高阶QAM信号多状态自适应卡尔曼滤波载波同步算法  

High-order QAM Carrier Synchronization Algorithm by a Multi-stages Adaptive Kalman Filter

作　　者：吴天琳 彭华[1] 黄艳艳[1] 杨勇[1] 

机构地区：[1]解放军信息工程大学信息工程学院,河南郑州450002

出　　处：《信号处理》2014年第6期718-727,共10页Journal of Signal Processing

基　　金：河南省自然科学基金资助项目(0611051400);河南省基础与前沿基金资助项目(082300413205)

摘　　要：通信信号盲载波恢复是非协作模式下接收方解调的关键环节之一。为提高频偏捕获范围与速度,同时有效增强算法跟踪时变频偏能力,本文针对正交幅度调制(QAM)信号,通过理论推导得出滤波器环路带宽的变化特性,提出一种基于自适应判决引导扩展卡尔曼滤波的载波同步算法。该算法在现有卡尔曼滤波载波同步算法的基础上,引入多状态自适应切换机制自适应地改变滤波器参数,并依据实验测试数据分析得出调整原则并完成滤波器参数的选取。理论分析和仿真表明,与已有的卡尔曼载波同步算法及二阶数字锁相环算法相比,该算法不仅捕获速度更快范围更大,且能在存在时变多普勒频移的情况下较好地跟踪时变频偏和相位,在大频偏条件下的算法跟踪性能与鲁棒性等方面均有优势。To a non-cooperative receiver, the blind carrier recovery is a key step of the demodulation process for communication signals. In order to increase the convergence speed, expand the scope of frequency acquisition and effectively improve the property of tracking time varying frequency, the variation characteristic of the filter loop bandwidth is gained from theoretical derivation and a carrier synchronization algorithm based on adaptive decision directed extended Kalman filter is proposed for Orthogonal Amplitude Modulation （QAM） signals. The algorithm which based on existing Kalman filter algorithms, adopts adaptive multi-states switching mechanism and regulates the parameter of the Kalman filter adaptively, which are chosen from the coordination principle obtained through the analysis of the experimental test data. It is indicated from the analysis and simulation results that compared with the existing Kalman filter based algorithm and phase lock loops, a- daptive decision directed extended Kalman filter algorithm not only enlarges the catching scope, improves the convergence speed and works well in the situation with time-varying doppler distortion, but also has advantages on the tracking perform- ance under larger frequency offset and robustness.

关 键 词：判决引导载波同步 扩展卡尔曼滤波 多状态 高阶QAM 多普勒频率变化率 

分 类 号：TN911.7[电子电信—通信与信息系统]