A recursive QR detector for space-frequency block coded OFDM systems with four transmit antennas

The use of orthogonal space-time block coding (O-STBC) across sub-carrier tones is a promising solution for future orthogonal frequency division multiplexing (OFDM) based broadband wireless systems. However, due to high channel gain variation across adjacent sub-carriers, conventional methods for O-STBC decoding yield poor performances. In this paper, we propose a square-root-free recursive QR detector for O-STBC based OFDM systems with four transmit antennas. Theoretical performance bounds are analyzed and compared with results obtained from exact link simulations. The performance gain attained by the proposed detector under multi-path fading environments is confirmed by simulation results.