On Remote Temperature Sensing Using Commercial UHF RFID Tags

With the fast-growing adoption of the radio-frequency identification (RFID) technology, RFID-based sensors have attracted great interest. Due to the limitation of RFID tags, most existing RFID-based temperature sensing works rely on hardware modification, which increases the cost and hampers its deployment. In this article, we propose RFThermometer, a remote temperature sensing system with commercial ultra high frequency (UHF) RFID tags. We first investigate the effect of temperature on RFID phases. To alleviate the precision deterioration caused by missing phase measurements, a tensor completion method is proposed to restore missing phases and a Gaussian process model is leveraged to construct a phase-temperature map in the offline stage. In the online stage, the unknown temperature is estimated by a dynamic time warping (DTW)-based greedy method. Extensive experimental results are presented to validate the performance of RFThermometer with off-the-shelf RFID devices.