Bandwidth Aware Slot Allocation in Hybrid MAC

Hybrid medium access control (MAC) protocols combine the strength of random and schedule based MAC schemes. From random MAC schemes, hybrid MAC protocols borrow flexibility and ease of operation while also incorporating the scalability and high capacity performance of schedule based schemes. A number of hybrid approaches exist. The most effective of those, as shown in (I. Chlamtac, 2000), can dynamically adapt to the contention level in the medium. They achieve this adaptability by combining TDMA (schedule-based) and CSMA (random-based). Whereas the combination of TDMA and CSMA enhance contentions resolution, the existing solutions do not allocate slots in proportion to the bandwidth requirements of the individual nodes. This affects the performance adversely. In this paper we propose an algorithm to optimize slot allocations during the schedule-based phase of the hybrid MAC protocol. Through simulations, we evaluate the performance of our algorithm in both single-hop and multihop networks. Our results show an improvement of up to 40% in some cases