Wireless Internet Access over GSM and UMTS

We dedicate this book to students 0/ computer science who want to under­ stand why the radio channel is at the heart of mobile communications, be it data or voice, and to students 0/ communications engineering looking for an introduction to the structure of the Internet protocols, and their application to mobile radio.

The book provides a comprehensive investigation of the performance and problems of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol stack, when data is transmitted over GSM, GPRS and UMTS. It gives an introduction into the protocols used for Internet access today and briefly into the Wireless application Protocol, WAP. The basics of GSM, GPRS and UMTS are given necessary for understanding the main topic, TCP performance over GSM, GPRS and UMTS. We then describe at length the problems that TCP has when operating over a mobile radio link, and what has been proposed to remedy these problems. We derive the optimum TCP packet length for maximum data throughput on wireless networks, analytically and by simulation. Results on the throughput and various other parameters of TCP over mobile networks are given. This book gives valuable advice to network operators and application programmers how to maximise data throughput, and which protocols, transmission modes, and coding schemes to prefer and which to avoid to achieve this goal.

We dedicate this book to students 0/ computer science who want to under­ stand why the radio channel is at the heart of mobile communications, be it data or voice, and to students 0/ communications engineering looking for an introduction to the structure of the Internet protocols, and their application to mobile radio. We also welcome the practicing engineer' working for mobile network operators and infrastructure suppliers, and the application program­ mer looking for the underlying reasons for the problems they encounter in their daily work. Given that convergence of the information technology and communica­ tions worlds has been talked about for almost 20 years, there is still surpris­ ingly little knowledge among specialists of each others' fields. Data communi­ cations over radio, notably Internet access, however, requires fuH understand­ ing of both fields. Internet protocols have been designed for fixed networks. There bit errors are so rare that interrupted transmission almost inevitably means congestion. In contrast, the radio channel constitutes a bottleneck for mobile data communications in that it introduces bit errors even at modest data rates. This book is based on the doctoral thesis of one of us (M. Taferner).