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Hệ thống 3G và mạng không dây thông minh P2

In recent years the concept of intelligent multi-mode, multimedia transceivers (IMMT) has emerged in the context of wireless systems [67a,150-1521 and the range of various existing solutions that have found favourin existing standard systems was summarised in the excellent overview by Nanda et al. [153]. | Third-Generation Systems and Intelligent Wireless Networking J.S. Blogh L. Hanzo Copyright 2002 John Wiley Sons Ltd ISBNs 0-470-84519-8 Hardback 0-470-84781-6 Electronic Chapter Burst-by-Burst Adaptive Wireless Transceivers L. Hanzo P.J. Cherriman C.H. Wong E.L. Kuan T. Keller1 2.1 Motivation In recent years the concept of intelligent multi-mode multimedia transceivers IMMT has emerged in the context of wireless systems 67 150-152 and the range of various existing solutions that have found favour in existing standard systems was summarised in the excellent overview by Nanda et al. 153 . The aim of these adaptive transceivers is to provide mobile users with the best possible compromise amongst a number of contradicting design factors such as the power consumption of the hand-held portable station PS robustness against transmission errors spectral efficiency teletraffic capacity audio video quality and so forth 152 . In this introductory chapter we have to limit our discourse to a small subset of the associated wireless transceiver design issues referring the reader for a deeper exposure to the literature cited 151 A further advantage of the IMMTs of the near future is that due to their flexibility they are likely to be able to reconfigure themselves in various operational modes in order to ensure backwards compatibility with existing so-called second generation standard wireless systems such as the Japanese Digital Cellular 154 the Pan-American IS-54 155 and IS-95 156 systems as well as the Global System of Mobile Communications GSM 11 standards. The fundamental advantage of burst-by-burst adaptive IMMTs is that - regardless of the propagation environment encountered - when the mobile roams across different environments subject to pathloss shadow- and fast-fading co-channel- intersymbol- and multi-user in- This chapter is based on L. Hanzo C.H. Wong P.J. Cherriman Channel-adaptive wideband wireless video telephony IEEE Signal Processing Magazine July 2000 Vol. 17. .