Multi-Antenna OFDM System Using Coded Wavelet and Weighted Beamforming

A major drawback in deploying beamforming scheme in orthogonal frequency division multiplexing (OFDM) is to obtain the optimal weights that are associated with information beams. Two beam weighting methods, namely co-phasing and singular vector decomposition (SVD), are considered to maximize the signal beams for such beamforming scheme. Initially the system performance with and without interleaving is investigated using coded fast Fourier transform (FFT)-OFDM and wavelet-based OFDM. The two beamforming schemes are applied to the wavelet-based OFDM as confirmed to perform better than the FFT-OFDM. It is found that the beamweight by SVD improves the performance of the system by about 2 dB at the expense of the co-phasing method. The capacity performances of the weighting methods are also compared and discussed.