A Concatenated ML Decoder for SFBC-OFDM Systems in Frequency Selective Fading Channels

This paper presents a concatenated maximum-likelihood (ML) decoder for space-frequency block coded orthogonal frequency division multiplexing (SFBC-OFDM) systems in severe frequency selective fading channels. The variation of subchannels during a codeword frame will cause the inter-transmit-antenna interference (ITAI), and reduce the diversity gain for SFBC-OFDM systems. The proposed decoder can eliminate the ITAI completely, hence improve the diversity advantage. Simulation results show that the performances of proposed decoder is very close to that of the optimal ML decoder in highly delay spread channels. However, the complexity of proposed decoder is much lower than that of the optimal ML decoder