Novel algorithm for STBC-OFDM identification in cognitive radios

This paper develops a space-time block code (STBC) identification algorithm for multi-antenna (MA) orthogonal frequency-division multiplexing (OFDM) transmission over frequency-selective channels. We show that, by taking advantage of the space-time redundancy, signal identification can be performed by exploiting the cross-correlation of the received signals from two antennas as a discriminating feature. With this feature, we develop a binary hypothesis test for decision making. The proposed algorithm does not require information about the channel coefficients, modulation, noise power, or start times of the OFDM and STBC blocks. Moreover, it does not need accurate clock timing information. Simulation experiments have verified the accuracy and feasibility of the proposed algorithm.