Phase noise analysis for mmwave massive MIMO: a design framework for scaling via tiled architectures

We consider a tiled architecture for scaling a millimeter wave (mmWave) massive MIMO uplink to support a large number of simultaneous users, targeting per-user data rates of multi-Gbps. Our goal in this paper is to evaluate the impact of phase noise, which is widely considered to be a significant bottleneck at high carrier frequencies and large bandwidths, on MIMO performance. Our analysis provides a cross-layer design framework which can be employed by hardware designers to determine allowable masks for the phase noise power spectral density for different circuit components. For typical settings, we conclude that scaling up to a large number of antenna elements by increasing the number of tiles (each tile supporting a fixed number of antenna elements) is attractive in two ways: (1) for a fixed number of users, reducing the load factor (ratio of number of users to number of antennas) improves performance with phase noise, and (2) the independent phase noise generated at each tile gets averaged across tiles. We illustrate our numerical results for a nominal 140 GHz system with per-user data rates of 10 Gbps.