文件名称:
GSM, cdmaOne and 3G Systems
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上传时间: 2010-08-20
详细说明： This book is concerned with the description and analysis of the global second generation (2G) mobile radio systems: the Global System of Mobile Communications (GSM) and cdmaOne. A subsidiary goal is to examine how these two systems will evolve into third generation (3G) ones with their requirement to support multimedia mobile radio communications. The motivation for this book originated when we were asked to compare the capacities of GSM and, as cdmaOne was known then, IS-95. The multiple access method used by GSM is time divisi on multiple access (TDMA), and this represented a significant change from the first generation (1G) analogue systems that operated with frequency division multiple access (FDMA). IS-95 had a more complex radio interface than GSM, employing code division multiple access (CDMA). Engineers at that time often held strong and somewhat uncompromising views regarding multiple access methods. We preferred CDMA from a spectral efficiency point of view, although that does not mean that CDMA should be deployed in preference to TDMA as there are many complex performance and economic factors to be considered when deciding on the type of system to select. GSM was deployed before cdmaOne and is the market leader, entrenched in many parts of the world. Its success is due to numerous factors: its advanced backbone network, the introduction of subscriber identitymodules (SIMs) that decoupled handsets from subscribers, its good security system, the low cost equipment due to open (i.e. public) interfaces, the relentless programme of evolution that has yielded substantial gains in spectral efficiency compared with the basic GSM system, and so on. cdmaOne started as a radio interface. It was a bold step to use CDMA at a time when few thought CDMA could work in a cellular environment. But it did so, acquiring the necessary backbone network, and became a global standard offering tough competition to GSM. It is also worthy of note that Europe, which had designed and promoted GSM, has opted for wideband CDMA for its third generation (3G) networks. Our cardinal objectives in this book are to present to the reader detailed descriptions ...展开收缩
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