A Scheduling Algorithm for Real-Time Traffic in IEEE802.11e HCCA

IEEE 802.11e HCCA 기반의 실시간 트래픽을 위한 스케줄링 알고리즘

  • Published : 2010.01.25

Abstract

In this paper we propose a scheduling algorithm for supporting Quality of Service(QoS) in IEEE 802.11e HCCA referred to as ASR-DRR and ASD-DRR, which aims at providing improved performance for the support of multimedia traffic. Although We identify the problem of the current IEEE 802.11e HCCA (Hybrid Coordination Function Controlled Channel Access) scheduler and its numerous variations, that the queue information cannot be notified to the Hybrid Coordinator (HC) timely, therefore the uplink delay lengthens unnecessarily. We suggests a simple solution and a couple of implementation practices, namely the Adaptive Scheduler with RTS/CTS (ASR) and Adaptive Scheduler with Data/Ack (ASD). They are both further elaborated to emulate the Deficit Round Robin (DRR) scheduler. They are also compared with existing exemplary schedulers through simulation, and shown to perform well.

본 논문에서는 멀티미디어 트래픽에 대한 성능 향상을 목표로 ASR-DRR, ASD-DRR이라 명명한 IEEE 802.11e HCCA기반에서 서비스 품질 보장이 가능한 스케줄링 알고리즘을 제안하였다. 또한 IEEE 802.11e HCCA(Hybrid Coordination Function Controlled Channel Access) 스케줄러와 관련된 다수의 개선된 형태의 스케줄러들이 실제 큐 사이즈 정보를 실시간으로 HC(Hybrid Coodinator)에 전달하지 못하여 생기는 불필요한 지연시간에 대해 지적하였다. 이러한 문제점을 해결하기 위해서 현재 큐 상태를 최대한 실시간으로 전달할 수 있는 간단한 해결책을 제안하였으며, 이를 바탕으로 두 가지 구현방안을 제시하였다. 이를 RTS(Request to Send)/CTS(Clear to Send)를 활용한 적응형 스케줄러(ASR)와 Data/Ack를 활용한 적응형 스케줄러(ASD)라고 한다. 이들 구현 방안들은 유선환경에서의 DRR(Deficit Round Robin) 스케줄러를 모방하여 최적화되었다. 또한 제안하는 스케줄러의 성능을 알아보기 위해 NS-2 시뮬레이터를 활용하여 기존 스케줄러와 비교한 결과 훨씬 좋은 성능을 보임을 확인하였다.

Keywords

References

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