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.