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電信常識

2010年01月11日 10:40 www.1cnz.cn 作者:佚名 用戶評論(0
關(guān)鍵字:電信(61355)

電信常識


1. 目前的移動世界是傳統(tǒng)語音電話的延伸,與每一個PSTN一樣,每個PLMN都有一個TDM語音電路層(傳送層)和一個信令層(控制層SS7);2.5G 增加了IP數(shù)據(jù)連接,語音電話絲毫不受影響;

2.? 電信業(yè)的發(fā)展:
? 1) FDMA 頻分多路 - Frequency Division Multiple Access (1920s - )
??????? . radio broadcasting
??????? . 1st generation mobile system(NMT, TACS, ...)
?? 2) TDMA 時分多路 - Time Division Multiple Access (1980-)
??????? . 2nd generation mobile systems: GSM, US-TDMA, PDC
??????? . narrowband systems
?? 3) CDMA 碼分多路 - Code Division Multiple Access (late 1990s - )
??????? . 3rd generation mobile systems: WCDMA, CDMA2000


國際上的電信標(biāo)準(zhǔn)化組織
===================================================

CWTS - China Wirelss Telecommunication Standard Group
ETSI?? - European Telecommunication Standard Institute
GSM?? - Global System for Mobile Communication
IETF?? - Internet Engineering Task Force
ITU-T - International Telecommunication Union - Telecommunication Standardization

1. 3GPP/3GPP2、IETS的分工:
? 1) 3GPP is responsible for system architecture standardisation for GSM/WCDMA
? 2) 3GPP2 is standardising cdma2000 evolution
? 3) IETF protocols to be used as applicable in 3GPP systems

2. 3GPP
?1) Release 99 (2000,3) - Major RAN release
? New radio interface - WCDMA
? New RAN architecture - soft handover
? New CN-AN interface(transcoder in CN, SGSN functions to RNC)
? Open Service Architecture for Services
? GSM-UMTS interworking
?
?2) Release 4 (2001,3) - Minor release
? UTRAN access with some QoS enhancements
? CS Domain Evolution, MSC Servers and MGWs, based on IP protocols
? IP transport of CN protocols
? IP Header compression(IETF)
? Locationi Services enhancements, MMS, WAP, MExE, Streaming
?
?3) Rlease 5(2002,3) - Major core ntw release
? IP Multimedia Services Subsystem - Basic communications platform
?? - SIP signalling, registration, session initiation, IMS SIM, IMS security architecture
?? - Usage of IETF protocols, e.g., IPv6, SIP, Diameter
?? - SIP-based service environment
?? - QoS for IMS: SIP Compression, QoS authorization and policy control
? GERAN alignment with UMTS
? WCDMA enhancements (e.g. HSDPA, IP transport)
? MMS enhancements, LCS enhancements
?
?4) Release 6 (2003,12) - IMS Part II
? IMS Phase 2
?? - Release 5 left-over items(regulatory requirements, circuit-switched interworking, service based local policy enhancements, etc)
?? - optimised voice communications
?? - Presence, Instance Messaging, Group Management and Conferencing
? New Work Items:
?? - 3GPP/3GPP2 IMS harmonisation (incl. access independency), UMTS-WLAN interworking, Multimedia Broadcast/Multimedia Service, etc

?

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