Dynamic Wi-Fi Reference Point Recognition along Public Transport Routes

Abstract

The ubiquity of Wireless Fidelity (Wi-Fi) signals in urban environments has the high potential to employ them for numerous applications for localization and guidance in urban environments. The reach of Wi-Fi localization is extended in this study for urban wide applications and therefore user localization is employed for outdoor and combined in-/outdoor environments. The chosen application is the localization and routing of public transport smartphone users. For the conducted investigations, Received Signal Strength Indicator (RSSI) values are collected for users who are travelling from home in a residential neighborhood to work in downtown and return along the same route. Special tram trains are selected which provide two on-board Wi-Fi Access Points (APs). Firstly, the availability, visibility and RSSI stability of the Wi-Fi signal behavior of these APs and the APs in the surrounding environment along the routes is analyzed. Then the trajectories are estimated based on location fingerprinting. A first analyses reveals that significant differences exists between the four employed smartphones as well as times of the day, e.g. in the morning at peak hours or at off-peak hours.