[srsran-users] HackRF One with srsRAN // rtl-sdr compatibility, concerns

[Andre Puschmann]

Hi,

On 17/12/21 23:51, Dan Dole-Muinos wrote:
> Thank you for the feedback on hackRF. If I choose that SDR, and get it 
> to work with srsRAN, I'll be sure to let the list know.

Great.

> 
> I was curious as well, what might be the limitations in trying to use a 
> rtl-sdr to capture a DL LTE signal? From what I understand, the rtl-sdr 
> is only capable of capturing a small number of subcarriers due to its 
> small bandwidth, but would this (or its sample rate of ~1 MS/s) affect 
> tracking the SSS signal for example?

Yes, but for all bandwidths, the sync (PSS/SSS) and PBCH occupy the same 
center PRBs. In fact, during cell search we use 1.92Msps to decode those 
signals and then increase the bandwidth to the actual cell bandwidth. If 
you're using the rtl-sdr, you can use the cell_search example for 
instance and decode MIB. What you can't do is to decode SIB, if the cell 
is larger than 6 PRBs (which is typically the case for commercial 
deployments).

> 
> Also, are there any implementation insights you could give me in regards 
> to adding rtl-sdr support to srsRAN? If it could be suitable for DL 
> reception, I am interested in putting the time into integrating the 
> rtl-sdr drivers into the codebase.

rtl-sdr support is already in place through Soapy. It works fine for 
narrow bandwidths, see above.

Cheers
Andre


-- 
Andre Puschmann

Software Radio Systems (SRS)
https://www.srs.io
andre at srs.io

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