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1、EDGE 技术简要介绍调制原理及编码方式GPRS/EGPRS所使用的链路质量控制算法（GPRS/EGPRS LQC）Other Features,Main content,1.EDGE 技术简要介绍,EDGE,EDGE=Enhanced Data rates for Global Evolution,EDGE is an accessory to GPRS!-EGPRS,Internet,GGSN,SGSN,PCU,BTS,GPRS,MS,GPRS,GPRS Protocol,SGSN,Internet,GPRS与EDGE的区别?,EDGE=GPRS+EDGE Modulation,GPRS与
2、EDGE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,EDGE is the name for the enhancements made from GPRS R97 to GPRS R99.EGPRS only refers to the packet switched(GPR
3、S)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,Used to transmit both packet switched(PS)and circuit switched(CS)data/voice Whereas GPRS allow data rates up t
4、o 160 kbps on the physical layer,EGPRS is capable of offering up to 473,6 bined with improved link adaptation mechanisms.,EDGE Basic,contd,EDGE/GPRS technical data,2.调制原理及编码方式,GPRS and EGPRS Modulations,GPRSGMSK Modulation,EDGE GPRS(EGPRS):8PSK Modulation,“1 bit per symbol”,“3 bits per symbol”,The m
5、odulation 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=M
6、CS)are introduced(MCS1 to MCS9),EDGE modulation technique,10,20,30,40,50,60,0,MCS1,MCS2,MCS3,MCS4,MCS5,MCS6,MCS7,MCS8,MCS9,CS1,CS2,CS3,CS4,GMSK 调制,8PSK 调制,kbps,GPRS,EGPRS,Standardized improvement I-EDGE 解码机制,Standardized improvement IGPRS vs EGPRS,Basically it comes down to different Coding and Modu
7、lation 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).,M
8、CS-1,MCS-2,MCS-3,MCS-4,MCS-5,MCS-6,MCS-7,MCS-8,MCS-9,22oct,28oct,37oct,44oct,56oct,74oct,2x56oct,2x68oct,2x74oct,C,B,A,C,B,A,B,A,A,GMSK,GMSK,GMSK,GMSK,8-PSK,8-PSK,8-PSK,8-PSK,8-PSK,ChannelCodingScheme,EGPRS RLC Data Size,Family,Modulation Technique,CS-1,CS-2,CS-3,CS-4,22oct,32oct,38oct,52oct,Channel
9、CodingScheme,GPRS RLC Data Size,GPRS,EGPRS,MCS-1,MCS-9,CS-1,CS-4,3.LQC:LA&IR,LQC EGPRS,Link Quality Control: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
10、 combining,Incremental redundancy,Two ways to do it.,Theoretical Edge performance(IR and LA),Link Quality Control:实现高速吞吐率,Link Quality Control for EDGE,LQC Further description,Link Adaptation,Incremental Redundancy,Receiver stores unsuccessfully decoded RLC data blockstransmitter uses same MCS but d
11、istinct Puncturing Schemereceiver uses old and new versions of RLC data units to perform decoding,Different MCS used for retransmission(more robust)adapting made easy by family grouping structure,LQC Throughput Graph,LQC Measurement Procedures,Bit Error Probability(BEP)estimated on burst levelVariat
12、ion of BEP,Burst 1,Burst 2,Burst 3,Burst 4,BEP est 1,BEP est 2,BEP est 3,BEP est 4,MEAN_BEP=(mean(BEP est),CV_BEP=std(BEP est)/mean(BEP est),MEAN_BEPnCV_BEPn,MEAN_BEPn+1CV_BEPn+1,MEAN_BEPn+2CV_BEPn+2,.,.,Filtered independentlybefore reporting,Block n,Block n+1,Block n+2,Results available per Radio B
13、lock(every 20 ms)!,LA Example:,PCU,MS,MCS-9 data block(PS 1),NACK,MCS-9 data block(PS 2),NACK,MCS-6,first part,PS 1,ACK,MS returns MEAN_BEP and CV_BEP in DL ack/nack,MS quality report still make LQC recommend MCS-9,MS returns MEAN_BEP and CV_BEP in DL ack/nack,MS quality report is worse.New recomend
14、ed MCS isMCS-7.,MCS-6,sec part,PS 1,NOTE!Only for EGPRS,IR Example,Joint decoding and Soft combining:,PCU,MS,MCS9 data block PS 1,Block is stored,NACK,MCS9 data block PS 2,Soft combining,NACK,Joint decoding,MCS9 data block PS 3,NACK,MCS9 data block PS 1,Joint decoding,Joint decoding,OK!,NOTE!Only fo
15、r EGPRS,LQC IR shift to LA,PCU,MS,MCS9 data block PS 1,Block is stored,NACK,MCS9 data block PS 2,(If same PS is used=Soft combining),NACK+out of memory,Shift to LA,MCS6 data block part 1,MCS6 data block part 2,Joint decoding,Switch from IR to LA,too many retransmissions,PCU,MS,MCS9 data block PS 1,B
16、lock is stored,NACK,MCS9 data block PS 3,(If same PS is used=Soft combining),Continue to run IR but act as LA for this block,MCS6 data block part 1,MCS6 data block part 2,Joint decoding,NACK,Repeated 6 times then temporarily switch from IR to LA,NOTE!Only for EGPRS,4.Other Features,数据传输EDGE寻址窗口测量报告交
17、织技术,Standardized improvement II-数据传输-,EGPRS,重传时可以应用另一种CS方式,LLC frame,1,.,CS3 coded,A),B),Packet DL ACK/NACK messageBitmap:-Packet 2 and 3 once more!,C),2,3,4,5,6,7,8,2,3,5,6,CS3,CS1,Packet Transfer and re-transmission,-Example GPRS-,Packet Transfer and re-transmission,LLC frame,1,.,MCS6 coded,A),B),
18、Packet DL ACK/NACK messageBitmap:-Packet 2 and 3 once more!,C),2,3,4,5,6,7,8,2,5,6,3,MCS3,-Example EGPRS-,Standardized improvement III-EDGE寻址窗口.,PCU,RLC/MACprotocol,1,2,0,3,4,2046,2047,0,1,2,3,4,2045,2046,2047,Sliding addressing window up to 1024,窗口大小从64增加到1024以避免信令的延迟,Standardized improvement IV-测量
19、报告-,The Effect,Network,SlowadaptingLA,FastadaptingLA,GPRS,EGPRS,Standardized improvement V-交织技术-,Quality,GPRS CS4,Time,Quality,EGPRS MCS8/9,Time,只需重传错误的数据块,Assume 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
20、bitrate at that time can then be calculated in the following way:,MCS-1,MCS-2,MCS-3,MCS-4,MCS-5,MCS-6,MCS-7,MCS-8,MCS-9,22oct,28oct,37oct,44oct,56oct,74oct,2x56oct,2x68oct,2x74oct,C,B,A,C,B,A,B,A,A,GMSK,GMSK,GMSK,GMSK,8-PSK,8-PSK,8-PSK,8-PSK,8-PSK,ChannelCodingScheme,EGPRS RLC Data Size,Family,Modul
21、ation Technique,(56 x 8)x 50 x 3,=67.2 kbps,1000,Number of octets for MCS-5,Octet to bits,Number 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 TS,Example,EGPRS Summary,Large addressing window f
22、or EGPRS with low risk for protocol stalling,Possible to re-transmit EGPRS packets with another coding scheme,EGPRS measurement report of high quality,Measurement values available per bursts allowing fast LQC,Applicable for real time services,Very good spectrum efficiency,Very good coverage performance,
