How is your event Wi-Fi doing? Performance measurements of large-scale and dense IEEE 802.11n/ac networks

The popularity of the IEEE 802.11 (Wi-Fi) standard has resulted in a plethora of hotspot deployments. While home hotspots offer high and consistent performance, at large-scale events such as conferences and festivals, Wi-Fi performance is often poor and highly fluctuating. There are several factors explaining this increased difficulty: the required scale, the complexity of backhaul network topologies, the density of devices connected to the access point (AP), and the interference caused by both people and radio frequency (RF) equipment. While these factors are all known to degrade the performance of public hotspots, little is known about the actual performance of IEEE 802.11 at large-scale events. In this paper, we present the results of quantitative Wi-Fi performance measurement study undertaken at a music festival with 80,000 visitors over a geographical area of 0.3 square kilometres. Two separate networks were constructed for this study. The first was an IEEE 802.11n-based wireless mesh consisting of 37 devices in 15 nodes working as a network backhaul and the second an IEEE 802.11n/ac-based public hotspot that was accessible by the festival goers. We characterise the performance of the wireless spectrum and illustrate the impact of interference factors such as crowds and RF equipment. Finally, we report on the results of the deployment of a public hotspot at the festival, focusing more on application-layer metrics parameters such as user experience and session statistics. The results show that the interference at such events is so high that adaptations to the protocol configuration are needed to improve performance.