A low complexity two-stage user scheduling scheme for MmWave massive MIMO hybrid beamforming systems

摘要

In an overloaded MU-MIMO system with hybrid beamforming that supports a very large number of users, user scheduling is necessary as the base station (BS) cannot simultaneously serve such a large number of users. Since hybrid beamforming provides a new resource to schedule, i.e. beams, user pairing becomes a joint optimization on user selection and beam selection, which is computationally demanding. In this paper, a low-complexity two-stage user scheduling scheme considering both the inter-user channel correlation and the channel energy is proposed. The idea is motivated by the fact that both the orthogonality between the user channels and the channel energy can affect the system achievable sum rate in a MU-MIMO system. Therefore, we propose to firstly sort the users from the perspective of channel orthogonality, and then carry out user and beam selection within a narrowed range for channel energy maximization. Simulation results validate the proposed scheduling strategy not only has a significant advantage in reducing computational complexity, but also achieves higher sum rate than other non-exhaustive schemes.