Capture effect on downlink throughput of a CSMA based WLAN

We study the capture effect on the downlink throughput of a carrier sense multiple access (CSMA) based wireless local area network (WLAN) in presence of path loss, Rayleigh fading and log-normal shadowing. For this purpose, we develop an analytical model to compute the saturation throughput of the AP in a WLAN without and with the capture effect. The developed analytical model is then validated via simulation. By means of the analytical model, we determine the throughput increment due to the capture effect by computing the throughput of a WLAN without and with the capture effect. We find that the throughput increment due to the capture effect is very significant. We also investigate the effect of the variations of some network and wireless channel parameters on the increment of downlink throughput due to the capture effect. We find that the throughput increment due to the capture effect increases with increasing the user transmission probability and the variance of shadowing. However, the throughput increment due to the capture effect decreases with increasing the data transmission rate.