QAM解调及频偏估计联合算法
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摘要
针对在水声传输环境下,载波频率偏移会导致较大的传输误码率的问题,提出一种能够同时进行载波频率偏移估计以及QAM解调的联合算法。在频域将接收信号样点与标准正弦信号进行最小二乘逼近,通过估计接收信号的频率实现载波频偏估计;同时得到接收信号的幅度和相位,从而得到QAM调制信号的I分量和Q分量系数。仿真证明,该算法降低了QAM调制解调算法的误码率。
In underwater acoustic propagation environment, the carrier frequency offset result in a large transmission error rate. This paper proposed a joint algorithm that can simultaneously perform carrier frequency offset estimation and QAM demodulation. In the frequency domain, the received signal sample points were approximated by the least squares with the standard sinusoidal signal, and the carrier frequency offset was estimated by estimating the frequency of the received signal. The amplitude and position of the received signal were obtained, thus the I component and Q component coefficients of the QAM modulated signal were obtained. The simulation results show that the proposed joint algorithm reduces the bit error rate of QAM modulation and demodulation algorithm.
In underwater acoustic propagation environment, the carrier frequency offset result in a large transmission error rate. This paper proposed a joint algorithm that can simultaneously perform carrier frequency offset estimation and QAM demodulation. In the frequency domain, the received signal sample points were approximated by the least squares with the standard sinusoidal signal, and the carrier frequency offset was estimated by estimating the frequency of the received signal. The amplitude and position of the received signal were obtained, thus the I component and Q component coefficients of the QAM modulated signal were obtained. The simulation results show that the proposed joint algorithm reduces the bit error rate of QAM modulation and demodulation algorithm.
引文
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[15] 李炎新,胡爱群,周璧华.自适应QAM解调及频偏估计方法研究[J].电波科学学报,2009,24(3):541-545.
[16] 王建新,付锐.一种QAM信号载波频偏估计算法[J].南京理工大学学报,2003,27(2):156-163.
[17] Yang C,Wei G.A Noniterative Frequency Estimator With Rational Combination of Three Spectrum Lines[J].IEEE Transactions on Signal Processing,2011,59(10):5065-5070.
[18] Rice F,Cowley B,Moran B,et al.Cramer-Rao lower bounds for QAM phase and frequency estimation[J].IEEE Transactions on Communications,2001,49(9):1582-1591.
[2] Das A,Kolangiammal S.Performance analysis of millimeter wave communication system using 256-QAM and 512-QAM techniques[C]//2017 International Conference on Communication and Signal Processing(ICCSP).IEEE,2017.
[3] Gappmair W,Schlemmer H,Ginesi A.Joint synchronization of symbol timing and carrier frequency using the extended zero-crossing property[C]//2016 8th Advanced Satellite Multimedia Systems Conference and the 14th Signal Processing for Space Communications Workshop(ASMS/SPSC).IEEE,2016.
[4] Navarro J R,Kakkar A,Pang X,et al.Carrier Phase Recovery Algorithms for Coherent Optical Circular mQAM Systems[J].Journal of Lightwave Technology,2016,34(11):2717-2723.
[5] 吴利平,李赞,李建东,等.复杂环境下基于噪声匹配的最大多普勒频移估计[J].电子学报,2011,39(4):842-847.
[6] 胡梅霞,刘毅,卢满宏,等.基于搜索范围预测的直扩系统多普勒频偏估计[J].吉林大学学报(工学版),2014,44(6):1838-1842.
[7] Li B,Zhou S,Stojanovic M,et al.Multicarrier Communication Over Underwater Acoustic Channels With Nonuniform Doppler Shifts[J].IEEE Journal of Oceanic Engineering,2008,33(2):198-209.
[8] Lee G K,Gelfand S B,Fitz M P.Recursive Bayesian techniques for blind equalization[C]//Proceedings of ICC/SUPERCOMM’94-1994 International Conference on Communications.IEEE,1994.
[9] Barger H A.Performance of 16-QAM demodulation in the rapid multipath environment[C]//Proceedings of MILCOM’96 IEEE Military Communications Conference.IEEE,1996.
[10] Uncini A,Capparelli F,Piazza F.Fast Complex Adaptive Spline Neural Networks for Digital Signal Processing[C]//IEEE World Congress on IEEE International Joint Conference on Neural Networks.IEEE,1998.
[11] Li Y X,Hu A Q.An Adaptive Demodulation Method for QAM Signals[C]//2007 International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications.IEEE,2007.
[12] 雷维嘉,宋海娜,谢显中.高阶QAM调制下基于对数似然比门限的自适应解调方案[J].电子与信息学报,2017,39(6):1305-1312.
[13] Sakaguchi J,Kumagai M,Li Y.DSP-complexity Reduction of QAM-based Coherent Optical Networks Enabled by Seed Lightwave Distribution[C]//2015 Conference on Lasers and Electro-Optics(CLEO).IEEE,2015.
[14] 何维,张士灏,熊炼.非数据辅助的QAM信号载波频偏估计算法[J].信号处理,2015,31(1):45-50.
[15] 李炎新,胡爱群,周璧华.自适应QAM解调及频偏估计方法研究[J].电波科学学报,2009,24(3):541-545.
[16] 王建新,付锐.一种QAM信号载波频偏估计算法[J].南京理工大学学报,2003,27(2):156-163.
[17] Yang C,Wei G.A Noniterative Frequency Estimator With Rational Combination of Three Spectrum Lines[J].IEEE Transactions on Signal Processing,2011,59(10):5065-5070.
[18] Rice F,Cowley B,Moran B,et al.Cramer-Rao lower bounds for QAM phase and frequency estimation[J].IEEE Transactions on Communications,2001,49(9):1582-1591.