Throughput-aware dynamic sensitivity control algorithm for next generation WLAN system

Abstract

Increasing use of IEEE 802.11 WLAN specifications has resulted in dense deployment of access points (AP) to provide service to stations (STA). Dynamic sensitivity control (DSC) technology, which adjusts the carrier sense threshold (CST) to encourage more APs and STAs to transmit simultaneously, is considered an effective approach to improve the throughput in densely-deployed WLAN networks. The DSC algorithm should take into account both the increase of transmission opportunity, and the possible transmission rate degradation of related links caused by the consequent interference. Conventional algorithms, which set the CST value to allow simultaneous transmission only when a required signal to interference plus noise ratio (usually for a high transmission rate) can be guaranteed, are too conservative to improve the throughput. In this paper, we propose a novel DSC algorithm that enables simultaneous transmissions which lead to improved system throughput even when the transmission rate is degraded. Since whether system throughput can be improved by simultaneous transmission is different for each communication link, we set different CST values for different links instead of setting just one common CST value. We first formulate the throughput of each downlink as a function of related links' CST, and then search a set of CST values for these links to maximize the system throughput. A heuristic procedure is adopted in our algorithm to reduce calculation complexity. From numerical simulation results, it is shown that our algorithm can improve the system throughput by up to 30% when compared to a conventional algorithm.