Enhanced Lattice-Reduction-Based Precoder with List Quantizer in Broadcast Channel

Abstract

In the multiple-antenna broadcast channel, each user is not allowed to cooperate with other users, so the efficient and well-designed precoding scheme to reduce other users’ interferences is required. Recently, the use of lattice basis reduction(LR) has been shown to be a very effective method for precoding in multiuser multiple antenna systems [12]. Lattice basis reduction helps to reduce the average transmitted energy by modifying the region which includes the constellation points. Even though the LR precoding method achieves a full diversity order, the performance loss caused by quantization error still remains. In this paper, we propose a simple precoding technique to reduce the quantization error. The proposed scheme establishes a lattice list to provide more candidates for transmission power reduction based on the analysis of the patterns of the error. Simulation results show that the proposed scheme achieves the BER performance as good as that of more complex precedents (such as the vector perturbation using sphere-encoding) with significant saving in complexity.