QMAC: a QoS-guaranteed MAC protocol with dynamic granularity control for local wireless ATM networks

We propose a QoS-guaranteed MAC protocol (QMAC) augmented with dynamic granularity (frame size) control, aiming to provide bandwidth-on-demand while retaining maximal throughput. QMAC supports three types of ATM traffic-CBR, VBR, ABR, along with reservation request (RVR) traffic for making connection reservation. While CBR/VBR/ABR is governed by reservation access over the reservation bandwidth, RVR is conducted by random access over the contention bandwidth. QMAC essentially exerts dynamic granularity control on per-frame-based allocation of the reservation and contention bandwidth. The reservation bandwidth is allocated following a weight-based scheduling policy. For the allocation of the contention bandwidth, based on a neural-fuzzy traffic prediction technique, QMAC derives the “favorable bandwidth” implying maximum throughput. The smaller value between the favorable bandwidth and remaining unreserved bandwidth is designated as the contention bandwidth. Simulation results demonstrate that, compared to a set of MAC alternatives under M-Pareto-distributed and dynamic traffic settings, QMAC invariantly achieves superior performance with respect to throughput, access delay, and blocking probability