A LoRa transmission uses 8 frequency channels. 1
We also discussed that several devices could transmit at the same time on the same channel, but there 2
was only one condition. 3
They had to use a different Spreading Factor. But that was not all, 4
and we said that the device had to limit its transmission time. 5
How exactly? 6
There is a rule in the 868 MHz band which says that you can transmit only 1% of the time 7
if you transmit during 1 second, then you have to remain silence during 99 seconds. 8
What does that mean in our case? 9
It means that our device transmitting at SF7 during 46.3 millisecond has to stay silent during 10
a minimum of 4.63 seconds. 11
And what's the impact on the bitrate ? 12
It will be considerably affected because as usual, we are interested in the average bitrate and this 13
1% rule simply reduce the average bitrate by 100. 14
So for the first case at SF7, the previous 173 bits per second are divided by 100 and are now 1.73 15
bits per second. 16
And for the second case at SF12, the 6.9 bits per second, are divided by 100 and are now 0.07 bit per second. 17
LoRaWAN is an extremely low speed network, much slower than we can imagine when we quickly 18
read the documentation. 19
So before stepping into LoRaWAN, you have to make a complete evaluation of your use case and to be 20
very careful with what LoRaWAN 21
can promise in terms of range and low power. In these two domains, it's probably one of the best 22
of the market. 23
But on the other hand, for the bitrate, we've just seen that it's extremely limited. 24
All right, then tell me your application and I will tell you if LoRaWAN is suitable for your 25
use case.