Lower Bound Capacity Based Scheduling in MU-MIMO System

Priority in higher multiplexing and diversity gains makes multiple-input multiple-output (MIMO) systems finally be adopted in several industrial wireless standards, e. g., the 3GPP long term evolution. Multi-user (MU) MIMO system realizes spatial multiplexing to communicate with several users, which can utilize multi-user diversity gain and thus provide improved system throughput, with the help of multi-user scheduling. User subset selection is required when the potential user pool exceeds the available transmission resources. When user selection or scheduling is done judiciously, it will obtain more multi-user diversity gain and help reducing the multi-user interference to ensure higher throughput. The current existed scheduling schemes are generally derived from the antenna selection algorithms. Indeed, they can improve the sum-rate of MU-MIMO system to some extent. However, these schemes can't make the best of multi-user diversity gain, thus incurring capacity loss. To overcome these disadvantages, in this paper, a novel user scheduling scheme based on the lower bound capacity of MU-MIMO broadcast channel is proposed for the multi-user zero-forcing precoding system. In the proposed scheme, the base station will schedule those users that can achieve the maximal lower bound capacity of MU-MIMO system by certain optimal criterion. Simulation results are exhibited to indicate that the proposed scheme can provide performance improvement than other existed scheduling schemes.