Academy for LoRaWAN®

While building your solution, it is essential to keep in mind how much airtime you consume. Airtime is the time that a single end device uses to send and receive a packet of data. The airtime of a LoRaWAN packet with a payload of 10 bytes is about 50 milliseconds when using SF7, and 1.5 seconds using SF12.

Why is it so important to keep the airtime to a minimum?

• The more packets a gateway receives, the higher the chance that there will be a collision of the packets and that the gateway will not be able to successfully receive them. This being the case, keeping the airtime to a minimum reduces this collision risk. Fortunately, this is inherently less risky for a LoRaWAN network because this will only become a problem if the gateway receives two messages sent over the same frequency that arrive at the gateway simultaneously using the same spreading factor. 
• An end device consumes more energy when it uses more airtime.