The Performance Analysis of Space-Time Trellis Coded MIMO-OFDM Systems

The space-time trellis coded orthogonal frequency division multiplexing (STTC-OFDM) has been implemented with the conventional maximum-likelihood decoder for multiple antenna transmission since the STTC-OFDM was initially proposed. In this paper, a modified maximum-likelihood decoding method with the utilization of a multiplexer at the transmitter and a demultiplexer at the receiver to isolate each transmitted signal at the corresponding receiver is presented. With this modified approach, the STTC-OFDM gives a better frame error rate (FER) performance than the traditional one over the Rayleigh frequency selective fading channels. The Doppler impact is additionally considered for the aggregate system to contrast the proposed methodology and the existing STTC-OFDM systems. Simulation results show that the modified STTC-OFDM framework enhances the FER performance by almost 4 dB at the FER value of 10 2 where the Doppler frequency equals to zero at the receiver. Even if a Doppler frequency exists in the system, the proposed scheme still gives a better performance than the existing STTC-OFDM systems.