Remote Firmware Execution Control in Computational RFID Systems

Computational RFID (CRFID) tags are an emerging class of UHF RFID tags, which are capable of communication, sensing, and computation. However, their computational units are pre-programmed to execute a specific task and cannot change their execution flow during runtime. They require a wired interface to reinstall a new firmware, which strictly limits their use. We address this issue by remotely changing the behavior of CRFIDs by switching their firmware during runtime through commercial RFID reader, without any modification to either CRFID tags or EPC protocol. We present the design, implementation, and evaluation of FirmSwitch-a wireless scheme that equips CRFIDs with the capability of switching amongst pre-installed firmwares during runtime. To achieve this goal, we wirelessly pass the encoded instructions to CRFID tag through RFID reader, which leverages the CRFID tags to switch among firmwares and execute them for intended cycles. For concept validation, three prototype tags belonging to two CRFID categories are evaluated. The results show that FirmSwitch incurs an overall switching delay of 5-35.7 ms, and a minimal energy overhead of 48.7 nJ-69.3 μJ. The success rate of 95% is achieved at the interrogation range of a half meter with no retransmission.