Comparison of POA and TOA based ranging behavior for RFID application

RFID can play great roles in future context-aware applications such as ambient intelligence and internet of things. Ranging technology will be one of interesting topics for RFID application. In the paper we compare the phase of arrival (POA) and time of arrival (TOA) based ranging behavior for RFID application. We characterize the ranging behaviors from the view of Cramer-Rao lower bounds (CRLB), ray tracing and empirical measurements. First, we analyze and compare the CRLB for POA and TOA based ranging in AWGN environment theoretically. Second, we use ray tracing method to model the distance and bandwidth influence on POA and TOA based RFID ranging in multipath environment. Third, we perform measurement to validate the noise and multipath influence on POA and TOA based RFID ranging. The parameters in ray tracing and measurements are also provided to further support the behavior comparison between TOA and POA ranging. The results show that in short range application such as RFID, POA based ranging has a comparatively better performance than TOA. It will benefit the future selection of POA or TOA technique, narrowband or wideband ranging method regarding specific scenarios for RFID application.