An adaptive contention-based scheduling scheme for proportional service differentiation in multichannel wireless networks

In this paper, we propose an adaptive contention-based MAC scheduling scheme called Multi-channel Contention-based TDMA (MC/TDMA) for Multichannel wireless networks which provides proportional service differentiation while achieving high resource utilization. The MC/TDMA scheme adaptively schedules the traffic over multiple non-overlapping channels by controlling the number of competing nodes on a common channel based on the system load. The scheduling problem of MC/TDMA scheme is solved in two phases. The first phase called the Timeslot Allocation phase is reduced to a modified open-shop scheduling problem which allows us to use known efficient open-shop scheduling algorithms. For the second phase called Channel Allocation Phase, which is a non-convex Non-linear Programming (NL-P) problem (an NP-Hard problem) we develop a greedy heuristic. In order to maximize the utilization of the network resources while achieving proportional service differentiation, we propose a tuning knob called the collision factor 'a' which can be adaptively adjusted based on the network load. Through extensive simulations using OPNET we show that the proposed MC/TDMA scheme can provide proportional service differentiation in a multichannel wireless network while optimizing the utilization of the network resources.