This paper investigates the effect of oscillator phase noise on a multiuser millimeter wave (mmWave) massive MIMO uplink as we scale up the number of base station antennas, fixing the load factor, defined as the ratio of the number of simultaneous users to the number of base station antennas. We consider a modular approach in which the base station employs an array of subarrays, or “tiles.” Each tile supports a fixed number of antennas, and can therefore be implemented using a separate radio frequency integrated circuit (RFIC), with synchronization across tiles accomplished by employing a phased locked loop in each tile to synthesize an on-chip oscillator at the carrier frequency by locking on to a common lower frequency reference clock. Assuming linear minimum mean squared error (LMMSE) multiuser detection, we provide an analytical framework that can be used to specify the required power spectral density (PSD) mask for phase noise for a target system performance. Our analysis for the phase noise at the output of the LMMSE receiver indicates two distinct effects: self-noise for each user which is inversely proportional to the number of tiles, and cross-talk between users which is insensitive to the number of tiles, and is proportional to the load factor. These analytical predictions, verified by simulations for a 140 GHz system targeting a per-user data rate of 10 Gbps, show that tiling is a robust approach for scaling. Numerical results for our proposed design approach yield relatively relaxed specifications for phase noise PSD masks.

中文翻译：

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模块化毫米波大规模 MIMO 中的相位噪声


本文研究了当我们增加基站天线数量、固定负载系数（定义为同时用户数与同时用户数之比）时，振荡器相位噪声对多用户毫米波 (mmWave) 大规模 MIMO 上行链路的影响。基站天线。我们考虑采用模块化方法，其中基站采用一系列子阵列或“瓦片”。每个区块支持固定数量的天线，因此可以使用单独的射频集成电路 (RFIC) 来实现，通过在每个区块中采用锁相环以在载波频率上合成片上振荡器来实现区块之间的同步通过锁定公共较低频率参考时钟。假设采用线性最小均方误差 (LMMSE) 多用户检测，我们提供了一个分析框架，可用于指定目标系统性能所需的相位噪声功率谱密度 (PSD) 模板。我们对 LMMSE 接收器输出端相位噪声的分析表明了两种不同的影响：每个用户的自噪声与图块数量成反比，以及用户之间的串扰对图块数量不敏感，以及与负载系数成正比。这些分析预测经过针对每用户 10 Gbps 数据速率的 140 GHz 系统的仿真验证，表明平铺是一种稳健的扩展方法。我们提出的设计方法的数值结果产生了相对宽松的相位噪声 PSD 掩模规范。