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1、GPRS Design and WAP Overview GPRS设计及应用概述 Leo Huang Motorola Greater China Network Solution Division摩托罗拉大中华区系统方案解决部Table of Content 目录4GPRS Overview GPRS概述4GPRS RF Characteristics GPRS的无线特性4Basic TCP/IP Concept TCP/IP基本原理4IP Related Topic in GPRS GPRS中与IP有关的话题4WAP Introduction WAP简介GPRS Overview GPRS
2、概述4What is GPRS 什么是GPRS4GPRS standard and SMG GPRS标准及SMG4The components of GPRS system GPRS系统的组成4GPRS end to end protocol stack GPRS端到端协议栈What is GPRS 什么是GPRS4GPRS is the abbreviation of General Packet Radio System GPRS是通用分组无线系统的英文缩写4For data application, circuit switching is wasteful of valuable sp
3、ectrum while packet switching is more efficient 对于数据应用来说,传统的电路交换浪费了宝贵的频率资源,而分组 交换在数据应用方面对频率利用的效率则高得多4GPRS is a way to provide wireless data service using the mature GSM technology and network. GPRS提供了在现有成熟的GSM技术及网络中实施数据服务的方 案4GPRS subscribers will be permanently connected, just like PC in the office
4、 LAN GPRS终端可以长时间保持与网络的连接, 就象PC机连接在办公室 内的局域网上一样 GPRS Standard and SMG GPRS标准及SMG4GPRS standard is made by ETSI GPRS标准是由ETSI制定的4ETSI stands for European Telecommunication Standards Institute ETSI是欧洲通信标准协会的英文缩写4ETSI can be visited at ETSI的主页在 http:/www.etsi.org4SMG stands for Special Mobile Group - A s
5、ub-organization of ETSI SMG是ETSI技术委员会的一个下属机构-特别移动组4SMG hold two major meetings each year, finalize standard changes on the meeting, SMG#31 stands for the standard version till the 31th SMG meeting SMG每年举办两次大会,并在会议上通过对标准的修订案, 通常提 到的SMG#31代表直到第31届SMG大会为止的标准版本4GSM/GPRS technical specifications are divi
6、ded into 13 parts GSM/GPRS技术规范都分为13个部分GSM/GPRS Technical Specification Category GSM/GPRS 技术规范分类400 Preamble 导言 01 General 总则402 Service Aspects 服务方面 03 Network Aspects 网络方面404 MS-BSS interface and Protocols 移动台与基站系统的接口及协议405 Physical Layer in the Radio Path 无线通道的物理层406 Audio Aspects 无线方面407 Terminal
7、 Adaptors for Mobile Station 移动台的终端适配器408 BTS/BSC and BSC/MSC Interface BTS/BSC和BSC/MSC接口409 Network Interworking 交互网络410 Service Interworking 交互服务411 Equipment Specification and Type Approval Specification 设备规范及批准类型规范412 Network management including Operations and Maintenance 网络管理,操作及维护GPRS Technic
8、al Specification Example GPRS 技术规范范例401.60 Requirements Specification of GPRS GPRS需求规范 402.60 Service description Stage 1 服务描述(第一阶段)403.60 Service description Stage 2 服务描述(第二阶段)404.60 RLC/MAC protocol 无线链路控制及媒体访问控制协议404.64 LLC Specification 逻辑链路控制协议规范404.65 Subnetwork Depend Convergence Protocol 子网依
9、赖集中协议407.60 Mobile Station supporting GPRS 支持GPRS的移动台408.16 BSS-SGSN interface; Network Service GPRS网络服务协议408.18 BSS-SGSN interface; BSSGP GPRS基站系统协议409.16 SGSN-VLR; Gs interface network service Gs接口网络服务规范409.60 GTP across Gn and Gp interface 在Gn和Gp上的GPRS隧道协议409.61 Interworking between PLMN supporti
10、ng GPRS and PDN 支持GPRS的PLMN与公用数据网的互联412.15 GPRS Charging GPRS的计费GPRS Nodes Design Goals GPRS节点设计目标4Scalability 可扩充性 Start small, expand easily as demand increases 从小规模开始, 容易根据需求的增长而扩充4Reliability 可靠性 High availability 高可用性 Telecom grade equipment 电信级别的设备4Modularity 模块性 Separate key functional elemen
11、ts 分离的功能单元 Functional modules scale independently 功能模块可独立改变容量 Isolate failures within individual modules 可在单独模块中隔离错误4Reuse and Integration 可再利用及集成 Build upon existing platforms and products 建立在现有平台及产品基础上 Reusable in the future 在将来可再利用BSS 基站系统The components of GPRS system (1) GPRS系统的组成(1)BSC基站控制器BTS基
12、站MSC/VLR移动交换中心 访问位置寄存器PSTN 公用电话网PCU 分组控制单元GGSN GPRS网关支持节点GbGr GnGGSNInternet 因特网PDN 公用数据网GiUmGPRS MobileSGSN GPRS服务支持节点HLR/AUC 归属位置寄存器 用户鉴权中心The components of GPRS system (2) GPRS系统的组成(2)BSCRXCDRBTSBTSMSC/VLRSMS-CSGSNGGSNHLRSMS-GMSC SMS-IWMSCSGSNGGSNEIRPDNOther PLMN Signalling & Data Interface Signa
13、lling InterfacePCUGsGsGrGrGpGpGnGnGnGnGiGiGfGfGbGbGbGbGdGdGcGcA AE EC CD DGbGbGPRS end to end protocol stack GPRS端到端协议栈GSM RFMACRLCLLCSNDCPIP/X.25ApplicationGSM RFMACRLCL1 bisNetwork ServiceBSSGPRelayL1 bisNetwork ServiceBSSGPL1L2IPL1L2IPUDP/TCPGTPIP/X.25LLCSNDCPUDP/TCPGTPRelayMSBSS/PCUSGSNGGSNUmGbG
14、nGiGPRS RF Characteristics GPRS 的无线特性4Speech Coding Review 话音编码方式简介4Data Coding in GPRS GPRS的数据编码方式4Speech & Data in Hopping Networks 跳频网络中的话音与数据4GPRS RF coverage GPRS的无线覆盖特性4Wireless Data Traffic Model 无线数据流量模型4QoS in GPRS GPRS的服务质量GSM Speech Air Interface Coding (1) GSM话音空中接口编码(1)4Each 20ms of GSM
15、, speech uses 456 bits across air interface GSM中每20毫秒为一时系,话音的空中接口编码为456比特 Convolutional coding applied for Forward Error Correction 卷积编码用于前向除错 45% of bits are for error correction 45%的比特用于除错 2 levels of interleaving to minimise effect of Rayleigh fading 两级交织使瑞利衰退影响为最小 Convolutional codes allow recov
16、ery of lost bits 卷积可以恢复丢失的比特 Perception of listener can also fill gaps 受话者的直觉可以容忍些微话音的丢失 High BER/FER = Poor speech quality and NO re-transmissions 高错误率将导致话音质量变差,不会有重传发生Class 1a 50 bits260 bits50 bits3 bits132 bits4 bits378 bits78 bitsTail bitsParityConvolutional Code456 bits57 bits Even57 bits Odd57 bits Even57 bits Odd57 bits Even57 bits Odd57 bits Even57 bits OddDiagonal Interleaving8 consec
