Underground Wireless Data Transmission Using 433-MHz LoRa for Agriculture

Area of Science:

• Agricultural Engineering
• Wireless Communication Systems
• Sensor Networks

Background:

• Wireless underground sensor networks (WUSNs) offer damage-resistant, real-time data collection for agriculture and industry.
• Soil's dielectric properties and moisture content pose significant challenges for underground radio communication.
• Existing Low-Power Wide-Area Network (LPWAN) technologies are primarily designed for aboveground applications.

Purpose of the Study:

• To evaluate the feasibility of 433-MHz LoRa-based wireless communication for both underground-to-underground (UG2UG) and underground-to-aboveground (UG2AG) scenarios.
• To assess the impact of soil properties and operational parameters on WUSN performance.
• To determine the potential for developing WUSNs for agricultural applications.

Main Methods:

• Development of a 433-MHz LoRa-based testbed for WUSN evaluation.
• In situ testing in four different soil types, assessing both UG2UG and UG2AG communication.
• Analysis of factors influencing signal quality and transmission distance, including burial depth, power, data rate, and antenna type.

Main Results:

• UG2UG communication achieved maximum transmission distances of 4-20 meters, highly dependent on soil type.
• UG2AG communication demonstrated significantly greater reach, with distances of 100-200 meters, influenced by operational variables and soil properties.
• Signal quality and transmission range were notably affected by transmitter burial depth, power, data rate, and receiver antenna type.

Conclusions:

• 433-MHz LoRa-based UG2AG WUSNs are readily achievable for agricultural applications with optimized power management.
• UG2UG WUSN applications face substantial limitations due to current transmission distance constraints.
• Further research is needed to enhance transmission capabilities for robust UG2UG WUSN deployments.