分布式多天线下行链路的空分复用性能分析

针对多天线下行链路的远近效应问题，研究了分布式多天线系统的空分复用性能，结果表明分布式多天线系统可以有效地降低远近效应的影响．在此基础上，提出了一种分布式多天线系统中的自适应传输方案．该方案根据用户与各天线端口的相对位置灵活地改变传输策略，在用户距离天线端口较远时，利用空分复用联合发送抑制用户间干扰，而在用户靠近天线端口时，采用选择式发送，以降低反馈负荷和复杂度．仿真实验结果表明，与空分复用联合发送相比，通过设置合适的自适应切换门限，所提出的方案仅以系统容量损失7％为代价，能在40％的信道实现中有效降低反馈负荷和处理复杂度．

Performance Analysis of Spatial Multiplexing for the Distributed Multiple-Antenna Downlink

Focusing on the near-far influence problem in the multiple-antenna downlink,the performance of spatial multiplexing(SM) in the distributed multiple-antenna system is studied.It is shown that the distributed multiple-antenna system can lead to effective reduction of the near-far influence.Thereby,an adaptive transmission scheme is proposed.This scheme flexibly switches the transmission strategy according to the locations of the users relating to the antenna ports.SM joint transmission is chosen to eliminate the inter-user interference when the users are far from the antenna ports,while the transmit selection(TS) is chosen to reduce the feedback load and the complexity when users come close to the antenna ports.Simulation results show that by rightly setting the adaptive switching threshold,the proposed scheme can considerably reduce the feedback load and the processing complexity in 40% of all the channel realizations with only 7% loss of system capacity compared to the SM joint transmission.