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【導(dǎo)讀】Copyright,2020©SUNYatBuffalo.IntroductiontoGSM. GPRS. EDGE. UMTS. WCDMA. Summery. WhatisGSM??Threebroadparts. Interfaces:. ME(mobileequipment). themobile.time,usingaTDMAscheme.GSMisadigitalwork. GSMFeaturescont.forwardfashion.sender.LogontoGPRS. withGGSN.
【正文】 de Mcps ?Long Code Generation by LFSR 1 x x2 x32 WCDMA Direct Sequence Spreading 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 0 1 0 1 1 1 0 0 1 1 1 1 0 0 1 1 0 1 1 0 0 0 0 0 1 1 1 1 0 0 1 t t t dw(t) C(t) Ds(t) Power Control In WCDMA )3(, pu s e r Pe NQP ??N: Spread Factor ?p : CarriertoInterferenceRatio for subscriber P ?Bit Error Rate and Power ?????10KpkkkppPP?Power Control In WCDMA )13(11????kNQPkep?? Perfect Power Control Power Control In WCDMA ? NearFar Problem in CDMA – Different Performance for Subcriber Links – A Few Subscribers closest to the BTS may contribute too much multiple Access Interference. Power Control In WCDMA ? How to do power control – Force all users to transmit the minimum amount of power – Reduce the power transmitted by users closest to the BTS。 increase the power transmitted by users farest to the BTS Power Control In WCDMA ? Open Loop vs. Close Loop – Open Loop Power Control Subscriber measures the DL power and adjusts its transmission power – Close Loop Power Control BS measures the UL power. MS measures the DL power and reports to the BS. BS instructs the user to raise or lower it transmission power WCDMA Soft Handoff Active set = BS1 BS1 BS2 Active set = BS1 amp。 BS2 BS2 SS add threshold BS1 BS2 Active set = BS2 BS1 SS drop threshold BS1 BS2 Active Research Topics ? Cellular system architecture ? UMTS air interface ? Power control in CDMA ? Handoff ? SatelliteUMTS traffic Reference ? ? ? ? ? ? ? ? ? ? Reference ? ? ? ? S. Dutnall, N. Lobley, A. Clapton, UMTS: The mobile part of broadband munications for the next century IEEE Atm Workshop, Proceedings. p242252,1998 ? S. Breyer, G. Dega, V. Kumar, L. Szabo, Global view of the UMTS concept Alcatel Telemunications Review. n 3 1999. p 219227 ? M. Lee, CDMA Network Security , PrenticeHall, 1998 ? U. Black, Mobile amp。 Wireless Networks, PrenticeHall, 1999 ? M. Gallagher, W. Webb, UMTS: The next generation of mobile radio, IEE Review. v 45 n 2 1999. p 5963 Reference ? A. Samukic, UMTS Universal Mobile Telemunications System:Development of standards for the third generation, IEEE Global Telemunications Conference amp。 Exhibition. v 4 1998. p 19761983 ? N. Prasad, GSM evolution towards third generation UMTS/IMT2020, IEEE International Conference on Personal Wireless Communications 1999, p 5054 ? A. Samukic, UMTS universal mobile telemunications system: Development of standards for the third generation, IEEE Transactions on Vehicular Technology. v 47 n 4 Nov 1998. p 10991104
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