On the interplay of orthogonal random beamforming and CSI quantization - strategies and robustness analysis

In this paper, we assess the impact of CSI quantization on the performance of the orthogonal random beamforming scheme. By resorting to a dynamic programming formulation, one can identify the optimal (i.e. pdf-matched) quantizer for which the sum-rate distortion is minimized. The robustness of such quantization scheme to uncertainty in the knowledge of specific system parameters along with the benefits resulting from inclusion of a second (and more refined) quantization step are analyzed as well. The performance, in terms of the resulting sum-rate, for this optimal quantizer is also assessed by means of computer simulations. Throughout this paper, a uniform quantizer is used as a benchmark.