RFID radar tag system design using ultrawideband noise waveforms.

摘要

Radio frequency identification (RFID) tags are small electronic devices working in the radio frequency range. They use wireless radio communications to automatically identify objects or people without the need for line-of-sight or contact, and are widely used in inventory tracking, object location, environmental monitoring due to their low cost, small size, and wireless functionality.;This dissertation explores the application of active RFID tags in outdoor environments responding to random noise radar interrogations with pre-determined messages. A conceptual system design for communication between radar and RFID tags using ultrawideband (UWB) noise waveforms is proposed and analyzed theoretically and via simulations. The tag structure comprises a sensing receiver and active receiver/transmitter. The sensing receiver senses the radar header consisting of a pre-arranged secret realization of the noise waveform. The active receiver/transmitter modulates the RFID tag's message onto the radar interrogation signal through weighted tapped delays and reradiates the tag message back to the radar. System performance is evaluated in terms of symbol error probability in an additive white Gaussian noise (AWGN) channel. An algorithm to combat multipath interferences on the RFID tag--to--radar link is presented. It is shown that this system is capable of communicating a suite of messages from the tags to the radar.;This dissertation also explores the application of active RFID tags in target discovery and information routing in the RFID networks. The design of a covert RFID tag network for target discovery and target information routing is presented. In the design, a static or very slowly moving target in the field of RFID tags transmits a distinct pseudo-noise signal, and the RFID tags in the network collect the target information and route it to the command center. A map of each RFID tag's location is saved at command center, which can determine where a RFID tag is located based on each RFID tag's ID. The target information collection method with target association and clustering, and the information routing algorithm within the RFID tag network are proposed. The design and operation of the proposed algorithms are illustrated through examples. Simulation results demonstrate the effectiveness of the design.