Performance evaluation of an efficient cooperative channel reservation MAC protocol in wireless ad Hoc networks

Although channel reservation technique can be used in distributed MAC protocols to overcome the problem of packet collisions among nodes, it is found that its stability is severely influenced by both the interference of neighboring nodes and the fading effects of wireless channels. In this paper, an efficient MAC protocol, i.e. CCRM, which is based on an efficient cooperative channel reservation mechanism, is proposed. In CCRM, in order to improve the stability of making channel reservations, channel reservation information (CRI) announced by a real-time node is cooperatively relayed by its neighboring nodes. Furthermore, considering the case where there are multiple CRIs announced by different real-time senders waiting to be relayed by a neighboring node, an efficient strategy for selecting a CRI among them is proposed. According to the selection strategy, the relayed CRI is chosen by jointly considering two basic rules: one is that the CRI which has been relayed for the least number of times should be relayed first; the other one is that the CRI whose corresponding reserved time slot comes first should be relayed with higher priority. Extensive simulations show that better performance can be achieved by the proposed CCRM.