Performance analysis of an IEEE 802.11ac WLAN with dynamic bandwidth channel access

Abstract

We consider a collocated WLAN with Nac 802.11ac users using dynamic 20/40 MHz channel access and Nl 802.11a/n legacy users operating in the secondary 20 MHz channel. Under ideal channel conditions, we seek to characterise the saturation throughput performance of the 802.11ac users and the legacy users. We propose an analytical model based on a decoupling approximation for saturation throughput analysis. Dynamic bandwidth channel access leads to correlation in the channel access of 802.11ac and legacy users and hence, we consider a DTMC to model the transmission opportunities in the primary and the secondary channel. Using simulations, we show that the proposed model accurately captures both high level performance measures such as long term average throughput and low level performance measures such as collision probability very well. Finally, we characterise the effect of Nac, Nl and packet size on the network performance.