Research On Downlink Packet Scheduling Algorithms For3GPP LTE Systems

In the3GPP LTE systems, a MAC layer packet scheduler governs the centre position. The research on scheduler is of primary importance to the wireless communication systems, since whether it’s well designed can significantly affect the user satisfaction and system performance.This paper analyzes several different performance metrics of MCI, RR and PF scheduling algorithms with full-buffer, FTP and VoIP traffic applications through system-level simulation. In the simulation platform, the control channel constraints are considered. The simulation results show that the control channel constraint is the bottleneck for dynamic scheduling with VoIP application. The control channel bottleneck is deeply analyzed.This paper still studies the semi-persistent scheduling designed for solving the control channel bottleneck. Compared with the dynamic scheduling under control channel constraints, the semi-persistent scheduling can effectively solve the control channel bottleneck, improving the system performance.This paper finally studies the characters of M2M (Machine to Machine) scenario. The reasons for why dynamic scheduling and semi-persistent scheduling can’t be used in M2M scenario are analyzed. According to the characters of M2M, a group control information sharing based scheduling algorithm is proposed, which is briefly called group-based scheduling. The structure of control channel is redesigned for control information sharing among group member UEs. The simulation results show the performance is significantly improved.