基于软件无线电的MQAM信号调制识别

摘要

This paper proposes a modulation recognition algorithm for QAM signals,which can be used in software deifned radio.In the proposed scheme,frequency and phase offset are estimated and recovered ifrst,and then baud rate and timing error are estimated.After low-pass ifltering,sampling rate alteration and baud rate sampling,constel ation was recovered.Cumulants of the samples of the real part of the constel ation are calculated and used to classify the modulation schemes.Experimental work shows that the recognition can get to 96%when SNR is larger than 12 dB and the number of symbols is 1000.%提出了一种软件无线电高阶QAM信号的识别算法。该算法直接从接收信号中估计出频偏和相偏并进行补偿，同时估计波特率和定时误差，并经过低通滤波、采样率变换、定时抽取等步骤，恢复出星座图，然后计算星座图实部信息的高阶累积量进行识别。实验结果表明，在SNR大于12dB，码元符号数为1000时，识别率可以达到96%。