MIMO beamforming for high-bit-rate transmission over frequency-selective fading channels

Smart antenna systems have been proposed and demonstrated at both the transmitter and receiver of wireless communication systems, so that the quality of service improves at both ends. We propose multiple-input multiple-output (MIMO) beamforming for frequency-selective fading channels to maximize the signal-to-noise-and-interference ratio (SINR) based on an iterative update algorithm of transmit and receive weight vectors with prior knowledge of the channel state information (CSI) at both the transmitter and receiver. We derive the necessary conditions for an optimum weight vector solution and propose an iterative weight update algorithm for an optimal SINR reception. The maximum signal-to-noise (MSN) method, where noise includes the additive Gaussian noise and interference signal, is used as a criterion. The proposed MIMO with M×N arrays allows the cancellation of M+N-2 delayed channels. Computer simulations are presented to verify our analysis. The results show that significant improvement in performance is possible in wireless communication systems.