3g通訊的發(fā)展與應(yīng)用趨勢(shì)技術(shù)篇(英文版)-資料下載頁(yè)
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【正文】 station can bine the signals of different time delay.? During a handoff, the mobile station contacts multiple base stations and searches for the strongest frame.165。 Space Diversity165。 When diversity is implemented two antennas are situated at the receiver. These antennas are placed several wavelengths apart to ensure minimum correlation between the two receive paths.165。 The two signals are then bined, this ensures that a low signal strength is less likely to occur.Compare oradd signalsResultant SignalApprox. 10 wavelengthsFrequency HoppingEach time the BTS or mobile transmits a burst, it does so on a different RF carrier frequency.timefrequencyRAKE ReceiverThe RAKE technology can overe the multipath fading and enhance the receive performance of the system.Receive setCorrelator 1Correlator 2Correlator 3Searcher correlator Calculate the time delay and signal strength Combiner The bined signaltts(t) s(t)VAD DTXEncoding the speech silences at a rate of 500 bit/s rather than the full 13Kb/s.If the mobile does not transmit during ‘silence’ there is a reduction in the overall power output requirementWithout DTXWith DTXComfort NoiseContents Basic Concepts of Mobile SystemDevelopment of Mobile CommunicationGSM Network ArchitectureCDMA Network ArchitectureObjectivesOnpletionofthissectionyouwillbeableto:DrawanArchitectureofGSMIdentifytheinterfacesbetweentheGSMsystementities GSM Network ComponentsHLRME SIMOMCAUCMSC/VLRBTS BSCPSTNOMCMSNSSBSSEIRThe GSM InterfaceHLRVLRMSCEIRAUCECIWFOMCVLRMSCIWF ECBTSBSCPSTNMSBHFGAECDUmAbisContents Basic Concepts of Mobile SystemDevelopment of Mobile CommunicationGSM Network ArchitectureCDMA Network ArchitectureObjectivesOnpletionofthissectionyouwillbeableto:DrawanArchitectureofCDMAIdentifytheinterfacesbetweentheCDMAsystementitiesReference Model of a CDMA NetworkACPSTNISDNMCUmHAiDiMCSMESMENMMMMS BS MSCHLREIRVLRABCDEMSCFVLRGQSCPSCP SSPAiT1T8IP HLR IP ISDNDiT2T3 T5T9SummaryBasic Concepts of Mobile SystemDevelopment of Mobile CommunicationGSM Network ArchitectureCDMA Network Architecture演講完畢，謝謝觀看！
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