Beamforming in Dense Wi-Fi Networks: Beam Management and Throughput Analysis

Facing the strong demands for high speed Wi-Fi access in the already crowded unlicensed spectrum, enabling beamforming at Wi-Fi access points (APs) can be an efficient way to improve the network throughput with its compelling advantages in beamforming gain and spatial reuse factor. However, how much beamforming Wi-Fi can benefit in an environment populated with legacy Wi-Fi stations remains an open problem. After all, it could be incompatible with the legacy Wi-Fi protocol or causing unbalanced downlink (DL) and uplink (UL) channel access opportunities due to improper beam switching mechanisms. As an effort to explore the potential of beamforming Wi-Fi, we present a novel Markov model to analyze its throughput in randomly deployed Wi-Fi networks, and propose a beam switching mechanism which is backward compatible with the legacy Wi-Fi and able to adjust the DL and UL access probabilities between beamforming Wi-Fi APs and typical users. Analysis shows that the proposed scheme significantly improves DL throughput while maintaining balanced DL/UL throughput over a wide range of user densities, particularly in dense deployments. This encourages future study of beamforming for more advanced Wi-Fi technologies.