Augmenting IoT networks with backscatter-enabled passive sensor tags

TLDR

IoT sensing modalities are typically fixed at deployment, and adding new sensors afterward is difficult because it requires hardware modification or maintenance of additional devices. The authors propose passive, battery‑free sensor tags that can be added to existing IoT deployments without altering the original hardware. These tags use backscatter communication that is compatible with the network’s radio protocol and requires no extra infrastructure; an FPGA‑based prototype demonstrates connectivity with unmodified 802.15.4 devices. Early experiments with the prototype confirm that the approach is feasible.

Abstract

The sensing modalities available in an Internet-of-Things (IoT) network are usually fixed before deployment, when the operator selects a suitable IoT platform. Retrofitting a deployment with additional sensors can be cumbersome, because it requires either modifying the deployed hardware or adding new devices that then have to be maintained. In this paper, we present our vision and work towards passive sensor tags: battery-free devices that allow to augment existing IoT deployments with additional sensing capabilities without the need to modify the existing deployment. Our passive sensor tags use backscatter transmissions to communicate with the deployed network. Crucially, they do this in a way that is compatible with the deployed network's radio protocol, and without the need for additional infrastructure. We present an FPGA-based prototype of a passive sensor tag that can communicate with unmodified 802.15.4 IoT devices. Our initial experiments with the prototype support the feasibility of our approach. We also lay out the next steps towards fully realizing the vision of passive sensor tags.