Performance of RVQ Limited Feedback Beamforming over Correlated Channels

This work considers the performance of multiple-input single-output (MISO) wireless systems employing beamforming over correlated wireless channels. More specifically, we examine the use of Random Vector Quantization (RVQ) as a limited feedback method of informing the transmitter of the appropriate beamforming vector. Using RVQ, we are able to derive the distribution functions of the beamforming gain in such a system in closed form. In addition, we derive the power offset in the delay-limited capacity for RVQ systems in closed form based on the approach of Au-Yeung and Love for i.i.d. channels [1]. This result is applicable to any channel model. For all of these results we derive simplifications for the case of two transmit antennas. Simulation results are provided that confirm our results and show a decrease in performance for the correlated channels.