-2000 has become a popular choice of 3G for
operators around the world, notably in Asia and the Americas.
This book has been written to address the technical concepts of IS-2000. The
focus is on basic issues, and every effort has been made to present the material in an
expository and interesting fashion. One strategy is to utilize examples not to offer
proofs (as they cannot) but to help the reader grasp the fundamental issues at hand.
In this regard, mathematical details and models have an important role but serve as
means to an end. While CDMA is by nature theory-intensive, every attempt is made
to strike a balance between theory and practice. In addition, to minimize the dupli-
cation of foundational material of spread spectrum communications and IS-95, this
book does not describe those introductory concepts (e.g., synchronization of PN
codes) in detail and assumes that the reader is familiar with basic material such as
those found in CDMA RF System Engineering (Samuel Yang, Artech House, 1998).
Furthermore, this book assumes that the reader is familiar with the layered frame
-
works of the Internet Model and OSI Model.
In 3G, the system requires the full participation of not only the physical layer
but also medium access control, link access control, and upper layers to provide not
only circuit voice call but also packet data call functions. Hence in 3G, one needs to
focus on the entire system rather than just on a particular layer. To that end, the

book starts with a layer-by-layer treatment of IS-2000. In Chapters 1 to 6, it follows
the protocol layer framework and describes IS-2000 from Layers 1 to 3. Chapter 1
introduces basic concepts and requirements of 3G and highlights key differences
between IS-2000 and IS-95. Chapters 2 and 3 describe physical layers of forward
and reverse links, respectively. The channel structure and functions of different
channels are described in these two chapters. Chapter 4 covers medium access
xiii
control and focuses on radio link protocol, signaling radio burst protocol, and sys
-
tem access. Then, Chapter 5 goes into link access control; this chapter first reviews
the functions of the sublayers of link access control, then it illustrates sublayer proc
-
essing on both forward and reverse links. Chapter 6 goes over Layer 3 or upper layer
signaling of IS-2000; the emphasis here is on call processing, state transition, and
mode transitions.
After building the foundation of the structure of an IS-2000 system, the book
proceeds to the systems aspects of IS-2000 in Chapters 7 to 12. Since IS-2000 con
-
tains power control and handoff functions that are superior to those in IS-95-A,
Chapters 7 and 8 describe in detail power control and handoff functionalities,
respectively. Chapter 9 then proceeds to cover system performance and describes
those features adopted by IS-2000 to increase performance such as code manage
-
ment, turbo codes, and transmit diversity.
Since a CDMA system essentially trades off coverage versus capacity, these
design aspects are presented in Chapters 10 and 11. In particular, Chapter 10 covers
coverage, and Chapter 11 covers capacity. These two chapters contain systematic
developments of key concepts, and necessary mathematical developments are
included where necessary to clarify the material.
Chapter 12 is on network architecture and serves as a capstone on all the chap-

ters presented thus far. It describes the IS-2000 architecture from a network perspec-
tive and shows how a 3G network differs and evolves from a 2G network. This
chapter introduces how IS-2000 works and interacts with other elements in the net-
work. Advanced concepts such mobile IP are also introduced here.
The last three chapters concern a special topic that is of particular inter-
est—1xEV-DO (1x Evolution for Data Optimized), which has gained popularity in
recent years and is designed to work with an IS-2000 system. The topics related
1xEV-DO are included to make the book a more complete reference. Specifically,
Chapter 13 focuses on the top five layers of 1xEV-DO (i.e., application, stream, ses-
sion, connection, and security), and Chapters 14 and 15 cover medium access con
-
trol and physical layers of forward and reverse links, respectively.
Without a loss generality, this book emphasizes Spreading Rate 1 at 1.25 MHz.
The discussions on Spreading Rate 1 can be readily extended to direct-spread or
multiple-carrier options of wider bandwidths. In addition, throughout the book we
cite specific examples of radio configurations instead of exhaustively describe the
details of every radio configuration. These selective descriptions serve to illustrate
more fully the reason for a particular implementation. Overall, the emphasis of the
book is on the conceptual understanding of the salient points, focusing on the
“how” and “why” instead of the “what.” It is hoped that the mastery of the material
presented will serve as a strong foundation from which readers can further explore
the technology.
This book is intended as a reference for radio frequency (RF) and system engi
-
neers, technical managers, and short-course students who desire to quickly get up to
speed on the essential technical issues of IS-2000. The material covered in the book
is broad enough to serve students of various backgrounds and interests and to allow
teachers much flexibility in designing their course material. As such, this book
should be a good complement to advanced undergraduate or first-year graduate
level courses in wireless communications as well.

xiv Preface
Finally, the material presented in this book is given for informational purpose
and instructional value and is not guaranteed for any particular purpose. The pub
-
lisher or the author does not offer any warranties or representations and does not
accept any liabilities with respect to the material presented in this book. Further
-
more, as technical information changes quickly, the purchaser of the book or user of
the information contained in this book should seek updated information from other
sources. The publisher or the author assumes no obligation to update or modify the
information, nor does the publisher or the author undertake any obligation to
notify the purchaser of the book or user of the information contained in the book of
any update. The purchase of the book or the use of the information contained in the
book signifies the purchaser’s or user’s agreement to the above.
Preface xv
.
Acknowledgments
As always, the completion of a book would not be possible without the support of
many people. I would like to thank Barry Pasternack who has given me encourage
-
ment during this project as well as guidance in other areas, Mabel Kung who has
spent many hours giving me support and words of wisdom, Paul Minh who has
given me advice during the writing of this book, and Joseph Sherif who is always
willing to make himself available for conversations. I appreciate Samir Chatterjee
who often meets with me to discuss various technical topics, and Lorne Olfman who
has continued to give me guidance out of his busy schedule. I also thank the reviewer
whose suggestions have made this a better book.
I am also grateful to the editors at Artech: Mark Walsh who has given me much
valuable feedback in the initial formulation of this project, and Barbara Lovenvirth
who has done a great job managing the project and keeping me on track. I also

thank Jill Stoodley and the staff at Artech for their help in the production of the
book.
No acknowledgment will be complete without mentioning my wife, Jenny, who
has supported all my endeavors with a gentle spirit and has always encouraged me. I
can always count on her for being there, and I am very much thankful for her. Last
and not the least, I would like to mention my son, Daniel, who has been a source of
my joy; his laughter and cheerful spirit have always given me strength during chal-
lenging parts of this project, and this book is also dedicated to him.
xvii
.
CHAPTER 1
Introduction to 3G CDMA
1.1 Third Generation Systems
While there are several wireless standards and systems that qualify as third genera
-
tion (3G) systems, this book specifically deals with the IS-2000 implementation of
3G. In the mid-1990s, the International Telecommunication Union (ITU) initiated
an effort to develop a framework of standards and systems that will provide wireless
and ubiquitous telecommunications services to users anywhere at anytime. Subse
-
quently, International Mobile Telecommunications-2000 (IMT-2000), a subgroup
of the ITU, published a set of performance requirements of 3G. It is useful to review
the performance requirements of a 3G wireless system, which are as follows (for
both packet-switched and circuit-switched data):
•
A minimum data rate of 144 Kbps in the vehicular environment;
•
A minimum data rate of 384 Kbps in the pedestrian environment;
•
A minimum data rate of 2 Mbps in the fixed indoor and picocell environment.

In addition, in all environments the system must support same data rates for
both forward and reverse links (symmetric data rates), as well as support different
data rates for both forward and reverse links (asymmetric data rates) [1].
Some standards and systems such as Universal Mobile Telephone System
(UMTS) are implemented in the new 3G spectrum (e.g., in Europe). While other
standards and systems such as IS-2000 can introduce 3G services in spectrums
already used by second generation (2G) systems (e.g., in North America). The latter
case takes into account those investments already deployed in the field where useful
and necessary [2]. The correction in the valuation of high-technology assets in early
2000 underscores the importance of making calculated infrastructure investment
while taking into account the market demand for these services. This consideration
is one reason why IS-2000 has gained popularity in the initial deployment of 3G [3].
In addition, as will be seen in later chapters of this book, IS-2000 is backward
compatible with existing 2G IS-95 systems. This backward compatibility gives
IS-2000 two important advantages. First, IS-2000 is able to support the reuse of
existing IS-95 infrastructure equipment and hence requires only incremental invest
-
ment to provide 3G services. Second, because IS-2000 represents a natural technical
evolution from its predecessor, there is a lower implementation risk when transi
-
tioning to 3G.
1
1.2 Protocol Architecture
One architectural difference between the IS-2000 standard and the IS-95 standard is
that IS-2000 calls out explicitly the functions of four different protocol layers. These
layers are the physical layer, medium access control, signaling link access control,
and upper layer.
Physical layer (Layer 1) [4]: The physical layer is responsible for transmitting
and receiving bits over the physical medium. Since the physical medium in this case
is over the air, the layer would have to convert bits into waveforms (i.e., modulation)

to enable their transmission through air. In addition to modulation, the physical
layer also carries out coding functions to perform error control functions at the bit
and frame levels.
Medium access control (MAC) sublayer (Layer 2) [5]: The MAC sublayer con
-
trols higher layers’ access to the physical medium that is shared among different
users. In this regard, MAC carries out analogous functions as a MAC entity that
controls a local area network (LAN). Whereas a LAN MAC controls different com
-
puters’ access to the shared bus, the IS-2000 MAC sublayer manages the access of
different (low-speed voice and high-speed data) users to the shared air interface.
Signaling link access control (LAC) sublayer (Layer 2) [6]: The LAC sublayer
is responsible for the reliability of signaling (or overhead) messages that are
exchanged. Recall that the over-the-air medium is extremely error-prone, and infor-
mation messages are at times received (and accepted) with errors. On the other
hand, since signaling messages provide important control functions, these messages
have to be reliably transmitted and received. The LAC sublayer performs a set of
functions that ensure the reliable delivery of signaling messages.
Upper layer (Layer 3) [7]: The upper layer carries out the overall control of the
IS-2000 system. It exercises this control by serving as the point that processes all and
originates new signaling messages. The information (both data and voice) messages
are also passed through Layer 3.
Recall that the IS-95 standard does not explicitly and separately describe the
functions of each layer. However in IS-95 those functions that are carried out by the
layers do exist. For example, in IS-95 mobile access is logically a function of the
MAC sublayer, but its descriptions are lumped together with the other functions
within a single standard.
At this point the reader may ask why the layered architecture was not employed
in IS-95 but now used in IS-2000. The layered architecture is now used in IS-2000
because it brings the system into conformance with the 3G architecture delineated in

IMT-2000. The IMT-2000 framework calls for different networks to cooperate to
provide services to end users, and the level and extent of these cooperation are more
clearly organized if viewed from the perspective of the layered architecture. Well-
defined layer functions provide modularity to the system. As long as a layer still per
-
forms its functions and provides the expected services, the specific implementation
2 Introduction to 3G CDMA
of its functions can be modified or replaced without requiring changes to the layers
above and below it [8].
Figure 1.1 shows the structure of the protocol architecture used by IS-2000.
Without a loss of generality, this figure is shown from the perspective of the mobile
station; a similar figure can also be drawn from the perspective of the base station by
reversing the direction of some arrows and changing the placement of some entities.
Figure 1.1 is a rather important figure and we will refer to it from time to time
throughout the book. For now, note the three different layers (Layers 1, 2, and 3),
the two sublayers in Layer 2 (MAC and LAC), the entities in the layers [e.g., Signal
-
ing Radio Burst Protocol (SRBP)], and the communication paths among the layers
and entities. Also note that the layer structure shown in Figure 1.1 resembles that of
the Open Systems Interconnection (OSI) Reference Model [9].
1.3 Other Elements of Protocol Architecture
In addition to the individual layers themselves, other important elements of the pro
-
tocol architecture are described as follows:
Physical channels: The physical channels are the communication paths between
the physical layer and the common/dedicated channel multiplex sublayers. The
physical channels are designated by uppercase letters. In the designation, the first
1.3 Other Elements of Protocol Architecture 3
Reverse link: coding and modulation
Forward link: demodulation and decoding

Common channel
multiplex sublayer
Dedicated channel
multiplex sublayer
SRBP
f-csch
f-csch
r-csch
LAC PDU
RLP
f-dtch
f-dsch
r-dtch
r-dsch
Signaling LAC
f-dtch voice
r-dtch voice
Signaling
RLP SDU
RLP SDU
L3PDU
L3PDU
Upper layers
LAC
sublayer
MAC
sublayer
Physical layer
Layer 3
Layer 2

Layer 1
Data
services
Voice
services
Data burst
Data burst
RL
FL
R-CCCH
R-EACH
R-ACH
F-DCCH
F-SCH
F-FCH
R-DCCH
R-SCH
R-FCH
F-BCCH
F-CCCH
F-PCH
F-CPCCH
F-CACH
F-SYNCH
Figure 1.1 Structure of the protocol architecture used by IS-2000. (Note that this structure is
shown from the perspective of the mobile station. After: [5].)
letter and the dash stand for either forward link (F-) or reverse link (R-), and the last
two letters “CH” always stand for “channel.” For example, R-ACH stands for
reverse access channel, and F-FCH stands for forward fundamental channel. A list
of physical channel names and their designations is shown in Table 1.1; note that

legacy IS-95 physical channels are denoted with asterisks.
Logical channels: The logical channels are the communication paths between the
common/dedicated channel multiplex sublayers and higher layer entities. One can
think of logical channels as carrying the logical units of signaling or user informa
-
tion. Contrast those with physical channels which can be thought of as the actual
physical vehicles that transport the signaling or user information over the air.
The logical channels are designated by lower-case letters. The first letter and the
dash stand for either forward link (f-) or reverse link (r-), and the last two letters
“ch” always stand for “channel.” For example, r-csch stands for reverse common
signaling channel, and f-dtch stands for forward dedicated traffic channel. A list of
logical channel names and their designations are shown in Table 1.2.
Data unit: The data units are logical units of signaling and user information that
are exchanged between SRBP entity/Radio Link Protocol (RLP) entity and higher
layer entities. There are two types of data units: payload data units (PDU) and serv-
ice data units (SDU). PDU is used to designate those data units that are accepted by a
4 Introduction to 3G CDMA
Table 1.1 Physical Channel Designations in IS-2000
Forward Link
Channel
Designation
Channel Name
Reverse Link
Channel
Designation
Channel Name
F-SCH Forward supplemental channel R-SCH Reverse supplemental channel
F-SCCH Forward supplemental code channel R-SCCH
Reverse supplemental code
channel

F-FCH* Forward fundamental channel R-FCH* Reverse fundamental channel
F-DCCH Forward dedicated control channel R-DCCH
Reverse dedicated control chan
-
nel
F-PCH* Paging channel
F-QPCH Quick paging channel
R-ACH* Access channel
R-EACH Enhanced access channel
F-CCCH Forward common control channel R-CCCH
Reverse common control
channel
F-BCCH Broadcast control channel
F-CPCCH Common power control channel
F-CACH Common assignment channel
F-SYNCH* Sync channel
F-PICH* Forward pilot channel R-PICH Reverse pilot channel
F-TDPICH Transmit diversity pilot channel
F-APICH Auxiliary pilot channel
F-ATDPICH
Auxiliary transmit diversity pilot
channel
provider of service from a requester of service, and SDU those data units that are
given to a provider of service by a requester of service
1
. The use of PDUs and SDUs is
discussed in more detail later in Chapter 4 (medium access control), Chapter 5 (link
access control), and Chapter 6 (upper layer signaling).
In the MAC sublayer, there are four different entities: SRBP, RLP, common
channel multiplex sublayer, and dedicated channel multiplex sublayer. Common

channel multiplex sublayer performs the mapping between the logical com-
mon channels (channels that are shared among multiple users) and the physical
common channels. Dedicated channel multiplex sublayer performs the mapping
between the logical dedicated channels (channels that are dedicated to specific
users) and the physical dedicated channels. Note that while dedicated channels
can be used for both signaling and user data, common channels are only used
for signaling.
SRBP and RLP are protocol entities in the MAC sublayer. They are described in
more detail in Chapter 4. It suffices to say now that SRBP handles common-channel
signaling (as opposed to dedicated-channel signaling) and RLP handles user infor-
mation that is packetized in nature.
1.4 Spreading Rate 1 and Spreading Rate 3
Without a loss of generality, this book will focus on Spreading Rate 1 (also known
as “1x”) of IS-2000. Spreading Rate 1 by definition uses one times the chip rate of
IS-95 (i.e., 1.2288 Mcps). See Figure 1.2. In addition, the IS-2000 standard also sup
-
ports Spreading Rate 3 (also known as “3x”). Spreading Rate 3 is used when higher
data rates are desired. Spreading Rate 3 has two implementation options: direct
spread (DS) or multicarrier (MC).
On the forward link, Spreading Rate 3 uses the MC option by utilizing three
separate RF carriers, each spread using a chip rate of 1.2288 Mcps. In this case, the
user data is multiplexed onto three separate RF carriers that are received by the
mobile. On the reverse link, Spreading Rate 3 uses the DS option. The DS option
allows the mobile to directly spread its data over a wider bandwidth using a chip
rate of 3.6864 Mcps. See Figure 1.3. To harmonize with other 3G systems such as
1.4 Spreading Rate 1 and Spreading Rate 3 5
Table 1.2 Logical Channel Designations in IS-2000
Forward Link
Channel
Designation

Channel Name
Reverse Link
Channel
Designation
Channel Name
f-csch Forward common signaling channel r-csch
Reverse common signaling
channel
f-dsch Forward dedicated signaling channel r-dsch
Reverse dedicated signaling
channel
f-dtch Forward dedicated traffic channel r-dtch Reverse dedicated traffic channel
1. In the OSI Reference Model, a higher layer entity typically requests services from a lower-layer entity.
UMTS, a Spreading Rate 3 signal can have 625 kHz of guard band on each side
resulting in a total RF bandwidth of 5 MHz.
These options for the forward and reverse links are included in the standard in
order to reduce the complexity of the mobile’s receiver. As readers may have already
noticed, the above-stated configurations mean that the mobile’s receiver only has to
receive and demodulate 1x carriers and does not have to receive and demodulate any
3x carrier.
Incidentally, a mobile can also receive at Spreading Rate 3 and transmit at
Spreading Rate 1. See Figure 1.4. This particular arrangement takes advantage of
the fact that data rates required for downstreaming are typically higher than those
required for upstreaming.
Wider bandwidth options such as 6x, 9x, and 12x are under consideration for
even higher data rate applications. As far as 3G systems are concerned, Spreading
Rate 3 satisfies all the performance requirements as set forth by IMT-2000.
6 Introduction to 3G CDMA
Base
station

Mobile
station
1.25 MHz
Forward link
Reverse link
1.25 MHz
Figure 1.2 Spreading Rate 1. A chip rate of 1.2288 Mcps occupies an RF bandwidth of 1.25
MHz.
Base
station
Mobile
station
3.75 MHz
Forward link
Reverse link
3.75 MHz
Figure 1.3 Spreading Rate 3.