Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Integrating Battery-Less Energy Harvesting Devices in Multi-hop Industrial Wireless Sensor Networks

Dries Van Leemput, Jeroen Hoebeke, Eli De Poorter

TL;DR

The paper tackles the challenge of integrating battery-less energy harvesting devices into multi-hop industrial wireless sensor networks, where intermittent power from supercapacitors disrupts joining and synchronization. It proposes three strategies—synchronized communication, ad-hoc joining, and non-synchronized communication—to mitigate intermittency by either aligning workload with energy availability or offloading workload to routers. Through an energy feasibility model and platform-specific parameters, it derives storage and power requirements (e.g., $>100 mF$ for synchronization, $~130-150 uW$ for ad-hoc joining, and $~100 uF$ for non-synchronized operation) and analyzes latency and reliability implications across harvesting sources such as RF, vibration, and solar. The results offer practical guidance for deploying battery-less devices in regulated industrial environments, outlining use-case scenarios and trade-offs to balance network performance, energy availability, and maintenance requirements.

Abstract

Industrial wireless sensor networks enable real-time data collection, analysis, and control by interconnecting diverse industrial devices. In these industrial settings, power outlets are not always available, and reliance on battery power can be impractical due to the need for frequent battery replacement or stringent safety regulations. Battery-less energy harvesters present a suitable alternative for powering these devices. However, these energy harvesters, equipped with supercapacitors instead of batteries, suffer from intermittent on-off behavior due to their limited energy storage capacity. As a result, they struggle with extended or frequent energy-consuming phases of multi-hop network formation, such as network joining and synchronization. To address these challenges, our work proposes three strategies for integrating battery-less energy harvesting devices into industrial multi-hop wireless sensor networks. In contrast to other works, our work prioritizes the mitigation of intermittency-related issues, rather than focusing solely on average energy consumption, as is typically the case with battery-powered devices. For each of the proposed strategies, we provide an in-depth discussion of their suitability based on several critical factors, including the type of energy source, storage capacity, device mobility, latency, and reliability.

Integrating Battery-Less Energy Harvesting Devices in Multi-hop Industrial Wireless Sensor Networks

TL;DR

The paper tackles the challenge of integrating battery-less energy harvesting devices into multi-hop industrial wireless sensor networks, where intermittent power from supercapacitors disrupts joining and synchronization. It proposes three strategies—synchronized communication, ad-hoc joining, and non-synchronized communication—to mitigate intermittency by either aligning workload with energy availability or offloading workload to routers. Through an energy feasibility model and platform-specific parameters, it derives storage and power requirements (e.g., for synchronization, for ad-hoc joining, and for non-synchronized operation) and analyzes latency and reliability implications across harvesting sources such as RF, vibration, and solar. The results offer practical guidance for deploying battery-less devices in regulated industrial environments, outlining use-case scenarios and trade-offs to balance network performance, energy availability, and maintenance requirements.

Abstract

Industrial wireless sensor networks enable real-time data collection, analysis, and control by interconnecting diverse industrial devices. In these industrial settings, power outlets are not always available, and reliance on battery power can be impractical due to the need for frequent battery replacement or stringent safety regulations. Battery-less energy harvesters present a suitable alternative for powering these devices. However, these energy harvesters, equipped with supercapacitors instead of batteries, suffer from intermittent on-off behavior due to their limited energy storage capacity. As a result, they struggle with extended or frequent energy-consuming phases of multi-hop network formation, such as network joining and synchronization. To address these challenges, our work proposes three strategies for integrating battery-less energy harvesting devices into industrial multi-hop wireless sensor networks. In contrast to other works, our work prioritizes the mitigation of intermittency-related issues, rather than focusing solely on average energy consumption, as is typically the case with battery-powered devices. For each of the proposed strategies, we provide an in-depth discussion of their suitability based on several critical factors, including the type of energy source, storage capacity, device mobility, latency, and reliability.
Paper Structure (14 sections, 5 figures, 1 table)

This paper contains 14 sections, 5 figures, 1 table.

Table of Contents

  1. Introduction
  2. Multi-hop Industrial wireless sensor networks and Intermittency
  3. Strategy 1: synchronized communication
  4. Joining Optimizations
  5. Synchronization Optimizations
  6. Use cases
  7. Strategy 2: Ad-hoc joining
  8. Joining Optimizations
  9. Use cases
  10. Strategy 3: Non-synchronized communication
  11. Implementation Challenges
  12. Use Cases
  13. Performance Analysis
  14. Conclusions

Figures (5)

  • Figure 1: Intermittent on-off behavior of a battery-less device. The supercapacitor is charged by the energy source to the turn-on threshold, permitting the device to turn on and execute tasks. This depletes the supercapacitor until the turn-off threshold is reached, forcing the device to power off and allowing the supercapacitor to be recharged by the energy source.
  • Figure 2: Synchronized communication including joining and synchronization. Battery-less devices join the network during bootstrap and periodically synchronize with a nearby router. Joining comprises scanning for beacons, protocol-dependent control messages, and multi-hop authentication with the border router (including a Join Request and Join Response required in all standards). Data transmission and optional reception occur during dedicated timeslots.
  • Figure 3: Ad-hoc joining without periodical synchronization. Whenever the battery-less device needs to send an update or sufficient energy is available, it rejoins the network until data is transmitted/received. Afterward, it disconnects and powers off to save and harvest energy.
  • Figure 4: Non-synchronized communication without joining and synchronization. The EH node does not join the network, but posts data non-synchronized and powers off immediately. Nearby routers alternate between scanning and TSCH to provide full coverage in time and frequency at each location to receive data, requiring tight coordination and dense network deployment.
  • Figure 5: Analysis of the minimal interval between transmissions (lower is better) for different types of energy sources for each proposed strategy. For each strategy, the impact of one optimization is shown in dotted lines: increased synchronization interval, hierarchical network management, and increased capacitance. For the synchronized approach, train vibrations and solar panels (indoor and outdoor) are suitable energy sources, whereas devices employing the ad-hoc joining or non-synchronized approaches can also be powered using machine vibrations and outdoor RF, depending on the desired transmission interval.