变换域通信信号的频域分集特性与非合作解调

Frequency-Diversity Characteristic and Non-cooperative Demodulation for Transform Domain Communication Signal

在新体制通信链路侦察应用中,对变换域通信信号进行非合作解调是获取其传输信息的前提。针对这一应用需求,介绍变换域通信信号的时频域模型,揭示其频域分集特性,回顾了通过近邻符号之间的频域相位差分处理来进行差分解调的方法。在此基础上,利用其频谱分集特性,提出了利用部分高信噪比子载波进行差分处理的解调新方法,减少了非合作条件下子载波个数估计误差和侦察传输信道畸变所产生的影响。最后,针对实际的变换域通信系统开展了信号解调与信息提取的实验,并重点对试验过程与实验数据进行了详细分析,验证了方法的有效性,为其实际的工程应用提供了重要参考。

The non-cooperative demodulation for transform domain communication signals is the precondition for obtaining its transmission information in reconnaissance on the new communication data link.The transform domain communication signal models in time and frequency domain are firstly introduced and the frequency diversity also revealed.Then the differential demodulation method for phase difference processing of between the nearby two symbols is reviewed.According to the frequency-diversity characteristic,a new demodulation method using partial subcarriers with high signal noise ratio for differential processing is proposed,thus to reduce the influence on the estimation error of the number of subcarriers and the distortion of the reconnaissance channel in the non-cooperative condition.Finally,the experiments of signal demodulation and information extraction are done,for the actual transform domain communication system.The experimental process and data are analyzed in detail and the effectiveness of the method is strongly demonstrated,thus providing an important reference for the practical engineering application.