Joint Decision-Directed Beamforming and Channel Equalization Approach for OFDM Systems

In this paper, a joint decision-directed beamforming and channel equalization approach is presented for OFDM systems in the presence of co-channel interference (CCI). According to the minimum mean-square error (MMSE) criterion, the cost function of the joint approach is proposed to minimize the MSE on each subchannel and to further improve the system performance. The joint approach is a dual-loop structure composed of a beamforming and a channel equalization loops. The beamforming loop is primarily employed to suppress CCI. The channel equalization loop is used to compensate the baseband equivalent channel variations caused by multipath fading channel and adaptation of beamformer. The simulations are done for the multipath frequency-selective fading channel with CCI to show that the proposed approach can effectively eliminate CCI and compensate the channel distortions, thereby enhancing the system performance compared with the considered pilot-aided approach.