Unable to decode wideband capture (BladeRF)

[Varbaek]

Hi Bogdan,

Excellent tool and guide you've written. I have recorded a "wideband capture" with a BladeRF using a slightly modified version of grgsm_capture, and I am able to "channelize" each ARFCN using grgsm_channelize.py.

I have tested that I am able to decode the individual files with grgsm_decode as well which works.

However, when I try to use your script (after modifying the parameters), with 0 decimation or 64 decimation, it doesn't work. I know that Airprobe for some reason, does not decode GSM frames/packets as well as gr-gsm for unknown reasons. (I only get some of the packets in wireshark with Airprobe.)

The combined capture/complex file created by airprobe-hopping is empty in my case, meaning the program that decodes the individual out_XX.cfile files, does not seem to understand the format I'm using. I tried modifying the sample rate, so that in my case I had nine ARFCNs at 1MSPS each, meaning I made the total MSPS to 9MSPS instead of the default which is 10MSPS.

I was wondering if you have any documentation about how you've implemented the frequency hopping into Airprobe? I'm not a programmer per se, but I am willing to try and implement this into grgsm for example if the official gr-gsm does not want to.

Let me know if you can help me out, I have figured out everything else so far, but I'm stuck on the frequency hopping part.

In my case, I have an additional obstacle at the "SDCCH8" part where frequency hopping is enabled, as my phone hops to another ARFCN, and then does the SDCCH8 part, and then hops back, but that's not really an issue for my testing at the moment, as I already have the Kc extracted.

[dvolvox]

Any luck?