Time Petri net based performance evaluation of traffic scheduling in WIMAX networks

IEEE 802.16 well known as WIMAX is defined as the standard of Broadband WMAN networks. This technology is able to mix real time and non real time services with the definition of service classes. To efficientlty schedule traffics of different classes, we proposed in a previous work a token bucket based scheme and evaluated its performances by means of probabilistic models. In this paper, we explore the use of TPN (Time Petri nets) for deterministic performance evaluation in order to compute quantitative and qualitative properties. We show how to model two different strategies of traffic scheduling by using TPN model extended to logical inhibitor arcs. The first strategy is based on strict priorities between traffics, the second is based on token bucket mechanism. Then in order to improve the efficiency of the latter scheme, we propose to extend it to a QoS-management mechanism. Then we simulate the obtained models by using the tool TINA in order to evaluate their performances when varying the load of the system. Preliminary results show that token bucket extension provides better figures in terms of service delay, than other schemes, in case of high service loads while maintaining fairness and priorities between traffics.