Considering the problem of blind identification of Unique Words(UW)for Time Division Multiple Access(TDMA)signals in non-cooperative communication,a blind identification algorithm for distributed UW is proposed in this paper.Different from the unique codes recognition algorithm at the bit layer,a unique words recognition algorithm at the waveform layer oriented to the correlation is proposed between different windows of the modulated data for centralised unique words and distributed unique words,respectively.The algorithm takes advantage of the consistency and correlation of the unique words and proceeds in two steps:firstly,the unique words of different burst signals are vertically aligned by eliminating the effects of frequency and phase bias between the different burst signals through differential accumulation,and then the positions and lengths of the unique words are identified by the multilayer differential conjugate fourth order correlation algorithm.The performance of the algorithm is simulated and analysed with different number of bursts,signal-to-noise ratios,and with or without frequency and phase biases,and the effectiveness of the waveform layer identification of unique words is verified,and the algorithm achieves more than 95％of the identification rate at a signal-to-noise ratio of 5dB for both centralized and distributed unique words,which is of certain value for engineering applications.
关键词
调制数据/时分多址信号/差分累积/4阶相关/独特码盲识别
Key words
Modulated data/Time Division Multiple Access(TDMA)signal/Differential accumulation/Fourth order correlation/Unique Words(UW)blind identification
维普
万方数据