RFID is an emerging technology, which is widely used in many areas, especially in tracking and localization for ubiquitous computing. Since the principles are quite different, the applications of localization of active and passive RFID tags make a great difference. In my research, both types are considered. To enable the pervasive usage of RFID systems in practice, a lot of challenges should be solved, including uncertain characteristics of RF signal in an indoor environment, blocking effects by moving objects and stochastically suitable reading performance of passive tags for different power levels. For dealing with above issues, I develop theoretical principles and design practical algorithms. In VIRE, I proposed the 'virtual reference tag' concept for the active RFID system. The Rece...[ Read more ]

RFID is an emerging technology, which is widely used in many areas, especially in tracking and localization for ubiquitous computing. Since the principles are quite different, the applications of localization of active and passive RFID tags make a great difference. In my research, both types are considered. To enable the pervasive usage of RFID systems in practice, a lot of challenges should be solved, including uncertain characteristics of RF signal in an indoor environment, blocking effects by moving objects and stochastically suitable reading performance of passive tags for different power levels. For dealing with above issues, I develop theoretical principles and design practical algorithms. In VIRE, I proposed the 'virtual reference tag' concept for the active RFID system. The Received Signal Strength Indicators (RSSI) value in each subarea is obtained by the liner interpolation scheme. The uncertain RSSI problem is solved by real time matching. For dealing with the blocking effect, we proposed the trajectory detection method. Employing the special temporal sequence of affected tags, we rebuild the trace of an object. The experimental results of our attachment free approach show that the frequent trajectory can be captured. To do the localization of the passive RFID system, I propose a relative positioning method, which is a range-free approach. Since the energy of the reader is limited, our method also is an energy efficient approach. Through implementations in real RFID systems, I evaluate my approaches and compare them with previous works. The results show the effectiveness and accuracy of my methods. The proposed approaches can be further applied to other application scenarios.