Reduction of blockage node and hidden terminal problem of CSMA/CA MAC protocol using directional antenna

Abstract

Avoidance of collision in wireless ad-hoc network is important and CSMA/CA MAC protocol is playing a major role to avoid collision. CSMA/CA MAC protocol handle it using sort RTS/CTS control message. Though reliability of data transmission increase, it blocks some nodes unnecessarily due to RTS and CTS control message and also makes existence of hidden-terminal (HT) problem which reduces the network performance. In wireless Ad-hoc network the nodes are mobile, infrastructure less and communicate through their radio range. If we can reduce the number of blockage nodes the network performance will increase by utilizing those nodes as other communication's source, destination or relay. In this paper, we propose two methods by which wireless ad-hoc network performance will increase. First we propose a method for enhancement of CSMA/CA MAC protocol by unblocking the nodes using directional antenna and setting up NAV values of RTS/CTS control message considering directional antenna and modified the CSMA/CA timing diagram accordingly. The second method shows how the hidden-terminal problem is reduced by the proposed method. The analytical model explains the performance of CSMA/CA protocol with reduction of HT problem.