Low Complexity Multiuser MIMO Scheduling with Channel Decomposition

In multiuser MIMO systems, the base station schedules transmissions to a group of users simultaneously. In order to avoid the inter-user interference, a transmit preprocessing technique which decomposes the multiuser MIMO downlink channel into multiple parallel independent single-user MIMO channels can be used. When the number of users is larger than the maximum that the system can support simultaneously, the base station selects a subset of users who have the best instantaneous channel quality to maximize the system throughput. Since the exhaustive search for the optimal user set is computationally prohibitive, a low complexity scheduling algorithm which aims to maximize the capacity upper bound is proposed in this paper. Simulation results show that the proposed scheduling algorithm achieves similar total throughput as the optimal algorithm but with much lower complexity.