多用户MIMO系统中基于不完全信道状态信息和天线选择的性能研究

摘要

In this paper,the performance of multiuser MIMO system based on imperfect channel state information (CSI) and antenna selection is investigated.By system modeling and performance analysis,utilizing mathematical transformations and conditional probability density functions,the accurate expression of average bit error rate (BER) for the system with imperfect feedback information is derived.This expression can evaluate the impact of feedback delay on the system performance,and it includes the BER expression under perfect CSI as a special case.In order to simplify the integration calculation of the accurate theoretical expression,an approximate BER expression is also derived by using the approximation of complementary error function.As a result,a simple closed-form expression is obtained.Computer simulation shows that the derived accurate and approximate theoretical expressions can accord with the corresponding simulation results.Moreover,the system in the presence of imperfect CSI only has slight BER performance degradation for the normalized time delay less than 0.01.%本文研究了基于不完全信道信息和天线选择的多用户MIMO系统下行链路性能.通过系统建模和性能分析,利用数学变换和条件概率密度函数,推导了有着不完全反馈信息时的系统误比特率(BER)准确表达式.该式可有效评估反馈时延对系统性能的影响,且包含了基于完全反馈信息的系统BER公式作为其特殊情况.为简化准确表达式中的积分计算,还利用互补误差函数的近似值推导了系统BER的近似表达式,可得到较为简单的闭式表达式.计算机仿真结果表明:所给的准确及近似理论分析可与仿真结果取得较好的一致;且当归一化时延低于0.01时,系统性能较之完全信道信息情况仅有轻微的下降.