Quantization and Bit Allocation for Channel State Feedback in Relay-Assisted Wireless Networks
This paper investigates quantization of Channel State Information (CSI) and bit allocation across wireless links in a multi-source, single-relay cooperative cellular network. Their goal is to minimize the loss in performance, measured as the achievable sum rate, due to limited-rate quantization of CSI. The authors develop both a channel quantization scheme and allocation of limited feedback bits to the various wireless links. They assume that the quantized CSI is reported to a central node responsible for optimal resource allocation. They first derive tight lower and upper bounds on the difference in rates between the perfect CSI and quantized CSI scenarios. These bounds are then used to derive an effective quantizer for arbitrary channel distributions.