Virtualized Controller for Computational RFID-based IoT Sensors.

This paper presents a Computational Radio Frequency Identification (CRFID) system that utilizes far-field RF for sensing, computing, and self-powering. We created a virtual environment that uses radio frequency to transmit SPI instructions and enable wireless control of the RFID-based IoT sensors. Our system tackles the issue of energy constraints on RFID-based IoT sensors by transferring the computation load from the tag sensor to the reader, accomplished by the virtualization of SPI functions over the RF channel. This virtualization of functions enables the design of a circuit without a microcontroller, providing greater flexibility and allowing for wireless reconfiguration of tag functions over RF using wireless SPI instructions, even after deploying the devices for operation. Furthermore, the results demonstrate a 97% reduction in energy consumption compared to other energy-harvesting RFID tags with microcontrollers. As a result, the saved power budget, previously allocated to power the tag's microcontroller, is now used to power the tag sensors without requiring batteries, thus maximizing the efficiency of the harvested RF power. The solution proposed in this work integrates an RFID reader, Tx antenna, and RFID tag with an advanced virtualized controller to achieve a cost-effective and ultra-low-power solution combined with a full-scale computational capacity.