how to use gr gsm to capture gsm wideband packet (hopping channel)

[lab.accesssolution]

Hi All,

Is there features available in gr-gsm to capture wideband gsm packet data?

Does grgsm_capture.py have the ability to capture wideband gsm? If yes, what parameter should be set to capture wideband gsm packet?

Thanks & Best Regards,

Erik

[Tomcsányi, Domonkos]

Hi Erik,

2017. febr. 16. dátummal, 8:05 időpontban lab.accesssolution <lab.acces...@gmail.com> írta:

> Hi All,
>
> Is there features available in gr-gsm to capture wideband gsm packet data?

Yes, certainly.

>
> Does grgsm_capture.py have the ability to capture wideband gsm?

No.

> If yes, what parameter should be set to capture wideband gsm packet?

It is a little bit more complicated than that. You need to capture the spectrum, then chanellize the file and then parse all file simultenously.

Cheers,

Domi

[lab.accesssolution]

Hi Domi,

Thanks for the quick reply, i understand it is not as simple as capture packet on single ARFCN, That is why i'm interesting to do wideband gsm analysis, as you mentioned in your explanation.

If you don't mind could you please give some hint to capture the spectrum, and for the channelize process i assume that we will be using grgsm_channelize.py as described in gr-gsm wiki?

Thanks,

erik

[Tomcsányi, Domonkos]

Piotr did a nice explanation about it in this video:

https://youtu.be/xnXMKRIqkZ4

Cheers,

Domi

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[lab.accesssolution]

Hi,

I have checked in the github page  https://github.com/ptrkrysik/gr-gsm/issues/51, there is some clue to capture wideband signals:

There are many steps currently:

1. capture all frequency channels to a file,
2. process C0 channel of a BTS with Wireshark listening on local interface,
3. from System Information messages read in Wireshark Cell Allocation (list of channels assigned to given BTS),
4. extract all needed channels for example with this program:
   https://app.box.com/s/vkirr7t6s79a9gzvy758nwx8o13w4g45
   (source in get_channel.grc migh require editing depending on format of samples in your capture file)
5. configure the receiver (cell allocation with C0 channel first and number of inputs),
6. configure file source block with your channels connected in the same order as in cell allocation,
7. configure hopping channel block with MA, MAIO and HSN taken from some Immediate Assignment or Assignment command,
8. configure demapper block with timeslot number taken from these commands

We want to make easier demonstration and then an application that support hopping without having to edit GRC flowgraph.

My question is, how to perform the step number 1? Is there any GRC flowgraph example to capture wideband GSM signals?

Thanks,

Erik