A novel fair medium access control for 802.11-based multi-hop ad hoc networks

This paper proposes a distributed and topology-independent contention control mechanism for IEEE 802.11-based multi-hop ad hoc networks, which aims at ensuring per-station fairness without degrading the total network throughput, and without requiring any information exchange between the nodes. The proposed algorithm dynamically controls the frequency each station accesses the channel according to the station´s channel share. The statistics of the stations´ channel shares are updated locally in each node based only on the standard physical carrier sensing activity. To avoid throughput degradations while seeking fair allocation of bandwidth, we have also developed a credit-based scheme that operates in cooperation with the backoff procedure. The credits are a virtual currency earned by stations refraining from transmitting, and spent to reclaim backoff-free transmission opportunities. Simulations conducted in several well-known problematic topologies show that our scheme can achieve a better fairness than standard IEEE 802.11, while increasing the total network throughput