联合时移和空间划分方法抑制大规模MIMO导频污染

Pilot decontamination in massive MIMO system combining time-shifted and cell sectorization pilot assignment

在大规模MIMO(multiple input multiple output)系统的信道估计过程中,不可避免地需要在不同小区中复用同样的导频序列,由此而产生导频污染问题,且当基站天线趋向于无穷多时,它成为了系统性能提升的瓶颈。为了抑制导频污染,提出一种联合时移和小区空间划分的导频序列分配(TS-CSPA,time shifted-cell sectorization pilot assignment)方法,该方法通过从时域和空间域2个角度降低导频复用程度来抑制导频污染。推导了系统使用该方案时的等效信干比和用户可达速率。仿真结果表明所提出的方法能有效地抑制大规模MIMO系统的导频污染,相比于其他几种抑制方法能够在系统性能上获得一定程度的提升。

Pilot contamination is appeared in massive MIMO（multiple input multiple output） system when using the same pilot sequences at different cells to get the channel state information.It becomes a bottleneck problem of massive MIMO when the number of antenna goes infinite.In order to dealt with pilot contamination,a new TS-CSPA joint scheme was proposed.This scheme can mitigate pilot contamination by reduce the reuse of pilot sequence through the time domain and space domain.And the closed-form expression for the achieved rates and signal to interference plus noise ratio（SINR） to verify the advantages of the proposed scheme were given.Numerical results show that significant performance gains to mitigate pilot contamination problem compared to other methods.