Preface

Wireless networks are evolving into wireless IP (Internet Protocol) networks to overcome the limitations of traditional circuit-switched wireless networks. Wireless IP networks are more suitable for supporting the rapidly growing mobile data and multimedia applications. IP technologies bring the globally successful Internet service creation and offering paradigm to wireless networks, bringing the vast array of Internet services to mobile users and providing a successful platform for fostering future mobile services. IP-based protocols, which are independent of the underlying radio technologies, are also better suited for supporting seamless services over heterogeneous radio technologies and for achieving global roaming.

Wireless networks are evolving on two major fronts. First, radio access systems are evolving to third and fourth generation systems that can support significantly higher system capacity and per-user data rates with enhanced quality-of-service (QoS) support capabilities. Second, wireless IP networking technologies are profoundly changing the overall wireless network architectures and protocols.

Many books are available on radio access systems, examining the physical, link, and network layers specific to each radio system. Few books, however, have been designed to systemically address the wireless IP networking aspect, i.e., architectures, protocols, and techniques at the IP layer and above of a wireless IP network. This book seeks to provide a systematic description and comparison of next-generation wireless IP network architectures, systems, and protocols, with a focus on the IP layer and above.

Several major efforts have emerged to define global standards for wireless IP networks. The two most influential standards bodies are 3GPP (Third Generation Partnership Project) and 3GPP2 (Third Generation Partnership Project 2). Different standards efforts have been taking significantly different approaches, which lead to different architectures and different migration paths toward future wireless IP networks. This book provides insights into critical issues in wireless IP networking, thoroughly illustrates the standards and network architectures defined by leading standards bodies such as 3GPP and 3GPP2, and discusses in detail protocols and techniques in four major technical areas: signaling, mobility, security, and QoS.

To provide the necessary background, the book starts by presenting a historical overview of the evolution of wireless networks in Chapter 1, Introduction. Chapter 1 then reviews the evolution of public mobile services by examining the first, second, and current waves of mobile data services. It continues on to discuss the motivations for IP-based wireless networks and provides an overview of related standards activities.

Chapter 2 details the network architectures defined by 3GPP and 3GPP2. To help readers quickly get a sense of the solutions proposed by 3GPP and 3GPP2 and to easily identify their fundamental differences, Chapter 2 presents the most important aspects of the architectures proposed by 3GPP and 3GPP2 in a consistent format and highlights their major differences. In addition, the all-IP mobile network architecture proposed by the Mobile Wireless Internet Forum (MWIF) is also discussed.

Chapters 3 to 6 address systematically four of the most critical topic areas in next-generation wireless networks: signaling, mobility management, security, and QoS. Because Chapter 2 discusses network-layer signaling and control necessary for the operations of the networks, Chapter 3 focuses on application-level signaling and session control needed to support real-time and multimedia applications in IP networks and in the IP Multimedia Subsystems (IMS) defined by 3GPP and 3GPP2. Chapters 4, 5, and 6 discuss issues and solutions related to mobility management, network security, and QoS, respectively. Each chapter looks first at the subject in IP networks, then at the architectures and protocols defined by 3GPP and 3GPP2. The MWIF specifications are discussed in some chapters if related issues in MWIF are also addressed.

The book is designed primarily for researchers, engineers, technical managers, and graduate and undergraduate students. People entering the field of wireless IP networking will also find this book a helpful reference. The book emphasizes the principles underlying each major architecture and illustrates these principles with abundant technical details. It provides the audience with perspectives that are difficult to obtain from reading the standards specifications directly.

We are grateful to the ITSUMO (Internet Technologies Supporting Universal Mobile Operation) team from Telcordia Technologies, Inc. and Toshiba America Research, Inc. (TARI). Our work on the ITSUMO project and discussions with the ITSUMO members contributed to the book. Special thanks are due to Dr. Prathima Agrawal of Telcordia and Dr. Toshikazu Kodama of TARI for their continuous support and invaluable advice throughout the writing of the book. We thank Mr. Chi-Chen Lee, Mr. Jui-Hung Yeh, and Mr. Chih-Hsing Lin of the National Tsing Hua University for preparing many of the figures, tables, and references in the book. Jyh-Cheng Chen would also like to acknowledge the project members of the "Program for Promoting Academic Excellence of Universities" for many insightful discussions. Jyh-Cheng Chen's work was supported in part by the Ministry of Education, Taiwan, National Science Council (NSC), and Industrial Technology Research Institute (ITRI).

Jyh-Cheng Chen
Tao Zhang

August 2003