MMSE relay precoding schemes based on quantization error compensation for multi-relay system

Abstract

In order to deal with the performance degradation resulting from the quantization error, this paper introduces the statistics of Grassmannian codebook’s quantization error into relay precoding design for multirelay system. Based on the two-step MMSE optimization algorithm for relay precoding and receiver equalizing with full feedback under QoS requirements, we first propose a limited feedback two-step MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation, and then we propose a limited feedback joint MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation subject to a global power constraint at the output of relays. Simulation results show that the proposed joint MMSE optimization scheme with quantization error compensation has a much lower bit-error rate than the two-step MMSE optimization scheme with quantization error compensation and the joint MMSE optimization scheme without quantization error compensation.