This paper considers the uplink of a massive MIMO communication system using 5G New Radio-compliant multiple access, which has to co-exist with a radar system using the same frequency band. A system model taking into account the reverberation (clutter) produced by the radar system onto the massive MIMO receiver is proposed. In this scenario, several receivers for uplink channel estimation and data detection are proposed, ranging from the simple channel-matched beamformer to the zero-forcing and linear minimum mean square error receivers for clutter disturbance rejection, under the two opposite situations of perfectly known and completely unknown clutter covariance. A theoretical analysis is also provided, deriving a lower bound on the achievable uplink spectral efficiency and the mutual information between the input Gaussian-encoded symbols and the observables available at the communication receiver of the cellular massive MIMO system: regarding the latter, in particular, it is shown that, in the large antenna number regime, and under the assumption of perfect channel state information (CSI), the effect of radar clutter at the base station is suppressed and single-user capacity may be restored. Numerical results, illustrating the performance of the proposed detection schemes, confirm the findings of the theoretical analysis, and permit quantifying the system robustness to clutter effect for increasing number of antennas at the base station.

中文翻译：

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大规模 MIMO 体制中的通信和雷达共存：上行链路分析

本文考虑了使用符合 5G 新无线电标准的多址接入的大规模 MIMO 通信系统的上行链路，该系统必须与使用相同频段的雷达系统共存。提出了一种系统模型，该模型考虑了雷达系统在大规模 MIMO 接收器上产生的混响（杂波）。在这种情况下，提出了几种用于上行链路信道估计和数据检测的接收器，从简单的信道匹配波束形成器到用于杂波干扰抑制的迫零和线性最小均方误差接收器，在完全已知和数据检测的两种相反情况下完全未知的杂波协方差。还提供了理论分析，推导出可实现的上行链路频谱效率和输入高斯编码符号与蜂窝大规模 MIMO 系统的通信接收器处可用的可观测值之间的互信息的下限：特别是对于后者，表明，在大天线数制度，在完美信道状态信息（CSI）假设下，抑制基站雷达杂波影响，恢复单用户容量。数值结果说明了所提出的检测方案的性能，证实了理论分析的结果，并允许量化系统对增加基站天线数量的杂波效应的鲁棒性。对于后者，特别是表明，在大天线数的情况下，在完美信道状态信息（CSI）的假设下，基站雷达杂波的影响被抑制，单用户容量可能会降低恢复了。数值结果说明了所提出的检测方案的性能，证实了理论分析的结果，并允许量化系统对增加基站天线数量的杂波效应的鲁棒性。对于后者，特别是表明，在大天线数的情况下，在完美信道状态信息（CSI）的假设下，基站雷达杂波的影响被抑制，单用户容量可能会降低恢复了。数值结果说明了所提出的检测方案的性能，证实了理论分析的结果，并允许量化系统对增加基站天线数量的杂波效应的鲁棒性。