低信噪比条件下的载波恢复
摘要
TDRSS高速数传对数据传输速率的要求不断提高,通信系统必然需要采用更高阶的调制样式和更高效率的编码方式,在功率和带宽同时受限的情况下,低信噪比条件下的载波恢复问题亟待深入研究和解决,否则将成为信号接收和解调的瓶颈。
本文简要分析了各种调制方式特别是TCM-8PSK信号的解调信噪比门限,提出了低信噪比条件下载波恢复这一命题;重点研究了低信噪比条件下载波恢复参数估计算法,并提出改进方案以降低信噪比门限;最后基于Xilinx公司的Virtex-Ⅳ系列FPGA设计了TDRSS高速数传8PSK数字接收机的载波恢复系统方案。
分析结果表明:改进后载波频偏估计的信噪比门限降低到5dB左右,该载波恢复系统在6dB信噪比条件下工作良好,能够满足TCM-8PSK在6dB条件下实现10~(-5)误比特率的性能要求。
The request of high speed data transmission in TDRSS (Track and Data Relay Satellite System) to transmission rate continuously rises. Communication systems have to adopt higher-alphabet-size modulations and more-efficient codes. When the power and bandwidth is limited at the same time, carrier recovery in low-SNR (Signal Noise Ratio) condition is one of problems which need to be researched and solved, otherwise it will be a bottleneck to signal receiving and demodulating.
Firstly, the SNR threshold of different modulations especially of TCM-8PSK is analyzed, and the problem of carrier recovery in low-SNR condition is put forward. Then, parameter estimation algorithms in carrier recovery are researched, and an improved project is proposed to reduce the SNR threshold. Finally, based on the FPGA of the Virtex-IV series of Xilinx company, a carrier recovery system in 8PSK digital receiver for high speed data transmission in TDRSS is designed.
Simulation result indicates that: The SNR threshold of the improved carrier frequency offset estimation algorithm is reduced to be as low as 5dB. The carrier recovery system proposed can work well under the situation of 6dB SNR, and the request that the BER performance comes down to 10~(-5) in 6dB SNR condition for TCM-8PSK signal can be satisfied.
本文简要分析了各种调制方式特别是TCM-8PSK信号的解调信噪比门限,提出了低信噪比条件下载波恢复这一命题;重点研究了低信噪比条件下载波恢复参数估计算法,并提出改进方案以降低信噪比门限;最后基于Xilinx公司的Virtex-Ⅳ系列FPGA设计了TDRSS高速数传8PSK数字接收机的载波恢复系统方案。
分析结果表明:改进后载波频偏估计的信噪比门限降低到5dB左右,该载波恢复系统在6dB信噪比条件下工作良好,能够满足TCM-8PSK在6dB条件下实现10~(-5)误比特率的性能要求。
The request of high speed data transmission in TDRSS (Track and Data Relay Satellite System) to transmission rate continuously rises. Communication systems have to adopt higher-alphabet-size modulations and more-efficient codes. When the power and bandwidth is limited at the same time, carrier recovery in low-SNR (Signal Noise Ratio) condition is one of problems which need to be researched and solved, otherwise it will be a bottleneck to signal receiving and demodulating.
Firstly, the SNR threshold of different modulations especially of TCM-8PSK is analyzed, and the problem of carrier recovery in low-SNR condition is put forward. Then, parameter estimation algorithms in carrier recovery are researched, and an improved project is proposed to reduce the SNR threshold. Finally, based on the FPGA of the Virtex-IV series of Xilinx company, a carrier recovery system in 8PSK digital receiver for high speed data transmission in TDRSS is designed.
Simulation result indicates that: The SNR threshold of the improved carrier frequency offset estimation algorithm is reduced to be as low as 5dB. The carrier recovery system proposed can work well under the situation of 6dB SNR, and the request that the BER performance comes down to 10~(-5) in 6dB SNR condition for TCM-8PSK signal can be satisfied.
引文
[1]Arthur H.Jackson,William S.Guion and Robert W.Chang,A TDRSS Program Overview(J),IEEE Globecom'91,188-194;
[2]戴淑珍,跟踪与数据中继卫星通信分系统综述,国防科工委第四届通信学术会议论文集,军事科学出版社,1998:254-258:
[3]Ramin Sadr,P.P.Vaidyanathan,Dan Raphaeli,Sami Hinedi,Parallel Digital Modern Using Multi-rate Digital Filter Banks(R),JPL Publication 94-20,N95-22478/8/HDM;
[4]P.Ghuman,S.Sheikh,S.Koubek,Andrew Gray,S.Hoy,High Rate Digital Demodulation ASIC(R),JPL,CA,26-30 Oct.1998;
[5]M.Srinivasan,C.C.Chen,G.Grebowsky,Andrew Gray,An All-Digital High Data-Rate Parallel Receiver(R),TDA Progress Report 42-131,1998;
[6]Andrew Gray,Meera Srinivasan,Marvin Simon,Flexible All-Digital Receiver for Bandwidth Efficient Modulations(R),JLP Publication 99';
[7]Ted J.Wolctt,James M.Gardner,Performance Evaluation of 8PSK at 450Mbps Through TDRSS(R).New Mexico State University,1996 IEEE International Conference on Communications;
[8]Daniel L.Brandel,William A.Watson,Aaron Weinberg,NASA's Advanced Tracking and Data Relay Satellite System for the Years 2000 and Beyond,Proceedings of The IEEE,Vol.78,No.7,July 1990,1141-1151;
[9]Ronald A.Mile and Allen K.Bemdt,NASA's Next Generation Tracking and Data Relay Satellite System(TDRSS) - Launch and Operational Ground Segment Architecture.http://nmsp.gsfc.nasa,gov;
[10]David J.Zillig,D.Robert McOmber,Neil Fox,TDRSS Demand Access Servic:Application of Advanced Technologies to Enhance User Operations,Paper ID:5a003;
[11]David J.Zillig,Kenneth L.Perko,Kathryn G.Nelson,New TDRSS Communications Options for Small Satellites,http://nmsp.gsfc.nasa.gov;
[12]J.C.Morakis,W.H.Miller,Bandwidth & Modulation Techniques Under Study by NASA,http://nmsp.gsfc.nasa.gov;
[13]Ungerboeck G.Trellis Coded Modulation with Redundant Signal Sets - Part 1,Introduction,IEEE Communication Magazine,1987,25(2),5-11;
[14]Ungerboeck G.Trellis Coded Modulation with Redundant Signal Sets - Part 2,Introduction,IEEE Communication Magazine,1987,25(2),12-21;
[15]张健,向敬成,软件无线电技术导论(M),成都:电子科技大学出版社,2001;
[16]John G.Proakis,Digital Communications(Fourth Edition)(M),北京:电子工业出版社,2003.1;
[17]J.L.Massey,Coding and Modulation in Digital Communications,Proc.1974,Int.Zurich Seminar on Digital Comm.,Zurich,Switzerland,Mar.1974:E2(2)-(4);
[18]杨军,高速数据传输中的TCM技术研究及其应用,国防科学技术大学博士学位论文(D),2005.10;
[19]S.A.Tretter,Estimating the Frequency of a Noisy Sinusoid by Linear Regression[J],IEEE Trans.Inform.Theory,VOL.IT-31,NO.6,Nov.1985;
[20]D.C.Rife and R.R.Boorstyn,Single Tone Parameter Estimation from Discrete-Time Observations(J),IEEE Trans.Vehicular Technology,1996,Vol.45,No.4;
[21]B.G.Quinn,Estimation Frequency by Interpolation Using Fourier Coefficient(J),IEEE Trans.Signal Processing,Vol.42,No.5,May 1994;
[22]李晶,高速数据传输中的载波恢复技术研究,国防科学技术大学博士学位论文(D),2005.10;
[23]陈大夫,TCM/8PSK高速数传全数字接收机关键技术研究及其FPGA实现,国防科学技术大学博士学位论文(D),2006.9;
[24]A.J.Viterbi,A.M.Viterbi,Nonlinear Estimation of PSK Modulated Carrier Phase with Application to Burst Digital Transmission(J),IEEE Trans.Inform.,1983,Vol.29,No.4;
[25]Xilinx Corporation,High-Performance 1024-Point Complex FFT(R),April 8,1999;
[26]张公礼,全数字接收机理论与技术(M),科学出版社,2005;
[27]黄葆华,数字系统中的内插技术,通信工程学院学报,1999,Vol.12,No.2;
[28]P.Y.Kam,Maximum Likelihood Carrier Phase Recovery for Linear Suppressed Carrier Digital Data Modulations,IEEE Trans.Comm.,1986,Vol.34,No.6;
[29]Mengali V,Morelli M,Data-aided Frequency Estimation for Burst Digital Transmission,IEE Trans.Comm.,1997,Vol.45,No.1;
[30]Ouyang Y,Wang C L,A New Cartier Recovery Loop For High Order Quadrature Amplitude Modulation,in Proc.IEEE GLOBECOM 2002,Taipei,Vol.1,PP.478-482;
[31]Chen J.C.,Cooper L.,Taggart D.,Performance of MPSK and 16 QAM in The Satellite Communication Environment,in Proc.2004 IEEE Aerospace Conference,Vol.2,PP.1383-1391.
[2]戴淑珍,跟踪与数据中继卫星通信分系统综述,国防科工委第四届通信学术会议论文集,军事科学出版社,1998:254-258:
[3]Ramin Sadr,P.P.Vaidyanathan,Dan Raphaeli,Sami Hinedi,Parallel Digital Modern Using Multi-rate Digital Filter Banks(R),JPL Publication 94-20,N95-22478/8/HDM;
[4]P.Ghuman,S.Sheikh,S.Koubek,Andrew Gray,S.Hoy,High Rate Digital Demodulation ASIC(R),JPL,CA,26-30 Oct.1998;
[5]M.Srinivasan,C.C.Chen,G.Grebowsky,Andrew Gray,An All-Digital High Data-Rate Parallel Receiver(R),TDA Progress Report 42-131,1998;
[6]Andrew Gray,Meera Srinivasan,Marvin Simon,Flexible All-Digital Receiver for Bandwidth Efficient Modulations(R),JLP Publication 99';
[7]Ted J.Wolctt,James M.Gardner,Performance Evaluation of 8PSK at 450Mbps Through TDRSS(R).New Mexico State University,1996 IEEE International Conference on Communications;
[8]Daniel L.Brandel,William A.Watson,Aaron Weinberg,NASA's Advanced Tracking and Data Relay Satellite System for the Years 2000 and Beyond,Proceedings of The IEEE,Vol.78,No.7,July 1990,1141-1151;
[9]Ronald A.Mile and Allen K.Bemdt,NASA's Next Generation Tracking and Data Relay Satellite System(TDRSS) - Launch and Operational Ground Segment Architecture.http://nmsp.gsfc.nasa,gov;
[10]David J.Zillig,D.Robert McOmber,Neil Fox,TDRSS Demand Access Servic:Application of Advanced Technologies to Enhance User Operations,Paper ID:5a003;
[11]David J.Zillig,Kenneth L.Perko,Kathryn G.Nelson,New TDRSS Communications Options for Small Satellites,http://nmsp.gsfc.nasa.gov;
[12]J.C.Morakis,W.H.Miller,Bandwidth & Modulation Techniques Under Study by NASA,http://nmsp.gsfc.nasa.gov;
[13]Ungerboeck G.Trellis Coded Modulation with Redundant Signal Sets - Part 1,Introduction,IEEE Communication Magazine,1987,25(2),5-11;
[14]Ungerboeck G.Trellis Coded Modulation with Redundant Signal Sets - Part 2,Introduction,IEEE Communication Magazine,1987,25(2),12-21;
[15]张健,向敬成,软件无线电技术导论(M),成都:电子科技大学出版社,2001;
[16]John G.Proakis,Digital Communications(Fourth Edition)(M),北京:电子工业出版社,2003.1;
[17]J.L.Massey,Coding and Modulation in Digital Communications,Proc.1974,Int.Zurich Seminar on Digital Comm.,Zurich,Switzerland,Mar.1974:E2(2)-(4);
[18]杨军,高速数据传输中的TCM技术研究及其应用,国防科学技术大学博士学位论文(D),2005.10;
[19]S.A.Tretter,Estimating the Frequency of a Noisy Sinusoid by Linear Regression[J],IEEE Trans.Inform.Theory,VOL.IT-31,NO.6,Nov.1985;
[20]D.C.Rife and R.R.Boorstyn,Single Tone Parameter Estimation from Discrete-Time Observations(J),IEEE Trans.Vehicular Technology,1996,Vol.45,No.4;
[21]B.G.Quinn,Estimation Frequency by Interpolation Using Fourier Coefficient(J),IEEE Trans.Signal Processing,Vol.42,No.5,May 1994;
[22]李晶,高速数据传输中的载波恢复技术研究,国防科学技术大学博士学位论文(D),2005.10;
[23]陈大夫,TCM/8PSK高速数传全数字接收机关键技术研究及其FPGA实现,国防科学技术大学博士学位论文(D),2006.9;
[24]A.J.Viterbi,A.M.Viterbi,Nonlinear Estimation of PSK Modulated Carrier Phase with Application to Burst Digital Transmission(J),IEEE Trans.Inform.,1983,Vol.29,No.4;
[25]Xilinx Corporation,High-Performance 1024-Point Complex FFT(R),April 8,1999;
[26]张公礼,全数字接收机理论与技术(M),科学出版社,2005;
[27]黄葆华,数字系统中的内插技术,通信工程学院学报,1999,Vol.12,No.2;
[28]P.Y.Kam,Maximum Likelihood Carrier Phase Recovery for Linear Suppressed Carrier Digital Data Modulations,IEEE Trans.Comm.,1986,Vol.34,No.6;
[29]Mengali V,Morelli M,Data-aided Frequency Estimation for Burst Digital Transmission,IEE Trans.Comm.,1997,Vol.45,No.1;
[30]Ouyang Y,Wang C L,A New Cartier Recovery Loop For High Order Quadrature Amplitude Modulation,in Proc.IEEE GLOBECOM 2002,Taipei,Vol.1,PP.478-482;
[31]Chen J.C.,Cooper L.,Taggart D.,Performance of MPSK and 16 QAM in The Satellite Communication Environment,in Proc.2004 IEEE Aerospace Conference,Vol.2,PP.1383-1391.