Hi Sylvain,
Thank you for getting back to me.
I suspected it would not be easy to decode the uplink speech and you
confirmed that. I will probably not spend more effort on it.
Your code and suggestions have helped me a lot. I have decoded my own
downlink speech and now the RACH.
Thanks again for your help.
Best regards,
Johann
On Thu, Jul 1, 2021 at 10:14 AM Sylvain Munaut <246tnt(a)gmail.com> wrote:
Hi,
Thanks to your suggestions, I managed to decode
the RACH from the
captures on L-band. I just had to tweak a few parameters in the
graphs. I
have decoded the Paging Response and Location Update messages.
TBH I'm impressed you managed to decode those from uplink without the
sync from the downlink channels.
Do you have some suggestions on decoding the
uplink speech? On the
downlink, the code follows the Immediate Assignment and
decodes the traffic
channel. Due to the limitation of the SDR, I am not able to capture both
the downlink and uplink channels simultaneously.
Not really, they are already tricky to get from downlink because they
are very small, use crappy sync patterns and have very little error
correction applied, so on uplink that's going to make it even harder.
Cheers,
Sylvain