In July 2019, a new world record was set when 24 LoRaWAN gateways simultaneously received a message transmitted by a node and one of the gateways resided at a distance of 766 kilometers from the node. The previous record was 702 kilometers. The new record was set by a team from the University of Zaragoza.
ibercivis held the event in July to explore the upper atmosphere through hot air balloons. Teachers, students and volunteers were invited to participate in the event. Each balloon was equipped with multiple sensors to measure different parameters in the stratosphere. The event was not intended to break or set any records.
For communication purposes (between balloon and base station) LoRaWAN technology was used. The low power consumption and wide area/network coverage is what makes the technology attractive to researchers and organizers.
In total, 7 balloons were launched from the Alfamen base station in Spain. One of the balloons, named “Diana I” by the computer engineering research group at the University of Zaragoza, transmitted a message while flying at an altitude of 24.8 kilometers. The message was successfully received and decoded by the gateway installed at an altitude of 2,253 kilometers and located 766 kilometers from “Diana I”.
The “Diana I” node was composed of a BME280 temperature, humidity and barometric pressure sensor together with a GPS tracker module. The Diana-I node transmitted the message in just 25mW. Theoretically, according to SEMTECH (the LoRaWAN developer academy), the maximum achievable distance in Europe from LoRaWAN at the cost of 25mW is 800 kilometers under ideal conditions (line of sight, temperature).
What paved the way?
The gateway that successfully received and decoded the message was installed in a snowy mountain resort at an altitude of 2,253 km. The node/balloon was flying at an altitude of 24.8 km. The height difference between the node and the gateway was 22.5 km, and there was no solid object between the node and the gateway, so the line-of-sight condition was met. The easiest way to achieve high sensitivity in radio planning is to increase the antenna height. The same principle was put into practice in the above scenario.
Interestingly, the atmospheric temperature at the node was recorded at -16.5 degrees Celsius. At this temperature, LoRaWAN radio waves at 154dB would not be expected to travel a distance of 766 km. However, the theoretical limit of 800 km can be met or even exceeded.
Achievable data rate
The data rate depends on many factors, for example, antenna type, line of sight, payload, frequency, capacitance, oscillator, etc. In the case of LoRaWAN, you can look at it this way. Everything has a cost, so if power is reduced, so will the data rate.
- Minimum 250 bits per second
- Maximum 50 kilobits per second
You cannot transfer files or play media via LoRaWAN. LoRaWAN is only suitable for sensor and actuator control, such as tank water level monitoring, parking space or garage monitoring, wildlife detection, and security alarms.
Where can parts be purchased for the DIY LoRaWAN project?
BME280: Mouser-BME280=
GPS: GPS-Mouser
LoRaWAN: LoRa Node (915Mhz-American standard)
LoRaWAN: LoRa Gateway (American standard 915Mhz)
