分布式天线系统中基于天线选择的容量分析

Capacity Analysis Based on Antenna Selection in Distributed Antenna System

研究分布式天线系统(DAS)在复合衰落信道中下行链路的容量性能。分析DAS采用天线选择发送的各态历经信道容量。基于容量性能分析,利用数值积分公式,推导各态历经容量的近似闭式表达式,该表达式能避免现有容量表达式采用对数正态分布近似所带来的不准确性。仿真结果表明,理论公式与仿真值一致性较高,能有效地评估分布式天线系统下行链路的容量性能。

The downlink capacity performance of Distributed Antenna System（DAS）is investigated over composite fading channels. Based on this,the ergodic capacity of DAS with Transmit Antenna Selection（TAS）is analyzed.According to the capacity performance analysis,an approximate closed-form expression of the average channel capacity is derived by employing numerical integration formulas. It can avoid inaccuracy of existing capacity expression which is obtained by means of log-normal approximation. Simulation results show that the derived expression can match the simulation well,and thus it can evaluate the capacity performance of DAS downlink effectively.