Abstract:

An efficient method for blind classification of space-time block codes-orthogonal frequency-division multiplexing (STBC-OFDM) signals based on fourth-order statistics is proposed, when a single antenna is employed at the receiver. Firstly, the model of the received STBC-OFDM signals in MISO systems is built. Secondly, the discrimination features function provided by fourth-order lag moment of the received OFDM blocks is constructed by using the correlation of the coding matrices of STBC-OFDM signals. Finally, the automatic classification of STBC-OFDM signals is realized by selecting the signal which minimizes the distance between the theoretical values and the experimental ones. The proposed algorithm does not need the estimation of the channel, noise statistics and modulation type, and consequently, is well-suited for non-cooperative communication context. The simulation result shows that the proposed algorithm performs well even at a low signal to noise ratio (SNR=0 dB), and is robust to carrier frequency offset, timing offset and Doppler frequency shift.