A multiple access control protocol with multiple reservation information relay and cooperative channel reservation

A new multiple access control (MAC) protocol called M-CCRM is proposed to solve the problem of poor channel access efficiency for real-time traffic in Ad Hoc networks with heavy background traffic loads. The proposed protocol bases on the idea of distributing channel reservation information (CRI) through cooperative relays of neighboring nodes. Before a node transmits a packet, multiple CRIs are carefully selected and piggy-backed with the packet so as to limit the corresponding overheads caused by carrying CRIs to be lower than a predefined threshold. By overhearing the packet, neighboring nodes record some of the CRIs as long as they are within the channel reservation distance of the CRIs, and then avoid to access the channel while the traffic indicated by the CRIs are carrying on. The proposed MAC protocol enlarges the coverage area of the announced CRIs, and avoids the possible missing of CRIs caused by channel fading and (or) packet collisions. Therefore, the channel access efficiency for real-time traffic is significantly increased. Simulations and comparisons with the basic channel reservation protocol and the basic cooperative channel reservation protocol show that when the overheads caused by carrying CRIs are limited to be lower than 2%, the transmission failure rates of real-time traffic of the proposed protocol are reduced by 31% and 20%, respectively.