Fairness aware back-off control scheme in wireless network using directional MAC protocol

In wireless multi-hop networks, a directional media access control (DMAC) protocol has been proposed and has attracted great attention recently. However, a deafness problem may occur when a transmitter uses DMAC protocol. The deafness problem is the problem that a transmitter fails to communicate with its intended receiver because of not knowing it is busy. As one of the ways to solve the deafness problem, NAV in node units (Node NAV) which is set according to overheard RTS/CTS frames has been proposed. However, there is a strong possibility that some nodes hardly communicate to nodes registered in the Node NAV table. In this paper, we propose a new back-off control scheme to improve such a fairness problem of the communication in the Node NAV scheme. In the proposed scheme, the back-off time of the transmitter is controlled in proportion to the way to set Node NAV.