BER improvement in a TDMA/FDMA cellular system using antenna array

We propose a novel strategy based on Capon´s method for multiple signal extraction in TDMA/FDMA cellular mobile communications. In this method, called SF-Capon, each intracell cochannel (IC) user is alternatively asked to decrease its transmitted power for a few bits. This enables the estimation of a so-called signal-free (SF) correlation matrix, which is then used in connection with Capon´s method to compute an improved beamforming weight vector with reduced sensitivity to DOA error and angular spread. The superiority of the proposed SF-Capon strategy over standard Capon´s and data independent least squares beamforming is demonstrated via simulation in a fast Rayleigh fading channel.