ISBN 0-471-81375-3 Online ISBN 0-470-84172-9 PREFACE The rapid growth in traffic volume and increase in new services has begun to change the configuration and structure of wireless networks. Thus, future mobile communica- tions systems will be distinguished by high integration of services, flexibility and higher throughput. To support such features, the efficient use of spectrum and optimum management of radio resources will be essential. To meet these challenges standardization bodies like ETSI (now expanded to 3GPP), have selected the Wideband Code Division Multiple Access (WCDMA) and the hybrid Time Division - CDMA as the radio techniques for the Universal Mobile Telecommu- nication Systems (UMTS). Hence, UMTS conceived at the eve of this new millennium will without doubt have a large impact on future wideband mobile networks and serve as the leading platform for wireless multimedia communications. The specification extracts in this book are intended to provide a concise reference for the many documents related to UMTS systems. After all, the whole UMTS specification set would probably exceed 4000 pages. Thus, it is hoped that the synthesis presented in this book will be useful in some way. In this context, in order to offer a complete source on the UMTS air interface and network issues, this book aims to present a description of the principles, methods and technology used in the standard specification. Different aspects of the UMTS multiple access and network configuration are presented; how- ever, this concise and integrated volume, which embodies the main design elements, goes further. Thus, the content of this book follows structurally the specifications of the 3GPP recommendations to comply entirely with the concept, terminology, approach and style, and not just the technical essence. In drafting the standards or UMTS technical specifications, the experts have tried to reduce the risk of ambivalent interpretation, and not necessarily ease the understanding for the common reader. The logic, constructive di