大多普勒频偏SOQPSK信号FFT引导COSTAS环载波跟踪技术
|
摘要
SOQPSK信号包络恒定、相位连续,拥有很高的功率、频谱效率,在卫星通信、深空通信、航空遥测等系统中具有广泛的应用前景.为保证SOQPSK信号能够适应上述系统较大的载波多普勒平移,本文提出一种FFT引导COSTAS环的SOQPSK信号载波跟踪技术.算法首先利用FFT粗略估计多普勒频率,将载波频偏牵引至较小的误差范围,再利用改进的COSTAS环跟踪载波残差及相位误差,进而实现了对大频偏SOQPSK信号载波的稳态跟踪.仿真结果表明,本文所提算法不仅能够跟踪大频偏载波,而且在小频偏时性能亦优于传统方法.
SOQPSK signal has constant envelope and continuous phase,and has high power and spectral efficiency. It will have broad application prospects in satellite communications,deep space communications and aeronautical telemetry systems. To ensure SOQPSK carrier signal can be applied to larger Doppler offset system,this paper presents a SOQPSK signal carrier tracking technology which uses FFT guide COSTAS loop. First,a rough estimate by FFT of the Doppler frequency makes carrier frequency offset be limited to a small range,and then uses the improved COSTAS loop to track carrier residuals and phase error,thus achieving a steady carrier track for SOQPSK signal with large carrier frequency offset. Simulation results showthat the proposed algorithm not only is able to track large carrier frequency offset,but also is better to track small frequency offsets than traditional methods.
SOQPSK signal has constant envelope and continuous phase,and has high power and spectral efficiency. It will have broad application prospects in satellite communications,deep space communications and aeronautical telemetry systems. To ensure SOQPSK carrier signal can be applied to larger Doppler offset system,this paper presents a SOQPSK signal carrier tracking technology which uses FFT guide COSTAS loop. First,a rough estimate by FFT of the Doppler frequency makes carrier frequency offset be limited to a small range,and then uses the improved COSTAS loop to track carrier residuals and phase error,thus achieving a steady carrier track for SOQPSK signal with large carrier frequency offset. Simulation results showthat the proposed algorithm not only is able to track large carrier frequency offset,but also is better to track small frequency offsets than traditional methods.
引文
[1]M K Simon,L Li.A cross-correlated trellis-coded quadrature modulation representation of M IL-STD shaped offset quadrature phase-shift keying[J].IPN Progress Report,2003:42-154.
[2]M K Simon,D Divsalar.Maximum-likelihood block detection of no coherent continuous phase modulation[J].IEEE Trans IT,1993,41(1):90-98.
[3]Umashankar B,Aswathy S,NNSSRK P,et al.SOQPSK-A spectrally efficient modulation scheme for aeronautical telemetry applications[J].International Journal of Engineering Science and Innovative Technology(IJESIT),2013,2(2):383-388.
[4]Williams I E,Saquib M.Linear frequency domain equalization of SOQPSK-TG for w ideband aeronautical telemetry channels[J].IEEE Transactions on Aerospace and Electronic Systems,2013,49(1):640-647.
[5]Graell i Amat A,Abdel Nour C,Douillard C.Serially concatenated continuous phase modulation for satellite communications[J].IEEE Transactions on Wireless Communications,2009,8(6):3260-3269.
[6]Perotti A,Benedetto S,Remlein P.Spectrally efficient multiuser continuous-phase modulation systems[A].2010IEEE International Conference on Communications[C].New York:IEEE,2010.1-5.
[7]Simon M K.Bandwidth-Efficient Digital Modulation with Application to Deep-Space Communications[M].WileyInterscience,2003.
[8]CCSDS401.0-B,Radio frequency and modulation systems--Part 1:earth stations and spacecraft[S].
[9]Erik Perrins,Michael Rice.Reduced-complexity approach to iterative detection of coded SOQPSK[J].IEEE Transactions on Communications,2007,55(7):1354-1362.
[10]Beidas B F,Cioni S,De Bie U,et al.Continuous phase modulation for broadband satellite communications:design and trade-offs[J].International Journal of Satellite Communications and Netw orking,2013,31(5):249-262.
[11]Maral G,Bousquet M.Satellite Communications Systems:Systems,Techniques and Technology[M].California:John Wiley&Sons,2011.
[12]Farr W.Technology development for high efficiency optical communications[A].IEEE Aerospace Conference[C].Big Sky:IEEE,2012.1-8.
[13]彭耿,黄知涛,姜文利,等.卫星通信信号的多普勒频率参数盲估计[J].系统工程与电子技术,2010,32(4):674-677.Peng Geng,Huang Zhi-tao,Jiang Wen-li,et al.Blind Doppler parameters estimation of satellite communication signals[J].Systems Engineering and Electronic,2010,32(4):674-677.(in Chinese)
[14]黄振,陆建华,杨士中.卫星通信中多普勒频移的快速捕获[J].电子学报,2003,31(7):1052-1056.Huang Zhen,Lu Jian-hua,Yang Shi-zhong.Rapid acquisition of Doppler shift in satellite communications[J].Acta Electronica Sinica,2003,31(7):1052-1056.(in Chinese)
[15]Natali F.AFC tracking algorithms[J].Communications,IEEE Transactions on,1984,32(8):935-947.
[16]Jinhua S,Jili Z,Xiaojun W.A joint pilot and demodulation soft information carrier synchronization for SOQPSK signals[A].M illimeter Waves(GSM M),2012 5th Global Symposium on[C].IEEE,2012.512-516.
[17]Liu X,Wang M,Wu H,et al.Joint timing and phase estimation algorithm for SOQPSK signals[J].Journal of Jiangsu University(Natural Science Edition),2011,32(4):443-448.
[18]D'Amico A.Feed-forward joint clock and phase estimation schemes for SOQPSK-Type signals[J].IEEE Wireless Communications Letters,2013,2(6):679-682.
[19]John GProakis.Digital Communications[M].3 Mc GramHill,1999.
[20]Hill T J.A non-proprietary,constant envelope,variant of shaped offset QPSK(SOQPSK)for improved spectral containment and detection efficiency[A].M ILCOM2000.21st Century M ilitary Communications Conference Proceedings[C].New York:IEEE,2000.347-352.
[2]M K Simon,D Divsalar.Maximum-likelihood block detection of no coherent continuous phase modulation[J].IEEE Trans IT,1993,41(1):90-98.
[3]Umashankar B,Aswathy S,NNSSRK P,et al.SOQPSK-A spectrally efficient modulation scheme for aeronautical telemetry applications[J].International Journal of Engineering Science and Innovative Technology(IJESIT),2013,2(2):383-388.
[4]Williams I E,Saquib M.Linear frequency domain equalization of SOQPSK-TG for w ideband aeronautical telemetry channels[J].IEEE Transactions on Aerospace and Electronic Systems,2013,49(1):640-647.
[5]Graell i Amat A,Abdel Nour C,Douillard C.Serially concatenated continuous phase modulation for satellite communications[J].IEEE Transactions on Wireless Communications,2009,8(6):3260-3269.
[6]Perotti A,Benedetto S,Remlein P.Spectrally efficient multiuser continuous-phase modulation systems[A].2010IEEE International Conference on Communications[C].New York:IEEE,2010.1-5.
[7]Simon M K.Bandwidth-Efficient Digital Modulation with Application to Deep-Space Communications[M].WileyInterscience,2003.
[8]CCSDS401.0-B,Radio frequency and modulation systems--Part 1:earth stations and spacecraft[S].
[9]Erik Perrins,Michael Rice.Reduced-complexity approach to iterative detection of coded SOQPSK[J].IEEE Transactions on Communications,2007,55(7):1354-1362.
[10]Beidas B F,Cioni S,De Bie U,et al.Continuous phase modulation for broadband satellite communications:design and trade-offs[J].International Journal of Satellite Communications and Netw orking,2013,31(5):249-262.
[11]Maral G,Bousquet M.Satellite Communications Systems:Systems,Techniques and Technology[M].California:John Wiley&Sons,2011.
[12]Farr W.Technology development for high efficiency optical communications[A].IEEE Aerospace Conference[C].Big Sky:IEEE,2012.1-8.
[13]彭耿,黄知涛,姜文利,等.卫星通信信号的多普勒频率参数盲估计[J].系统工程与电子技术,2010,32(4):674-677.Peng Geng,Huang Zhi-tao,Jiang Wen-li,et al.Blind Doppler parameters estimation of satellite communication signals[J].Systems Engineering and Electronic,2010,32(4):674-677.(in Chinese)
[14]黄振,陆建华,杨士中.卫星通信中多普勒频移的快速捕获[J].电子学报,2003,31(7):1052-1056.Huang Zhen,Lu Jian-hua,Yang Shi-zhong.Rapid acquisition of Doppler shift in satellite communications[J].Acta Electronica Sinica,2003,31(7):1052-1056.(in Chinese)
[15]Natali F.AFC tracking algorithms[J].Communications,IEEE Transactions on,1984,32(8):935-947.
[16]Jinhua S,Jili Z,Xiaojun W.A joint pilot and demodulation soft information carrier synchronization for SOQPSK signals[A].M illimeter Waves(GSM M),2012 5th Global Symposium on[C].IEEE,2012.512-516.
[17]Liu X,Wang M,Wu H,et al.Joint timing and phase estimation algorithm for SOQPSK signals[J].Journal of Jiangsu University(Natural Science Edition),2011,32(4):443-448.
[18]D'Amico A.Feed-forward joint clock and phase estimation schemes for SOQPSK-Type signals[J].IEEE Wireless Communications Letters,2013,2(6):679-682.
[19]John GProakis.Digital Communications[M].3 Mc GramHill,1999.
[20]Hill T J.A non-proprietary,constant envelope,variant of shaped offset QPSK(SOQPSK)for improved spectral containment and detection efficiency[A].M ILCOM2000.21st Century M ilitary Communications Conference Proceedings[C].New York:IEEE,2000.347-352.