Packet delay analysis of the advanced infrared (AIr) CSMA/CA MAC protocol in optical wireless LANs

Abstract

AbstractDuring the past few years the wireless technology market has experienced a tremendous growth. Users today expect to be able to communicate and access data anytime, anywhere, using almost any portable device. Infrared Data Association (IrDA) addressed the requirement for indoor multipoint wireless connectivity with the development of the advanced infrared (AIr) protocol stack utilizing the infrared spectrum. AIr medium access control (MAC) protocol employs a carrier sensing multiple access with collision avoidance (CSMA/CA) protocol in addition to a request to send/clear to send (RTS/CTS) packet exchange reservation scheme and a linear adjustment of the contention window (CW). This paper develops a new modelling approach to evaluate saturation performance of the AIr protocol based on conditional probability arguments rather than bi‐dimensional Markov chains. Moreover, we extend performance studies in former literature papers by providing an intuitive AIr packet delay analysis assuming error‐free transmissions and a fixed number of stations. Using OPNET simulation results, we validate our mathematical analysis and we show that the proposed model predicts AIr packet delay performance very accurately. Utilizing the derived mathematical analysis, we determine the significance of both link layer and physical parameters, such as burst size, minimum CW size value and minimum turnaround time on AIr packet delay performance. Finally, we propose suitable values for both backoff and protocol parameters that reduce average packet delay and, thus, maximize performance. Copyright © 2005 John Wiley & Sons, Ltd.