Deafness Avoidance in Wireless Ad Hoc Network

Abstract

In age of advanced communication systems, wireless ad hoc networks have becomean important field to have transmission without any infrastructure and control station at any place and terrain conditions. The wireless nodes used in such communication systems are self-organizing nodes, which can be deployed rapidly and adaptable to frequent topology changes. In recent years incorporation of directional antennas in mobile nodes has greatly improved the performance of the wireless ad hoc network by improving spatial reuse, reducing radio interference and improving the radio range drastically. However, there are certain issues, which have come up while using directional medium access control protocols in the network. They are: hidden terminal problem, exposed terminal problem and deafness problem. Among these problems the deafness problem has been a major challenge as it not only affects the MAC layer but also higher layer, which is network layer as when sender does not receive CTS it goes into backoff interval and routing algorithm initiates route recovery procedure in the network and results in performance degradation. Thus it is required to eradicate the problem of deafness because sometimes it may undo the advantages of using directional antennas in the wireless network. It also increases overheads due to repeated requests in the network for getting control of the channel for communication as there is control packet flooding in the network due to repeated attempts for possible communication. In large networks there may be many deaf terminals and packet flooding may increase drastically, which degrades performance of the network to a large extent. newlineTo improve the performance of the wireless ad hoc networks, it is required to mitigate/avoid deafness in the network. It is therefore proposed to use pure directional MAC protocol where directional antenna has been used for control signal packet transmission as well as for data packet transmission unlike the other protocols used for mitigating the deafness problem.