VAR综合多业务光传输交换系统的设计
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摘要
VAR综合多业务光传输交换系统是为了满足目前市场上日益庞大且指标日益高涨多级联网监控的要求而提出,它将取代传统监控系统的众多设备,使系统简洁实用,并能满足未来监控网络扩大的需求。
本文在研究VAR系统产生背景、原理和相关技术的基础上,重点进行系统时钟同步设计。设计时根据同步策略的不同分为VAR传输交换网络的时钟同步和VAR系统中心与前端、终端接收系统的时钟同步这两个方面来考虑。VAR传输交换网络采用同步网技术进行同步;VAR系统中心与前端、终端接收系统采用了基于缓存的自适应时钟同步方案进行同步。
在设计VAR系统中心与前端、终端接收系统同步方案的时候,首先对两者间的连接网络进行时延测量,证明其时延变化很小。因此在端设备处适合用基于缓存的自适应同步方式。然后在详细分析文献[18]的同步方案基础上,提出了一种基于最小二乘线性回归的时钟同步方案,并经过仿真分析证明其能有效地滤除时延抖动对缓存变化的影响,使接收端能够准确地跟踪源端时钟频率。本文还尝试把加权平均算法引入到缓存采样数据去抖中,分析其性能。并在FPGA电路板上对基于缓存的自适应时钟同步算法进行具体实现。还提出一种分组丢包检测处理机制。
VAR multi-services optical transmission and switching integrated system can satisfy the requirement of future monitoring system. It can replace many equipments in traditional monitoring system, and it is very simple and useful.
The backgrounds, principle and some important technologies are described in the thesis. The clock synchronization of VAR is studied as emphases, and it is divided into two parts for designing. SDH technologies are used in VAR transmission and switching integrated network, and adaptive synchronous algorithm is used between VAR center and terminal.
During the study of synchronization between VAR center and terminal, delay variety of packets network which between VAR center and terminal is measured, and the result shows that the delay variety of packets network is very small. So the adaptive synchronous algorithm for clock recovery can be used at terminal. Then the thesis analyzes the adaptive synchronous algorithm[18] in detail. And introduces Least Square Linear Regression based clock recovery algorithm at terminal. The algorithm has the ability to filter out buffer level flucation efficiently and remove the negative contribution of delay jitter in clock recovery. The new algorithm enables the terminal clock to be synchronized with the VAR center more accuracy. The thesis also try to adopt weighted average algorithm to smooth the packet jitter, and analyses performance of the algorithm. The algorithm is implemented on FPGA circuit board. At last, a new scheme about detection and processing of packet lost is gived in thesis.
本文在研究VAR系统产生背景、原理和相关技术的基础上,重点进行系统时钟同步设计。设计时根据同步策略的不同分为VAR传输交换网络的时钟同步和VAR系统中心与前端、终端接收系统的时钟同步这两个方面来考虑。VAR传输交换网络采用同步网技术进行同步;VAR系统中心与前端、终端接收系统采用了基于缓存的自适应时钟同步方案进行同步。
在设计VAR系统中心与前端、终端接收系统同步方案的时候,首先对两者间的连接网络进行时延测量,证明其时延变化很小。因此在端设备处适合用基于缓存的自适应同步方式。然后在详细分析文献[18]的同步方案基础上,提出了一种基于最小二乘线性回归的时钟同步方案,并经过仿真分析证明其能有效地滤除时延抖动对缓存变化的影响,使接收端能够准确地跟踪源端时钟频率。本文还尝试把加权平均算法引入到缓存采样数据去抖中,分析其性能。并在FPGA电路板上对基于缓存的自适应时钟同步算法进行具体实现。还提出一种分组丢包检测处理机制。
VAR multi-services optical transmission and switching integrated system can satisfy the requirement of future monitoring system. It can replace many equipments in traditional monitoring system, and it is very simple and useful.
The backgrounds, principle and some important technologies are described in the thesis. The clock synchronization of VAR is studied as emphases, and it is divided into two parts for designing. SDH technologies are used in VAR transmission and switching integrated network, and adaptive synchronous algorithm is used between VAR center and terminal.
During the study of synchronization between VAR center and terminal, delay variety of packets network which between VAR center and terminal is measured, and the result shows that the delay variety of packets network is very small. So the adaptive synchronous algorithm for clock recovery can be used at terminal. Then the thesis analyzes the adaptive synchronous algorithm[18] in detail. And introduces Least Square Linear Regression based clock recovery algorithm at terminal. The algorithm has the ability to filter out buffer level flucation efficiently and remove the negative contribution of delay jitter in clock recovery. The new algorithm enables the terminal clock to be synchronized with the VAR center more accuracy. The thesis also try to adopt weighted average algorithm to smooth the packet jitter, and analyses performance of the algorithm. The algorithm is implemented on FPGA circuit board. At last, a new scheme about detection and processing of packet lost is gived in thesis.
引文
[1]R.Noro,J.P.Hubaux.Clock synchronization of MPEG-2 services over packet network[J].Telecommunication Systems Journal,Mar.1999,10(1-2):3-16
[2]R.Noro.Synchronization over packet-switching networks:theory and applications[D].Ph.D thesis,EPFL,2000
[3]H.Hassanzadegan,N.Sarshar.A new method for clock recovery in MPEG decoders[J].Proceeding of OSEE,2001
[4]Daniel Collins著,舒华英等译.VoIP技术及应用[M],人民邮电出版社,2003
[5]任丰原,董思颖等.基于锁相环的时间同步机制与算法[J].软件学报,2007,2:372-380
[6]张占军,韩承德,杨学良.多媒体实时传输协议RTP[J].计算机工程与应用,2000,4:9-11
[7]罗建川,刘守印等.实时传输协议RTP的研究及应用[J].计算机工程与应用,2001,8:82-84
[8]H.Schulzrinne,S.Casner.RTP:A Transport Protocol for Real-Time Applications[S].RFC 1889,January 1996
[9]郑继禹,林基明等.同步理论与技术[M].北京:电子工业出版社,2003[10]吕或.SDH传输技术及其工程应用[D],北京邮电大学硕士学位论文,2002[11]周晓明.SDH网络的同步[J].有线电视技术,2004,10(156):14-20
[12]范亚希,王一超.TDM over Ethemet技术及应用[J].通讯世界,2003,2:40-41
[13]范亚希,TDM over Ethernet技术[J].电信技术,2003,4:42-44
[14]张厥盛等.锁相技术[M].西安:西安电子科技大学出版社,1996
[15]F.M.Gardner.Phaselock Techniques[J].New York:Wiley,1979,2~(nd)ed
[16]A Introduction to Circuit Emulation Services[Z].http://www.cisco.com/warp/public/121/ces.html,Cisco,2003
[17]B.Kaxe.Synchronization of MPEG-2 based digital TV services over IP networks[D].Master thesis,Telia Research AB
[18]R.P.Singh.Jitter and clock recovery for periodic traffic in broadband packet networks[J].IEEE trans,on Communications,May 1994,42(5):2189-2196
[19]沈宇飞,葛宁.TDMoIP时钟恢复算法的设计与实现[J].微计算机管理,2007,23(2-3):94-101
[20]A.Geva.Noval Adaptive Clock for TDM over IP Network[J].RAD Data Communication Inc,2003:131-134
[21]郭永冲,冯泽森等.基于分组网络的实时语音自适应同步算法[J].计算机工程与应用,2003,5:178-180
[22]王广才.电路仿真中抖动缓冲器性能对业务时延影响的研究[J].现代有线传输,2005:55-59
[23]K.Mochalski,J Micheel,S Donnelly.Packets delay and loss at the Auckland Internet access path.In:Proc of Passive and Active Measurement Workshop 2002.Colorado:AgilentTechnologies,2002:47-57
[24]Mills D L.Internet delay experiments[Z].RFC 889,1983
[25]Bolot J C.End-to-end packet delay and loss behavior in the Internet[J].In:Proceedings of SIGCOMM'93,San Francisco,USA,1993:289-298
[26]Moon S B,Kurose J.Correlation of packet delay and loss in the Internet[R].Technical Report 98-11,Department of Computer Science,University of Massachusetts,1998
[27]Almes G,Kaidindi S,Zekauskas M.A one-way delay metric for IPPM[Z].RFC2679,1999
[28]Almes G,Kaidindi S,Zekauskas M.A round-trip delay metric for IPPM[Z].RFC2679,1999
[29]黎文伟,王俊峰等.基于包对采样的IP网络时延变化测量方法[J].计算机研究与发展,2004,8(41):1352-1360
[30]孙海燕,侯朝桢.Internet网络时延测量中的时钟同步算法[J].计算机工程,2006,14(32):20-22
[31]黎文伟,张大方等.基于通用PC架构的高精度网络时延测量方法[J].软件学报,2006,2:275-284
[32]郭永冲.实时数据传输的研究及实现[D].新疆大学硕士研究生毕业论文,2002
[33]徐勋业,熊中柱等.VoIP语音时延的分析和研究[J].光通信研究,2007,1:11-14
[34]柏林,陈雯柏等.TDMoIP技术关键问题的研究[J].重庆工业高等专科学校学报,2004,2(19):25-28
[35]R.P.singh,S.H.Lee.Adaptive clock synchronization schemes for real-time traffic in broadband packet networks[J],in 8rh European Conf.Electrotech.Stockholm.Sweden,June 1988
[36]沈刚,金珊.一种用于包交换网络的自适应时钟恢复算法[P].国家专利局申请号:03141883.X,2006.12
[37]沈刚.wireless mesh支持实时业务的研究[R].博士后研究报告,2004
[38]苏建锋,吴海涛.自适应滤波技术的研究[J].飞行器测控学报,2006,2(25):71-74
[39]李贺冰.Simulink通信仿真教程[M].北京:国防工业出版社,2006
[40]张贤达.现代信号处理[M].北京:清华大学出版社,2002
[41]D.W.Clarke.Designing Phase-locked loops for instrumentation applications measurement[Z].2002
[42]ITU-T Studyqroup 15.Proposal for investigating precision timing synchronization requirements & charcnteristics over asynchronous packet Networks[R].October 2003
[43]赵英.基于异步网络环境的自适应时钟同步[D].北京化工大学硕士学位论文,2004
[44]张然,项学智.SDH网的定时结构设计[J].应用科技,2005,7(32):4-6
[2]R.Noro.Synchronization over packet-switching networks:theory and applications[D].Ph.D thesis,EPFL,2000
[3]H.Hassanzadegan,N.Sarshar.A new method for clock recovery in MPEG decoders[J].Proceeding of OSEE,2001
[4]Daniel Collins著,舒华英等译.VoIP技术及应用[M],人民邮电出版社,2003
[5]任丰原,董思颖等.基于锁相环的时间同步机制与算法[J].软件学报,2007,2:372-380
[6]张占军,韩承德,杨学良.多媒体实时传输协议RTP[J].计算机工程与应用,2000,4:9-11
[7]罗建川,刘守印等.实时传输协议RTP的研究及应用[J].计算机工程与应用,2001,8:82-84
[8]H.Schulzrinne,S.Casner.RTP:A Transport Protocol for Real-Time Applications[S].RFC 1889,January 1996
[9]郑继禹,林基明等.同步理论与技术[M].北京:电子工业出版社,2003[10]吕或.SDH传输技术及其工程应用[D],北京邮电大学硕士学位论文,2002[11]周晓明.SDH网络的同步[J].有线电视技术,2004,10(156):14-20
[12]范亚希,王一超.TDM over Ethemet技术及应用[J].通讯世界,2003,2:40-41
[13]范亚希,TDM over Ethernet技术[J].电信技术,2003,4:42-44
[14]张厥盛等.锁相技术[M].西安:西安电子科技大学出版社,1996
[15]F.M.Gardner.Phaselock Techniques[J].New York:Wiley,1979,2~(nd)ed
[16]A Introduction to Circuit Emulation Services[Z].http://www.cisco.com/warp/public/121/ces.html,Cisco,2003
[17]B.Kaxe.Synchronization of MPEG-2 based digital TV services over IP networks[D].Master thesis,Telia Research AB
[18]R.P.Singh.Jitter and clock recovery for periodic traffic in broadband packet networks[J].IEEE trans,on Communications,May 1994,42(5):2189-2196
[19]沈宇飞,葛宁.TDMoIP时钟恢复算法的设计与实现[J].微计算机管理,2007,23(2-3):94-101
[20]A.Geva.Noval Adaptive Clock for TDM over IP Network[J].RAD Data Communication Inc,2003:131-134
[21]郭永冲,冯泽森等.基于分组网络的实时语音自适应同步算法[J].计算机工程与应用,2003,5:178-180
[22]王广才.电路仿真中抖动缓冲器性能对业务时延影响的研究[J].现代有线传输,2005:55-59
[23]K.Mochalski,J Micheel,S Donnelly.Packets delay and loss at the Auckland Internet access path.In:Proc of Passive and Active Measurement Workshop 2002.Colorado:AgilentTechnologies,2002:47-57
[24]Mills D L.Internet delay experiments[Z].RFC 889,1983
[25]Bolot J C.End-to-end packet delay and loss behavior in the Internet[J].In:Proceedings of SIGCOMM'93,San Francisco,USA,1993:289-298
[26]Moon S B,Kurose J.Correlation of packet delay and loss in the Internet[R].Technical Report 98-11,Department of Computer Science,University of Massachusetts,1998
[27]Almes G,Kaidindi S,Zekauskas M.A one-way delay metric for IPPM[Z].RFC2679,1999
[28]Almes G,Kaidindi S,Zekauskas M.A round-trip delay metric for IPPM[Z].RFC2679,1999
[29]黎文伟,王俊峰等.基于包对采样的IP网络时延变化测量方法[J].计算机研究与发展,2004,8(41):1352-1360
[30]孙海燕,侯朝桢.Internet网络时延测量中的时钟同步算法[J].计算机工程,2006,14(32):20-22
[31]黎文伟,张大方等.基于通用PC架构的高精度网络时延测量方法[J].软件学报,2006,2:275-284
[32]郭永冲.实时数据传输的研究及实现[D].新疆大学硕士研究生毕业论文,2002
[33]徐勋业,熊中柱等.VoIP语音时延的分析和研究[J].光通信研究,2007,1:11-14
[34]柏林,陈雯柏等.TDMoIP技术关键问题的研究[J].重庆工业高等专科学校学报,2004,2(19):25-28
[35]R.P.singh,S.H.Lee.Adaptive clock synchronization schemes for real-time traffic in broadband packet networks[J],in 8rh European Conf.Electrotech.Stockholm.Sweden,June 1988
[36]沈刚,金珊.一种用于包交换网络的自适应时钟恢复算法[P].国家专利局申请号:03141883.X,2006.12
[37]沈刚.wireless mesh支持实时业务的研究[R].博士后研究报告,2004
[38]苏建锋,吴海涛.自适应滤波技术的研究[J].飞行器测控学报,2006,2(25):71-74
[39]李贺冰.Simulink通信仿真教程[M].北京:国防工业出版社,2006
[40]张贤达.现代信号处理[M].北京:清华大学出版社,2002
[41]D.W.Clarke.Designing Phase-locked loops for instrumentation applications measurement[Z].2002
[42]ITU-T Studyqroup 15.Proposal for investigating precision timing synchronization requirements & charcnteristics over asynchronous packet Networks[R].October 2003
[43]赵英.基于异步网络环境的自适应时钟同步[D].北京化工大学硕士学位论文,2004
[44]张然,项学智.SDH网的定时结构设计[J].应用科技,2005,7(32):4-6