An Analytical Model of the TXOP Scheme with Heterogeneous Classes of Stations

The enhanced distributed channel access (EDCA) protocol has been proposed to support differentiated quality-of-service (QoS) of wireless local area networks (WLANs). edca introduces a promising scheme, transmission opportunity (TXOP), which enables a station to transmit multiple frames consecutively in a burst upon winning the contention of the channel. The analytical models of the TXOP scheme have been mainly developed under the assumptions that the traffic generated by the stations is saturated or follows a non-bursty Poisson arrival process. These assumptions are unable to capture the characteristics of heterogeneous multimedia traffic. This paper proposes a new analytical model for the TXOP scheme in WLANs comprising heterogeneous classes of stations with multimedia applications. The traffic of such applications is modelled by the non-bursty Poisson, bursty Markov-modulated Poisson process (MMPP), and fractal self-similar traffic. The accuracy of the proposed model is validated through extensive NS-2 simulation experiments.