针对大规模MIMO系统中存在的导频污染问题,提出一种有效的导频设计方案.在所有小区复用同一组正交导频的情况下,为每个小区分配不同时延的伪随机码,利用各小区内的伪随机码对小区内用户导频进行同步加扰,以获得用户的发送导频.推导并分析了该导频设计方案下期望信道估计的均方误差.理论和仿真结果表明,该导频设计方案能有效提高信道估计性能,提升整个系统下行链路的性能.
To deal with pilot contamination in massive MIMO systems, an efficient pilot design scheme is proposed. Different pseudo-random codes are assigned to different cells, all using the same set of orthogonal pilots. These codes are used to scramble the user pilot in each cell to get a transmission pilot. Mean square error (MSE) performance of expected channel estimation is derived and analyzed. Simulation results show that the channel estimation performance can be effectively improved when a proper pseudo-random code is chosen with the proposed pilot design method. It can greatly enhance the downlink performance in all cells.
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