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FORUM

Problem with duplicated packets

LoRaWAN® implementation Networks
#1

Good afternoon! I have the following setup:

1 x kerlink Wirnet iStation (LoRaWAN GW): Wirnet iStation - Kerlink
1 x Microchip RN2903 based Wireless Board (LoRa node): RN2903 - Wireless Modules

Also, I have an Application Server running here at thethingsnetwork.org_.
However, for some reason, I see duplicated packets at Application Server level.

image

I see two packets with different timestamps and the same Tº (like this one).

I am running a small program in the node sending fake Tº, incrementing them by one in each packet sent (so, If I have the same Tº in two packets, it means they are duplicated).

PD1: For some reason I see that duplicated packets have different frequencies and channels, but I cannot find an exact pattern neither explain why.

Could you please explain why this is happening and if ii is correct or not? What can I do to filter these duplicated packets at gateway (remember that I have only one gateway) or at Network Server level?

Thanks in advance!

PD2: I also see no downlinks. Is it normal? Where do I have to look to diagnose this problem?

#2

HI, could you please post an example with a duplicated packet? I am especially interested in the time and fCnt fields for both duplicates.

Then how close are your gateway and your devices? Do you still see the issue if you put the device away form the gateway, in another room ?

1 Like
#3

My device is at 50 cm. from my gateway. And, here are the two packets:

image

The other has the following values (I cannot post two images):

  • time:“2021-03-04T16:36:43.163510Z”
  • fCnt:92
  • temperatureSensor: 1:33

Thanks a lot!

#4

This is the issue. Your device is saturating the gateway RX path, easy solution is to move them apart. You can also lower TX power and add attenuators on your antenna

1 Like
#5

I tried to move the device apart but the issue persist. I still see duplicated packets at App Server level.