Performance Analysis of Matched-Filter Precoded MISO-OFDM Systems in the Presence of Imperfect CSI

Nguyen, Trung-Hien [OPERA department, Université libre de Bruxelles (ULB), Belgium] Louveaux, Jérôme [UCL] De Doncker, Philippe [OPERA department, Université libre de Bruxelles (ULB), Belgium] Horlin, Francois [OPERA department, Université libre de Bruxelles (ULB), Belgium]

Multiple-antenna technologies provide a good spatial diversity gain for emerging communication systems. In combination to the orthogonal frequency division multiplexing (OFDM) modulation, a precoding system can be easily implemented and efficient to combat the effect of fading channels. However, the precoding system requires a perfect knowledge of the channel, which is not usually hold in practical cases. In this paper, we investigate the impact of the imperfect channel state information (CSI) on the downlink performance of multiple-input single-output (MISO) OFDM systems using a matched-filter (MF) precoder. Particularly, the exact mean-square-error (MSE) expression of the equalized received signal of the MF precoding system is derived. Numerical simulations with Rayleigh fading channels are carried out to validate the analysis. The results show that the imperfect CSI-based precoder causes a MSE plateau compared to the ideal case of using the perfect CSI.