Toward a Low-Cost Software-Defined UHF RFID System for Distributed Parallel Sensing

This article presents the design and implementation of a low-cost software-defined radio-frequency identification (RFID) system for distributed parallel sensing. We aim to implement essential sensing functionalities with low-cost commodity radio components and provide full access to physical layer raw data (e.g., PHY samples of backscatter signals) to enable various RFID sensing applications at low implementation cost. The proposed solution is built in a distributed way where the functionalities of interrogating RFID tags and receiving their backscattered signals are separated into two modules, which naturally supports distributed parallel sensing. A set of innovative techniques is developed, e.g., packet-in-packet communication, carrier frequency offset (CFO) cancellation, self-interference cancellation, etc., to address a range of practical challenges, including RFID command generation with cross technology communication, real-time correction of CFO, etc. We present three case studies enabled by the proposed solution, which demonstrates its applicability and potential of boosting RFID sensing research by substantially cutting the implementation cost of software-defined RFID sensing system.