大规模MIMO系统中融合用户调度的叠加导频信道估计方法

Superimposed pilot-based channel estimation method combined with user scheduling for large-scale MIMO system

传统的信道估计策略通常基于时分复用方式实现导频配置,导致大规模多输入多输出系统的带宽利用率有限,同时受信道相干时间的限制,大规模MIMO系统可利用的导频资源非常有限,因此,相邻小区不得不通过导频复用来实现信道估计,从而引起导频污染问题。针对上述问题,融合用户调度,提出了一种基于叠加周期性导频的信道估计方法。该方法通过优化功率分配因子,以信号泄露噪比(SLNR)作为度量指标,对不同小区的用户进行协作调度并分配相同的导频,不仅减轻了导频污染,而且提高了信道估计的精度。数值仿真验证了方法的有效性。

Time division multiplexing method is commonly used in conventional channel estimation, which results in poor efficiency of bandwidth usage. Additionally, the available pilot resources are finite due to the limited channel coherence time, and the pilot sequences must be multiplexed between the neighbor cells, which leads to problems of pilot contamination. To solve these problems above, superimposed pilot-based channel estimation method combined with user scheduling was proposed. In the method, the users in different cells were cooperatively scheduled and assigned the same pilot by optimizing the factor of power allocation and using the signal to leakage and noise ratio（SLNR） as measure metric. Simulation results demonstrate the validity of the proposed method.