3_(E)GPRS高级功能.pptx

1、(E)GPRS高级功能,2,目录,GPRS 专用信令信道 (GPRS Packet Control Channels),1,网络辅助的小区重选 Network Assisted Cell Change,2,双传模式 DTM -Dual Transfer Mode,3,扩展动态MAC模式 Extended Dynamic MAC mode,4,扩展上行TBF模式 Extended Uplink TBF mode,5,4粒度USF USF Granularity 4,6,GPRS 专用信令信道(PCCCH/PBCCH),PCCCH/PBCCH 配置,GPRS signalling traffic

2、shall be carried over the TRAU GDS PBCCH/PCCCH减少了经过GSL/RSL的内部信令流量,PCCCH/PBCCH 配置,New/Modified MMI Command Description: pccch_enabled indicates whether the PBCCH/PCCCH Feature is turned on or not. Dependencies: Modification of pccch_enabled is only allowed when all of the following conditions are sat

3、isfied: PBCCH/PCCCH Optional feature is unrestricted gprs_enabled is = 0 The BSS has configured the BCCH carrier of a cell as a non-hopping carrier. The cell is a normal-range cell. ts_sharing is set to 0 on the same cell site.,PCCCH/PBCCH 配置,bs_pbcch_blks -the number of blocks on the PBCCH timeslot

4、 that will be reserved for PBCCH broadcasts. bs_pag_blks_res - the number of blocks on the PBCCH timeslot that will be reserved for PAGCH broadcasts. Range: 04 Default: 2,PCCCH/PBCCH 配置,Number of PPCH = 12 - bs_pbcch_blks bs_pag_blks_res bs_pcc_chans - the number of PCCCH timeslots in a cell Range:

5、1 bs_prach_blks -the number of Packet Random Access Channel (PRACH) blocks. Range 1 11 Default 4,如信道的组合方式为PBCCH+PCCCH: 例一: BS_PBCCH_BLKS=4、 BS_PAG_BLKS _RES=4、 BS_PRACH_BLKS=3 Number of PPCH = 12-4-4=4 那么逻辑信道至PDCH的映射方式如下图PDCH的映射方式如下图所示:,UL,DL,PCCCH/PBCCH 配置,如信道的组合方式为PBCCH+PCCCH: 例二: BS_PBCCH_BLKS=2、

6、 BS_PAG_BLKS _RES=3、 BS_PRACH_BLKS=4 那么Number of PPCH = ?,UL,DL,B0,B1,B2,12,B3,B4,B5,25,B6,B7,B8,38,B9,B10,B11,51,B0,B1,B2,12,B3,B4,B5,25,B6,B7,B8,38,B9,B10,B11,51,做对了吗?,PCCCH/PBCCH 配置,Number of PPCH =12-2-3=7,Applications and Benefits: Higher system throughput because of faster set up Enhanced Cell

7、 re-selection algorithms (C31/C32) - avoid useless re-selection (and hence extra messaging) Increase in paging capacity by more efficient use of paging channels Feature Limitations The feature can not be enabled on a cell if: GPRS is enabled when the feature is turned on. The cell is an extended ran

8、ge cell. The carrier where the PBCCH/PCCCH is hopping. When using PBCCH, the PBCCH timeslot will only support 2 mobiles interleaving at anyone time.,PBCCH/PCCCH and GPRS Network Operations Mode,操作模式I 需要Gs接口支持 B类MS在分组传输模式下不要求解码CCCH寻呼子信道上的信息。 C类MS在GPRS附着后，对于非GPRS业务为不可及。,12,目录,GPRS 专用信令信道 (GPRS Packet

9、Control Channels),1,网络辅助的小区重选 Network Assisted Cell Change,2,双传模式 DTM -Dual Transfer Mode,3,扩展动态MAC模式 Extended Dynamic MAC mode,4,扩展上行TBF模式 Extended Uplink TBF mode,5,4粒度USF USF Granularity 4,6,GPRS 手机的小区重选,网络控制模式(Network Control Mode) GPRS手机通常有NC0、NC1、NC2三种工作方式： NC0 Normal MS control The MS shall p

10、erform autonomous cell re-selection. NC1 MS control with measurement reports The MS shall send measurement reports to the network The MS shall perform autonomous cell re-selection. NC2 Network control The MS shall send measurement reports to the network The MS shall not perform autonomous cell re-se

11、lection.,NACC,手机进行自主重选时的缺点： 1.手机对目标小区的信息知道有限,可能选到一个不是最优的小区. 可能是拥塞的小区 可能是没有GPRS服务的小区 2. 进行自主重选时,在接入目标小区前,手机必须读取一套系统信息. 小区重选时长需要215秒 网络控制小区重选时的缺点： 没有拥塞时, 手机可能停留在-80dBm左右的小区上.,Performance Degradation,NACC 消除了以上不利因素 .,NACC,NACC 的优点: 将手机自主的和网络控制的小区重选的好处结合起来. 使BSS参与决策最好的目标小区. 避免了手机自主小区重选和网络控制小区重选的缺点. 减少小区

12、重选引起的中断时间. 平均从2秒减少到1秒) 减少小区重选引起的中断时间主要通过在小区重选前先把目标小区的系统消息发送给手机.,NACC,NACC,实验室测试数据(NSN BSS GSM/EDGE BSS11.5):,(PNCD),NACC由两个独立的步骤组成. PCCN (Packet Cell Change Notification) :手机告诉网络需要进行小区重选. PNCD (Packet Neighbour Cell Data) procedure:网络为手机提供邻小区的系统信息. 使BSS参与决策最好的目标小区,NACC,手机所选小区是最优小区， 且目标小区数据存在 (同PCU).

13、 BSS通过PNCD(Packet Neighbour Cell Data)发送系统消息， 再发PCCC,手机所选小区是最优小区， 但目标小区数据不存在(不同PCU)。 BSS直接发送PCCC，手机从CCN模式改为NC0/NC1模式，继续小区重选,“Approve” Packet Cell Change Continoue,允许手机重选到目标小区,并发送邻小区信息(如果可能的话).,NACC,手机所选小区不是最优小区， 网络发现一个更合适的小区， 但目标小区数据不存在。 BSS直接发送PCCC，手机从CCN模式改NC0/NC1模式， 继续小区重选,手机所选小区不是最优小区， 网络发现一个更合适

14、的小区， 且目标小区数据存在。 BSS通过PNCD发送系统消息， 再发PCCO,“ Redirect ” Packet Cell Change Order,另一个邻小区更合适,指示手机重选到那个小区,并发送邻小区信息(如果可能的话).,NACC,“ Deny” Packet Measurement Order NC2,网络发现不需要进行小区重选， 网络发送PMO消息。 手机从CCN模式进入NC2模式。,手机已在最优的小区,不用重选,NACC,NACC 算法简介： 1. LLC 边界检测算法 PCU 决定当前的LLC frame 能否在 0.96s内传完. 否, 立即终止TBF. 是, 传完此L

15、LC frame后再指示手机重选到新小区.,Avantage: Seamless cell reselection works on LLC layer, meaning, the current LLC frame would have to be forwarded and started again in the new cell. This feature eliminates this overhead whenever possible,Problem in current system: When the MS performs an autonomous cell resele

16、ction, the BSS cannot determine the exact time that the MS has left the serving cell. the packets in the current LLC frame have to be retransmitted in the target cell from the beginning of the frame even if there was very little data left in the source cell. In NC2 mode however, there is no timing c

17、onstraint as the network initiates the cell reselection procedures without receiving the PCCN from the MS.,NACC,NACC 算法简介： 2. 微蜂窝算法 (Type-5 Microcellular Algorithm For GPRS) 使小区重选的次数最小化. 让带有短TBF (e.g. WAP)的手机保持在宏蜂窝. 让快速移动的手机保持在宏蜂窝. 将定点的业务挪到微蜂窝可提高系统性能.,NACC,NACC 算法简介： 3. 空闲模式的重选增强算法 根据服务小区的拥塞程度,改变空闲模

18、式下的小区重选参数 (reselection offset). 优势 减少传输模式下的重选 避免拥塞 限制 需PBCCH,NACC,24,目录,GPRS 专用信令信道 (GPRS Packet Control Channels),1,网络辅助的小区重选 Network Assisted Cell Change,2,双传模式 DTM -Dual Transfer Mode,3,扩展动态MAC模式 Extended Dynamic MAC mode,4,扩展上行TBF模式 Extended Uplink TBF mode,5,4粒度USF USF Granularity 4,6,Radio Res

19、ource Operationg Modes,operating modes and transitions for class A (DTM not supported),双传模式(DTM mode),3 Radio Resource Operation Modes are defined in GSM03.64: Packet idle mode Packet transfer mode Dual transfer mode,RR operating modes and transitions for classes A (DTM supported) and B,双传模式(DTM mod

20、e),双传模式(DTM mode),Table10.4.1/3GPPTS04.18:Message types for Radio Resource management 8 7 6 5 4 3 2 1 0 0 1 1 1 - - - Channel establishment messages: 1 0 0 - RR INITIALISATION REQUEST 0 1 1 - ADDITIONAL ASSIGNMENT 1 1 1 - IMMEDIATE ASSIGNMENT 0 0 1 - IMMEDIATE ASSIGNMENT EXTENDED 0 1 0 - IMMEDIATE A

21、SSIGNMENT REJECT 0 1 0 0 1 0 0 0 - DTM ASSIGNMENT FAILURE 0 1 0 0 1 0 0 1 - DTM REJECT 0 1 0 0 1 0 1 0 - DTM REQUEST 0 1 0 0 1 0 1 1 - PACKET ASSIGNMENT 0 0 1 1 0 - - - Ciphering messages: 1 0 1 - CIPHERING MODE COMMAND 0 1 0 - CIPHERING MODE COMPLETE 0 0 1 1 0 - - - Configuration change messages: 0

22、 0 0 - CONFIGURATION CHANGE COMMAND 0 0 1 - CONFIGURATION CHANGE ACK. 0 1 1 - CONFIGURATION CHANGE REJECT 0 0 1 0 1 - - - Handover messages: 1 1 0 - ASSIGNMENT COMMAND 0 0 1 - ASSIGNMENT COMPLETE 1 1 1 - ASSIGNMENT FAILURE 0 1 1 - HANDOVER COMMAND 1 0 0 - HANDOVER COMPLETE 0 0 0 - HANDOVER FAILURE 1

23、 0 1 - PHYSICAL INFORMATION 0 1 0 0 1 1 0 0 - DTM ASSIGNMENT COMMAND 0 0 0 0 1 0 0 0 - RR-CELL CHANGE ORDER 0 0 1 0 0 0 1 1 - PDCH ASSIGNMENT COMMAND . . . .,摩托罗拉GSR9版本 DTM 功能支持 classes 5, 9 and 11,Class 5, 9 & 11, 1 TCH/F (or TCH/H) + 1 PDTCH/F (1DL,1UL),Class 9 & 11, 1 TCH/F (or TCH/H) + 2 PDTCH/F

24、 (2DL,1UL),Class 11, 1 TCH/F (or TCH/H) + 2 PDTCH/F (1DL, 2UL),双传模式(DTM mode),29,目录,GPRS 专用信令信道 (GPRS Packet Control Channels),1,网络辅助的小区重选 Network Assisted Cell Change,2,双传模式 DTM -Dual Transfer Mode,3,扩展动态MAC模式 Extended Dynamic MAC mode,4,扩展上行TBF模式 Extended Uplink TBF mode,5,4粒度USF USF Granularity 4

25、,6,DA and EDA mode EDA模式是一种新的MAC模式，它是对DA模式的一种扩展 应用EDA模式，使网络端可以更多地分配上行时隙给一个Type 1的手机(不支持同时接收和发送信号) 可以显著提高单个EDGE用户的上行吞吐率,扩展动态MAC模式,DA and EDA mode In DA mode, a mobile monitors the assigned PDTCHs for the assigned USF value for each assigned PDTCH. Whenever the mobile station detects an assigned USF v

26、alue on an assigned PDTCH, it transmits a single RLC/MAC block on the same PDTCH. Some mobiles assigned multiple timeslots on the uplink can only monitor USFs on restricted DL timeslots due to its multi-slot class capability, e.g. when DL time slots are less than UL time slots. In EDMAC mode, the mo

27、bile station monitors its assigned PDTCHs starting with the lowest numbered PDTCH, then the next lowest numbered PDTCH, etc. Whenever the mobile station detects an assigned USF value on an assigned PDTCH, the mobile station transmits a single RLC/MAC block on the same PDTCH and all higher numbered a

28、ssigned PDTCHs.,扩展动态MAC模式,No EDA support of Class 3 or Class 7 Class 3 treated as Class 2 Class 7 treated as Class 6,扩展动态MAC模式,摩托罗拉GSR9版本 支持EDMAC情况:,33,目录,GPRS 专用信令信道 (GPRS Packet Control Channels),1,网络辅助的小区重选 Network Assisted Cell Change,2,双传模式 DTM -Dual Transfer Mode,3,扩展动态MAC模式 Extended Dynamic M

29、AC mode,4,扩展上行TBF模式 Extended Uplink TBF mode,5,4粒度USF USF Granularity 4,6,Normal UL TBF release procedure (without Extended UL TBF ),Extended Uplink TBF release procedure (with extended mode),扩展动态上行TBF模式,FEATURE BENEFITS / SELLING POINTS Enhances data performance by minimizing the interruptions of U

30、L data flow in GPRS networks due to frequent release and establishment of UL TBFs Improve the system performance in terms of the Round Trip Time (RTT) and RTT variance. Accordingly, the throughput performance on both UL and DL will also be improved taking advantage of the reduced RTT. Extended UL TBF significantly reduces the latency in UL direction, but also DL TBF establishment can be improved due to fast DL TBF setup using PACCH signalling of the concurrent TBFs. This results in significantly lower