Arbitration Interframe Space-controlled Medium Access Control: a medium access control protocol guaranteeing absolute priority in wireless local area networks

Abstract

SUMMARY The demand for multimedia services, such as voice over Internet Protocol, video on demand, information dissemination, and file sharing, is increasing explosively in wireless local area networks. These multimedia services require a certain level of QoS. Thus, it is important to provide QoS for multimedia applications. IEEE 802.11e tries to meet the QoS requirement of multimedia services by using Enhanced Distributed Channel Access. This gives more weights to high-priority traffic than low-priority traffic in accessing the wireless channel. However, Enhanced Distributed Channel Access suffers from many problems such as low aggregate throughput, high collision rates, and ineffective QoS differentiation among priority classes. In this paper, we propose a new medium access scheme, the Arbitration Interframe Space-controlled Medium Access Control (AC-MAC), that guarantees absolute priority in 802.11 wireless networks. In AC-MAC, the AIFS and contention window values are controlled, so that a higher-priority traffic can preferentially access and effectively utilize the channel. Extensive simulations show that AC-MAC can perfectly provide absolute priority and good throughput performance regardless of the number of contending nodes. In the simulation of voice over Internet Protocol service, AC-MAC provides effective QoS differentiation among services and also meets the high level of QoS requirements. AC-MAC also adapts quickly in a dynamic environment and provides good fairness among the nodes belonging to the same priority class. Copyright © 2011 John Wiley & Sons, Ltd.