GSM, cdmaOne and 3G systems P2

Năm 1982, các quản chính cơ thể của các nhà khai thác viễn thông châu Âu, được gọi là CEPT (Conf rence Europ Tháng Giêng des Postes et l T thông tin liên lạc), tạo ra các ee Groupe Xã ee Sp di động (GSM) và ủy ban được giao nhiệm vụ nó với quy định cụ thể một pan-Châu Âu hệ thống đài phát thanh di động điện tử hoạt động trong băng tần 900 MHz. Hệ thống này đã được hình thành để khắc phục những hạn chế khả năng nhận thức của các hệ thống tương...
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GSM, cdmaOne and 3G systems P2 GSM, cdmaOne and 3G Systems. Raymond Steele, Chin-Chun Lee and Peter Gould Copyright © 2001 John Wiley & Sons Ltd Print ISBN 0-471-49185-3 Electronic ISBN 0-470-84167-2Chapter 2The GSM System2.1 IntroductionIn 1982, the main governing body of the European telecommunication operators, knownas CEPT (Conf´ rence Europ´ ene des Postes et T´ l´ communications), created the Groupe e e eeSp´ cial Mobile (GSM) committee and tasked it with specifying a pan-European cellular eradio system to operate in the 900 MHz band. The system was conceived to overcomethe perceived capacity limitations of the successful analogue systems already deployed inseveral European countries (e.g. the Nordic Mobile Telephone system, NMT, in the Nordiccountries). The pan-European cellular standard would support international roaming andprovide a boost for the European telecommunications industry. The power centres behindthe proposed system were the 12 countries of the European Economic Community (EEC),the 26 countries involved in CEPT and the French and German PTTs. There was also strongsupport from the Nordic countries and the UK Government and industry. The French andGerman alliance, formed in 1983, was joined by Italy in 1985, and in 1986 the UK joinedto form the Quadripartite [1]. After initial discussions, three working parties (WPs) were created to deal with specificaspects of the system definition, and later on a fourth WP was added. In 1986, a permanentnucleus was set up in Paris to co-ordinate the efforts of the working parties and also managethe generation of the system recommendations. The WPs were required to define the systeminterfaces that would allow a mobile, in the form of either a hand-held or vehicular mountedunit, to roam throughout the countries where the new system had been deployed and haveaccess to the full range of services. Compared with the existing analogue systems, thenew system was required to have a higher capacity, comparable or lower operating costsand a comparable or better speech quality. The system was also required to co-exist withthe analogue systems. A common pan-European bandwidth allocation for the new system 6566 CHAPTER 2. THE GSM SYSTEMof 890–915 MHz and 935–960 MHz was agreed; however, by the time the system was tobe deployed, parts of this band would be occupied by analogue cellular systems in somecountries (e.g. the Total Access Communications System, TACS, in the United Kingdom).In these countries only a portion of the band would be used initially for GSM. Although studies in various European countries had concluded that digital systems wereto be preferred over analogue systems, the choice of the multiple access scheme was notas clear-cut. It was decided that a number of different system proposals, put forward bycompanies and consortia from a number of different European countries, should be evalu-ated in prototype form. There were eight different system proposals. The MATS-D systemproposed by TEKADE incorporated three different multiple access schemes, namely codedivision multiple access (CDMA), frequency division multiple access (FDMA) and timedivision multiple access (TDMA). The CD900 system proposed by SEL was a widebandTDMA system in conjunction with spectral spreading [2, 3]. The remaining six proposalswere all based on narrow-band TDMA. The SFH900 system proposed by LCT used fre-quency hopping in combination with Gaussian minimum shift keying (GMSK) modulation,Viterbi equalisation and Reed–Solomon channel coding. Bosch proposed the S900-D sys-tem, which used four-level frequency shift keying (FSK) modulation, and Ericsson proposedthe DMS90 system which used frequency hopping, GMSK modulation and an adaptive de-cision feedback equaliser (DFE). The Mobira system and the MAX II system proposed byTeleverket were similar to the DMS90 system. Finally, the system proposed by ELAB ofNorway employed adaptive digital phase modulation (ADPM) and a Viterbi equaliser tocombat the effects of intersymbol interference (ISI). Some of the basic features of the eightdifferent systems are given in Table 2.1 [4]. The different systems were trialled in Paris at the end of 1986 and the most spectrally effi-cient (and ‘unofficial winner’) was the system proposed by ELAB. During 1987 the resultsof the trial were discussed and eventually agreement was reached on the main characteris-tics of the new system. The wideband solutions advocated by the French and Germans werenot adopted for a number of reasons, including the probability that the 1 µm VLSI technol-ogy, needed to support the com ...