A load awareness medium access control protocol for wireless ad hoc network

A contention-based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA/CA), has the excellence of simple and efficient when the system is light-loaded. The main drawback of such protocols is their inefficiency and unbounded delay when system load is heavy. On the other hand, a contention-free MAC protocol, such as token passing, has better and fair throughput when the system is heavy-loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness wireless ad hoc MAC protocol (which is called the LA protocol) that exploits the benefits of both contention-based and contention-free protocols. A contention-based MAC protocol is used when system is light-loaded and a contention-free one is used otherwise. Our LA protocol, which operates distributed and is fully compatible with IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention-based protocol and the contention-free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols and performs well in all systems loads.