多小区有限反馈系统中的双码本设计

Design of Double Codebook for Multi-cell Systems with Limited Feedback

针对两小区的Wyner模型有限反馈无法达到满复用增益的问题,提出一种能使系统达到满复用增益的双码本方案.该方案利用反馈的信道夹角信息(perfect channel,PI)的统计特性,获得PI的概率密度函数,在此基础上设计了一种非均匀量化的反馈夹角码本.仿真结果表明,与传统的CDI反馈方案的系统容量相比,在不增加反馈比特的条件下性能有2.5 dB的提升;相对于均匀量化PI方案,系统容量性能有1 dB的提升.

We consider a two-cell Wyner model with limited feedback. Due to the existence of channel quantizing error, the system cannot reach the theoretical full multiplexing gain. This paper proposes to use feedback information of the phase between channel direction and perfect channel （PI） to achieve the full multiplexing gain. To design phase of the feedback codebook, we derive the probability density function of phase, and design a non-uniform quantification codebook based on the PDF. Simulation results show that the proposed scheme can improve the system capacity by 2.5 dB as compared to the traditional CDI scheme. Compared to uniform quantification, the system capacity has 1 dB improvement.