Optimal Diagonal Precoder for Multi-Antenna Communication System

In this paper we develop an efficient diagonal matrix pre-coder which minimizes the lower bound of the average bit error rate (BER) for a multi-antenna wireless communication system with a QR receiver in flat fading channel. The precoder also minimizes the average block error rate at the same time. It provides substantially lower error rates than the MMSE precoder and Foschini's BLAST scheme. The corresponding signal-to-noise ratio (SNR) gains can be several decibels.