1、GPRS Design and WAP Overview GPRS设计及应用概述设计及应用概述 Leo HuangMotorola 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 Overv
2、iew GPRS概述概述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 o
3、f valuable spectrum 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
4、the office LANGPRS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
5、Group - A sub-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 meetingSMG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
6、 are divided into 13 parts GSM/GPRS技术规范都分为13个部分GSM/GPRS Technical Specification CategoryGSM/GPRS 技术规范分类技术规范分类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
7、方面407 Terminal 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
8、护GPRS Technical Specification Example GPRS 技术规范范例技术规范范例401.60 Requirements Specification of GPRS GPRS需求规范需求规范 402.60 Service description Stage 1 服务描述服务描述(第一阶段第一阶段)403.60 Service description Stage 2 服务描述服务描述(第二阶段第二阶段)404.60 RLC/MAC protocol 无线链路控制及媒体访问控制协议无线链路控制及媒体访问控制协议404.64 LLC Specification 逻辑链路控
9、制协议规范逻辑链路控制协议规范404.65 Subnetwork Depend Convergence Protocol 子网依赖集中协议子网依赖集中协议407.60 Mobile Station supporting GPRS 支持支持GPRS的移动台的移动台408.16 BSS-SGSN interface; Network Service GPRS网络服务协议网络服务协议408.18 BSS-SGSN interface; BSSGP GPRS基站系统协议基站系统协议409.16 SGSN-VLR; Gs interface network service Gs接口网络服务规范接口网络服
10、务规范409.60 GTP across Gn and Gp interface 在在Gn和和Gp上的上的GPRS隧道协议隧道协议409.61 Interworking between PLMN supporting GPRS and PDN支持支持GPRS的的PLMN与公用数据网的互联与公用数据网的互联412.15 GPRS Charging GPRS的计费的计费GPRS Nodes Design GoalsGPRS节点设计目标节点设计目标4Scalability 可扩充性 Start small, expand easily as demand increases从小规模开始, 容易根据需
11、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 elements 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
12、 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系统的组成系统的组成(1)BSC基站控制器基站控制器BTS基站基站MSC/VLR移动交换中心移动交换中心访问位置寄存器访问位置寄存器PSTN公用电话网公用电话网PCU分组控制单元分组控制单元GGSNGPRS网关支持节点网关支持节点GbGrGnGGSNInternet因特网因特网PDN公用数据网公用数据网GiUmGPRS MobileSGSNGPRS服务支持节点服务支持节点HLR/AUC归属位
13、置寄存器归属位置寄存器用户鉴权中心用户鉴权中心The components of GPRS system (2) GPRS系统的组成系统的组成(2)BSCRXCDRBTSBTSMSC/VLRSMS-CSGSNGGSNHLRSMS-GMSCSMS-IWMSCSGSNGGSNEIRPDNOther PLMNSignalling & Data InterfaceSignalling InterfacePCUGPRS end to end protocol stack GPRS端到端协议栈端到端协议栈GSM RFMACRLCLLCSNDCPIP/X.25ApplicationGSM RFMACRLCL
14、1 bisNetworkServiceBSSGPRelayL1 bisNetworkServiceBSSGPL1L2IPL1L2IPUDP/TCPGTPIP/X.25LLCSNDCPUDP/TCPGTPRelayMSBSS/PCUSGSNGGSNUmGbGnGiGPRS RF Characteristics GPRS 的无线特性的无线特性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
15、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话音空中接口编码话音空中接口编码(1)4Each 20ms of GSM, speech uses 456 bits across air interfaceGSM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
16、 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 recovery 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
17、传发生Class 1a50 bits260 bits50 bits3 bits132 bits4 bits378 bits78 bitsTailbitsParityConvolutional Code456 bits57 bitsEven57 bitsOdd57 bitsEven57 bitsOdd57 bitsEven57 bitsOdd57 bitsEven57 bitsOddDiagonalInterleaving8 consecutive TDMA burst over the Um air interfaceClass 1b132 bitsClass 278 bitsGSM Spee
18、ch Air Interface Coding (2)GSM话音空中接口编码话音空中接口编码(2)UmNetworkSNDCPLLC(Note)RLCMACPhys. LinkPhys. RFSNDCPLLCRLCMACPhys. LinkPhys. RFMSScope of GSM 03.60Scope of GSM 03.64Note: In the network the LLC issplit between BSS and SGSN.The BSS functionality is calledLLC relay.GPRS Data Air Interface CodingGPRS数
19、据空中接口编码数据空中接口编码4Data must be decoded in perfect condition, unlike speech不象话音,数据在解码中不允许任何错误4If errors cannot be corrected, re-transmission is required如果错误无法纠正,则必须重传4RLC layer controls backward error correction over Air InterfaceRLC层控制空中接口的后向除错Coding SchemeCoded bitsPuncturedbitsDataRate(kbps)Multiple
20、 SlotMax.DataRate(kbps)CS-145609.0572.4CS-258813213.4107.2CS-367622015.6124.8CS-4456021.4171.2Max. Per TS Data rate (kbps)0510152025CS-1CS-2CS-3CS-4KBits per SecondGPRS Coding SchemesGPRS的编码方案的编码方案4GPRS using same physical RF layer as GSM speechGPRS 用与GSM话音同样的物理层4Data is coded into normal bursts数据也在
21、普通脉冲内编码(456 bits / 20ms)4Higher data rates per timeslot achieved by removing error protection每时系的更高数据传输速度是以降低容错性能换来的4GPRS has four RF coding scheme GPRS有四种无线编码方式4The throughput rate in table below is for physical layer on air interface下表中最后一列的数据, 是指空中接口物理层的最高速度4右表中的最后一列数据是指逻辑链路控制层的最高数据流量,当RLC层中有可选项时
22、速率还会低一些SchemeCodeRateUSFbitsPre-codedUSFbitsRadioBlock(excl. USFand BCS)BCSTailbitsCodedbitsPuncturedbitsDataRate(kbps)CS-11/23318140445609.05CS-22/33626816458813213.4CS-33/43631216467622015.6CS-41312428160456021.4SchemeMACHeader(ex. USF)(bits)SparebitsRLCData(octects)RLCUserData(octects)UserDataThr
23、oughput(kbps)CS-15022208.0CS-257323012.0CS-353383614.4CS-457525020.0GPRS Coding SchemesGPRS的编码方案的编码方案Add BCS加块检查序列加块检查序列Add precoded USF加预编码的上行状态标识符加预编码的上行状态标识符Add tail bits加结尾码加结尾码Coding编码编码Puncture穿孔减码穿孔减码456bitsPayload有效负有效负载载 BCS : Block Check Sequence USF : Uplink State FlagGPRS Coding Procedur
24、eGPRS编码的步骤编码的步骤rate 1/2 convolutional codingpuncturing456 bitsUSFBCSRadio BlockB0B1B2TB3B4B5XB6B7B8TB9B10B11X52 TDMA Frames12 Radio Block Periods = 240 ms*Rectangular interleaving of one Radio Block over four bursts in consecutive TDMA frames*InterleavingCS1 - CS3 Radio Block StructureCS1到到CS3的无线块结构
25、的无线块结构CS4 Radio Block StructureCS4的无线块结构的无线块结构blockcodeno coding456 bitsUSFBCSRadio Block*InterleavingB0B1B2TB3B4B5XB6B7B8TB9B10B11X52 TDMA Frames12 Radio Block Periods = 240 ms*Rectangular interleaving of one Radio Block over four bursts in consecutive TDMA framesUSFTPC RLC HeaderRLC dataBCSUSFTPCR
26、LC / MAC signaling informationBCSPayloadPayloadMAC headerRLC data blockBlocchecksequenceMAC headerRLC / MAC control blockBlocchecksequenceUserdataControlT : Block Type indicator PC : Power Control fieldsGPRS Radio Block StructureGPRS无线块结构无线块结构User data 用户数据用户数据Segment 段段Segment 段段Info 信息信息FHFCSPHSeg
27、ment 段段Segment 段段Segment 段段InfoBHBCSTailConvolutional encoding 卷积编码卷积编码Burst 脉冲脉冲 Burst 脉冲脉冲 Burst 脉冲脉冲 Burst 脉冲脉冲.Network layerSNDCP layerSNDCP layerLLC layerLLC layerRLC / MAC layerRLC / MAC layerPhysical layerPacket(PDU)LLC frame 逻辑链路控制帧逻辑链路控制帧RLC block无线链路控制块无线链路控制块Normal Burst普通脉冲普通脉冲PH : Packe
28、t Header 分组首标分组首标 BH : Block Header 块首标块首标FCS : Frame Check SequenceFH : Frame Header 帧首标帧首标 BCS : Block Check Sequence 块核查序列块核查序列456 bits114 bits114 bits114 bits114 bitsPacket transformation data flow分组传输的数据流分组传输的数据流No HoppingHoppingSpeech & Data in Hopping Network跳频网络中的话音及数据跳频网络中的话音及数据4Hopping pro
29、vides frequency diversity which averages fading & distributes errors in the frame跳频技术通过提供多频点交替使用,使衰减平均化并将错误离散的各帧中4Works in favour of convolutional coding with interleaving跳频最好要与卷积和交织技术共用4Hopping is good for speech but donot benefit data跳频对提高话音质量很有好处, 但一般情况下对数据传输无益BLER Rate - TU3 No Hopping块错误率块错误率 -
30、 TU3 无跳频无跳频Typical Urban 3 km/h - No Hopping典型城区,移动速度每小时3公里,无跳频0.010.111010004812162024C/I载干比载干比 (dB)CS1CS2CS3CS4BLER Rate - TU3 No Hopping块错误率块错误率 - TU3 无跳频无跳频010203040506070809010004812162024C/I载干比载干比(dB)CS1CS2CS3CS4 CS4 has rapid rate of change between 6 & 14 dB (near 75% BLER improvement) CS4对载干
31、比在对载干比在6-14分贝间的变化分贝间的变化反应明显反应明显(块错误率降低块错误率降低75%)Typical Urban 3 km/h - No Hopping典型城区,移动速度每小时3公里,无跳频Throughput - TU3 No Hopping信道数据流速信道数据流速 - TU3 无跳频无跳频051015202504812162024C/I载干比载干比(dB)CS1CS2CS3CS4 CS1 & CS2 show the least change vs. C/I CS1和和CS2受载干比的影响最受载干比的影响最小小 CS3 & CS4 inefficient at low C/I C
32、S3和和CS4在低载干比时效率很低在低载干比时效率很低 All Schemes converge to Max rate at high C/I随载干比的增高各编码方案均收敛于其最高速随载干比的增高各编码方案均收敛于其最高速率率 CS3 & CS4 best at C/I 10dBCS3和和CS4最好在载干比大于最好在载干比大于10dB时应时应用用Typical Urban 3 km/h - No Hopping典型城区,移动速度每小时3公里,无跳频GSM traffic model vs. GPRS traffic modelGSM流量模型与流量模型与GPRS流量模型的对比流量模型的对比4G
33、SM traffic model base on user air timeGSM的流量模型的基础是用户平均占用空中信道的时间4GPRS traffic model base on user data volumeGPRS的流量模型的基础是用户平均传输数据的总量4In GSM, mobile user can not make a phone call if there is no free channel at a certain time in a cell在G SM中,如果某一时刻在某扇区内已无空闲信道, 则手机用户将无法打电话4In GPRS, data service user ca
34、n always attached to the system, share channels with other user, if the channel is too busy, user will notice that the service response become slower在GPRS系统中,数据业务的用户可以始终保持与系统的连接, 与其他用户共享有限的信道, 如果信道很忙, 用户会感觉到服务的响应速度减慢, 但服务并不停止QoS Concept in GPRSGPRS中的服务质量概念中的服务质量概念4Quality of Service in GPRS is not a
35、 guarantee concept but a priority concept质量服务在GPRS中不是一个保证的概念, 而是一个优先权的概念4High QoS level in BSS and MS means the ability to occupy more timeslots when available在基站及手机方面, 高的服务质量意味着当系统信道资源允许时, 可以同时占用多个时系4High QoS level in GSN will try to set high priority flag when transmit packets between nodes, wheth
36、er it work depends on the network technology GSN use在G SN部分中, 高服务质量的标识将设置在节点之间传输的数据分组中, 是否有效则根据不同的网络技术有所不同GPRS Channel Usage SampleGPRS信道利用方式举例信道利用方式举例 例子：例子：三载波小区三载波小区GPRS TerminalGPRS中的终端中的终端4Class A A类 同时支持GPRS和电路交换(包括短消息SMS) 用户能够同时作语音和数据服务的呼叫计被叫 语音和数据服务均需要最少一个独立无线信道4Class B B类 支持GPRS和电路交换 在同一时间，
37、只能够提供语音或数据服务 同时连接(Attach)语音和数据服务4Class C C类 只能够连接一种服务(语音或数据服务) 需要利用手机菜单(Menu/Default)更改服务类型(语音、数据)4理论上一台手机可支持1至8个时系PDU transmissionGPRS AttachorSTANDBYtimerExpireGPRS DetachGPRS AttachPDU receptionGPRS DetachofCancel LocationMM State Model of MSMM State Model of SGSNIDLEREADYSTANDBYIDLEREADYSTANDBYo
38、rorLocationUnknownRouting AreaCellGPRS ActionsNoneGPRS PagesCS PagesData TransferREADY timer expiry orforce to STANDBYorAbnormal RLC conditionREADY timer expiryorForce to STANDBYSTANDBY timer expiryorCancel LocationMobility Management State ModelGPRS终端及终端及SGSN的移动管理状态模型的移动管理状态模型Conclusions无线部分小结无线部分小
39、结4Sending data across GSM Air Interface with reduced error protection requires low interference RF environment用降低容错的方法在GSM的空中接口传数据需要高载干比的环境4Maximum bit rate on CS3 & CS4 will probably be restricted to indoor & microcell CS3和CS4所带来的最大速度只能限制在室内及微蜂窝覆盖区4Hopping networks will not benefit GPRS data transf
40、er due to the spreading of errors跳频网络将错误离散的方法不会给GPRS的数据传输带来好处 4Data traffic model is different from speech, the most valuable character of GPRS is the ability to share same channel by multiple users数据与话音的传输模型不同, GPRS最大的优势在于多用户共享有限的信道4QoS in GPRS is different from traditional meaning in CSGPRS中的服务质量概
41、念与传统电路交换中的概念有所不同Basic TCP/IP ConceptTCP/IP基本概念基本概念4TCP/IP systemTCP/IP协议系统4Network Access Layer网络访问层4Internet Layer因特网层4Transport Layer传输层4Routing Protocol路由协议Network and TCP/IP Protocol网络与网络与TCP/IP协议协议4Network is a system which connects devices such as computers, these devices can communicate throu
42、gh public transmission media网络是计算机和类似计算机的设备连接起来的一个系统,这些设备能够通过公共传输媒体进行通信 4TCP/IP Protocol defines the process of network communication, most important, it defines what aspect of a data unit should be and what kind of information it should include, this makes the target computer can decode the message
43、s come from source computer correctly.TCP/IP协议定义了网络通信的进程, 更重要的是, 定义了数据单元应该采用什么样的外观及应该包含什么信息, 使得接收端的计算机能够正确地翻译对方发来的信息 TCP/IP CharactersTCP/IP的特性的特性4Logical address - IP address逻辑编址 - IP地址4Routing selection路由选择4Name service - DNS域名服务- DNS4Error checking and flow control错误检查与流控制4Support for application
44、s - port对应用程序的支持 - 端口Application Layer应用层Transport Layer传输层Internet Layer因特网层Network Access Layer网络访问层TCP/IP Protocol SystemTCP/IP协议系统协议系统Application Layer应用层Transport Layer传输层Internet Layer因特网层Network Access Layer网络访问层Application Layer应用层Presentation Layer表示层Session Layer会话层Transport Layer传输层Networ
45、k Layer网络层Data Link Layer数据链路层Physical Layer物理层TCP/IP and OSI ModelTCP/IP与与OSI模型模型Application LayerTransport LayerInternet LayerNetwork Access LayerData数据Header首标At each layer, a new header is added to the data packet数据包在每一层加一个新首标Message消息Segment段(TCP) Datagram(UDP)Datagram数据报Frame帧Bit Stream 二进制流Da
46、ta packet数据包数据包(分组分组)Application LayerTransport LayerInternet LayerNetwork Access LayerNetwork applicationsTCPUDPIPARP/RARPFTSFDDIPPP (Modem)EthernetToken RingPhysical NetworkTCP/IP NetworkTCP/IP网络简介网络简介Application LayerPresentation LayerSession LayerTransport LayerNetwork LayerPhysical Layer物理层Appl
47、ication LayerTransport LayerInternet LayerNetwork Access Layer网络访问层TCP/IPOSIData Link Layer 数据链路层Media Access Control SublayerLogical Link Control SublayerNetwork Access Layer and OSI model网络访问层与网络访问层与OSI模型对比模型对比媒体访问控制子层逻辑链路控制子层Functions of network access layer网络访问层的功能网络访问层的功能4Interface to computer
48、NIC 与计算机网卡的接口4Coordinate data transport and access method对数据传输与相应访问方法的约定实施协调4Format data to frame, convert frame to physical signal将数据格式化为帧这样的单元, 并将帧转换成在传输媒体上传递的电脉冲或模拟脉冲4Error checking for input frame 检查输入进来的数据帧中的错误4Add error checking information to output frame将错误检查信息添加给输出的数据, 使接收端能够检查它的错误4Check ac
49、knowledgment and retransmit frame when can not receive acknowledgment 确认数据帧已收到,如果没有收到这个确认信息, 则重新发送数据帧Physical Address物理地址物理地址4Physical Address is network card address pre-set by manufactory物理地址是厂家在网卡中预设的地址 4We call physical address MAC address物理地址也叫MAC地址4MAC address is a 48 bits binary numberMAC地址由4
50、8位二进制数组成4TCP/IP user ARP and RARP to translate IP address to and from MAC address 在TCP/IP中使用地址解析协议(ARP)和反向地址解析协议(RARP)来实现IP地址与本地网络上的网卡物理地址之间的转换Internet Protocol因特网协议因特网协议(IP)4IP software decide how to create a datagram and how to send the datagram through a network IP协议是执行一系列功能的软件, IP软件决定如何创建数据报及如何使
