Drones could be used to connect smart sensors to the IoT, according to researchers at the King Abdullah University of Science & Technology (Kaust) in Saudi Arabia.
 
The researchers have shown that using drones, or unmanned aerial vehicles (UAVs), to fly between clusters of IoT objects to collect their data could be highly efficient.
 
“IoT networks will revolutionise the way we monitor, control and communicate with everything around us,” says Osama Bushnaq (pictured right), a PhD student in the laboratory of associate professor Tareq Al Naffouri (pictured left).
 
For example, crop fields could be filled with sensors that monitor water and nutrient levels. Networks of sensors that detect wildlife could also be deployed.
 
“To enable IoT networks, a huge number of low-cost, self-powered sensors are needed,” Bushnaq said.
 
Traditional wireless data transfer is unsuitable for this purpose due to the limited power supply of each sensor and the complexity of connecting so many devices.
 
Sending UAVs to gather data via low-power, short-range transmission could be an alternative, transferring the burden of data aggregation from each individual sensor to a single machine that can autonomously return to base for recharging. The challenge comes in calculating the most efficient approach to data collection to reduce mission time and increase productivity.
 
“Imagine a field randomly covered with IoT sensors,” Bushnaq said. “Covering a small area of the field at each hovering location improves communication between the UAV and the devices, reducing data aggregation time.”
 
However, the UAV needs to spend more time traveling between all the IoT devices in the field. Reducing the total mission time involves optimising UAV coverage area, the number and location of hovering locations, and the UAV’s path between each location.
 
The team split the problem into components. For a given number of hovering locations, the team first calculated where the optimal hovering locations would be. They then applied the classic Traveling Salesman computer science problem to identify the best route between locations and optimised the data transmission rate.
 
“The process is repeated for different numbers of hovering locations until an optimal trade-off between hovering and traveling times is obtained,” Bushnaq said.
 
The approach cut the mission time by up to ten times for a field of 100 square metres. The team is currently testing the idea of using UAVs with IoT sensors for fire detection.
 
“We are studying how such a system can be used for forest fire detection and the trade-off between system cost and fire detection reliability,” Al Naffouri said.