一种抗频偏的卫星幅相调制信号识别算法

An Anti-frequency-offset Algorithm for Modulation Recognition of Satellite Amplitude-phase Modulated Signals

该文针对卫星中的常用调制QPSK,16QAM和新型调制16APSK,32APSK,提出一种自适应构造幅度分布模板,并通过计算实际信号幅度分布向量与幅度分布模板间的匹配误差来进行调制识别的算法。该方法不需要知晓载噪比,不需要人为确定阈值,且对频偏误差的容忍能力强,适合实际工程应用。仿真表明,在载噪比为9 dB,符号个数为4000时,该算法对4种调制信号的识别率能达到98%以上,证明了其有效性。

An anti-frequency-offset algorithm is proposed by utilizing amplitude distribution feature for modulation recognition of conventional satellite modulations, such as QPSK, 16QAM and new modulations like 16APSK and 32APSK. The algorithm is based on adaptive construction of amplitude distribution template. After calculating the matching error between the amplitude distribution template and the actual amplitude distribution vector, the algorithm can recognize the modulation type by choosing the modulation type with the minimum matching error. This method does not need any prior knowledge about Carrier-to-Noise ratio （C/N）, as well as threshold, and it is not sensitive to frequency offset. Becasuse of these advantages, the algorith is suitable for engineering application. Computer simulations show that the correct recognition probability is more than 98% when C/N is greater than 9 dB and 4000 symbols are used. It verifies the effectiveness of the algorithm.