On the Impact of PDF-matched Quantization on Orthogonal Random Beamforming

Orthogonal random beamforming (ORB) schemes provide multi-user diversity and spatial multiplexing gains by exclusively using partial channel state information (CSI) at the transmitter. In this paper, we explore the impact of CSI quantization on the performance of ORB. By resorting to a dynamic programming formulation, we identify the optimal (i.e. pdf-matched) quantizer for which the sum-rate distortion is minimized. Performance is assessed by means of computer simulations and compared with that of a uniform quantizer