Solution to Beacon Overhead in 802.11 Hotspot Environment

Abstract

These days, a large number of APs are deployed in 802.11 hotspot environment. When we use a smartphone or laptop in a café near an avenue or in subway station, we find that a lot of APs are on Wi-Fi connection list. We closely checked problems that may occur in such occasions. We especially focused on the beacon frame transmitted periodically by APs. As the number of APs increases, the number of beacon frames intending to access wireless medium also increases. We expect that an increased number of beacon frames disturb data transmission. And we show the results of measurements which we performed packet capture using wireshark at Gangnam station and INMC(we regard these two spots as hotspot environments). We analyze the portion of airtime occupied by beacon frames at hotspot and we further show that large portion of airtime occupied by beacon frames has harmful effect on the data throughput. And we show two factors of beacon frame for reducing airtime of beacon frame. The two factors are beacon interval and beacon transmission rate. When we change the value of these two factors, we should consider side effects. We look closely at the effects of these factors on airtime and the other sides. Based on the analysis of beacon interval and beacon transmission rate, we propose algorithm that select the values of beacon interval and beacon transmission rate satisfying 3 constraints.