BER Based Transmit Beamforming for MISO-OFDM with Limited Feedback

In this paper, a new transmit beamforming scheme with limited feedback is presented in Multiple-Input Single-Output Orthogonal Frequency Division Multiplexing (MISO-OFDM) systems. By dividing the total subcarriers of an OFDM symbol into a series of clusters, from the codebook a proper one minimizing the average Bit Error Rate (BER) per subcarrier of the considered cluster is chosen as the beamforming vector for this cluster. The scheme can reduce the feedback overhead remarkably while obtain good BER performance. Additionally, a simple sub-optimal algorithm based on the correlation of subcarriers is proposed to avoid exhaustive search in the optimal solution. The simulation results show that the proposed algorithm, with low computational complexity, provides improvement over existing schemes.