Zero-energy Devices for 6G: Technical Enablers at a Glance

TL;DR

This paper reviews the technical enablers for zero-energy IoT devices in 6G networks, focusing on energy harvesting, low-power communication, and innovative protocols, highlighting challenges and future research directions.

Contribution

It provides a comprehensive overview of the key technologies, challenges, and open research issues for implementing zero-energy devices in next-generation mobile networks.

Findings

Identified main characteristics and enabling technologies of ZEDs.

Discussed potential approaches like TinyML and RF wireless power transfer.

Presented an experimental proof-of-concept for ambient cellular backscattering.

Abstract

Low-cost, resource-constrained, maintenance-free, and energy-harvesting (EH) Internet of Things (IoT) devices, referred to as zero-energy devices (ZEDs), are rapidly attracting attention from industry and academia due to their myriad of applications. To date, such devices remain primarily unsupported by modern IoT connectivity solutions due to their intrinsic fabrication, hardware, deployment, and operation limitations, while lacking clarity on their key technical enablers and prospects. Herein, we address this by discussing the main characteristics and enabling technologies of ZEDs within the next generation of mobile networks, specifically focusing on unconventional EH sources, multi-source EH, power management, energy storage solutions, manufacturing material and practices, backscattering, and low-complexity receivers. Moreover, we highlight the need for lightweight and energy-aware computing, communication, and scheduling protocols, while discussing potential approaches related to TinyML, duty cycling, and infrastructure enablers like radio frequency wireless power transfer and wake-up protocols. Challenging aspects and open research directions are identified and discussed in all the cases. Finally, we showcase an experimental ZED proof-of-concept related to ambient cellular backscattering.