移动通信与仿真2-GPRS.pptx

GPRS - EDGE吴伟民电子与信息工程系第一页，共五十二页。 2 GPRS - EDGEOverviewGPRS ServicesNetwork ArchitectureUm Interface (MS-Bss)52- MultitrameLogical ChannelsPhysical ChannelGPRS Stack LayerSNDCPLLCGPRS en mode IdleGPRS Network modeClasses des mobilesMultislot ClassSession ManagementEvolution to EDGEModulations GPRS vs EDGEEDGE: RLC/MACRLC / MACTBF 第二页，共五十二页。 3GPRS: OverviewWhat is GPRSGeneralBut… only applicable to specific servicesPacketObviouslyRadioBut… much moreServiceBut… rather a transmission method第三页，共五十二页。 4GPRS: OverviewCircuit vs. PacketCircuitPacket第四页，共五十二页。 5GPRS: OverviewGPRS vs. non GPRSDifferences between GPRS and GSMWarranty on trafficWarranty on delay vs. Best effortCharging on time vs. charging on volumeRadio resource sharingDedicated channels vs. Shared channelsTransmission mode in the networkCircuit 64 kbps vs. IP networkUser rate up to 160 kbps第五页，共五十二页。 6GPRS: OverviewCircuit vs. PacketService (point to point protocol)GSM allows both circuit and packet serviceGPRS allows only packet serviceSwitch mode in the networkIn MSC, circuit switch at 64 kbpsIn GPRS, datagram switchRadio path transmissionGSM use a resource during the complete call (circuit)But data are always in packet format (burst)第六页，共五十二页。 7GPRS: OverviewShared ChannelsThe equivalent of a TCH is allocated to 16 (max)multiplexed flowsPossible to allocate several such resources to one user(multi-slot)Release through timerIndependent handling of directionWEB application traffic is not symmetricalLimitation through GSM symmetrical scheme第七页，共五十二页。 8 GPRS: Overview? Location Area Code is relevant to LA (Location Area) inside a PLMN.? Routing Area Code is relevant to RA (Routing Area) inside a LA.PLMN A LAC A Cell C RAC ARAC BLAC BPLMN BCell ACell B第八页，共五十二页。 9IP GPRS: OverviewTCP/IP IP: Internet Protocol To route datagram (32 bits address) through interconnected network segmentationTCP: Transmission Control Protocol Point to point transportTCPUDP Numbering and acknowledge of data multiplexingUDP