合理反馈机制下保证混合业务QoS的调度算法

Scheduling algorithm with feedback based mixed-service QoS

针对正交频分复用(orthogonal frequency division multiplexing,OFDM)系统多用户中继场景中混合业务对时延的不同需求,提出一种基于合理反馈机制下的降低时延、保证混合业务服务质量的调度算法(mixed services with feedback scheduling,MSFS)。MSFS算法针对用户实时业务及非实时业务的不同需求分别采用不同的调度准则及反馈方式,以达到优化系统性能的目的。针对实时业务,增大其调度优先级以减少等待时延,并在其等待时延接近时延门限时,使其调度优先级迅速增加,以避免丢包;针对非实时业务,加入时延公平因子,使得该类用户业务在时延公平性方面得到改善,同时设置适当的反馈门限,在不影响业务服务质量需求的同时达到降低系统反馈量的目的。仿真结果表明,该算法在保证系统吞吐量和用户公平性的同时,不仅能够有效降低实时用户的时延,而且能够较大程度地减少系统反馈量。

Aiming at different delay requirements for the mixed services of multi-user relay scenario in the Orthogonal Fre- quency Division Multiplexing （OFDM） system, we propose a Mixed Services with Feedback Scheduling （MSFS） algorithm for cooperative relaying communication system. The MSFS algorithm designs different scheduling and feedback criteria for different delay characteristics of real-/non-real-time services respectively, which can also reduce the feedback of Channel State Information by setting a feedback threshold for the non-real-time users. Simulation results show that MSFS algorithm can minimize the delay of real-time users and decrease the feedback load at cost of little system throughput and users＇ fairness.