A QoS-guaranteed MAC protocol using variable frame granularity for wireless access networks

In this paper, we propose a MAC protocol, called QMAC+, which adopts variable frame granularity, aiming to provide bandwidth-on-demand and QoS guarantees while retaining maximal network throughput. QMAC+ supports three traffic types-BR, VBR, and reservation request (RVR) for making CBR/VBR connection reservation. Essentially, QMAC+ governs weight-based reservation access (for VBR/CBR) and premier contention access (for RVR) over dynamically allocated reservation and premier contention bandwidths, respectively. In particular, the premier contention access performs incremental contention resolution by means of feedback control using an envelope-pdf-based estimator for the estimation of the number of concurrently transmitting users. As a result, the frame granularity is dynamically changed adapting to traffic fluctuations. Simulation results demonstrate that QMAC+ achieves superior performance with respect to throughput, delay, and blocking probability