Optimal Tx-BF for MIMO SC-FDE Systems

TL;DR

This paper presents an optimal transmit beamforming design for MIMO SC-FDE systems that minimizes stream MSEs under power constraints, improving performance in frequency-selective channels.

Contribution

It derives a closed-form optimal Tx-BF structure and proposes an efficient power allocation algorithm for MIMO SC-FDE with MMSE receivers.

Findings

Significant BER reduction demonstrated in simulations

Achieves higher bit rates compared to existing schemes

Optimal beamforming structure validated through performance analysis

Abstract

Transmit beamforming (Tx-BF) for multiple-input multiple-output (MIMO) channels is an effective means to improve system performance. In frequency-selective channels, Tx-BF can be implemented in combination with single-carrier frequency-domain equalization (SC-FDE) to combat inter-symbol interference. In this paper, we consider the optimal design of the Tx-BF matrix for a MIMO SC-FDE system employing a linear minimum mean square error (MSE) receiver. We formulate the Tx-BF optimization problem as the minimization of a general function of the stream MSEs, subject to a transmit power constraint. The optimal structure of the Tx-BF matrix is obtained in closed form and an efficient algorithm is proposed for computing the optimal power allocation. Our simulation results validate the excellent performance of the proposed scheme in terms of uncoded bit-error rate and achievable bit rate.