How does chirpstack manage TxPower in LinkADRReq command?

The Lorawan 1.0.4 specification has a statement that reads:

If the uplink ADR bit is set, the Network may control the number of retransmissions, the data rate, and the TX power of the end-device through the appropriate MAC commands.

Does chirpstack have the algorithms to make power adjustments based on measured RSSI or other criterion? In my setup the ONLY mac commands I see for power say to use TXPower = 0 which maps to maximum power I believe.

My RSSI on join is typically around -40 so I’m trying to understand if the command to use maximum power is driven by this this measured RSSI or chirpstack always says use maximum power, If the power decision is dynamic any hints on where I can find the algorithm to make such decisions?

Hi there :wave:,

Yes, Chirpstack default ADR manages the Tx Power.

See: ADR algorithm and configuration - #2 by brocaar


Thanks for the pointer! It was very useful.

My application has one more complication.

I’m using only channels with FSK modulation rather than LoRa. In FSK the SNR measurement is not available and all chirpstack has to look at is rssi.

In this special case, what should I expect from chirpstack for power targets? I didn’t see a recommended strategy for FSK channels in the ADR discussions.

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