trx output power config in bts

Keith keith at
Mon Dec 14 21:43:36 UTC 2020

On 14/12/2020 13:55, Mario Lucas wrote:
> Dear team could you pls help me with this question
> In bts config  we have following entries:
> trx 0
>    nominal power 23
>    ! to use full TRX power, set max_power_red 0
>    max_power_red 20
>  and
> osmotrx tx-attenuation (oml|<0-50>)

^^ This command does not exist in all osmo-bts-* variants.

> If we want to have a weak signal why we just don’t use only «nominal
> power» with whatever weak or strong signal value we want?

Somebody else might correct me if I am wrong, but I'm pretty sure than
"nominal power" is only used to calculate informational reports for the
operator, in "show trx" for example.

So after calibration of any RF power attenuation or amplification
equipment connected to your BTS, you might adjust "nominal power" to
reflect that. Then, you might want to control your cell size from the
BSC, with max_power_red

I'm not sure of the origins of the osmotrx commands, nor am I absolutely
sure about the override capabilities of that command, but I believe that
the idea is that if you use osmotrx tx-attenuation 0, then the bts
should ignore attentuation commands sent over the Abis as a result of
having max_power_red in the BSC config.

This has been discussed before BTW, more than once, I believe, for example:

even though the title is about ms-max-power there.

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