[srslte-users] Clock Rate Definitions and Overclocking

[Xavier Arteaga]

Hi Aygun,
The first clock rate is for cell search. The initial cell search and
selection procedure is done at a sampling rate of 1.92MHz. Once the cell is
found and selected, the sampling rate is set according to the cell
bandwidth. Since the sampling rate during cell search stage is too low
(<10MHz), the clock is set to a higher multiple.

You could try to run the lib/examples/pdsch_enodeb and the
lib/examples/pdsch_ue
examples with double sampling rate. Do they work ok?

Also, does a 50PRB cell work at double rate? You could have encountered
some USB3 throughput issues if you are using the default configuration. By
default, the over the wire format is in 16bit width integers while the ADC
has only 12bits (in B210). you could add to device_args (in ue.conf) the
parameter otw_format=sc12 for having a more compact format over the usb3.

Regards,
Xavier




On 25 June 2018 at 15:06, BALTACI, Ayguen <ayguen.baltaci at airbus.com> wrote:

> Hi mates,
>
>
>
> I am new to the forum and srsLTE. I am running srsepc + srsenb + srsue. I
> am trying to understand why USRP board is set to two different clock rates
> during initialization (see the attached image). Is 30.72 MHz clock rate
> overwritten by 23.04 MHz in the end?
>
>
>
> I want to overclock the system to measure the performance changes. Could
> you direct me how to do so? I modified the source code so that I could
> increase the clock rate from “23.04” MHz to “46.08” MHz (2nd one in the
> image) both at eNB and at UE, but then UE could not find the eNB.
>
>
>
> I look forward to your suggestions,
>
>
>
> Best Regards
>
> Aygun
>
>
> The information in this e-mail is confidential. The contents may not be
> disclosed or used by anyone other than the addressee. Access to this e-mail
> by anyone else is unauthorised.
> If you are not the intended recipient, please notify Airbus immediately
> and delete this e-mail.
> Airbus cannot accept any responsibility for the accuracy or completeness
> of this e-mail as it has been sent over public networks. If you have any
> concerns over the content of this message or its Accuracy or Integrity,
> please contact Airbus immediately.
> All outgoing e-mails from Airbus are checked using regularly updated virus
> scanning software but you should take whatever measures you deem to be
> appropriate to ensure that this message and any attachments are virus free.
>
> _______________________________________________
> srslte-users mailing list
> srslte-users at lists.softwareradiosystems.com
> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.srsran.com/pipermail/srsran-users/attachments/20180625/1ee7a026/attachment.htm>