Foundations for Energy-Aware Zero-Energy Devices: From Energy Sensing to Adaptive Protocols

TL;DR

This paper provides a comprehensive overview of modeling components, trade-offs, and design guidelines for energy-aware protocols in zero-energy devices, aiming to enhance their sustainability and operational efficiency.

Contribution

It offers a structured analysis of energy information acquisition, task variability, and storage dynamics, filling gaps in existing models and proposing design insights for ZED protocols.

Findings

Dissects energy information acquisition methods and costs

Analyzes core operational task energy usage

Provides design guidelines for energy-aware protocols

Abstract

Zero-energy devices (ZEDs) are key enablers of sustainable Internet of Things networks by operating solely on harvested ambient energy. Their limited and dynamic energy budget calls for protocols that are energy-aware and intelligently adaptive. However, designing effective energy-aware protocols for ZEDs requires theoretical models that realistically reflect device constraints. Indeed, existing approaches often oversimplify key aspects such as energy information (EI) acquisition, task-level variability, and energy storage dynamics, limiting their practical relevance and transferability. This article addresses this gap by offering a structured overview of the key modeling components, trade-offs, and limitations involved in energy-aware ZED protocol design. For this, we dissect EI acquisition methods and costs, characterize core operational tasks, analyze energy usage models and storage constraints, and review representative protocol strategies. Moreover, we offer design insights and guidelines on how ZED operation protocols can leverage EI, often illustrated through selected in-house examples. Finally, we outline key research directions to inspire more efficient and scalable protocol solutions for future ZEDs.