Please suggest Loss communication issues when having many devices in a network.

[NakornThree]

I developed a LoRa device with STM32L072RZ+SX1272MB2xAS. The device could send data every 40 s and It's working well. But the problem happened when a Lora network has devices with more than 10 nodes. The problem is sometimes devices can't send any data to a server for an hour and it happens at random times and on random devices.

What is the cause of the problem and how to solve it?

[Vangelis Fortounas]

Hello .

It seems like packet collision issue. I supose that the server is not acts as a coordinator but as a simple receiver. At least a CCA Clear Channel assessment protocol must be implemented.

[NakornThree]

Thank you, Vangelis. What is a CCA Channel assessment protocol and how to use it?

[Tesla DeLorean]

Google is your friend... http://www.wirelesscommunication.nl/reference/chaptr01/wrlslans/80211_page2.htm

Basically you're going to have to tread more carefully so your own transmission aren't treading on top of each other, perhaps via time displacement, or random back-off. If reporting GPS/GNSS positions, there gets to be a unintended synchronization to top-of-second, you need to manage that.

Also the medium is generally half-duplex, so you can jam it in either direction.

LoRa or LoRaWAN ?

[NakornThree]

Thank you, Tesla DeLorean. I used LoRaWAN. Gateway is Femto Gateway from Gemtek.