GPRS设计及应用概述.ppt

GPRS Design and WAP Overview GPRS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,GPRS Overview GPRS概述GPRS RF Characteristics GPRS的无线特性Basic TCP/IP Concept TCP/IP基本原理IP Related Topic in GPRS GPRS中与IP有关的话题WAP Introduction WAP简介,GPRS Overview GPRS概述,What is GPRS 什么是GPRSGPRS standard and SMG GPRS标准及SMGThe components of GPRS system GPRS系统的组成GPRS end to end protocol stack GPRS端到端协议栈,What is GPRS 什么是GPRS,GPRS is the abbreviation of General Packet Radio System GPRS是通用分组无线系统的英文缩写For data application,circuit switching is wasteful of 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GPRS 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GPRS subscribers will be permanently connected,just like PC in 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SMG,GPRS standard is made by ETSI GPRS标准是由ETSI制定的ETSI stands for European Telecommunication Standards Institute ETSI是欧洲通信标准协会的英文缩写ETSI can be visited at ETSI的主页在 http:/www.etsi.orgSMG stands for Special Mobile 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SMG 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GSM/GPRS technical specifications 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,00 Preamble 导言 01 General 总则02 Service Aspects 服务方面 03 Network Aspects 网络方面04 MS-BSS interface and Protocols 移动台与基站系统的接口及协议05 Physical Layer in the Radio Path 无线通道的物理层06 Audio Aspects 无线方面07 Terminal Adaptors for Mobile Station 移动台的终端适配器08 BTS/BSC and BSC/MSC Interface BTS/BSC和BSC/MSC接口09 Network Interworking 交互网络10 Service Interworking 交互服务11 Equipment Specification and Type Approval Specification设备规范及批准类型规范12 Network management including Operations and Maintenance 网络管理,操作及维护,GPRS Technical Specification Example GPRS 技术规范范例,01.60 Requirements Specification of GPRS GPRS需求规范 02.60 Service description Stage 1 服务描述(第一阶段)03.60 Service description Stage 2 服务描述(第二阶段)04.60 RLC/MAC protocol 无线链路控制及媒体访问控制协议04.64 LLC Specification 逻辑链路控制协议规范04.65 Subnetwork Depend Convergence Protocol 子网依赖集中协议07.60 Mobile Station supporting GPRS 支持GPRS的移动台08.16 BSS-SGSN interface;Network Service GPRS网络服务协议08.18 BSS-SGSN interface;BSSGP GPRS基站系统协议09.16 SGSN-VLR;Gs interface network service Gs接口网络服务规范09.60 GTP across Gn and Gp interface 在Gn和Gp上的GPRS隧道协议09.61 Interworking between PLMN supporting GPRS and PDN支持GPRS的PLMN与公用数据网的互联12.15 GPRS Charging GPRS的计费,GPRS Nodes Design GoalsGPRS节点设计目标,Scalability 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Reliability 可靠性High availability 高可用性Telecom grade equipment 电信级别的设备Modularity 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Reuse 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,The components of GPRS system(1)GPRS系统的组成(1),GGSNGPRS网关支持节点,SGSNGPRS服务支持节点,The components of GPRS system(2)GPRS系统的组成(2),GPRS end to end protocol stack GPRS端到端协议栈,GPRS RF Characteristics GPRS 的无线特性,Speech Coding Review 话音编码方式简介Data Coding in GPRS GPRS的数据编码方式Speech&Data in Hopping Networks 跳频网络中的话音与数据GPRS RF coverage GPRS的无线覆盖特性Wireless Data Traffic Model 无线数据流量模型QoS in GPRS GPRS的服务质量,GSM Speech Air Interface Coding(1)GSM话音空中接口编码(1),Each 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 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,不会有重传发生,Class 1a50 bits,260 bits,50 bits,3 bits,132 bits,4 bits,378 bits,78 bits,Tailbits,Parity,Convolutional Code,456 bits,57 bits,Even,57 bits,Odd,57 bits,Even,57 bits,Odd,57 bits,Even,57 bits,Odd,57 bits,Even,57 bits,Odd,DiagonalInterleaving,8 consecutive TDMA burst over the Um air interface,Class 1b132 bits,Class 278 bits,GSM Speech Air Interface Coding(2)GSM话音空中接口编码(2),GPRS Data Air Interface CodingGPRS数据空中接口编码,Data 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If errors cannot be corrected,re-transmission is required如果错误无法纠正,则必须重传RLC layer controls backward error correction over Air InterfaceRLC层控制空中接口的后向除错,GPRS Coding SchemesGPRS的编码方案,GPRS using same physical RF layer as GSM speechGPRS 用与GSM话音同样的物理层Data is coded into normal bursts数据也在普通脉冲内编码(456 bits/20ms)Higher 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,GPRS has four RF coding scheme GPRS有四种无线编码方式The 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层中有可选项时速率还会低一些,GPRS Coding SchemesGPRS的编码方案,Add BCS加块检查序列,Add precoded USF加预编码的上行状态标识符,Add tail bits加结尾码,Coding编码,Puncture穿孔减码,456bits,Payload有效负载,GPRS Coding ProcedureGPRS编码的步骤,*Rectangular interleaving of one Radio Block over four bursts in consecutive TDMA frames,*Interleaving,CS1-CS3 Radio Block StructureCS1到CS3的无线块结构,CS4 Radio Block StructureCS4的无线块结构,*Interleaving,*Rectangular interleaving of one Radio Block over four bursts in consecutive TDMA frames,GPRS Radio Block StructureGPRS无线块结构,User data 用户数据,Segment 段,Segment 段,Info 信息,FH,FCS,PH,Segment 段,Segment 段,Segment 段,Info,BH,BCS,Tail,Convolutional encoding 卷积编码,Burst 脉冲,Burst 脉冲,Burst 脉冲,Burst 脉冲,.,.,Network layer,SNDCP layer,SNDCP layer,LLC layer,LLC layer,RLC/MAC layer,RLC/MAC layer,Physical layer,Packet(PDU),LLC frame 逻辑链路控制帧,RLC block无线链路控制块,Normal Burst普通脉冲,PH:Packet Header 分组首标 BH:Block Header 块首标FCS:Frame Check SequenceFH:Frame Header 帧首标 BCS:Block Check Sequence 块核查序列,456 bits,114 bits,114 bits,114 bits,114 bits,Packet transformation data flow分组传输的数据流,No Hopping,Hopping,Speech&Data in Hopping Network跳频网络中的话音及数据,Hopping provides 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Works in favour of convolutional coding with interleaving跳频最好要与卷积和交织技术共用Hopping 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-TU3 无跳频,BLER Rate-TU3 No Hopping块错误率-TU3 无跳频,0,10,20,30,40,50,60,70,80,90,100,0,4,8,12,16,20,24,C/I载干比(dB),CS1,CS2,CS3,CS4,CS4 has rapid rate of change between 6&14 dB(near 75%BLER improvement)CS4对载干比在6-14分贝间的变化反应明显(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-TU3 无跳频,GSM traffic model vs.GPRS traffic modelGSM流量模型与GPRS流量模型的对比,GSM 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GPRS 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In 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In GPRS,data service user can 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,Quality of Service in GPRS is not a 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High 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High QoS level in GSN will try to set high priority flag when transmit packets between nodes,whether 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,GPRS TerminalGPRS中的终端,Class 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Class B B类支持GPRS和电路交换在同一时间，只能够提供语音或数据服务同时连接(Attach)语音和数据服务Class 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)理论上一台手机可支持1至8个时系,Mobility Management State ModelGPRS终端及SGSN的移动管理状态模型,Conclusions无线部分小结,Sending 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Maximum 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Hopping networks will not benefit GPRS data transfer 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 Data 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QoS in GPRS is different from traditional meaning in CSGPRS中的服务质量概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,TCP/IP systemTCP/IP协议系统Network Access Layer网络访问层Internet Layer因特网层Transport Layer传输层Routing Protocol路由协议,Network and TCP/IP Protocol网络与TCP/IP协议,Network is a system which connects devices such as computers,these devices can communicate through 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 TCP/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 messages 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,Logical address-IP address逻辑编址-IP地址Routing selection路由选择Name service-DNS域名服务-DNSError checking and flow control错误检查与流控制Support for applications-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,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,Network Layer网络层,Data Link Layer数据链路层,Physical Layer物理层,TCP/IP and OSI ModelTCP/IP与OSI模型,Application Layer,Transport Layer,Internet Layer,Network Access Layer,Data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,Data packet数据包(分组),Application Layer,Transport Layer,Internet Layer,Network Access Layer,Network applications,TCP,UDP,IP,ARP/RARP,FTS,FDDI,PPP(Modem),Ethernet,Token Ring,Physical Network,TCP/IP NetworkTCP/IP网络简介,Application Layer,Presentation Layer,Session Layer,Transport Layer,Network Layer,Physical Layer物理层,OSI,Data Link Layer 数据链路层,Media Access Control Sublayer,Logical Link Control Sublayer,Network Access Layer and OSI model网络访问层与OSI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,Interface to computer NIC 与计算机网卡的接口Coordinate data transport and access method对数据传输与相应访问方法的约定实施协调Format 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Error checking for input frame 检查输入进来的数据帧中的错误Add 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Check acknowledgment 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,Physical 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 We call physical address MAC address物理地址也叫MAC地址MAC address is a 48 bits binary numberMAC地址由48位二进制数组成TCP/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(IP),IP 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数据报通过一个网络IP software has 3 important information area IP软件的三个重要信息域IP address:a unique 32bits address IP地址域-一个独一无二的32位地址Sub network mask:a 32bits information bits group,indicate which part of the IP address is network ID and which part is host Id 子网掩码域Default gateway:an optional 32bits address,indicate a router.All packets send to other network will go to this router if no specific route for that network 缺省网关域When sending data,IP get data from transport layer and send to network access layer在发送数据时,IP从传输层得到数据,处理后送往网络访问层,00 01 02 03,04 05 06 07,08 09 10 11,12 13 14 15,16 17 18 19,20 21 22 23,24 25 26 27,28 29 30 31,Version,IHL0,Service Type1,Packet length(Include header and data)2,ID,FFlag3,Fragmentation Offset,Time-To-Live,Protocol4,Header Checksum,Source IP address,Destination IP address,Optional Fields(0 to many bytes),1 bit0-2:priority bit3:Delay bit4:Throughput bit5:Reliability bit6-7:Reserved,2 Maximum size is 65535,default is 576(512bytes data+64bytes header),3 bit0:Reserved,must be 0 bit1(DF):0=allow 1-disallow bit2(MF):0=last 1=more,4 1:ICMP 2:IGMP 3:GGP 4:IP 5:ST 6:TCP 8:EGP 17:UDP 80:CLNP 88:IGRP 89:OSPF,IP Data payload(Many bytes),Padding,0 scope 5-15,number of DWORD(32bits)notes:Byte(8bits)WORD(16bits)DWORD(32bits),IP HeaderIP的首标,IP AddressIP地址,IP address consists of four dot separated numbersIP地址由四个被圆点隔开的数字组成IP address just like house address IP地址好比住宅的地址Network ID like street name 网络名好比街道名Host ID like house number 主机名好比门牌号Each computer(node)should have a unique IP address每台计算机(节点)都应有独一无二的IP地址,Binary,Decimal,27,26,128,25,24,23,22,21,20,64,32,16,8,4,2,1,Hexadecimal,80,40,20,10,8,4,2,1,Binary,Hexadecimal,Decimal,0001,1,1,0010,2,2,0011,3,3,0100,4,4,0101,5,5,0110,6,6,0111,7,7,Binary,Hexadecimal,Decimal,1001,9,9,1010,10,A,1011,11,B,1100,12,C,1101,13,D,1110,14,E,1111,15,F,0000,0,0,1000,8,8,Binary,Hexadecimal,Decimal,8bits,0-255,00-FF,16bits,0-65,535,00-FFFF,24bits,0-16,777,215,00-FFFFFF,32bits,0-4,294,967,295,00-FFFFFFFF,10bits,0-1023(1K),20bits,0-1,048,575(1M),0-3FF,0-FFFFF,Use Octet Address(1)使用8位组地址(1),10000000,128,Bin,Dec,11000000,192,11100000,224,11110000,240,11111000,248,11111100,252,11111110,254,01111111,127,Bin,Dec,00111111,63,00011111,31,00001111,15,00000111,7,00000011,3,00000001,1,80,Hex,C0,E0,F0,F8,FC,FE,7F,Hex,3F,1F,0F,07,03,01,Bin,Dec,11000000,192,01000100,68,00000011,3,10000101,133,Hex,C0,44,03,85,Binary,Hexadecimal,1,0,80,0,1,1,0,1,0,0,0,10,8,0,2,0,Decimal,128,0,0,16,8,0,2,0,10011010,154,9A,Use Octet Address(2)使用8位组地址(2),Address Class地址分类,Theoretically 32bits IP address can support 4 billion nodes理论上32位的IP地址能支持超过40亿个节点IP Address have 5 classes 目前将IP地址分为了5类Class A have 8 bits network ID A类地址有8位表示网络名Class B have 16 bits network ID B类地址有16位表示网络名Class C have 24 bits network ID C类地址有24位表示网络名Class D is for multicast D类地址用于多点广播Class E is reserved for test network E类地址保留作测试用,00000000,00000001,0 xxxxxxx,01111110,01111111,Network ID,0,1,2-125,126,127,Decimal,Local network,First usable class A network,Usable Class A networks,Last usable class A network,Loopback or Local host,Meaning,Format,0 xxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx,Netmask,11111111 00000000 00000000 00000000,Network ID,0 xxxxxxx 00000000 00000000 00000000,Host ID,00000000 xxxxxxxx xxxxxxxx xxxxxxxx,Class A AddressA类地址,10000000 00000000,10000000 00000001,10 xxxxxx xxxxxxxx,1011111