A Region-Based Downlink Scheduling Algorithm in MIMO Precoding Systems

Although significant throughput gains and system fairness can be obtained by slot-based scheduling algorithms, the corresponding complexities are considerable. In this paper, we propose a region-based downlink scheduling algorithm for QoS-guaranteed services in multi-user multiple-input multiple-output (MIMO) precoding systems. In contrast with conventional slot- based scheduling, region-based scheduling allocates bandwidth based on resource regions consisting of several slots. The proposed algorithm combines QoS-urgent-degree and the proportional fairness to select candidate connections, and determines the size of each SDMA region. In addition, multi-user scheduling is performed in all SDMA regions to completely exploit spatial multiplexing gains. Simulation results show that, at the cost of slightly lower spectrum efficiency and data rate guarantee, the proposed region-based scheduling algorithm has much lower complexity, while at the same time it can achieve higher performances in system fairness and delay guarantee.