Source-linked AI summary
Wireless Technologies for Agricultural Monitoring using Internet of Things Devices with Energy Harvesting Capabilities
Sebastian Sadowski, Petros Spachos
TL;DR
Agricultural IoT monitoring must operate where electricity is unavailable, making energy use and node lifetime important design concerns. The paper compares Zigbee, LoRaWAN, and WiFi in solar-energy-harvesting monitoring systems, finding LoRaWAN most suitable when power consumption and network lifetime are priorities.
Problem
Outdoor agricultural IoT and WSN nodes often rely on batteries because electricity is not readily available, creating power and lifetime concerns.
Method
The study experimentally compares Zigbee, LoRaWAN, and WiFi using identical agricultural monitoring systems with solar energy harvesting.
Results
LoRaWAN was the ideal technology, functioning for the longest period before failing, followed by Zigbee and WiFi.
Takeaways & Limitations
The experimental results can guide wireless-technology selection for agricultural monitoring when power consumption and network lifetime are important.
Takeaways & Limitations
Estimated and actual lifetimes differed, partly because LiPo batteries have nonlinear discharge rates and power converters can stop operation to prevent over-discharge.
Abstract
from arXiv · showhide
Technological advances in the Internet of Things (IoT) have lead the way for technology to be used in ways that were never possible before. Through the development of devices with low-power radios, Wireless Sensor Networks (WSN) can be configured for almost any type of application. Agricultural has been one example where IoT and WSN have been able to increase productivity, efficiency, and output yield. Systems that previously required manual operation can be easily replaced with sensors and actuators to automate the process such as irrigation and disease management. Powering these devices is a concern as batteries are often required due to devices being located where electricity is not readily available. In this paper, a comparison is performed between three wireless technologies: IEEE 802.15.4 (Zigbee), Long Range Wireless Area Network (LoRaWAN), and IEEE 802.11g (WiFi 2.4~GHz) for agricultural monitoring with energy harvesting capabilities. According to experimental results, LoRaWAN is the optimal technology to use in an agricultural monitoring system where power consumption and network lifetime are a priority. The experimental results can be used for the selection of wireless technology for agricultural monitoring following application requirements.
1. Introduction
Agricultural IoT and WSN systems can improve monitoring and farming efficiency, but outdoor nodes face battery and power constraints. This work compares three wireless technologies in solar-powered agricultural monitoring and identifies LoRaWAN as the preferred option when power consumption and network lifetime matter.
- Agricultural monitoring with IoT and WSN can support precision agriculture by improving crop and livestock management, efficiency, and cost control.
- Outdoor agricultural sensor nodes commonly require batteries because electricity is not readily available, making battery replacement or recharging a major concern.
- The study compares Zigbee, LoRaWAN, and WiFi using identical agricultural monitoring systems with solar energy harvesting capabilities.
- The work combines a prototype, three experiments across different seasons, and power-requirement analysis to inform wireless-technology selection.
- LoRaWAN is identified as the optimal wireless technology for agricultural monitoring when power consumption and network lifetime are priorities.
2. Related Work
Prior agricultural monitoring research has used wireless technologies, energy harvesting, routing, and adaptive sampling to extend system operation. The paper addresses a stated lack of comparisons among wireless technologies for agricultural applications by evaluating Zigbee, LoRaWAN, and WiFi together.
- Prior literature commonly pursued longer network lifetime through renewable energy or energy-saving techniques, while this work extends that focus to wireless-technology selection.
- Earlier agricultural systems selected WiFi for low cost and throughput or Zigbee for low cost, readily available components, and reduced transmit power.
- Related studies used solar harvesting, wireless charging, energy management, and specialized circuits to extend sensor-node operation under variable energy conditions.
- Other work improved energy use through adaptive sampling, routing protocols, and solar-powered relay nodes in agricultural monitoring deployments.
- The paper identifies limited prior research comparing different wireless technologies for agricultural applications and proposes a three-technology comparison.
3. System Framework
The system framework compares Zigbee, LoRaWAN, and WiFi sensor nodes using matched agricultural-monitoring hardware and power-related parameters. The comparison considers throughput, transmission range, current consumption, and estimated node or relay lifetime.
- 3.1. Components: Three otherwise comparable sensor nodes use an Arduino Uno, power converter, rechargeable battery, solar panel, soil-moisture sensor, and different communication units.Zigbee uses an XBee, LoRaWAN a Dragino LoRa Shield, and WiFi a CC3000 WiFi Shield.
- 3.2. System Parameters: LoRaWAN reaches up to 15000 m in line of sight, compared with 120 m for Zigbee and 50 m for WiFi.LoRaWAN operates at 915 MHz, while the cited WiFi implementation uses IEEE 802.11g.
- 3.2. System Parameters: WiFi provides the highest throughput at 54 Mbit/s, followed by Zigbee at 250 kbit/s and LoRaWAN at 50 kbit/s.These values summarize the technologies compared in the system framework.
- 3.2. System Parameters: The framework evaluates current consumption, sampling frequency, transmission interval, and transmission power as parameters affecting power consumption.The system also estimates monitoring-node and relay-node lifetime under the configured technology choices.
- 3.2. System Parameters: A longer transmission range can reduce the number of monitoring or relay nodes needed to cover an agricultural field.The framework links range selection with node deployment and power-supply longevity considerations.
4. Experimental Procedure
The experiments compare identical outdoor sensor nodes that differ only in wireless communication technology under controlled sampling and transmission settings. Four battery-drain experiments include one without harvesting and three with solar harvesting across different months.
- 4.1. Experimental Setup: Identical nodes were tested outdoors with different wireless communication methods while their solar panels received similar daily solar exposure.Testing took place at the University of Guelph Engineering Building roof research lab.
- 4.1. Experimental Setup: Nodes sampled battery charge at 1 Hz and transmitted the information every 1 s.These settings were selected to increase power use and shorten the time until systems ceased functioning.
- 4.2. Experiments: Four experiments drained each system until its power supply was exhausted: one without harvesting and three with harvesting.The harvesting experiments occurred in August 2018, December 2018, and May 2019.
- 4.2. Experiments: The three harvesting experiments used different months to demonstrate system operation under varying amounts of sunlight caused by uncontrollable weather conditions.Before testing, the batteries connected to the nodes were fully charged.
- 4.3. Current Measurement: A Monsoon Power Monitor measured device current after each node was powered and warmed up until fully operational.Current values were recorded over two minutes, and the instrument could estimate lifetime for a selected battery size.
5. Results and Discussion
Experiments comparing Zigbee, LoRaWAN, and WiFi in agricultural monitoring found that LoRaWAN generally provided the longest runtime, while solar benefits depended on sunlight and technology.
- 5.2. Discussion: Estimated lifetimes were not accurate in the first comparison because nonlinear battery discharge and converter cutoff affected real-world runtimes.The observed runtimes were 80.28 h for Zigbee, 166.23 h for LoRaWAN, and 29.06 h for WiFi.
- 5.2. Discussion: Solar harvesting increased node lifetime, but the benefit varied with available sunlight across the experiments.The August experiment supplied substantial energy, December supplied little energy, and May fell between them.
- 5.2. Discussion: WiFi gained approximately 1 h from energy harvesting because its power consumption drained the battery too quickly.Solar panels provided substantially more benefit to the Zigbee and LoRaWAN systems than to WiFi.
- 5.2. Discussion: Wireless choice involves a throughput, range, and power trade-off: WiFi favors high-throughput short-distance transmission, while LoRaWAN favors long distance with minimal power.Zigbee offers slightly higher throughput than LoRaWAN, but with reduced range; its nodes can be configured and meshed easily.
6. Conclusions
The paper experimentally compares three wireless technologies in outdoor agricultural monitoring systems with rechargeable batteries and energy harvesting. LoRaWAN functioned longest, but throughput and other application requirements also matter when selecting a technology.
- 6. Conclusions: Identical outdoor systems compared Zigbee, LoRaWAN, and WiFi by the lifetime of their sensor nodes.The systems used rechargeable batteries and different wireless technologies while performing the same monitoring tasks.
- 6. Conclusions: LoRaWAN was the most suitable technology by runtime, followed by Zigbee and then WiFi.The conclusion identifies LoRaWAN as functioning for the longest period before failure.
- 6. Conclusions: Wireless selection should also consider throughput and other application requirements, because WiFi transmits more information despite poor power consumption.The results are presented as an indicator for selecting wireless technology in agricultural monitoring systems with energy harvesting.