航空信道下基于假设检验的MQAM信号识别

Modulation recognition of MQAM signals based on hypothesis testing in the aeronautical channel

信号的调制识别是信号处理领域的一个重要研究方向。航空信道时变特征明显,是一种非平稳的信道。针对航空信道下MQAM类信号的调制识别,提出了基于假设检验的平均似然比识别算法,构造出信号的似然函数,在判决准则下实现信号的识别。另外运用多天线分集接收技术对该算法进行一定的优化,优化后的算法不仅可以明显地提高信号的正确识别率,而且还可以有效地降低航空信道中多普勒频移和多径衰落等对信号接收带来的影响。仿真结果表明,该算法和优化后的算法均能够实现航空信道下MQAM类信号的调制识别,优化后的算法识别效果更好。

Modulation recognition of signals is an important research direction in the field of signal processing.Aeronautical channel is the channel that is non-stationary and time-varying obviously.The modulation recognition of MQAM signals is studied in the aeronautical channel.Based on hypothesis,the average likelihood ratio test（ALRT）algorithm testing is proposed,the likelihood function of signals is constructed,and then signals are recognized in the decision criterion.The multi-antenna receive diversity technique is used to optimize the algorithm,the optimized algorithm not only can significantly improve the correct recognition rate of signals,but also can effectively reduce the influence that is caused by Doppler frequency shift and multipath fading to signal receiving.Simulation results show that the algorithm and the optimized algorithm can meet the recognition requirement of MQAM signals,and the recognition performance of the optimized algorithm is better.