TX Output Power

[Pascal PROVOST]

I use a MTCDTIP-LEU1-266A-868 with AEP package.
Gateway sends mac commands to end-devices to reduce their ouput power.
On which criteria does gateway sets this parameters: RSSI and/or SNR, or anotherone?
Have you a detailed description of gateway used algorithm?

Is it linked to SF/BW settings that gateways also controls?

Regards,

[Steve Kovarik]

Hello Pascal

When ADR is enabled on a LoRa end node, the Network Server can adjust
the Datarate (Spreading Factor) and Transmit Power of the Lora end node
based on SNR values of a set of received packets on the Network Server.
A more detailed description can be found at the link below.

[Steve Kovarik]

[Pascal PROVOST]

Hello Steve,
You sent me a link to an interesting tutorial for LoRa beginners.
I develop LoRa end devices for several years now.

So I need more details:
For a given SF, for which SNR range does gateway ADR sends command to reduce TX Output power of 1, 2 and so on.
Is it described in LoRawan spec or Multitech proprietary algorithm?

[Jason Reiss]

The LoRaWAN spec does not describe an ADR algorithm.

The time-on-air for an SF reduced one step is halved. This saves more power than a tx power reduction of 3 dBm.

Tx power is only reduced when the maximum datarate is set.
The network server on Conduit will reduce the Tx Power one step at a time while the SNR is maintained above 3 dB in uplinks.

[Pascal PROVOST]

Hello Jason,

Thanks for these explanations.
For EU868, it means that end device TX ouput power may only be reduced in SF7BW250 if gateway uses its default configuration. Please confirm.

Regards,

[Jason Reiss]

The Max Datarate setting allowed by ADR, will be the datarate needed for power to be reduced. If Max Datarate is set to DR6:SF7BW250 then yes.
If Max Datarate is set to DR4:SF8BW125, then the ADR will set DR4 and then reduce power on additional ADR commands.

On Conduit AEP see LoRaWAN > Network Settings > Max Datarate

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