A recent study showed that by 2020, 22 billion devices will be connected to one of the biggest IoT Networks. This IoT Network will be low cost, low bandwidth, and mostly deployed on license-free frequencies. Its main goal will be to ensure communication between devices, in a message-based context.
The connectivity of all those devices will have to be compliant with a large number of constraints…
- Local Connectivity with no power requirement (WLAN, Wi-Fi, Bluetooth)
- Local Connectivity with low power requirement (ZigBee, Z-Wave, Bluetooth-LE)
- Wan Connectivity with no power requirement (WWAN / LTE/ 3G) (Costly monthly cost)
- Wan Connectivity with low power requirements (Lora, SigFox, Dash7)
… in order to bring the messaging capability to a great number of day-to-day devices:
- The fridge or any domestic appliance, can alert the manufacturer in case of failure (predictive maintenance)
- Water meter / electrical meter /… can be monitored without any human intervention
- In a restaurant, bottles of gas level can be monitored so that they can be replaced in advance, without any intervention from the restaurant.
- Device tracking, temperature, pollution, …
In this article, we will discuss the Low Power / Long Range usecases.
LoRaWAN (Low Power Wide Area Network)
Classes of Objects
To enable rapid and uncongestioned data communication, there are 3 classes of objects: classes A, B and C.
Class A devices are mostly used to communicate from the device to the network, at the device discretion. A device will for example monitor the temperature of a fridge, send hourly temperature reports, and if the temperature changes, send an unscheduled report. The device is therefore unreachable by the network, until the device decides to send a message, and only then, with the ACK (acknowledge), the network will be able to post a message, most of the time configuration items.
Class B devices act like a Class A device, but then will additionally, schedule a listening planning. At regular intervals, exchanged with the LoRa server previously, the device will awake and listen for eventual data communication from the network, this could be to activate a pump, or any other device as well as read a value.
Class C Devices listen to the network all the time, and they are able to receive direct orders. We could imagine a usage like turning on the street light when someone is detected in the neighborhood