Despite the large benefits that can be fulfilled through the exploitation of Massive Multi-input Multioutput (M-MIMO), this technology still constrained by a well-known constraint, called as pilot contamination problem (PCP), which is the main consequence of, simultaneously, reusing the same set of orthogonal pilot sequences (OPSs) for the users of several cells. Due to the scarcity of the OPS resources, the reuse of the same set of the OPSs for the users of different cells is unavoidable. Hence, this work proposes a novel decontaminating strategy, which is aimed at guaranteeing a trade-off between the use of the OPSs and the mitigation of the PCP. Specifically, to make the use of the available OPSs better, we propose the consolidation of two powerful decontaminating strategies. Under a derived supervision rule (SR), these strategies are the soft pilot reuse-based multicell block diagonalization precoding (SPR-MBDP) and the weighted graph coloring-based pilot assignment (WGC-PA). The SR enables the switching mechanism between the two strategies, which leads to address the PCP with a fewer number of the OPSs compared to the SPR-MBDP, therefore boosting the per-cell achievable rate. Simulation results prove the effectiveness of our proposed strategy.

中文翻译：

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基于智能交换策略的监管规则可缓解大规模MIMO系统中的飞行员污染问题

尽管通过使用大规模多输入多输出（M-MIMO）可以实现巨大的收益，但是这项技术仍然受到众所周知的约束（称为飞行员污染问题（PCP））的约束，这是导致以下问题的主要原因：同时，为多个小区的用户重用同一组正交导频序列（OPS）。由于OPS资源的稀缺性，不可避免地对于不同小区的用户重复使用同一组OPS。因此，这项工作提出了一种新颖的去污策略，旨在确保在使用OPS和缓解PCP之间进行权衡。具体来说，为了更好地利用可用的OPS，我们建议合并两种强大的净化策略。根据派生的监督规则（SR），这些策略是基于软导频复用的多小区块对角化预编码（SPR-MBDP）和基于加权图着色的导频分配（WGC-PA）。SR启用了这两种策略之间的切换机制，与SPR-MBDP相比，它可以使用较少数量的OPS来寻址PCP，从而提高了每单元可达到的速率。仿真结果证明了所提策略的有效性。