基于多用户多输入多输出系统的自适应有限反馈

Adaptive limited feedback for MU-MIMO system

为了减少多用户多输入多输出系统中上行链路的反馈开销,研究了多用户的有限反馈问题.在分析反馈比特数与用户速率关系的基础上,推导出用户自适应有限反馈的最优解,并提出一种实现简单的次最优方案,即用户根据自身和系统整体的信道质量状况,自适应地选择反馈比特数.通过增加信道较好用户以及减少信道较差用户的反馈比特数,有效提高了反馈比特的利用效率.研究结果表明,该方案实现简单,在不增加系统反馈开销的条件下明显增加系统吞吐量.

The limited feedback in multi-user Multiple-Input Multiple-Output（MU-MIMO） systems is addressed in this paper.In order to reduce the feedback overhead in the uplink channel,we analyze the relation between user＇s feedback bits and rate,deduce the optimal solution for adaptive limited feedback,and propose a suboptimal feedback scheme which is more practical.In this scheme,users choose the feedback bits according to both their channel gains and the average gain of the system.Users with high SNR are assigned with more feedback bits than the low-SNR users so as to improve the feedback efficiency.Simulation results and analysis show that the proposed scheme is easy-to-implement and can enhance the throughput with no additional feedback overhead.