[srslte-users] AGC Mode

[Xavier Arteaga]

Hi Charbel,
With AGC_DEFAULT_TARGET greater than 1, I have the following questions:
- Is the signal coming from the N321 having a greater amplitude than 1?
- Is it always settling in the maximum gain?

Regarding AGC_HOLD_COUNT, it looks like a lot of latency. I wonder if the
Rx gain settling takes that long. This makes the AGC take a while to
settle. Does the UE recover the performance after moving?

I guess the best is to add some traces in `agc.c` to understand how the AGC
is interacting with the RF and see if it settles into a bounded value.

Regards,
Xavier

On Wed, 18 Aug 2021 at 09:04, Charbel Lahoud <
charbel.lahoud at etit.tu-chemnitz.de> wrote:

> Hi Xavier,
>
>
>
> Thanks a lot for your email.
>
> I have work it out by modifying the AGC parameters as you mentioned
> (AGC_HOLD_COUNT = 200 or 300; AGC_DEFAULT_TARGET = 2.5). While the system
> is stationary, it works well but while UE is moving the performance drops
> again resulting in high BER.
>
> Any suggestions?
>
> Thank you.
>
>
>
> Best regards
>
> Charbel
>
>
>
> *From:* Xavier Arteaga <xavier at srs.io>
> *Sent:* Tuesday, August 17, 2021 8:19 AM
> *To:* Charbel Lahoud <charbel.lahoud at etit.tu-chemnitz.de>
> *Cc:* srslte-users at lists.softwareradiosystems.com
> *Subject:* Re: [srslte-users] AGC Mode
>
>
>
> Hi Charbel,
>
> Many thanks for your email. You could try the following:
>
> - It could be the gain setting is slow, could you try
> increasing SRSRAN_AGC_HOLD_COUNT to >100;
>
> - Lower SRSRAN_AGC_DEFAULT_TARGET
>
>
>
> Regards,
>
> Xavier
>
>
>
> On Mon, 16 Aug 2021 at 16:07, Charbel Lahoud <
> charbel.lahoud at etit.tu-chemnitz.de> wrote:
>
> Hi,
>
>
>
> Recently, I have been testing using srsRAN AGC mode. I have recognized
> that on srseNB and srsUE, the AGC mode isn’t working properly.
>
> While AGC is enabled, the RSRP is changing a lot and I have a high BER. On
> the other hand, while specifying the RX gain on both eNB and UE, I am able
> to reach max performance.
>
>
>
> I am using USRP N321 with UHD 3.15 LTS on both sides eNB and UE. As well,
> I have modified the max gain inside AGC.c  to 60.0 and increased the number
> of measurements, but still getting the same results from high BER and low
> performance.
>
>
>
> Any suggestions will be helpful. Thanks a lot.
>
>
>
> Best regards,
>
> Charbel
>
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