The Design Of Multi-user MIMO Scheduling Techniques

Multiple-input multiple-output(MIMO), as one of the important techniques of 4G, has got more and more attention. Multiple users compete for the limited resources, so it is particularly important to find a suitable scheduling strategy. This paper mainly analyzes the user scheduling problem of the multi-user MIMO(MU-MIMO) downlink system.This paper introduces the development of the mobile communication, states the MIMO system and analyzes MU-MIMO user scheduling techniques. Then it discusses the capacity of single-user MIMO(SU-MIMO) according to the channel state information(CSI) and analyzes the capacity of MU-MIMO. In addition, this paper introduces the concept and characteristics of multi-user scheduling.After introducing and comparing several traditional precoding techniques, the paper plans to apply SLNR to engineering practice. Moreover, it introduces and compares several user scheduling methods.According to the capacity formula, scheduling users needs a lot of calculations. To reduce the complexity, an objective function based on both spatial correlation and channel gains is considered. In addition, team progress algorithm(TPA) is used to search the best user subset with the function above, which has much lower complexity. The simulation results show that TPA can accelerate the convergence speed and maximize the system capacity.Besides the capacity, the paper also considers the fairness and uses the scheduling policy, combining proportional fair(PF) scheduling with TPA, which maximizes the capacity and improves the fairness at the same time.