大规模MIMO系统中基于图着色的半动态导频分配

Semi-dynamic pilot allocation based on graph coloring in massive MIMO systems

针对大规模MIMO系统中存在的导频污染问题,提出了一种基于图着色的半动态导频分配方案。首先,推导出各个小区可以复用导频的用户与其服务基站的最大距离门限。然后,根据该门限值将系统内各小区的用户分为小区中心用户和小区边缘用户;允许各个小区门限值之内的用户(小区中心用户)复用相同的导频;最后,基于图着色理论协同分配各个小区的小区边缘用户的导频,达到降低导频干扰的目的。仿真结果显示,该方案减少了用户间的导频干扰,有效地提升了整个系统的上行可达和速率。

To alleviate the performance loss caused by pilot contamination in massive multiple-input multiple-output(MIMO)systems,a semi-dynamic pilot allocation scheme based on graph coloring was proposed.Firstly,a pilot reuse threshold was derived for users.Then,based on the pilot reuse threshold,users of each cell are divided into cell-center users and cell-edge users,where cell-center users were allowed to reuse the same pilot.Finally,based on the graph coloring theory,the pilot resources were allocated to cell-edge users with serious pilot interference by multi-cell coordination.The simulation results show that the proposed pilot allocation scheme reduces the pilot interference and improves the uplink achievable rate of the whole system effectively.