Collision-free MAC scheduling algorithms for wireless ad hoc networks

Providing quality of service (QoS) in wireless ad hoc networks introduces a major challenge due to their dynamic topologies. In general, a QoS scheme requires close collaboration between all layers in the protocol stack. At the base of the scheme is a QoS capable MAC protocol. In ad hoc networks nowadays, the widely deployed distributed coordination function (DCF) proposed by the IEEE 802.11 standard is a random access scheme and suffers from a fairness problem. In order to provide a guarantee of minimal throughput and improve the fairness of bandwidth sharing, a class of collision-free MAC scheduling algorithms is proposed. When implementing these algorithms, the set of node identifiers (IDs) that can connect to the network should be known in advance. In addition, neighborhood information sharing is required. Compared with their counterparts proposed in the literature, these algorithms can guarantee a minimal throughput and do not rely on per-packet information exchange. Simulation results show that these algorithms can provide better long term fairness when compared with IEEE 802.11 DCF, even when they are implemented in coarse time granularity.