Ubiquitous computing refers to providing a global computing service where the user access seamlessly resources. User tracking is one of the most important location-aware applications for maintaining the service even with the users' mobility.Unlike outdoor localization technologies like GPS, indoor localization systems have to encounter many problems such as interferences from external sources, low cost and low latency infrastructure requirements, and high accuracy in a limited space.Our localization approaches associate with technologies that are currently equipped in mobile devices, including NFC technology and inertial sensors and Wireless LAN. The aim of this thesis is to design simple and effective architecture ensuring two requirements: a high accuracy and an adaptation to the multiple scenarios. Therefore, our proposed system does not address to the fingerprint technique and learning machine algorithms. In this thesis, we propose three approaches as follows:- The NFC-tagging approach is an instant on-the-spot localization with almost zero-latency- A combination of accelerometer and magnetometer in the sensors-based approach permits to characterize the user's movement- The signal-strength-based approach using the similarity of radio conditions between the neighbors can update in real time the radio map for long period localization.We analyze the performance of the proposed approaches based on rigorous simulation and experimentation tests. We then implement the proposed approaches in a wireless testbed with Android smartphone. Although the implementation is not a final product, the current application can be used to evaluate the feasibility and the performance of the proposed approaches.
