2004-11-10, GUC11)1)EDGE EDGE 技术简要介绍技术简要介绍2)调制原理及编码方式调制原理及编码方式3)GPRS/EGPRSGPRS/EGPRS所使用的链路质量控制算法所使用的链路质量控制算法所使用的链路质量控制算法所使用的链路质量控制算法（（（（GPRS/EGPRS LQCGPRS/EGPRS LQC））））4)Other FeaturesMain content 2004-11-10, GUC21. EDGE 1. EDGE 技术简要介绍技术简要介绍EDGEEDGE = EDGE = Enhanced Data rates for Global Evolution 2004-11-10, GUC3EDGE is an accessory to GPRS ! -EGPRSInternetGGSNSGSNPCUBTSGPRSMSGPRSGPRS ProtocolMSEGPRSEDGETRUEGPRS ProtocolSGSNInternetEGPRS=GPRSGPRS与与EDGEEDGE的区别的区别 ? ?EDGE =GPRS+EDGE Modulation 2004-11-10, GUC4GPRSGPRS与与EDGEEDGE的主要区别的主要区别Modulation: GMSK vs 8PSKLA: Link adaptation IR: Incremental redundancyEGPRS mode TBFs only supported on 64 kbit/s abis TSsBoth GPRS and EGPRS can be supported on 64 kbit/s abis TS 2004-11-10, GUC5EDGE is the name for the enhancements made from GPRS R’97 to GPRS R’99. EGPRS only refers to the packet switched (GPRS) enhancements made in the standard EDGE is a method to increase the data rates on the radio link for GSM EDGE is basically only a new modulation technique and new channel coding EDGE Basic 2004-11-10, GUC6Used to transmit both packet switched (PS) and circuit switched (CS) data/voice Whereas GPRS allow data rates up to 160 kbps on the physical layer, EGPRS is capable of offering up to 473,6 kbps. combined with improved link adaptation mechanisms. EDGE Basic, cont’d 2004-11-10, GUC7 GPRSEDGEModulationGMSK8-PSK/GMSKSymbol rate270 ksym/s270 ksym/sModulation bit rate270 kb/s810 kb/sRadio data rate per timeslot22.8 kb/s69.2 kb/sMax user data rate per timeslot20 kb/s59.2 kb/sMax user data rate (8 timeslots)160 kb/s473.6 kb/sEDGE/GPRS technical data 2004-11-10, GUC82. 调制原理及编码方式调制原理及编码方式 2004-11-10, GUC9GPRS and EGPRS ModulationsIQ(0,1,1)(1,1,0)(1,0,1)(0,0,0)(0,0,1)(1,1,1)(1,0,0)(0,1,0)IQ“1”“0”GPRSGMSK ModulationEDGE GPRS (EGPRS):8PSK Modulation“1 bit per symbol”“3 bits per symbol” 2004-11-10, GUC10The modulation type that is used in GSM is called Gaussian Minimum Shift Keying (GMSK), which is a kind of phase modulation. Every symbol that is transmitted represents one bit, i.e. each shift in the phase represents one bit 8PSK, is a linear modulation, Nine coding schemes (actually Modulation & Coding Schemes = MCS) are introduced (MCS1 to MCS9) EDGE modulation technique 2004-11-10, GUC111020304050600MCS1MCS2MCS3MCS4MCS5MCS6MCS7MCS8MCS9CS1CS2CS3CS4GMSK 调制调制8PSK 调制调制8.012.014.420.08.411.214.817.622.429.644.854.459.2kbpsGPRSEGPRSStandardized improvement I - - EDGE 解码机制解码机制 2004-11-10, GUC12Standardized improvement IStandardized improvement IGPRS vs EGPRSBasically it comes down to different Coding and Modulation techniqes. This in turn requires larger send windows, GSL with higher capacity (64k links) etc. Many of the details in the RLC, MAC & GSL protocols are different. However the different techniques allow us to transfer various amount of data within the same timeperiod (i.e. in the same timeslot period).MCS-1MCS-2MCS-3MCS-4MCS-5MCS-6MCS-7MCS-8MCS-922oct28oct37oct44oct56oct74oct2x56oct2x68oct2x74octCBACBABAAGMSKGMSKGMSKGMSK8-PSK8-PSK8-PSK8-PSK8-PSKChannelCodingSchemeEGPRS RLC Data SizeFamilyModulation TechniqueCS-1CS-2CS-3CS-422oct32oct38oct52octChannelCodingSchemeGPRS RLC Data SizeGPRSEGPRSMCS-1MCS-9CS-1CS-4MCS-1MCS-422oct44octCCGMSKGMSKMCS-2MCS-5MCS-728oct56oct2x56octBBBGMSK8-PSK8-PSKMCS-3MCS-6MCS-8MCS-937oct74oct2x68oct2x74octAAAAGMSK8-PSK8-PSK8-PSKMCS-2MCS-5MCS-728oct56oct2x56octBBBGMSK8-PSK8-PSKMCS-3MCS-6MCS-8MCS-937oct74oct2x68oct2x74octAAAAGMSK8-PSK8-PSK8-PSK 2004-11-10, GUC133. LQC: LA & IR 2004-11-10, GUC14LQC EGPRSLink Quality ControlLink Quality Control: Achieve highest throughput!: Achieve highest throughput!Link adaptation- Estimate quality- Choose coding scheme- Re-segmentation is possible - Use very little coding at first - Send more coding if necessary- Receiver uses soft combiningIncremental redundancyTwo ways to do it ... 2004-11-10, GUC15Theoretical Edge performance (IR and LA)Theoretical Edge performance (IR and LA) 2004-11-10, GUC16Link Quality ControlLink Quality Control: : 实现高速吞吐率实现高速吞吐率实现高速吞吐率实现高速吞吐率Link adaptation(GPRS CS1-4, EGPRS)- - 估测比特误码可能性估测比特误码可能性- - 选择解码机制选择解码机制- 可以重新打包可以重新打包- 内存消耗低内存消耗低- - 服务初始应用很少的编码服务初始应用很少的编码 - - 如果需要再采用更多的编码如果需要再采用更多的编码- 接收端采用接收端采用soft combiningsoft combining- 高质量的性能高质量的性能Incremental redundancyEGPRSLink Quality Control for EDGE 2004-11-10, GUC17LQC Further description•Link Adaptation•Incremental RedundancyüReceiver stores unsuccessfully decoded RLC data blocksütransmitter uses same MCS but distinct Puncturing Schemeüreceiver uses old and new versions of RLC data units to perform decodingüDifferent MCS used for retransmission (more robust)üadapting made easy by family grouping structure 2004-11-10, GUC18LQC Throughput GraphLA curveLA curveIR curveIR curve8PSK8PSKGMSKGMSK 2004-11-10, GUC19LQC Measurement Procedures•Bit Error Probability (BEP) estimated on burst level•Variation of BEPBurst 1Burst 2Burst 3Burst 4BEP est 1BEP est 2BEP est 3BEP est 4MEAN_BEP=(mean(BEP est)CV_BEP=std(BEP est)/mean(BEP est)MEAN_BEPnCV_BEPnMEAN_BEPn+1CV_BEPn+1MEAN_BEPn+2CV_BEPn+2......Filtered independentlybefore reportingBlock nBlock n+1Block n+2 Results available per Radio Block (every 20 ms) !!! 2004-11-10, GUC20LA Example:PCUMSMCS-9 data block (PS 1)NACKMCS-9 data block (PS 2)NACKMCS-6, first part, PS 1ACKMS returns MEAN_BEP and CV_BEP in DL ack/nackMS quality report still make LQC recommend MCS-9MS returns MEAN_BEP and CV_BEP in DL ack/nackMS quality report is worse. New recomended MCS isMCS-7.MCS-6, sec part, PS 1NOTE! Only for EGPRS 2004-11-10, GUC21IR Example, Joint decoding and Soft combining:PCUMSMCS9 data block PS 1Block is storedNACKMCS9 data block PS 2Soft combiningNACKJoint decodingMCS9 data block PS 3NACKMCS9 data block PS 1Joint decodingJoint decodingOK!NOTE! Only for EGPRS 2004-11-10, GUC22LQC IR shift to LAPCUMSMCS9 data block PS 1Block is storedNACKMCS9 data block PS 2(If same PS is used = Soft combining)NACK + out of memoryShift to LAMCS6 data block part 1MCS6 data block part 2Joint decoding 2004-11-10, GUC23 Switch from IR to LA, too many retransmissionsPCUMSMCS9 data block PS 1Block is storedNACKMCS9 data block PS 3(If same PS is used = Soft combining)Continue to run IR but act as LA for this blockMCS6 data block part 1MCS6 data block part 2Joint decodingNACKRepeated 6 times then temporarily switch from IR to LA NOTE! Only for EGPRS 2004-11-10, GUC244. Other Features1)数据传输数据传输2)EDGEEDGE寻址窗口寻址窗口3)测量报告测量报告4)交织技术交织技术 2004-11-10, GUC25Standardized improvement II- 数据传输数据传输 - EGPRS重传时可以应用另一种重传时可以应用另一种CSCS方式方式GPRS重传时不能应用另一种重传时不能应用另一种CSCS方式方式 2004-11-10, GUC26LLC frameLLC frame1 1......CS3 codedCS3 codedA)A)B)B)Packet DL ACK/NACK messagePacket DL ACK/NACK messageBitmap:Bitmap:- Packet 2 and 3 once more !- Packet 2 and 3 once more !C)C)2 23 34 45 56 67 78 81 12 23 34 42 23 35 56 6CS3CS3CS1CS1Packet Transfer and re-transmissionPacket Transfer and re-transmission- Example GPRS - 2004-11-10, GUC27Packet Transfer and re-transmissionPacket Transfer and re-transmissionLLC frameLLC frame1 1......MCS6 codedMCS6 codedA)A)B)B)Packet DL ACK/NACK messagePacket DL ACK/NACK messageBitmap:Bitmap:- Packet 2 and 3 once more !- Packet 2 and 3 once more !C)C)2 23 34 45 56 67 78 81 12 23 34 42 25 56 63 3MCS3- Example EGPRS - 2004-11-10, GUC28Standardized improvement IIIStandardized improvement III- - EDGE EDGE寻址窗口寻址窗口寻址窗口寻址窗口 ... ... PCUPCURLC/MACRLC/MACprotocolprotocol1 12 20 03 34 420462046 204720470 01 12 23 34 420452045 20462046 20472047Sliding addressing window up to 1024Sliding addressing window up to 1024… … 窗口大小从窗口大小从窗口大小从窗口大小从64646464增加到增加到增加到增加到1024102410241024以避免信令的延迟以避免信令的延迟以避免信令的延迟以避免信令的延迟 2004-11-10, GUC29EGPRS质量报告依据质量报告依据EDGEEDGE中中专门的比特误码率功能专门的比特误码率功能( (B Bit it E Error rror P Probabilityrobability)Standardized improvement IV- 测量报告测量报告测量报告测量报告 -GPRS质量报告依据质量报告依据GSMGSM的测量的测量报告中信号强度，干扰报告中信号强度，干扰 2004-11-10, GUC30The EffectNetworkNetworkSlowadaptingLAFastadaptingLAGPRSGPRSEGPRSEGPRS 2004-11-10, GUC31Standardized improvement V- 交织技术交织技术 -QualityGPRS CS4Burst1Burst3Burst2Burst4Interleaved over 4 Bursts !Time数据块丢失数据块丢失 !全部数据块重传全部数据块重传 QualityEGPRS MCS8/9Burst1Burst3Burst2Burst4Interleaved over 2 Bursts !前半块正确前半块正确后半块丢失后半块丢失Time只需重传错误的数据块只需重传错误的数据块 2004-11-10, GUC32Assume we are running EGPRS on 3 Timeslots DL. The current radio environment suggest that MCS-5 is the best Coding Scheme to be used. The maximum bitrate at that time can then be calculated in the following way:MCS-1MCS-2MCS-3MCS-4MCS-5MCS-6MCS-7MCS-8MCS-922oct28oct37oct44oct56oct74oct2x56oct2x68oct2x74octCBACBABAAGMSKGMSKGMSKGMSK8-PSK8-PSK8-PSK8-PSK8-PSKChannelCodingSchemeEGPRS RLC Data SizeFamilyModulation Technique(56 x 8) x 50 x 3= 67.2 kbps1000Number of octets for MCS-5Octet to bitsNumber of times a RLC data block can be sent per second (one block scheduled once every 20ms by the MAC layer. (1000ms/20ms = 50 times blocks per second)Number of TSExample 2004-11-10, GUC33EGPRS Summary• • LargeLarge addressing window for EGPRS with low risk for protocol stalling addressing window for EGPRS with low risk for protocol stalling• • PossiblePossible to re-transmit EGPRS packets with another coding scheme to re-transmit EGPRS packets with another coding scheme • • EGPRS measurement report of EGPRS measurement report of highhigh qualityquality • • Measurement values available per bursts allowing Measurement values available per bursts allowing fastfast LQC LQC • • ApplicableApplicable for real time services for real time services• • Very Very goodgood spectrum efficiency spectrum efficiency • • Very Very goodgood coverage performance coverage performance 。