Performance improvement for D-STTD OFDM system in correlated fading channels

In this paper, we study performance improvement for double space time transmit diversity (D-STTD) with orthogonal frequency division multiplexing (OFDM) system. The D-STTD OFDM system can achieve both spatial diversity and multiplexing gains simultaneously in frequency selective MIMO channels. For this system, zero forcing (ZF) and minimum mean square error (MMSE) linear receivers are derived by a simple transformation. To improve error rate performance, we propose weighted soft decision Viterbi decoding by using the SINR of the transformed equivalent channel matrix. The proposed scheme can mitigate noise enhancement inherent to ZF and MMSE linear detectors. Simulations show that the proposed technique with low complexity exhibit robust performance improvement in both uncorrelated and highly correlated fading channels.