RMAC: A Reliable MAC Protocol Supporting Multicastfor Wireless Ad Hoc Networks

This paper presents a new reliable MACprotocol called ``RMAC'' supporting reliable multicast for wireless adhoc networks. By utilizing the busy tones to realize the multicastreliability, RMAC has three novelties: (1) it uses a variable-lengthcontrol frame to stipulate an order for the receivers to respond, thussolving the feedback collision problem; (2) it extends the usage of busytone for preventing data frame collisions into themulticast scenario; and (3) it introduces a new usage of busy tone foracknowledging data frames positively. In addition, RMAC is generalizedinto a comprehensive MAC protocol that provides both reliable andunreliable services for all the three modes of communications: unicast,multicast, and broadcast, making it capable of supporting variousupper-layer protocols. The evaluation shows that RMAC achieves highreliability with very limited overhead. RMAC is also compared with otherreliable MAC protocols, showing that RMAC not only provides higherreliability but also involves lower cost.