基于四阶循环平稳的STBC-OFDM信号盲识别

针对非理想信道环境下多输入单输出(MISO)通信系统中STBC-OFDM信号的盲识别问题,提出了一种基于四阶循环平稳的STBC-OFDM信号盲识别算法。该方法首先对MISO通信系统中STBC-OFDM信号进行建模；然后利用STBC-OFDM信号编码矩阵的相关性,结合四阶循环平稳特性,推导了不同时延向量下接收信号块的四阶循环矩；最后根据有无尖峰盲识别空时分组码的类型。该方法采用分层识别的思想,无需信道系数、噪声功率和调制方式等先验信息,适合非合作通信场所。仿真结果表明:算法适应于低信噪比的环境,且不受调制方式、相位噪声和多普勒频移影响,实用性很强。 

Blind Classification of STBC-OFDM Signals based on Fourth-order Cyclostationarity

An efficient method for blind classification of Space-Time Block Codes (STBC) orthogonal frequency-division multiplexing (OFDM) signals in presence of transmission impairments based on fourth-order cyclostationarity is proposed, when a single antenna is employed at the receiver. Firstly, the paper gives the model of received STBC-OFDM signals in MISO systems. Secondly, we utilize the correlation of the coding matrices of STBC-OFDM signals, and rely on the fourth-order cyclic moment as a discriminating feature. Finally, we classify the transmitted STBC in according to the peak. Unlike the methods, this algorithm does not require any prior information of modulation type, the channel coefficients, and noise power and, consequently, is well-suited for non-cooperative context. Simulations show that our method performs well even at low signal-to-ratios (SNRs). Furthermore, the proposed algorithm provides a good performance with low sensitivity to modulation type, phase noise and Doppler frequency.