Research of suppressing the Co-Channel interference in STC-OFDM with robust algorithm based on extended bayesian filter

It is well known that Space-Time Coded Orthogonal Frequency Division Multiplexing (STC-OFDM) is easy to be affected by the Co-Channel Interference (CCI) and it is effective to mitigate CCI by beamforming. However, the existing methods are based on the accurate estimation of source Direction-Of-Arrival (DOA). In fact, the performance of system will degrade significantly when there is error in the estimation of DOA. In this paper, a robust algorithm based on Extended Bayesian (E-Bayesian) filter is proposed to improve the performance of the beamformers with uncertainty or error in desired DOA. In this algorithm, each DOA of desired signal is regarded as a random variable composed by several discrete samples. The posterior probability of these samples will be estimated by Bayesian formula and the samples will be resampled when some posterior probability is under certain threshold. Then, the optimized weights are determined by the posterior probability of these samples. Simulation results show that the proposed algorithm can significantly improve the robustness of the beamformers to combat the co-channel interference over Rayleigh multipath fading channel.