Adaptation of Carrier Sensing Threshold to Increase Throughput in Dense 802.11ac Wireless Networks

Abstract

Carrier sensing mechanisms in many of today’s wireless devices are based on virtual carrier sensing and physical carrier sensing. Virtual carrier sensing functions through the use of request to send and clear to send handshake signaling. Physical carrier sensing makes use of the carrier sense threshold (CST), which indeed aims to mitigate the collisions and interference related problems. In densely deployed networks, however, such classic carrier sensing mechanisms limit the spatial reuse rate, which can result in unsatisfied user demands. In this paper, an adaptive carrier sensing algorithm, which adjusts the CST depending on the overall throughput gain and fairness among the networks, is proposed to increase the spatial reuse and the system throughput. The connectivity issue of the associated clients has been addressed. As a first step, the effect of CST change is investigated in terms of airtime usage, fairness and different node densities in a simple grid 802.11ac dense network deployment. The performance evaluation of the proposed approach is done by using Network Simulator-3 (ns-3). Simulation results show that with the use of the proposed approach, the overall system throughput can be increased by as much as 100% of the throughput provided by the traditional carrier sense multiple access (CSMA)protocol.