UMTS
The Fundamentals
B. WALKE P. SEIDENBERG M. P. ALTHOFF
Contents
Preface IX
1 Digital Data Transmission 1
1.1 Digital modulation 1
1.2 QPSK modulation 2
1.3 Spectral characteristics of modulated signals 4
1.4 Noisy transmission 7
2 Cellular Mobile Radio Networks 11
2.1 First generation mobile radio systems 11
2.2 The cellular concept 12
2.3 Frequency reuse and cluster formation 13
2.4 Propagation attenuation 15
2.5 Interference and co-channel interference 16
2.6 Range, interference and capacity limited systems 18
2.7 Handover and location update 21
3 Standardisation and Spectrum 23
3.1 From 2G to 3G 23
3.2 The IMT-2000 family 8
3.3 Standardisation of UMTS 33
3.4 Timetable for the introduction of UMTS 37
3.5 Release 99, Release 4 and Release 5
3.6 Frequency spectrum for UMTS 42
3.7 Questions 45
4 UMTS System Architecture 47
4.1 Basic system architecture 47
4.2 Functional units in UMTS 8
4.3 Types of switching 50
4.4 Architecture of the access plane
4.4.1 Mobile Services Switching Centre (MSC)
4.4.2 Home Location Register (HLR)
4.4.3 Visitor Location Register (VLR)
4.4.4 Serving GPRS Support Node (SGSN)
4.4.5 Gateway GPRS Support Node (GGSN)
4.4.6 GPRS Register (GR) VI Contents
4.4.7 Radio Network Controller (RNC)
4.4.8 Node B
4.4.9 User Equipment (UE) 61
4.5 Handover in UMTS
4.5.1 The role of RNC in a handover
4.5.2 Handover types in UMTS 66
4.6 Location management 68
4.7 Circuit-switched and packet-switched connections 71
4.8 Protocols in the fixed network 75
4.9 Protocols at the Iu-interface
4.9.1 Radio Access Network Application Part (RANAP)...
4.9.2 Radio Network Subsystem Application Part (RNSAP).
4.9.3 Protocol stack for circuit-switched services
4.9.4 Protocol stack for packet-switched services 80
4.10 Pure IP core network architecture 82
4.10.1 Session Initiation Protocol (SIP) 84
4.10.2 IP core network - pros and cons 6
4.11 Questions 89
5 The Protocol Stack at the Radio Interface 91
5.1 The ISO/OSI reference model 91
5.2 The UTRA protocol stack 4
5.3 The physical layer 95
5.4 The MAC layer 6
5.5 The RLC layer 7
5.6 The BMC layer 99
5.7 The PDCP layer 100
5.8 The RRC layer
5.9 Transport channels 102
5.10 Transport formats 3
5.11 Logical channels 106
5.12 Questions 108
6 Data Transmission at the UMTS Radio Interface 111
6.1 The UTRA radio interface 111
6.2 Duplex procedures 112
6.3 The frequency-division duplex tech-nique 112
6.4 The time-division duplex technique 113
6.5 Multiple-access procedures 114
6.6 Direct-sequence CDMA 118
6.7 Spectral characteristics of CDMA signals 119
6.8 Reception of CDMA signals 120
9 Processing gain 123
6.10 A CDMA transmission system 5 1 Spreading codes
6.12 Orthogonal spreading codes in UMTS 128
6.13 Modulation in UMTS 131
6.14 CDMA receivers 2
6.15 The nearfar effect 134
6.16 Questions 136
7 The Physical Layer at the Radio Interface 139
7.1 The physical layer in the UTRA protocol stack 139
7.2 Mapping transport channels to physical channels 139
7.3 Multiple access in UMTS
7.3.1 Multiple access in FDD mode
7.3.2 Multiple access in TDD mode
7.3.3 Multiple access in the TDD mode low chip rate option. 145
7.4 Power control
7.4.1 Power control in FDD mode
7.4.2 Power control in TDD mode 149
7.5 Channel coding, multiplexing and interleaving
7.5.1 TDD mode and FDD uplink
7.5.2 FDD down-link
7.5.3 Summary 156
7.6 Mapping of 12.2 kbit/s voice transport channel 156
7.7 Questions 158
8 Physical Channels and Procedures at the Radio Interface 159
8.1 Physical channels in the UTRA protocol stack 159
8.2 Physical channels in FDD
8.2.1 Dedicated transmission on the FDD uplink
8.2.2 Dedicated transmission on the FDD downlink
8.2.3 Compressed mode
8.2.4 Random access procedure in FDD
8.2.5 Cell search procedure in FDD 172
8.3 Physical channels in TDD mode 173
8.4 Physical chan-nels in TDD mode low chip rate option 178
8.5 Mapping of transport channels to physical channels 180
8.6 Questions 186
9 Cellular CDMA Networks 187
9.1 Interference 187
9.2 Cell breathing
9.3 Traffic capacity in cellular CDMA networks 191
9.4 Soft handover 194
9.5 Questions
10 Service Architectures and Services in UMTS 201
10.1 Virtual Home Environment (VHE) 201
10.2 MExE 206
10.3 SIM Application Toolkit (SAT) 208
10.4 Open Service Architecture (OSA) 9
10.5 Services and mobile applications 211
10.6 The voice service in UMTS 216
10.7 Questions 217
11 The Next Generation of Mobile Radio Systems 219
11.1 Cordless, wireless and mobile radio systems 220
11.2 Asymmetric traffic in mobile radio systems 225
11.3 Spectrum issues 226
11.4 Mobile radio and television fre-quencies 229
11.5 Electromagnetic compatibility 233
11.6 UMTS traffic capacity 234
11.7 Developments with W-LANs 237
11.8 W-LANs in integrated radio networks 243
11.9 The wireless media system 246
11.10 Multi-hop and Ad-Hoc Communication 254
11.11Conclusion 257
Answers to questions 261
List of UMTS Release 4 specifications 279
Acronyms 293 Index
Preface
UMTS
is a socalled Third Generation (3G) mobile radio system and is seen as
the successor to Second Generation (2G) systems such as GSM and to
evolved 2G systems such as the General Packet Radio Service (GPRS). It
has a completely different air inter-face that is based on Code Division
Multiple Access (CDMA), whereas most of the 2G and evolved 2G systems
in use in most parts of the world use Time Division Multiple Access
(TDMA). The expert knowledge on the functioning and behaviour of 2G
networks can only be of limited use in 3G systems.
As
a consequence, people working in UMTS develop-ment, marketing,
operation and teaching have to update the knowl edge to be able to
fulfil their duties. The introduction of UMTS in the field as the next
generation technology re-quires knowledge of its concepts, archi
tecture, procedures and techniques as a prerequisite for all those
involved in the introduction of UMTS in one way or another.
This
book presents the valuable experience gained by the authors from teach
ing university courses on UMTS graduate students and teaching continuing
education courses to engineers and man-agement personnel in industrial
com panies. The material contained is based on the au-thors' research
work on UMTS and the implementation and traffic performance evaluation
of the complete UMTS protocol stack [35]. In presenting the course in
form of a book we are acceding to the requests of companies and
professional teaching organizations to make the material available to
the public.
The
material has not been selected with the intention of providing
developers of UMTS with the detailed knowledge necessary to design and
im-prove a real system but to enable those working with UMTS to be able
to understand the relevant concepts and their impact on the roll-out,
operation, usability and capabilities of the system. The comprehensive
introduction to UMTS is aimed at teaching the basics, functions and ways
of operation of UMTS to those working in development departments and to
operators of UMTS in an easy-to-follow manner. Since it is planned to
introduce two versions of UMTS, namely one frequency and one time
division duplexing based sys-tem, both are covered here. To ease the
study of the material and to allow for a common basis of un derstanding,
we open the book with two chapters on the basic functioning of cellular
mobile radio systems and digital transmission of information via radio
channels.
After
that, chapters on the transmission technique and the proto cols of the
UMTS air in-terface follow. Later sections of the book are devoted to
the system architecture, the various network elements and the protocols
used in the UMTS fixed core network. The keys to the commercial success
of UMTS are new services that are not available with the existing mobile
radio systems. This is why we introduce future service architectures
and services for UMTS that have already been exper-imented with in the
GPRS. Further, we describe the development paths to evolved 3G sys-tems
and as well as discussing spectrum availability, we evaluate the
suitability of Wireless Broadband Systems based on Local Area Networks
(LAN) to supplement 3G mobile radio systems. UMTS: The Fundamentals is
primarily aimed as a course book for self-study and as background
material for course teaching. Beyond what is available from the textbook
we offer additional teaching material that can be ordered using the.
Based
on their knowledge of GSM, GPRS and UMTS, the authors have started a
consulting company called P3 Solutions, which offers courses, consulting
services and testing in the field of 2G and 3G
(http://www.p3-solutions.com). Our warm thanks go to Ingo Forkel, PhD
student at the chair for Communi cation Networks at Aachen University of
Technology (RWTH) for his valuable input and his assistance in the
completion of the book.
The
text has been gradually expanded from a first version pub-lished in
German. Our thanks go also to Hedwig Jourdan von Schmoeger for the
careful translation into English. Thanks are also due to Mark Hammond of
Wiley & Sons for his excellent cooperation during the preparation
of this book.
Aachen, March 2003 Bernhard Walke,
Peter Seidenberg, Marc Peter Althoff
1 Digital Data Transmission
This
course unit briefly summarizes some of the basic con-cepts of digital
mes sage transmission that are important for understanding data
transmis-sion in UMTS. The particular topics covered are digital
modulation, the spectral character-istics of signals, the problematic
aspects of error-prone transmission and the throughput achievable in
digital wireless communication systems.
1.1 Digital modulation
Digital
Modulation information source information sink receiver Digital
modulation transforms a character sequence so that it can be transmitted
over a channel and be reconstructed again in the receiver.
Figure
1.1: Digital modulation A message transmission system generally
consists of a message source, a trans mitter, a channel, a receiver and
an information sink.
Digital
modulation is the modulation of messages represented by characters that
takes place in the transmitter (see Figure 1.1). This means that by
digital modulation a charac ter sequence supplied by an information
source is transformed so that it can be transmitted over a channel and
be reconstructed again in the receiver.
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