CDMA Mobile Radio Design
`
`Petitioner's Exhibit 1009
`Page 001
`
`

`

`CDMA Mobile Radio Design
`
`John B. Groe
`Lawrence E. Larson
`
`Artech House
`Boston l London
`www.artechhouse.com
`
`Petitioner's Exhibit 1009
`Page 002
`
`

`

`Library of Congress Cataloging-in-Publication Data
`Groe, John B.
`CDMA mobile radio design/John B. Groe, Lawrence E. Larson.
`p. cm. -
`(Artech House mobile communications series)
`Includes bibliographical
`references and
`index.
`ISBN l-58053-059-1 (alk. paper)
`telephone systems. 3. Mobile
`1. Code division multiple access. 2. Cellular
`communication systems. I. Larson, Lawrence E. II. Tide. III. Series.
`
`TK5 103.452.G76 2000
`621.3845-dc21
`
`00-027455
`CIP
`
`British Library Cataloguing in Publication Data
`Groe, John B.
`CDMA mobile radio design. - (Artech House mobile
`communications series)
`1. Cellular radio -- Design 2. Wireless communication systems
`-Design 3. Code division multiple access
`I. Tide II. Larson, Lawrence E.
`621.3’845
`
`ISBN l-58053-059-1
`
`Cover design by Igor Valdman
`
`0 2000 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, including
`photocopying, recording, or by any information storage and retrieval system, without permis-
`sion in writing from the publisher.
`All terms mentioned in this book that ate known to be trademarks or service marks have
`been appropriately capita&d. Artech House cannot attest to the accuracy of this information.
`Use of a term in this book should not be regarded as affecting the validity of any trademark or
`service mark.
`
`International Standard Book Number: l-58053-059-1
`Library of Congress Catalog Card Number: 00-027455
`
`1 0 9 8 7 6 5 4 3 2 1
`
`Petitioner's Exhibit 1009
`Page 003
`
`

`

`Contents
`
`. . .
`XIII
`
`1
`
`7 7 8
`
`14
`16
`19
`
`21
`
`21
`24
`27
`
`Preface
`
`1 Introduction to Wireless
`Communications
`
`1.1
`
`1.2
`1.3
`1.4
`
`1.4.1
`1.4.2
`1.4.3
`1.5
`
`2
`2.1
`
`2.1 .l
`2.1.2
`
`for Cellular
`Network Architecture
`Wireless Communications
`
`Data Communication Techniques
`
`Protocols for Wireless Communications
`
`Radio Propagation in a Mobile Wireless
`Environment
`
`Path Loss
`
`Muitipath Fading
`
`Modeling the Communication Channel
`
`Wireless Standards
`
`References
`
`The CDMA Concept
`
`Direct-Sequence Spread-Spectrum
`Communications
`
`Spreading Codes
`
`Spread-Spectrum Performance
`
`Petitioner's Exhibit 1009
`Page 004
`
`

`

`Viii
`
`CDMA Mobile Radio Design
`
`2.2
`2.2.1
`2.2.2
`2.2.3
`2.2.4
`
`3
`3.1
`3.1.1
`3.1.2
`3.1.3
`3.2
`3.2.1
`3.2.2
`3.3
`3.3.1
`3.3.2
`3.3.3
`3.3.4
`3.3.5
`3.3.6
`
`4
`4.1
`4.2
`4.2.1
`4.2.2
`4.2.3
`
`4.3
`
`Overview of the CDMA IS95 Air Interface
`
`Forward Link
`
`Reverse Link
`
`Power Control Algorithm
`
`Performance Summary
`
`References
`
`The Digital System
`Architecture Issues
`
`The MCU
`
`The DSP
`
`Memory
`
`MCU Functions
`
`Protocol Administration
`
`Power Management
`
`
`Digital Signal Processing Algorithms
`
`The Sampling Theorem
`
`Sample Rate Conversion
`
`Digital Filters
`
`Fast Fourier Transforms
`
`Windowing Operations
`
`Detection Process
`
`References
`
`Speech Coding
`
`Characteristics of Human Speech
`
`Speech-Coding Algorithms
`
`Waveform Coders
`
`Vocoders
`
`Speech Coders for Wireless
`Communication Systems
`
`Speech Quality
`
`References
`
`29
`
`29
`
`34
`
`38
`
`39
`
`40
`
`43
`44
`
`4 4
`
`45
`
`4 6
`
`46
`
`4 7
`
`47
`
`49
`
`49
`
`52
`
`55
`
`57
`
`58
`
`60
`
`64
`
`67
`
`68
`
`69
`
`70
`
`72
`
`82
`
`83
`
`85
`
`Petitioner's Exhibit 1009
`Page 005
`
`

`

`5
`5.1
`5.1.1
`5.1'2
`5.1'3.
`5.2
`5.2.1
`5.2.2
`5.2.3
`5.2.4
`5.2.5
`
`6
`61
`6.1'1
`6.1.2
`6.2
`6.2'1
`6.2'2
`6.2'3
`6.2'4.
`6 3
`6.3'1
`6.3'2.
`6 4
`6.4'1
`6.4'2.
`
`7
`71
`7.1'1.
`
`Digital Modem
`
`Digital Modulator
`
`Synchronization
`
`Channel Coding
`
`Signal Filtering
`
`Digital Demodulator
`
`Pilot Acquisition
`
`Carrier Recovery
`
`Signal Leveling
`
`Data Detection
`
`Data Recovery
`
`References
`
`Data Converters
`A/D Conversion
`
`Ideal Sampling Process
`
`Nonideal Effects
`
`A/D Converter Architectures
`
`Parallel A/D Converters
`
`Multistage A/D Converters
`
`Algorithmic A/D Converters
`
`Noise-Shaping A/D Converters
`
`D/A Conversion
`
`Ideal Process
`
`Nonideal Effects
`
`D/A Converter Architectures
`
`Scaling D/A Converter Concepts
`
`Oversampled D/A Converters
`
`References
`
`RF System Fundamentals
`RF Engineering Concepts
`
`Duplex Operation
`
`87
`
`87
`
`88
`
`91
`
`94
`100
`101
`
`103
`
`106
`
`109
`
`113
`118
`
`121
`122
`122
`
`126
`
`127
`128
`129
`
`132
`
`134
`140
`140
`141
`
`145
`
`145
`
`146
`
`146
`
`149
`
`150
`
`150
`
`II
`
`Petitioner's Exhibit 1009
`Page 006
`
`

`

`X
`
`CDMA Mobile Radio Design
`
`7.1.2
`7.1.3
`7.1.4.
`7.1.5
`7 2
`7.2'1
`7.2'2
`7.2.3
`7 3
`7.3'1
`7.3'2
`7.3'3
`7.3.4
`7.4
`7.4'1
`7.4'2
`7.4'3
`7.4'4.
`
`8
`81
`8.1'1
`8.1'2. .
`8 2.
`83.
`8 4.
`8 5.
`
`8.5.1
`8.5.2
`8.5.3
`
`Frequency
`
`Translation
`
`Phase Modulation
`
`Noise
`
`Distortion
`
`Frequency
`
`Synthesis
`
`PLL Modes of Operation
`
`PLL Operation in Synchronous Mode
`
`PLL Nonideal Effects
`
`Transmitter
`
`System
`
`Spurious Response
`
`Spectral Regrowth
`
`Noise
`
`Gain Distribution
`
`Receiver System
`
`Sensitivity
`
`Selectivity
`
`Bit Error Rate and Frame Error Rate
`
`Gain Distribution
`
`References
`
`RF Transmitter Circuits
`I/Q Modulator
`
`Nonideal Effects in the I/Q Modulator
`
`I/Q Modulator Circuit Techniques
`
`Power Control
`
`in
`
`the RF Transmitter
`
`Upconverter Design
`
`SAW Filter Technology
`
`Power Amplifiers
`Applications
`
`for Transmitter
`
`PA Design Specifications
`
`PA Design Techniques
`
`Devices for PAs
`
`References
`
`151
`152
`154
`
`1 6 1
`1 6 2
`162 -
`165
`167
`168
`1 6 8
`1 7 0
`1 7 2
`1 7 3
`1 7 5
`176
`1 8 1
`1 8 2
`1 8 4
`
`187
`1 8 8
`1 8 9
`1 9 0
`1 9 3
`1 9 5
`1 9 6
`
`200
`202
`204
`210
`213
`
`Petitioner's Exhibit 1009
`Page 007
`
`

`

`Contents
`
`Xi
`
`RF Receiver Circuits
`
`R F LNAs
`
`Automatic Level Control
`
`I/Q Demodulator
`
`215
`215
`226
`Downconversion Mixers
`Passive Mixer Design 230
` 234
`Active Mixer Design
` 237
` 238
`240
`247
`
`Baseband Channel Select Filters
`
`References
`
`CDMA
`Next-Generation
`Concepts of Next-Generation CDMA
`
`Next-Generation CDMA and
`Channel
`
`the Physical
`
`Multirate Design in Next-Generation
`C D M A
`
`Spreading Technique for Next-
`Generation CDMA
`
`Advanced Error Control Techniques
`Next-Generation CDMA
`
`for
`
`Coherent Detection Methods
`
`Interoperability
`C D M A
`
`in Next-Generation
`
`Single-Carrier CDMA Option
`
`Forward Link
`
`in
`
`the Single-Carrier Option
`
`Reverse Link of Single-Carrier Option
`
`Acquisition
`
`and
`
`Synchronization
`
`Fast Power Control
`
`Air
`
`Interface
`
`for
`
`the Single-Carrier Option
`
`TDD CDMA Option
`
`Multicarrier CDMA Option
`
`Forward Link
`
`for
`
`the Multicarrier Option
`
`Reverse Link of
`
`the Multicarrier Option
`
`251
`252
`
`252
`
`253
`
`257
`
`261
`266
`
`266
`267
`268
`270
`273
`274
`276
`277
`278
`279
`281
`
`9
`9.1
`9.2
`9.2.1
`9.2.2
`9.3
`9.4
`9.5
`
`10
`10.1
`10.1.1
`
`10.1.2
`
`10.1.3
`
`10.1.4
`
`10.1.5
`10.1.6
`
`10.2
`10.2.1
`10.2.2
`10.2.3
`10.2.4
`10.2.5
`10.3
`10.4
`10.4.1
`10.4.2
`
`Petitioner's Exhibit 1009
`Page 008
`
`

`

`xii
`
`CDMA Mobile Radio Design
`
`10.4.3
`
`Power Control
`
`References
`
`11
`11.1
`11.1'1
`11.1'2.
`11.2
`11.2'1
`11.2'2
`11.2'3
`11.2'4.
`
`113
`11.3.1
`11.3'2
`11.3'3.
`
`11.3.4
`11.3.5
`11.4
`
`Advanced CDMA Mobile Radios
`Advances
`in Digital Signal Processing
`
`DSP Performance
`
`Improvements
`
`to
`
`the Digital Receiver
`
`Advanced RF Receivers
`
`Image Rejection Techniques
`
`Direct Conversion Receivers
`
`Digital
`
`IF Receivers
`
`Comparison of Advanced RF Receiver
`Architectures
`Advanced RF Transmitters
`.
`Direct Conversion Transmitters
`
`SSB Techniques
`Predistortion Techniques
`Linearization
`
`for Amplifier
`
`Feedforward PAs
`Linearized PAs With Nonlinear Circuits
`
`Advanced Frequency Synthesizers
`
`References
`
`Glossary
`
`About the Authors
`
`Index
`
`282
`
`283
`
`285
`
`285
`
`286
`
`287
`
`294
`
`294
`
`298
`301
`
`304
`
`304
`
`305
`
`306
`
`308
`3 1 1
`313
`
`317
`321
`
`325
`
`331
`
`333
`
`Petitioner's Exhibit 1009
`Page 009
`
`

`

`Preface
`
`Wireless communications is growing at a phenomenal rate. From 1991 to
`1999, the number of subscribers increased from about 25 million to over 250
`million. Incredibly, over the next seven years, the number. of subscribers is
` That growth rate is faster than
`expected to quadruple, to over 1 billion [ 1].
`that of any other consumer electronics product and is similar to that of the
`Internet.
`Originally, wireless communications were motivated by and intended for
`mobile voice services. Later on, the first analog systems were improved with
`digital techniques, providing increased robustness and subscriber capacity. In
`the near future, digital systems will be augmented to try to meet users’ insatiable
`need for even greater capacity and high-speed mobile data services.
`Wireless communications rely on multiple-access techniques to share
`limited radio spectrum resources. These techniques, which use frequency, time,
`and power to divide the precious radio spectrum, are described in standards
`and are highly regulated. As such, infrastructure and subscriber manufacturers
`can be different and interchangeable.
`This book details the complete operation of a mobile phone. It describes
`code division multiple access (CDMA) design issues but presents concepts and
`principles that are applicable to any standard. The book emphasizes CDMA
`because next-generation standards are based on that multiple-access technology.
`This book uniquely ties together all the different concepts that form the
`mobile radio. Each of these concepts, in its own right, is suitable material for
`a book, if not several books, but is presented in such a way as to highlight
`key design issues and to emphasize the connection to other parts of the mobile
`radio.
`
`Xiii
`
`Petitioner's Exhibit 1009
`Page 010
`
`

`

`xiv
`
`CDMA Mobile Radio Design
`
`Chapter 1 introduces some fundamentals of wireless communications. It
`describes the wireless network, which interfaces with landline services, and the
`procedures for communicating through the network. Chapter 1 illustrates the
`effects of radio propagation and reveals its impact on the mobile phone. It
`also lists some familiar wireless standards. Chapter 2 provides an overview of
`CDMA. It presents the basic concepts and highlights the key air interface
`requirements for the CDMA IS95 standard.
`Chapter 3 introduces the digital system, which consists of a digital signal
`processor (DSP) and a microcontroller unit (MCU). The chapter uncovers the
`myriad of important roles the digital system plays. It also reviews some digital
`signal processing fundamentals and describes some tradeoffs in architecture.
`Chapter 4 introduces speech coding, a key function of the digital system. It
`shows how voice signals are translated to low bit rate data streams and vice
`versa. Chapter 5 provides detailed information about digital modulation and
`demodulaton. It presents a practical Rake receiver and describes the receiver’s
`operation in the network. It also points out key timing issues and their effects
`on the performance of the mobile phone in the wireless network.
`Chapter 6 describes data converters, circuits that interface- the digital
`system to the auditory transducers (microphone and speaker) and the radio
`frequency (RF) transceiver. The chapter analyzes the nonideal effects of these
`interfaces and also presents fundamental data conversion techniques.
`Chapter 7 is the first of three chapters dedicated to the RF transceiver,
`the mobile radio’s connection to the air interface. It describes both the RF
`transmitter and the receiver from a system perspective, providing critical infor-
`mation about gain distribution and signal integrity. The chapter also presents
`insight into frequency synthesis and frequency planning in the mobile radio.
`Chapter 8 details the RF transmitter. It describes the transmit circuits between
`the digital-to-analog (D/A) converters’ outputs and the antenna. The chapter
`covers the I/Q modulator, variable gain amplifier (VGA), up-converter, filters,
`driver, and power amplifier (PA). Chapter 9 details the operation of the RF
`receiver. It provides a circuit level view of the receiver from the antenna to
`the A/D converters’ inputs. This chapter covers the low-noise amplifier (LNA),
`mixer, VGA, I/Q demodulator, and filters.
`Chapter 10 describes next-generation wireless services and standards. The
`chapter points out improvements to CDMA IS95 that will accommodate more
`users and higher data rates. It also details leading next-generation CDMA
`proposals. Chapter 11 illustrates architecture advances to support improved
`CDMA IS95 pe rformance and to meet the demands of next-generation CDMA
`networks. It addresses key areas, including the DSP, the RF transmitter, and
`the RF receiver.
`A book covering such a range of systems, architectures, and circuits crosses
`several engineering disciplines. As a result, we benefited from discussions with
`
`Petitioner's Exhibit 1009
`Page 011
`
`

`

`Preface
`
`xv
`
`and reviews by several colleagues. We would like to acknowledge Mr. Tom
`Kenney, Ryan Heidari, Sassan Ahmadi, and Ken Hsu of Nokia Mobile Phones;
`Professor George Cunningham of New Mexico Technical University; Professor
`Behzad Razavi of the University of California-Los Angeles; Professors Lau-
` Anthony Acompora, and Ian Galton of the
`rence Milstein, Peter Asbeck,
`University of California-San Diego; Professor John Long of the University
`of Toronto; and Mr. David Rowe of Sierra Monolithics.
`
`Reference
`
`[I] Viterbi, A. J., CDMA: Principles of Spread-Spectrum Communications, Reading, MA:
`Addison-Wesley, 1795.
`
`Petitioner's Exhibit 1009
`Page 012
`
`

`

`Introduction to Wireless
`Communications
`
`Wireless technology offers untethered service, newfound freedom, and the
`potential for “anytime, anyplace” communications. Consumers are embracing
`these services enthusiastically; their numbers are growing at a phenomenal rate
`and will continue to do so, as illustrated in Figure 1.1. The growth and
`the excitement of wireless communications are being driven by technological
`advancements that are making portable radio equipment smaller, cheaper,
`and more reliable. Those advancements include improved signal processing
`
`1000
`
`l -
`
`F0
`.---.-
`zw 600
`eaa.-
`
`800
`
`400
`
`200
`
`0
`
`1997
`
`1998
`
`1999
`
`2000 2001
`Year
`
`2002 2003
`
`t 4
`
`0
`
`Figure 1.1 The growth rate of wireless subscribers is phenomenal [1].
`
`1
`
`Petitioner's Exhibit 1009
`Page 013
`
`

`

`2
`
`CDMA Mobile Radio Design
`
`techniques, innovative digital and radio frequency (RF) circuit design, and
`new large-scale integrated circuit methods.
`This chapter introduces and describes key aspects of wireless networks.
`It investigates the wireline backbone, which facilitates wireless communications.
`That leads to an overview of the communication procedures used by both
`wireline and wireless networks. The chapter also details the effects of the radio
`link, which complicates radio design and leads to a variety of wireless standards.
`
`1.1 Network Architecture for Cellular Wireless
`Communications
`
`The wireless network supports over-the-air communications between mobile
`radios and stationary transceivers’ known as base stations. These links are
`reliable only over short distances, typically tens of meters to a few kilometers.
`As such, a network of base stations is needed to cover a large geographic area,
`for example, a city. Base stations communicate through mobile switching
`centers, which connect to external networks such as the public telephone
`switching network (PTSN), the integrated services digital network (ISDN),
`and the Internet, as shown in Figure 1.2.
`The mobile radio is free to move about the network. It relies on radio
`signals to form a wireless link to the base stations and therefore requires an
`RF transceiver. To support modern communication methods, the mobile radio
`
`0<
`
`Mobile
`
`radio
`
`Mobile
`
`radio
`
`Base station
`
`Public telephone
`switching network,
`Internet
`
`Figure 1.2 Wireless network architecture is an interconnection of mobile radios, base
`stations, mobile switching centers, and the external network.
`
`1.
`
`Transmitter-receiver
`
`combinations.
`
`Petitioner's Exhibit 1009
`Page 014
`
`

`

`Wire& Communications
`
`3
`
`includes a microcontroller unit (MCU) and a digital signal processor (DSP)
`to condition the signal before transmission and to demodulate the received
`signal (Figure 1.3).
`The base stations translate the radio signals into data packets and signaling
`messages that are readable by the wireline network, which then forwards the
`information to the mobile switching center.
`The mobile switching center routes the data packets based on the signaling
`messages and typically does not originate messages. In some cases, the mobile
`switching center may need to send queries to find wireless subscribers or
`portable local numbers (800- and 888-numbers).
`The external network provides the communications backbone that con-
`nects the mobile switching centers. It routes data packets, screens messages for
`authorization, verifies routing integrity, and converts protocols. The external
`network may also act as a gateway to different networks.
`The mobile switching center and the external network are signal transfer
`points that include measurement capabilities to indicate network problems and
`to monitor usage for billing purposes. Built-in redundancies in the network
`allow rerouting around faulty network points.
`The network also includes service control points that interface to comput-
`ers and provide database access. For example, the mobile switching center uses
`a service control point to access the home location register (HLR), the visitor
`location register (VLR), and the operation and maintenance center (OMC)
`files. Those databases list the subscribers in the home service area, track any
`
`RF transceiver
`
`Digital system
`
`Speaker
`
`Microphone
`
`Jser interface
`
`Figure 1.3 Modern mobile radio architecture consists of an RF transceiver and a digital
`system.
`
`Petitioner's Exhibit 1009
`Page 015
`
`

`

`4
`
`CDMA Mobile Radio Design
`
`roaming (i.e., visiting) subscribers in the coverage area, and hold authentication
`files.
`
`More information on network architectures can be found in [2-4].
`
`1.2 Data Communication Techniques
`
`Modern wireline and wireless networks rely on digital techniques for efficient
`communications. The techniques format message signals into data packets,
`thereby allowing multiple users to be “bundled’ at higher network levels. That
`is important because it reduces the number of physical connections required
`to connect a set of users. The bundling occurs at signal transfer points and
`typically uses time multiplexing methods [2].
`A basic wireline telephone channel for a single user supports a data rate
`of 64 Kbps; digital and optical data trunks carry higher data rates, as listed in
`Table 1.1.
`The data packets are routed through the network by either circuit-switched
`or packet-switched connections. In circuit-switched networks, the path between
`the user and the destination node is set up at the time the connection is
`established, and any needed resources are reserved until the connection is
`terminated. In packet-switched networks, the path is not fixed but is dynamically
`selected based on network loading conditions and the destination address
`appended to each data packet.
`low
`Circuit-switched networks provide dedicated connections with
`latency, while packet-switched networks offer greater flexibility with improved
`efficiency. Packet-switched networks are more complicated because data packets
`can take different paths and can be received out of order; the data packets
`must then be reassembled prior to final delivery to the user.
`
`Table 1.1
`Common Data Rates for Digital and Optical Networks
`
`[21
`
`Carrier Designation
`
`DSO
`T-1
`r-3
`STM-1
`STM-3
`STM-16
`
`Type
`
`Digital
`Digital
`Digital
`Optical
`Optical
`Optical
`
`Bandwidth
`
`Channels
`
`64 Kbps
`1.544 Mbps
`44.736 Mbps
`51.84 Mbps
`155.52 Mbps
`2,488.32 Mbps
`
`1
`24
`672
`810
`2,430
`38,880
`
`Petitioner's Exhibit 1009
`Page 016
`
`

`

`Wireh Communications
`
`5
`
`1.3 Protocols for Wireless Communications
`
`Multiple users in communication networks are organized using routing and
`flow control procedures, known as protocols. A protocol is a set of rules
`governing data transmission and recovery in communication networks. The
`rules ensure reliable, seamless transmission of data and provide network manage-
`ment functions.
`Protocols usually are organized as layers in a communication “stack.”
`Data is passed up or down the stack one layer at a time, with specific functions
`performed at each layer.
`Most communication networks follow the open system interconnections
`(OSI) model [5]. The seven-layer protocol stack, shown in Figure 1.4(a),
`includes the physical, data link, network, transport, session, presentation, and
`application layers. In wireless communication networks, a variation of the OS1
`model, the signaIing system number 7 (SS7) model [2-31, is used. This four-
`level protocol stack, shown in Figure 1.4(b), mirrors the first three layers of
`the OS1 model and combines the higher levels into a single application layer.
`The protocol stack defines the architecture of each signal transfer point
`or node in the network. It uses the physical layer to interconnect those nodes
`and provide a path through the network, plus the data link and network layers
`to translate control signals and reformat data for communication with different
`
`(a)
`
`(b)
`
`Figure 1.4 Network models: (a) OSI protocol stack typical of wireline networks and (b)
`SS7 protocol stack followed by wireless networks.
`
`Petitioner's Exhibit 1009
`Page 017
`
`

`

`6
`
`CDMA Mobile Radio Design
`
`networks. Data always flows from one layer to the next in the protocol stack,
`as shown in Figure 1.5, to ensure robust communications.
`Each layer in the protocol stack performs essential operations that are
`defined by the topology of the communication network. Those operations are
`outlined next.
`The physical layer is the interface between two communication nodes.
`In a wireless network, the physical layer is the air interface between the mobile
`terminal and the base station. In a typical wireline network, it is the digital
`or optical trunk. The physical layer provides transfer services to higher layers
`in the protocol stack. Those transfer services use physical channels, also known
`as transport channels, with defined data rates, modulation schemes, power
`control methods, and RF parameters. The physical layer is different for each
`unique communication standard.
`The data link layer combines the medium access control (MAC) and
`radio link control sublayers. The MAC sublayer maps basic functions known
`as logical channels to physical channels. That can be straightforward, or it can
`include multiplexing several logical channels onto a common physical channel.
`The data link layer also provides message sequencing, traffic monitoring, and
`signal routing to higher protocol layers.
`The radio link control sublayer breaks down the data stream into data
`packets, also known as transport blocks, for transmission. It includes error
`control to ensure the integrity of the transmitted data. Typically, that means
`a parity check or a cyclic redundancy check (CRC) based on a polynomial
`generator [6]. The radio link control layer also interfaces with the higher
`protocol layers and provides call initialization, connection, and termination.
`The network layer (or radio resource control layer) provides control and
`notification services. It supervises radio resources, including physical channel
`assignments, paging requests, and transmit power levels. It also interfaces to
`the wireline network and thereby enables connections to other users.
`
`Mobile radio
`
`Destination
`
`Network path
`
`Network
`I
`I
`Data link
`I
`I
`physical -.....
`
`Iaa.I-
`
`Figure 1.5 Data flow through the protocol stack for mobile communications.
`
`Petitioner's Exhibit 1009
`Page 018
`
`

`

`Wirehs Com~unicatiom
`
`7
`
`The application layer represents the destination node. It specifies quality-
`of-service (QoS) requirements (priority levels, security, response time expecta-
`tions, error rates, and recovery strategies) without the restrictions of the air
`and network interfaces. The application layer compresses and expands data in
`time to match the expectations of the mobile user.
`The physical layer, the data link layer, and the network layer combine
`to form the message transfer part (MTP) of the SS7 protocol stack, as shown
`in Figure 1.6. The MTP of the SS7 model covers transmission from node to
`node in the communication network. It also interfaces with high-level protocols
`tailored to specific applications. For voice communications, one of two high-
`level protocols is used: the telephone user part (TUP) or the ISDN user part
`(ISUP).
`
`1.4 Radio Propagation in a Mobile Wireless Environment
`
`The radio interface is unique to wireless communications and is responsible
`for much of the complexity associated with wireless networks and mobile
`phones. The radio interface between the mobile phone and the base station
`is referred to as the communication channel and is affected by large- and
`small-scale factors. The large-scale effects are due to simple attenuation of the
`transmitted signal through the atmosphere. The small-scale effects behave
`unpredictably, vary sharply over small distances, and change quickly.
`
`1.4.1 Path Loss
`A transmitted signal is attenuated as it propagates through the atmosphere.
`This large-scale effect, known as path loss, is modeled by
`
`,,,,, ,,,...,..,.. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,
`
` l..,.,.,,,..l...,..l.,,.
`
` ,,,,,,,,,,,,,, ,,,,,,,,,,,, ,,,,,,,,,,
`
`Control
`
`-Telephone user part
`TUP
`- Mobile application part
`MAP
`ISUP - ISDN user part
`MTP
`- Mobile
`telephone part
`
`Figure 1.6 The SS7 model and the relationships among its constituent parts.
`
`Petitioner's Exhibit 1009
`Page 019
`
`

`

`8
`
`COMA Mobile Radio Oesign
`
`r(d) cc d-”
`
`(1.1)
`
`where r(d) is the received power at a distance d separating the mobile and the
`base station, and n is the path loss exponent with typical values of 2.7 to 3.5
`for urban cellular radio [7]. The model is quite simple and is appropriate only
`for line-of-sight propagation.
`In practice, the signal path typically is cluttered by obstructions that
`reflect or block the transmitted signal and introduce statistical variability to
`the simple path loss model, as shown in Figure 1.7. This effect is known as
`shadowing and is modeled as a log-normal random variable [7]. That leads to
`a new expression for the received power:
`
`r(d) 0~
`
`lox/lo&-n
`
`(1.2)
`
`where x is the log-normal random variable used to model the shadowing effect.
`
`‘1.4.2 Multipath Fading
`
`The transmitted signal is not restricted to line-of-sight propagation. It can
`bounce off nearby obstructions, such as buildings and mountains, and arrive
`at the receiving antenna as shown in Figure 1.8. The reflected waves travel
`different paths to the receiving antenna and therefore experience different
`propagation delays and path losses. The resulting time-delayed versions of the
`signal are known as multipath rays. Multipath rays add vectorially and produce
`the fluctuations in the received power level shown in Figure 1.9, known as
`small-scale fading. Unfortunately, it is possible for multipath rays to combine
`
`d
`
`Figure 1.7 Received signal strength with path loss and log-normal shadowing.
`
`Petitioner's Exhibit 1009
`Page 020
`
`

`

`Introduct& to Wi’rcks Communications
`
`Figure 1.8 Multipath propagation of a transmitted signal arrives at the receiver with
`different delays.
`
`Elapsed Time (mS)
`
`Figure 1.9 Multipath fading produces a wide variation in the received signal strength as
`a function of time in a mobile environment. (from: T. S. Rappaport, Wireless
` 0 1995; reprinted by permission of Prentice-Hall, Inc., Upper
`Communicarions,
`Saddle River, NJ.)
`
`Petitioner's Exhibit 1009
`Page 021
`
`

`

`10
`
`CDMA Mobile Radio Des@
`
`destructively, and the received signal can disappear completely for a short
`period of time.
`The effects of multipath fading combine with large-scale path losses to
`attenuate the transmitted signal as it passes through the channel, as shown in
`Figure 1.10. The graph shows that the received power level at a distance d
`from the transmitting antenna depends on the simple path loss model altered
`by the shadowing and multipath distributions.
`Multipath fading is created by the frequency-selective and time-varying
`characteristics of the communication channel. Those characteristics are not
`deterministic and therefore must be analyzed using statistical methods. This
`approach is illustrated in the following examples.
`In the first case, two sinusoidal signals at frequencies fl and f2 are
`transmitted through the channel as shown in Figure 1 .l 1. The signals are
`affected by the channel, which attenuates the power level, T, of each signal
`independently. The attenuation process for each signal varies with frequency
`and can be described by two distinct probability density functions (pdf’s). If
`fi = f2, then the pdf’s o t
`f h e received power levels p (7) will be nearly the
`same, and the cross-correlation ‘between the two, R(Af ), will be high. As the
`separation between fi and f2 increases, their amplitude pdf’s will become
`dissimilar and their cross-correlation will be lower.
`The coherence bandwidth, (Af ),, is the range of frequencies in which the
`response of the channel remains roughly constant, that is, the cross-correlation is
`greater than one-half. In other words, the channel affects a range of frequencies
`(Af )C, from fi to fi, similarly.
`Therefore, narrowband signals that fit within the coherence bandwidth,
`experience nearly constant, or “flat,” frequency fading. That implies that the
`
`d
`
`Figure 1.10 Shadowing and multipath propagation affect received signal strength.
`
`Petitioner's Exhibit 1009
`Page 022
`
`

`

`Wire&x Communication5
`
`11
`
`S(f)
`
`WI
`
`tl-
`f
`fl
`
`li-
`f*
`f
`
`P(r)
`
`.*
`
`.*:
`P(f)
`
`‘.
`‘.
`‘.,
`
`fl
`
`‘.
`
`fi
`
`tLL.
`.
`lb!?-
`
`_c( Channel +W
`
`Path loss shadowing,
`multipath
`fading
`
`Figure 1.11 The frequency selective behavior of the channel affects the two transmitted
`signals differently.
`
`transfer function of the communication channel is spectrally uniform, with
`constant gain and linear phase. Wideband signals, like the ones generated
`by direct-sequence spread-spectrum modulation,2 typically extend beyond the
`coherence bandwidth and experience frequency-selective fading. With wide-
`band signals, only a portion of the signal fades; thus, the integrity of the radio
`link is preserved through frequency diversity.
`In the second example, two identical signals are transmitted at different
`times, tl and t2, as shown in Figure 1.12. The channel affects each signal’s
`received power level independently and produces distinct pdf’s for the two
`output waveforms. The pdf’s are cross-correlated to reveal changes in the
`channel. If tl = t2, the cross-correlation of the two waveforms will be high.
`But as the separation between tl and t2 increases, the cross-correlation will
`become lower and eventually fall below one-half. That indicates the time
`separation benveen signals where the channel response stays constant, that is,
`the time coherence of the channel, (At),. In other words, the response of the
`channel and the received power level is predictable as long as the separation
`in time between signals is less than the time coherence of the channel.
`The coherence bandwidth and time coherence parameters are key mea-
`sures of the communication channel. These parameters lead to a second set
`of parameters, known as the scattering functions, that describe the effect on
`
`2. Most cellular CDMA systems, such as CDMA IS95 and WCDMA, use direct-sequence
`spread-spectrum modulation.
`
`Petitioner's Exhibit 1009
`Page 023
`
`

`

`12
`
`COMA Mobile Radio Design
`
`Path loss shadowing,
`multipath fading -
`
`Figure 1.12 Time-varying behavior of the channel affects two pulses transmitted at
`separate times differently.
`
`the transmitted signal. The scattering functions S(T, Y) are found by taking
`the Fourier transforms of the cross-correlation functions, that is,
`
`where the multipath delay spread, r, is related to ll(Af)c and the doppler
`spread, Y, is associated with l/(At),.
`The cross-correlation parameters and scattering functions are small-scale
`effects caused by multipath propagation through the communication channel.
`These multipath rays are duplicate signals that are scaled and phase rotated
`relative to each other. Interestingly, at any instant t,, the received signal is a
`composite of these replica signals. Consequently, the received signal at time
`t, is described by
`
`Y2(to) = y&J
`n=O
`
`(1.4)
`
`where a, is the complex amplitude of the nth multipath rays.
`The multipath delay spread (7) is especially important in digital communi-
`cation systems. It measures the smearing or spreading in the received signal
`when an impulse is transmitted through the communication channel. Impulse
`smearing is shown in Figure 1.13 for a typical cellular system. The first peak
`in the response generally corresponds to the line-of-sight ray, while the other
`peaks reveal the scaling and propagation delay of the strong multipath rays.
`The delay spread covers the time interval from the first peak to the last significant
`peak.
`
`Petitioner's Exhibit 10