Minimum Bit Error Rate Pre-FFT Beamforming for OFDM Communication Systems

In broadband wireless communication, the adaptive antenna array (AAA) is combined with orthogonal frequency division multiplexing (OFDM) to combat the inter-symbol interference (ISI) and the directional interferences. One of the two main techniques which are used in OFDM systems is called Pre-FFT, where an optimum beamformer weight set is obtained in time domain before Fast Fourier Transform (Pre-FFT). In this paper, the optimum weight set is obtained based on minimum bit error rate (MBER) criteria in pilot-assisted OFDM systems under multipath fading channel. Here, the development of the block-data adaptive to implementation of the MBR beamforming solution is based on the Parzen window estimate of probability density function (pdf). The simulation results show that the MBER technique utilizes the antenna array elements more intelligently than the standard minimum mean square error (MMSE) technique. The MBER technique can be used to achieve excellent performance since it directly minimizes the BER and requires shorter training symbols.