EMAC: An Asynchronous Routing-Enhanced MAC Protocol in Multi-Hop Wireless Networks

Traditional contention-based random-access wireless MAC protocols such as IEEE 802.11 DCF are designed for single-hop wireless networks and do not perform well in multi-hop scenarios due to inefficiency in their medium reservation mechanisms. In this paper, the authors introduce a new MAC protocol, called EMAC, which improves the efficiency of wireless medium reservation for general asynchronous multi-hop wireless networks. By exploiting limited routing information at the MAC layer, EMAC enables multiple asynchronous stations along a delivery path to cooperate in their random medium access. In particular, a control frame can travel across a multi-hop path composed of asynchronous nodes, and make synchronized medium reservations for an upcoming data frame transmission.