LOad based Contention resOlution Media Access Control (LOCO-MAC) Protocol

Abstract

This work presents a MAC protocol for wireless ad hoc networks that is adaptive to stations load. LOCO MAC novelty lies in its backoff scheme that achieves short time collision resolution among many competing stations, even when they are hidden from each other. In LOCO-MAC the channel access time is calculated as a function of the station load, thus enabling to estimate the load of stations at the receiver side, regardless of the successful reception of transmission request. This load estimation is used to grant channel access to one of the stations whose load is the highest. Station's load is measured and normalized adaptively in terms of queue length and maximum end-to-end packet delay time. An analytical analysis to the throughput reveals that the expected throughput of LOCO MAC is ~80%. A network simulator was used to verify the effectiveness of the protocol under more realistic communication scenarios. Simulations results show that the high throughput is achieved almost regardless of the traffic load and is maintained at bursty traffic load distributions and even at loads that momentarily exceed the channel capacity. In addition, the fact that LOCO- MAC serves the most loaded station promotes fairness among stations, while maintaining high goodput, short queue lengths as well as short packet delays.