An Adaptive Hierarchical Medium Access Control Protocol for Highly Dynamic Wireless Networks

To solve the channel resource wastage problem caused by single multiple access method in highly dynamic wireless networks and improve the channel utilization, an adaptive hierarchical medium access control (AHMAC) protocol is proposed. It divides the traffic load into three different levels, i.e. low traffic load, medium traffic load and high traffic load. For different levels of traffic load, appropriate multiple access methods are selected. For low traffic load, a random access-based MAC protocol, such as request-to-send/clear-to-send (RTS/CTS) protocol, is adopted. For medium traffic load, an on-demand reservation-based MAC (ODR-MAC) protocol is applied. For high traffic load, an adaptive polling-based MAC (AP-MAC) protocol is employed. The traffic load during a predefined time period is evaluated by a central control node (CCN). When the newly-evaluated traffic load is different with the currently-used traffic load and reaches the new level, the corresponding MAC protocol for the new traffic load is adopted. Simulation results show that the proposed protocol can explore the advantages of all single multiple access methods, eliminate their disadvantages and improve the multiple access efficiency.