What is LoRaWAN?
LoRaWAN is the long-range, low-power radio network that carries readings from your CropWatch sensors to a gateway, and from there to the cloud.
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LoRa is a radio technique designed to send small amounts of data over long distances using very little energy. That is why a sensor can run on a battery for a long time and still reach a gateway on the far side of a farm.
- Range: from hundreds of metres to several kilometres, depending on terrain and obstacles
- Data: small messages, such as one temperature reading, sent at intervals rather than continuously
- The sensor takes a reading and sends it by radio.
- Any gateway in range receives it and forwards it over the internet.
- The network server checks the message and passes it to CropWatch.
- CropWatch stores the reading and shows it on your dashboard.
Sensors do not connect to your Wi-Fi. They only talk through a LoRaWAN gateway.
- LoRaWAN (Class A) is a connectionless / no persistent gateway connection, this means it does not need to maintain a connection to the gateway to continue sending data.
- WiFi on the other hand is a persistent access point association while connected, this means it needs to keep it's login, ip, connection intact while connected, lossing it's "state" would request in the need to re-connect using valuable power on time and power.
This allows LoRaWAN devices to wake quickly, send data, and sleep quickly. WiFi needs to wake, send a password, wait for a response, and get connection information. This eats device activity time, and that means device battery power.
Height, obstacles and distance matter most. Buildings, metal structures, hills and dense vegetation all shorten the range. A well-placed gateway makes the biggest difference: see Choosing a mounting location.
A perfect placement would be at the edge of a very tall location, no obstructions between the gateway and the transmitting devices.
Note how the gateway is at the corder of the building, preventing the building's walls from blocking it on both the left, and right side. Only the back of the building will have reduced signal coverage, but that is not the target location.