Realizing Uplink MU-MIMO Communication in mmWave WLANs: Bayesian Optimization and Asynchronous Transmission

With the rapid proliferation of mobile devices, the marriage of millimeter-wave (mmWave) and MIMO technologies is a natural trend to meet the communication demand of data-hungry applications. Following this trend, mmWave multiuser MIMO (MU-MIMO) has been standardized by the IEEE 802.11ay for its downlink to achieve multi-Gbps data rate. Yet, its uplink counterpart has not been well studied, and its way to wireless local area networks (WLANs) remains unclear. In this paper, we present a practical uplink MU-MIMO mmWave communication (UMMC) scheme for WLANs. UMMC has two key components: i) an efficient Bayesian optimization (BayOpt) framework for joint beam search over multiple directional antennas, and ii) a new MU-MIMO detector that can decode asynchronous data packets from multiple user devices. We have built a prototype of UMMC on a mmWave testbed and evaluated its performance through a blend of over-the-air experiments and extensive simulations. Experimental and simulation results confirm the efficiency of UMMC in practical network settings.