A survey on ubiquitous WiFi-based indoor localization system for smartphone users from implementation perspectives

Indoor localization has the capability to change the way of providing location-based services in a closed environment and has more potential than that of GPS if the present shortcomings can be overcome. Thus, developing a ubiquitous Indoor Localization System (ILS) is the need of the day. WiFi-based indoor localization using smartphones is a promising approach to achieve ubiquity since smartphones are widely available today and most of the buildings are WiFi enabled. However, the significant variation of WiFi signal strengths with ambient conditions as well as device configuration badly affects the localization accuracy. Hence, a ubiquitous ILS, which would be widely available and would not require any specialized hardware support is still out of reach. Thus, this paper surveys state-of-the-art WiFi-based indoor localization techniques with a critical analysis of their applicability as a ubiquitous system. Consequently, the main objective of this paper is to highlight the key research challenges of implementing a WiFi-based ILS when system ubiquity is the prime concern with a discussion on future direction. Some of the experiments have been implemented on a real-life dataset in order to indicate the implementation challenges of such a system.