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GPRS信令详解

来源：知库网

阿尔卡特B7版本中GPRS信令流程及时延分析

阿尔卡特B7版本中， GPRS方面增加了DL TBF延迟释放和UL TBF Final Ack延迟发送的功能，加快了TBF建立的时间。另外，在参数设置上，我们将TBF_Init_CS从CS1调整到CS2，加快了空中接口数据传送速率。所以，在新的版本中，PING时延、WAP时延、Attach和PDP激活时延等较B6均有不同程度的缩短。

但是，我们也看到，即便如此，我们在一些方面，一些特定情况下的时延仍比我们的竞争对手（如爱立信、诺基亚等）长了很多。

下文中给出了阿尔卡特B7版本GPRS的一些主要信令流程，并对各信令阶段的时延进行了统计。

由于时间仓促，数据样本不多，而且关于手机方面的处理时延均为推测，所以统计数据可能有一定偏差，仅供参考。

在以下的分析中，我们可以看到，在各信令流程中，TBF的建立和准备均占到总时长的一半或一半以上。（除了500Byte连续PING。）所以，缩短TBF的建立和准备时间，特别是在CCCH上建立UL TBF的建立和准备时间，是缩短阿尔卡特GPRS个流程时长的关键所在。

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE 一、阿尔科特B7版本GPRS主要信令流程时延：

信令流程 500Byte PING （首PING，包括PDCH建立） 500Byte PING （首PING，不包括PDCH建立） 500Byte PING （连续PING中的非首PING） GPRS Attach （包括Identification，包括PDCH建立） GPRS Attach （包括Identification，不包括PDCH建立） GPRS Attach （包括Auth&Ciph，包括PDCH建立） GPRS Attach （包括Auth&Ciph，不包括PDCH建立） GPRS Attach （不包括Auth&Ciph，包括PDCH建立） GPRS Attach （不包括Auth&Ciph，不包括PDCH建立） PDP激活（包括PDCH建立） PDP激活（不包括PDCH建立） WAP （包括PDP激活，包括PDCH建立） WAP （包括PDP激活，不包括PDCH建立）总时间 ms 2030~ 2150 1660~ 1780 1330~ 1530 ？ TBF建立时间 ms 960~ 1080 590~ 710 320~ 520 ？数据传送时间 ms 640 640 580 ？核心网回应时间 ms 30 30 30 ？手机或PC 处理时间 ms 400 400 400 ？？ 2150~ 2470 1780~ 2100 1080~ 1200 710~ 830 1090~ 1210 720~ 840 6120~ 7040 5750~ 6670 ？ 1280~ 1600 910~ 1230 960~ 1080 590~ 710 960~ 1080 590~ 710 2380~ 3300 2010~ 2930 ？？？ 150 20 700 150 20 700 105 15 ---- 105 105 105 985 15 25 25 615 ---- ---- ---- 2140 985 615 2140

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE 二、阿尔科特B7版本GPRS信令流程各阶段时延：

TBF建立/准备时间上行TBF准备时间根据[GSM TS04.08]， Channel 660~780ms Request消息上发时延为[0~Max(T,8)-1]个RACH时隙。假设Tx_Integer=25，则对应290~410ms 0~120ms DL TBF Delay时，手机每200ms发240~440ms 送一次PDAN 从手机应用层数据准备完毕到空中接？口RLC/MAC层开始上传数据的时间下行TBF准备时间？通过Paging ？通过Paging ？通过Immediately Assignment 300ms 即从MFS收到Gb口数据到空中接口80ms RLC/MAC层开始下传数据的时间数据传送时间与以下因素有关： 1）数据包的大小； 2） TBF分配到的时隙数； 3） CS方式； 4）是否与其它TBF共用PDCH 核心网处理时间 PING回应 Attach Request回应 PDP激活 WAP（GetReply） PING 计算SRES（Attach流程）准备Connect上发（WAP） 30ms 10~15ms 25ms 530ms 手机/终端处理时间 400ms 700ms 1300ms 在CCCH上建立UL TBF （包括PDCH建立）在CCCH上建立UL TBF （不包括PDCH建立）在DL TBF上建立UL TBF （DL TBF Delay阶段）在已有的UL TBF上传送数据在DRX阶段建立DL TBF 在Non-DRX阶段建立DL TBF 在T3912阶段建立DL TBF 在UL TBF上建立DL TBF 在已有的DL TBF上传送数据 ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE 三、阿尔科特B7版本GPRS信令流程：

500BYTES PING SCENARIO(First PING, with PDCH Establishment, B7)MSBCCHChannel Request1)0~120msChannel RequiredChannel Request2) 5ms30ms7msUL TBF Establish Time662~782msMS&PC200msDL DataTransfer160msDL TBF Est.Time300msCNReplyTime32msUL DataTransfer480msBTSBSCMFSCN200msMS&PC200msRACHRadio Alloc. Req.Radio Alloc. Conf.70msAGCHTM Alloc. Req.8msTM Alloc. Conf.190msChannel Ass. ULImm. Ass. CommandImm. AssignmentPacket UL Dummy Control Block (with TLLI)110ms32ms210msDATAPDCHULTBFPacket DL Assignment(Echo Request)23Blocks = 11CS1_Blks + 12CS2_BlksEcho Request(LLC:538Bytes)Echo Reply(LLC:538Bytes)460ms20ms32ms80ms136msAccess BurstPacket Power Control / Timing Advance84msDATAPDCHDLTBF...(Echo Reply)18CS2_Blks140ms3) 20ms200msNote 1) Channel Request Delay——[GSM TS04.08] the number of slots belonging to the mobile station's RACH betweeninitiation of the immediate assignment procedure and the first CHANNEL REQUEST message (excluding the slotcontaining the message itself) is a random value drawn randomly for each new initial assignment initiation withuniform probability distribution in the set {0, 1, ..., max (T,8) - 1}, where T stands for Tx_Integer. AssumingTx_Integer=25, corresponding time delay will be 0~120ms.Note 2) Transmission time for Channel Request message on Um interface.Note 3) Transmission time for last DL DATA on Um interface.Note 4) Considering the PC delay for COM-port data transmission and receiving, and also the SW time consumptions,which is totally about 400ms, the GLOBAL TIME DELAY for FIRST PING WITH PDCH ESTABLISHMENT willbe 2030ms to 2150ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE 500BYTES PING SCENARIO(First PING, without PDCH Establishment, B7)MSBTSBSCMFSCN200msMS&PC200msMS&PC200msDL DataTransfer160msDL TBF Est.Time300msCNReplyTime32msUL DataTransfer480msUL TBF Establish Time289~409msBCCH1)0~120msChannel RequestRACHChannel RequiredChannel Request2) 5ms30ms12ms32msAGCHImm. Ass. CommandImm. AssignmentChannel Ass. UL210msPacket UL Dummy Control Block (with TLLI)PDCHULTBFDATA(Echo Request)23Blocks = 11CS1_Blks + 12CS2_BlksEcho Request(LLC:538Bytes)Echo Reply(LLC:538Bytes)Packet DL Assignment460ms20ms32ms80ms136msAccess BurstPacket Power Control / Timing Advance84msDATAPDCHDLTBF...(Echo Reply)18CS2_Blks140ms3) 20ms200msNote 1) Channel Request Delay——[GSM TS04.08] the number of slots belonging to the mobile station's RACH betweeninitiation of the immediate assignment procedure and the first CHANNEL REQUEST message (excluding the slotcontaining the message itself) is a random value drawn randomly for each new initial assignment initiation withuniform probability distribution in the set {0, 1, ..., max (T,8) - 1}, where T stands for Tx_Integer. AssumingTx_Integer=25, corresponding time delay will be 0~120ms.Note 2) Transmission time for Channel Request message on Um interface.Note 3) Transmission time for last DL DATA on Um interface.Note 4) Considering the PC delay for COM-port data transmission and receiving, and also the SW time consumptions,which is totally about 400ms, the GLOBAL TIME DELAY for FIRST PING WITHOUT PDCH ESTABLISHMENTwill be 1660ms to 1780ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE 500BYTES PING SCENARIO(Consecutive PING, with Delayed DL TBF Release, B7)MSPDCHDLTBF(oflastPING)PDCHULTBFBTSBSCMFSCN200msPacket DL Data Ack/Nack (Channel Request)1)0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(Echo Request)18CS2_BlksEcho Request(LLC:538Bytes)Echo Reply(LLC:538Bytes)2) 400ms20ms32ms3) 80msDATA(Echo Reply)18CS2_Blks140ms4) 20ms200msPDCHDLTBF...Note 1) During the DL TBF delay of last PING, Packet DL Data Ack/Nack is sent by MS every 200ms. Detecting a datatransfer request from upper layer, MS will send Channel Request IE in the next Packet DL Data Ack/Nack message andwait for the UL TBF Assignment from network. Therefore, the delay of sending out channel request in the MS will be0~200ms.Note 2) The transmission time for UL Data is shorter comparing to the one in First PING, since all of the data istransmitted with CS2 coding.Note 3) DL TBF is already exist and no need to be re-established, therefore, the delay time for DL datatransmitting is shortened to 80msNote 4) Transmission time for last DL DATA on Um interface.Note 5) Considering the PC delay for COM-port data transmission and receiving, and also the SW time consumptions,which is totally about 400ms, the GLOBAL TIME DELAY for CONSECUTIVE PING WITH DELAYED DL TBFMS&PC200msDL DataTransfer160msDLtransPrep80msCNReplyTime32msUL DataTransfer420msUL TBF Establish Time240~440msMS&PC200msRELEASE will be 1330ms to 1530ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE GPRS ATTACH SCENARIO (1 of 2)(with Authentication & Ciphering Procedure, B7)MSBCCHChannel RequestBTSBSCMFSCN1)0~120msRACHChannel RequiredChannel Request2) 5ms30ms3)UL TBF Establish Time662~782msDL DataTransfer40msDL TBF Est.Time300msCNReplyTime10msUL DataTransfer65msRadio Alloc. Req.7msRadio Alloc. Conf.70msAGCHTM Alloc. Req.8msTM Alloc. Conf.190msChannel Ass. ULImm. Ass. CommandImm. Assignment110ms32ms210msPacket UL Dummy Control Block (with TLLI)PDCHULTBFDATA(Attach Request)3CS1_BlksAttach Request(LLC:37Bytes)Auth. & Ciph. Req.(LLC:22Bytes)Packet DL Assignment60ms5ms10ms80ms136msAccess BurstPacket Power Control / Timing Advance84msPDCHDLTBF...DATA(Auth. & Ciph. Request)1CS2_Blks20ms20ms(TO BE CONTINUED)Note 1) Channel Request Delay——[GSM TS04.08] the number of slots belonging to the mobile station's RACH betweeninitiation of the immediate assignment procedure and the first CHANNEL REQUEST message (excluding the slotcontaining the message itself) is a random value drawn randomly for each new initial assignment initiation withuniform probability distribution in the set {0, 1, ..., max (T,8) - 1}, where T stands for Tx_Integer. AssumingTx_Integer=25, corresponding time delay will be 0~120ms.Note 2) Transmission time for Channel Request message on Um interface.Note 3) If the PDCHs are already exist, and no need to be established, the time delay between Channel Request toChannel Assignment UL on GSL interface will be about 12ms (pls. refer to 500BYTE PING SCENARIO——First PING,without PDCH establishment, B7). In this case, the global delay for the UL TBF establish will be 289~409ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE GPRS ATTACH SCENARIO (2 of 2)(with Authentication & Ciphering Procedure, B7)MSBTSBSCMFSCN4)700msSRESPreparing Time700msUL DataTransfer25msUL TBF Establish Time240~440msMSPrepTime130msDLDataTransfer20msDLTransPrep80msCNReplyTime12msUL DataTransfer25msUL TBF EstablishTime240~440msPDCHDLTBFPacket DL Data Ack/Nack (Channel Request)5)0~200ms85msPacket UL AssignmentPacket UL Dummy Control Block (with TLLI)155msPDCHULTBFDATA(Auth. & Ciph. Response)1CS2_Blks20msAuth. & Ciph. Resp(LLC:19Bytes)Attach Accept(LLC:30Bytes)5ms12msDATA(Attach Accept)1CS2_Blks6) 80ms20ms130ms0~200msPDCHDLTBFPacket DL Data Ack/Nack (Channel Request)85msPacket UL AssignmentPacket UL Dummy Control Block (with TLLI)155msDATA(Attach Complete)1CS2_Blks20msAttach Complete(LLC:8Bytes)5msASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

...Note 4) “SRES Preparing Time” is the time that MS calculates SRESNote 5) During the DL TBF delay, Packet DL Data Ack/Nack is sent by MS every 200ms. When MS finished SREScalculation, it will send Channel Request IE in the next Packet DL Data Ack/Nack message and wait for the UL TBFAssignment from network. Therefore, the corresponding delay will be 0~200ms.Note 6) DL TBF is already exist and no need to be re-established, therefore, the delay time for DL datatransmitting is shortened.Note 7) According to the CMCC GPRS DT/CQT Test Criterion, GPRS Attach Delay is timing from when an Attach Requestis about to be sent in the MS, to an Attach Accept message received by the MS. Considering the delay in Uminterface for the last DL data (Attach Accept), which is about 20ms, the GLOBAL TIME DELAY for GPRSAttach with PDCH establishment will be 2150ms to 2470ms, while the GLOBAL TIME DELAY forGPRS Attach without PDCH establishment will be 1780ms to 2100ms....

MOBILE GPRS ATTACH SCENARIO(without Authentication & Ciphering Procedure, B7)MSBCCHRACHChannel RequestChannel RequiredChannel RequestBTSBSCMFSCN0~120ms5ms30ms7msUL TBF Establish Time662~782msUL DataTransfer25msUL TBF EstablishTime240~440msMSPrepTime130msDL DataTransfer40msDL TBF Est.Time300msCNReplyTime14msUL DataTransfer65msRadio Alloc. Req.Radio Alloc. Conf.70msAGCHTM Alloc. Req.8msTM Alloc. Conf.190msChannel Ass. ULImm. Ass. CommandImm. AssignmentPacket UL Dummy Control Block (with TLLI)110ms32ms210msPDCHULTBFDATA(Attach Request)3CS1_BlksAttach Request(LLC:37Bytes)Attach Accept(LLC:30Bytes)Packet DL Assignment60ms5ms14ms80ms136msAccess BurstPacket Power Control / Timing Advance84msDATA(Attach Accept)1CS2_Blks20ms20msPDCHDLTBFPacket DL Data Ack/Nack (Channel Request)130ms0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

...Note 1) The GLOBAL TIME DELAY for GPRS Attach with PDCH establishment will be 1080ms to1200ms, while the GLOBAL TIME DELAY for GPRS Attach without PDCH establishment will be710ms to 830ms....DATA(Attach Complete)1CS2_Blks20msAttach Complete(LLC:8Bytes)5ms

MOBILE PDP CONTEXT ACTIVATION SCENARIO(B7)MSBCCHChannel RequestBTSBSCMFSCN0~120msRACHChannel RequiredChannel Request5ms30msUL TBF Establish Time662~782msDL DataTransfer40msDL TBF Est.Time300msCNReplyTime23msUL DataTransfer65msRadio Alloc. Req.7msRadio Alloc. Conf.70msAGCHTM Alloc. Req.8msTM Alloc. Conf.190msChannel Ass. ULImm. Ass. CommandImm. Assignment110ms32ms210msPacket UL Dummy Control Block (with TLLI)PDCHULTBFDATA(Active PDP Context Request)3CS1_BlksAct. PDP Cont. Req(LLC:43Bytes)Act. PDP Cont. Acc(LLC:25Bytes)Packet DL Assignment60ms5ms23ms80ms136msAccess BurstPacket Power Control / Timing Advance84msPDCHDLTBF...DATA(Active PDP Context Accept)1CS2_Blks20ms20msNote 1) The GLOBAL TIME DELAY for GPRS Attach with PDCH establishment will be 1090ms to1210ms, while the GLOBAL TIME DELAY for GPRS Attach without PDCH establishment will be720ms to 840ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE WAP SCENARIO (1 of 4)(with PDP Context Activation, B7)MSBCCHChannel RequestBTSBSCMFSCN0~120msRACHChannel RequiredChannel Request5ms30msUL TBF Establish Time662~782msDL DataTransfer40msDL TBF Est.Time300msCNReplyTime23msUL DataTransfer65msRadio Alloc. Req.7msRadio Alloc. Conf.70msAGCHTM Alloc. Req.8msTM Alloc. Conf.190msChannel Ass. ULImm. Ass. CommandImm. Assignment110ms32ms210msPacket UL Dummy Control Block (with TLLI)PDCHULTBFDATA(Active PDP Context Request)3CS1_BlksAct. PDP Cont. Req(LLC:43Bytes)Act. PDP Cont. Acc(LLC:25Bytes)Packet DL Assignment60ms5ms23ms80ms136msAccess BurstPacket Power Control / Timing Advance84msPDCHDLTBF...DATA(Active PDP Context Accept)1CS2_Blks20ms20ms(TO BE CONTINUED)

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE WAP SCENARIO (2 of 4)(with PDP Context Activation, B7)MSBTSBSCMFSCN~1300msMS PrepTime1300msUL Data Transfer87msUL TBF EstablishTime240~440msDL DataTransfer80msMSPrepTime320msDL TBF EstablishTime300msUL DataTransfer240msCNReplyTime32msUL TBF EstablishTime240~440msPDCHDLTBFPacket DL Data Ack/Nack (Channel Request)0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(INVOKE(Connect))10CS2_BlksINVOKE(Connect)(LLC:281Bytes)RESULT(Conn Reply)(LLC:74Bytes)220ms20ms32msPDCHUL TBFPacket DL Assignment80msAccess Burst136msPacket Power Control / Timing Advance84msDATA(RESULT(Connect Reply))3CS2_Blks60msPDCHDLTBF...Packet DL Data Ack/Nack (Channel Request)20ms320ms0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(ACK)2CS2_BlksACK(LLC:41Bytes)80msDATA(INVOKE(Get))2CS2_BlksINVOKE(Get)(LLC:69Bytes)7ms(TO BE CONTINUED)

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE WAP SCENARIO (3 of 4)(with PDP Context Activation, B7)MSBTSBSCMFSRESULT(Reply)(LLC:506Bytes+506Bytes+370Btyes)CN530msCNReplyTime530msDL DataTransfer40msDLtransPrep80msCNReplyTime30msUL DataTransfer47msUL TBF EstablishTime240~440msMSPrepTime400msUL DataTransfer47msUL TBF EstablishTime240~440msMSPrepTime120msDL DataTransfer340msDLtransPrep80ms80msDATA(RESULT(Reply))47CS2_Blks320ms20msPDCHDLTBFPacket DL Data Ack/Nack (Channel Request)120ms0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(ACK)2CS2_BlksACK(LLC:41Bytes)2) 40ms7ms400msPacket DL Data Ack/Nack (Channel Request)0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(INVOKE)2CS2_BlksINVOKE(LLC:44Bytes)RESULT(Reply)(LLC:48Bytes)2) 40ms7ms30ms80msDATA(RESULT(Reply))2CS2_Blks20ms20ms(TO BE CONTINUED)Note 1) The GLOBAL TIME DELAY for GPRS First WAP PAGE with PDCH establishment will be6120ms to 7040ms, while the GLOBAL TIME DELAY for GPRS First WAP PAGE without PDCHestablishment will be 5750ms to 6670ms.

ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

MOBILE WAP SCENARIO (4 of 4)(with PDP Context Activation, B7)MSBTSBSCMFSCN100msPacket DL Data Ack/Nack (Channel Request)0~200msPacket UL Assignment85msPacket UL Dummy Control Block (with TLLI)155msDATA(ACK)2CS2_BlksACK(LLC:41Bytes)2) 40ms7msUL DataTransfer47msUL TBF EstablishTime240~440msMSPrepTime100ms ASB BU2 MNO (Radio Network Optimization) ALCATEL SHANGHAI BELL

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