Title: IoT Localization for Bistatic Passive UHF RFID Systems with 3D Radiation Pattern,
Abstract: Passive Radio-Frequency IDentification (RFID) systems carry critical
importance for Internet of Things (IoT) applications due to their energy
harvesting capabilities. RFID based position estimation, in particular, is
expected to facilitate a wide array of location based services for IoT
applications with low-power requirements. In this paper, considering monostatic
and bistatic configurations and 3D antenna radiation pattern, we investigate
the accuracy of received signal strength based wireless localization using
passive ultra high frequency (UHF) RFID systems. The Cramer-Rao Lower Bound
(CRLB) for the localization accuracy is derived, and is compared with the
accuracy of maximum likelihood estimators for various RFID antenna
configurations. Numerical results show that due to RFID tag/antenna
sensitivity, and the directional antenna pattern, the localization accuracy can
degrade at blind locations that remain outside of the RFID reader antennas'
main beam patterns. In such cases optimizing elevation angle of antennas are
shown to improve localization coverage, while using bistatic configuration
improves localization accuracy significantly.