Indoor Localization Using Commodity Wi-Fi APs: Techniques and Challenges

Over the past decade, many research studies have contributed to making indoor localization of Wi-Fi devices accurate and practically useful for emerging applications wherein GPS becomes incompetent. Significant interest is shown and efforts have been put by the research community on using WiFi technology such as 802.11n standard for indoor localization because of its minimal deployment complexity and cost. Also, the Wi-Fi capability in almost every electronic device makes it a promising technology for indoor localization. The main aim of this survey is to review the most recent works on WiFi based localization systems that use commodity hardware highlighting their strengths and limitations, investigating major technical challenges, and outlining opportunities for future research. Commodity Wi-Fi equipments have fewer number of physical antennas, suffer from non-trivial phase noises due to imperfect signal processing hardware and operates in narrow bandwidth range. We elaborate state-of-the-art methods used by a number of research papers to overcome above-mentioned hurdles in order to achieve decimeter level accuracy which will benefit a plethora of applications. We also intend to make the interested readers aware of possible improvements that can be done to make the existing work even better.