窄带COFDM系统的同步与信道估计研究及硬件实现
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摘要
数字电视地面广播移动传输技术是融合数字电视、纠错编码、数字信号处理、计算机技术、超大规模集成电路、无线通信等高新技术成果而综合发展起来的一项前沿技术。地面移动传输的环境比较复杂,频谱资源有限并且用户比较分散,所以数字电视地面广播尚无统一的国际标准,这一领域还有很大的研发潜力。随着MPEG-4 AVC标准的提出,研究和开发与H.264/MPEG-4 AVC相匹配的窄带数字视频地面移动传输系统具有十分重要的意义。
本项目研究了窄带数字视频地面移动传输系统的基本原理及其在片上系统(SOC, System On Chip)上的具体实现。该项目在设计过程中采用了MPEG-4 AVC信源编码标准、窄带编码调制、最新数字上变频器(DUC)和数字下变频器(DDC)分集接收以及自适应复接等多项先进技术。多项先进技术的运用使系统提高了抗瑞利衰落能力,节省了频率资源,并提高了系统抗突发干扰能力,系统的性能得到显著提高。本窄带编码调制系统填补了我国在移动视频领域的空白。
窄带数字视频地面移动传输系统(NBCOFDM)的设计包括信源编码和信道编码两部分,信源编码的目的在于将声音图像等信号转换为可进行信号处理的电信号,信道编码的目的在于保证电信号的正确传输。本论文详细论述了信道编码部分的设计。信道编码的主要任务是编码调制,包括RS码与卷积码级联编解码、正交频分复用技术的IFFT/FFT实现、数字上/下变频的设计、同步恢复及信道估计等关键技术的实现。本文最开始阐述了整个系统的设计方案,接下来详细阐述了无线移动信道下的信道估计及同步恢复技术,并且在Matlab软件仿真的基础上,针对同步及信道估计的信号原理、常用算法及典型算法进行了分析,结合XILINX公司的ISE 6.1i仿真环境,采用FPGA实现了适合本系统的同步及信道估计与均衡算法的硬件设计,并在PCB电路板上得到验证。
DTTB (Digital Television Terrestrial Broadcasting) technology is a newly developed technology which has comprehensively combined with many Hi-tech productions such as Digital Television, Coding theory, Digital Signal Processing, Computer Technology, SLSI (Super Large-Scale Integration), Communication Technology and so on. In view of current complex terrestrial transmission environment, limited spectrum resource and dispersed users, there is no undisputed international standard of Digital Television Terrestrial Broadcasting up till now. Therefore, rich research potential has been remained in this field. Researching and designing a narrow band Digital Television Terrestrial Broadcasting transmitting system is significant as soon as MPEG-4 AVC standard was put forward.
This project has been focused on the research of basic theory of narrow band Digital Television Broadcasting transmitting system and its practical realization on SOC (system on Chip). The system has taken advantage of many advanced technologies including MPEG-4 AVC theory, narrow band coding and modulation, update digital up transducer, and digital down transducer. The application of so many advanced technologies has improved the ability of Rayleigh fading and saved frequency resource. Meanwhile, the capability of system burst interruption and the comprehensive performance of this system has been obviously upgraded. In final analysis, this narrow band coding and modulation system has injected new energy into the weak field of domestic mobile video.
The design of Narrow Band Coded Orthogonal Frequency Multiplexing system contains Signal resource encoding and Channel encoding. The order of Signal resource encoding is transferring image and sound signal to electric signal, and the order of channel encoding is making sure of effectual transmission of electric signal. In this paper, the design of Channel encoding is disserted. It contains RS code、convolutional code、the realization of OFDM with IFFT/FFT、DDC/DUC、Synchronization and channel estimator and so on. The scheme of the system is introduced firstly, and then Synchronization and channel estimator are expatiated. Based on the simulation with Matlab, it expatiates signal theory, common arithmetic and typical arithmetic. In the end, FPGA circuit is designed of Synchronization and channel estimator module in ISE6.1i, and the circuit was checked on PCB board.
本项目研究了窄带数字视频地面移动传输系统的基本原理及其在片上系统(SOC, System On Chip)上的具体实现。该项目在设计过程中采用了MPEG-4 AVC信源编码标准、窄带编码调制、最新数字上变频器(DUC)和数字下变频器(DDC)分集接收以及自适应复接等多项先进技术。多项先进技术的运用使系统提高了抗瑞利衰落能力,节省了频率资源,并提高了系统抗突发干扰能力,系统的性能得到显著提高。本窄带编码调制系统填补了我国在移动视频领域的空白。
窄带数字视频地面移动传输系统(NBCOFDM)的设计包括信源编码和信道编码两部分,信源编码的目的在于将声音图像等信号转换为可进行信号处理的电信号,信道编码的目的在于保证电信号的正确传输。本论文详细论述了信道编码部分的设计。信道编码的主要任务是编码调制,包括RS码与卷积码级联编解码、正交频分复用技术的IFFT/FFT实现、数字上/下变频的设计、同步恢复及信道估计等关键技术的实现。本文最开始阐述了整个系统的设计方案,接下来详细阐述了无线移动信道下的信道估计及同步恢复技术,并且在Matlab软件仿真的基础上,针对同步及信道估计的信号原理、常用算法及典型算法进行了分析,结合XILINX公司的ISE 6.1i仿真环境,采用FPGA实现了适合本系统的同步及信道估计与均衡算法的硬件设计,并在PCB电路板上得到验证。
DTTB (Digital Television Terrestrial Broadcasting) technology is a newly developed technology which has comprehensively combined with many Hi-tech productions such as Digital Television, Coding theory, Digital Signal Processing, Computer Technology, SLSI (Super Large-Scale Integration), Communication Technology and so on. In view of current complex terrestrial transmission environment, limited spectrum resource and dispersed users, there is no undisputed international standard of Digital Television Terrestrial Broadcasting up till now. Therefore, rich research potential has been remained in this field. Researching and designing a narrow band Digital Television Terrestrial Broadcasting transmitting system is significant as soon as MPEG-4 AVC standard was put forward.
This project has been focused on the research of basic theory of narrow band Digital Television Broadcasting transmitting system and its practical realization on SOC (system on Chip). The system has taken advantage of many advanced technologies including MPEG-4 AVC theory, narrow band coding and modulation, update digital up transducer, and digital down transducer. The application of so many advanced technologies has improved the ability of Rayleigh fading and saved frequency resource. Meanwhile, the capability of system burst interruption and the comprehensive performance of this system has been obviously upgraded. In final analysis, this narrow band coding and modulation system has injected new energy into the weak field of domestic mobile video.
The design of Narrow Band Coded Orthogonal Frequency Multiplexing system contains Signal resource encoding and Channel encoding. The order of Signal resource encoding is transferring image and sound signal to electric signal, and the order of channel encoding is making sure of effectual transmission of electric signal. In this paper, the design of Channel encoding is disserted. It contains RS code、convolutional code、the realization of OFDM with IFFT/FFT、DDC/DUC、Synchronization and channel estimator and so on. The scheme of the system is introduced firstly, and then Synchronization and channel estimator are expatiated. Based on the simulation with Matlab, it expatiates signal theory, common arithmetic and typical arithmetic. In the end, FPGA circuit is designed of Synchronization and channel estimator module in ISE6.1i, and the circuit was checked on PCB board.
引文
[1] 姚冬苹,蔡超时等译.数字电视接收技术.北京:电子工业出版社,2003,10-26
[2] 郑志航.数字电视原理与应用.北京:中国广播电视出版社,2001.1,188-262
[3] ATSC.“Guide to the Use of the ATSC Digital television Standard”.Advanced Television Systems Committee.Washington.DC,Doc.A/54,Otc,1995
[4] ATSC.“Performance Assessment of the ATSC Transmition System,Equipment,and Future Directions”.ATSC Task Force on RF System Performance.Advanced Television Systems Committee.Washington.DC.Doc,revision: 1.0,April,1995
[5] ETSI.EN 300 744.“Digital Video broadcasting(DVB); Framing structure,channel coding and modulation for digital terrestrial television”, 2001.01
[6] ETSI.EN 300 421. “Digital Video Broadcasting (DVB);Framing structure, channel coding and modulation for 11/12 GHz satellite services”,1997.8
[7] EBU/ETSI JTC.ETS 300 429. “Digital broadcasting systems for television,sound and data services; Framing structure, channel coding and modulation for cable systems”,1994.10
[8] NEC(中国).日本地面数字电视广播(ISDB-T)技术规范概要介绍,2003.7
[9] 傅殷.中国数字电视研究开发及产业化探索.深圳:广东经济出版社,2001,134-152
[10]清华大学.DMB-TH地面数字电视传输技术白皮书.第二版,2006.5
[11]清华大学.地面数字电视传输技术白皮书.2004.8
[12]James K. Cavers. "Mobile Channel Characteristics", Kluwer Academic Publishers, 2000
[13]谭泽富,聂祥飞等.OFDM关键技术及应用.成都:西南交通大学出版社,2005,13-20
[14]黄毅,方晓颖,尹秋艳.DVB-T 中的 COFDM 调制技术.现代电视技术,2003.12,92-93
[15]郑雯等. 数字电视原理、传输与接收.北京:人民邮电出版社,2006
[16]王新梅,肖国镇.纠错编码-原理与方法.西安:西安电子科技大学出版社,2001,52-83
[17]R. Johannesson,K. Zigangirov. “Fundamentals of Convolutional Coding”. New York: IEEE Press, 1999
[18]桑林,郝建军,刘丹谱.数字通信.北京:北京邮电出版社,2002.2
[19]VigneshSeth, Bruce Hajek.. “Bit-Interleaved Coded Modulation”. IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 52, NO. 4, APRIL 2006,1795-1797
[20]佟学俭,罗涛.OFDM 移动通信技术原理与应用.北京:人民邮电出版社,2003.6
[21]胡健栋.现代无线通信技术.北京:机械工业出版社,2003
[22]杨大成等著.现代移动通信中的先进技术.北京:机械工业外出版社,2005.7
[23]王伟伟.OFDM系统的同步技术的研究:[硕士学位论文],大连:大连海事大学.2006.3
[24]Chien-Chih Chen,Jung-Shan Lin. Iterative ML Estimation for Offset and Time Synchronization in OFDM Systems. Proceedings of the 2004 IEEE International Conference on Networking, Sensing&Control, Taipei, Taiwan. 2004.3, 1412-1417
[25]曹增峰等.一种基于特殊导频方案的 OFDM 载波频率同步,无线电工程,2003,33(3),11-15
[26]B.Debaillie,B.Come.“Impact of front-end filter on bit-error rate performances in WLAN- OFDM transceivers” in Proc. IEEE Radio Wireless Conf, Boston, MA, 2001.8,193-196
[27]Yun Hee Kim, Young Kwon Hahm,Hye Jung Jung. An Efficient Frequency Offset Estimator for Timing and Frequency Synchronization in OFDM System.1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, 1999,580-583
[28]J.Van de Beek, M. Sandell and P.O. Borjesson, “ML Estimation of Time and Frequency Offset in OFDM Systems”,IEEE Transactions on Signal Processingl, July 1997, 1800-1805
[29]J.van de Beek, M. Sandell and P.O. Borjession, “Low-complex frame synchronization in OFDM systems” in Proc. Of ICUPC’95, Tokyo, 1995, 982-986
[30]Panavirci E. “A New Algorithm for Joint Time and Phase Synchronization in OFDM Systems”, The 11th IEEE International Symposium on Personal,Indoor and Mobile Radio communications, 2000. PIMRC 2000. 18-21 Sept. 2000. vol. 2, 819-823
[31]Pierre Combelles, Christophe Del Toso, Dietmar Hepper.”A Receiver Architecture Conforming to the OFDM Based Digital Video Broadcasting Standard for Terrestrial Transmission (DVB-T)”, IEEE , 1998
[32]Stefan Johansson, Daniel Landstr?m,Peter Nilsson.“An OFDM Timing Synchronization ASIC”. IEEE,2000,324-327
[33]Samir Palnitar 著(夏宇闻等译).Verilog 数字系统设计教程.北京:北京航空航天大学出版社,2003.1
[34]杨晓.突发OFDM系统接收机同步算法设计及其FPGA实现:[硕士学位论文].浙江:浙江大学,2005.1
[35]孙翠珍.正交频分复用(OFDM)系统中信到估计算法的研究:[硕士学位论文].西安:西安科技大学,2005.4
[36]周利岗、傅海阳.“OFDM 系统中基于导频插入的信道估计技术”,通信技术,2003,第 8期
[37]Che-Shen Yeh and Yinyi Lin.“Channel Estimation Using Pilot Tones in OFDM Systems”.IEEE Transactions on Broadcasting,,VOL. 45, NO. 4, DECEMBER 1999
[38]Y Zhao,A Huang.A novel channel estimation methods for OFDM mobile communication systems based on pilot signals and transform domain processing in Proc IEEE 47th Vehicular Technology Conference,Phoenix, USA,1997.5,2089-2093
[39]杨晖.DVB-T接收机中信道估计和多普勒干扰消除算法研究及其硬件实现:[硕士学位论文],浙江:浙江大学,2006.1
[2] 郑志航.数字电视原理与应用.北京:中国广播电视出版社,2001.1,188-262
[3] ATSC.“Guide to the Use of the ATSC Digital television Standard”.Advanced Television Systems Committee.Washington.DC,Doc.A/54,Otc,1995
[4] ATSC.“Performance Assessment of the ATSC Transmition System,Equipment,and Future Directions”.ATSC Task Force on RF System Performance.Advanced Television Systems Committee.Washington.DC.Doc,revision: 1.0,April,1995
[5] ETSI.EN 300 744.“Digital Video broadcasting(DVB); Framing structure,channel coding and modulation for digital terrestrial television”, 2001.01
[6] ETSI.EN 300 421. “Digital Video Broadcasting (DVB);Framing structure, channel coding and modulation for 11/12 GHz satellite services”,1997.8
[7] EBU/ETSI JTC.ETS 300 429. “Digital broadcasting systems for television,sound and data services; Framing structure, channel coding and modulation for cable systems”,1994.10
[8] NEC(中国).日本地面数字电视广播(ISDB-T)技术规范概要介绍,2003.7
[9] 傅殷.中国数字电视研究开发及产业化探索.深圳:广东经济出版社,2001,134-152
[10]清华大学.DMB-TH地面数字电视传输技术白皮书.第二版,2006.5
[11]清华大学.地面数字电视传输技术白皮书.2004.8
[12]James K. Cavers. "Mobile Channel Characteristics", Kluwer Academic Publishers, 2000
[13]谭泽富,聂祥飞等.OFDM关键技术及应用.成都:西南交通大学出版社,2005,13-20
[14]黄毅,方晓颖,尹秋艳.DVB-T 中的 COFDM 调制技术.现代电视技术,2003.12,92-93
[15]郑雯等. 数字电视原理、传输与接收.北京:人民邮电出版社,2006
[16]王新梅,肖国镇.纠错编码-原理与方法.西安:西安电子科技大学出版社,2001,52-83
[17]R. Johannesson,K. Zigangirov. “Fundamentals of Convolutional Coding”. New York: IEEE Press, 1999
[18]桑林,郝建军,刘丹谱.数字通信.北京:北京邮电出版社,2002.2
[19]VigneshSeth, Bruce Hajek.. “Bit-Interleaved Coded Modulation”. IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 52, NO. 4, APRIL 2006,1795-1797
[20]佟学俭,罗涛.OFDM 移动通信技术原理与应用.北京:人民邮电出版社,2003.6
[21]胡健栋.现代无线通信技术.北京:机械工业出版社,2003
[22]杨大成等著.现代移动通信中的先进技术.北京:机械工业外出版社,2005.7
[23]王伟伟.OFDM系统的同步技术的研究:[硕士学位论文],大连:大连海事大学.2006.3
[24]Chien-Chih Chen,Jung-Shan Lin. Iterative ML Estimation for Offset and Time Synchronization in OFDM Systems. Proceedings of the 2004 IEEE International Conference on Networking, Sensing&Control, Taipei, Taiwan. 2004.3, 1412-1417
[25]曹增峰等.一种基于特殊导频方案的 OFDM 载波频率同步,无线电工程,2003,33(3),11-15
[26]B.Debaillie,B.Come.“Impact of front-end filter on bit-error rate performances in WLAN- OFDM transceivers” in Proc. IEEE Radio Wireless Conf, Boston, MA, 2001.8,193-196
[27]Yun Hee Kim, Young Kwon Hahm,Hye Jung Jung. An Efficient Frequency Offset Estimator for Timing and Frequency Synchronization in OFDM System.1999 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, 1999,580-583
[28]J.Van de Beek, M. Sandell and P.O. Borjesson, “ML Estimation of Time and Frequency Offset in OFDM Systems”,IEEE Transactions on Signal Processingl, July 1997, 1800-1805
[29]J.van de Beek, M. Sandell and P.O. Borjession, “Low-complex frame synchronization in OFDM systems” in Proc. Of ICUPC’95, Tokyo, 1995, 982-986
[30]Panavirci E. “A New Algorithm for Joint Time and Phase Synchronization in OFDM Systems”, The 11th IEEE International Symposium on Personal,Indoor and Mobile Radio communications, 2000. PIMRC 2000. 18-21 Sept. 2000. vol. 2, 819-823
[31]Pierre Combelles, Christophe Del Toso, Dietmar Hepper.”A Receiver Architecture Conforming to the OFDM Based Digital Video Broadcasting Standard for Terrestrial Transmission (DVB-T)”, IEEE , 1998
[32]Stefan Johansson, Daniel Landstr?m,Peter Nilsson.“An OFDM Timing Synchronization ASIC”. IEEE,2000,324-327
[33]Samir Palnitar 著(夏宇闻等译).Verilog 数字系统设计教程.北京:北京航空航天大学出版社,2003.1
[34]杨晓.突发OFDM系统接收机同步算法设计及其FPGA实现:[硕士学位论文].浙江:浙江大学,2005.1
[35]孙翠珍.正交频分复用(OFDM)系统中信到估计算法的研究:[硕士学位论文].西安:西安科技大学,2005.4
[36]周利岗、傅海阳.“OFDM 系统中基于导频插入的信道估计技术”,通信技术,2003,第 8期
[37]Che-Shen Yeh and Yinyi Lin.“Channel Estimation Using Pilot Tones in OFDM Systems”.IEEE Transactions on Broadcasting,,VOL. 45, NO. 4, DECEMBER 1999
[38]Y Zhao,A Huang.A novel channel estimation methods for OFDM mobile communication systems based on pilot signals and transform domain processing in Proc IEEE 47th Vehicular Technology Conference,Phoenix, USA,1997.5,2089-2093
[39]杨晖.DVB-T接收机中信道估计和多普勒干扰消除算法研究及其硬件实现:[硕士学位论文],浙江:浙江大学,2006.1