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Marc Peña Segarra segarrra at gmail.comHi Vadim & Piotr! I've managed to get ccch_scan working with a RTL-SDR using Vadim instructions and this container I've created: https://hub.docker.com/r/pachulo/xenial-gr-gsm-osmocombb/ With something like this to start a container: docker run --device=/dev/bus/usb/002 -it --name test-osmocombb-trx pachulo/xenial-gr-gsm-osmocombb And something like this to get more consoles inside the container: docker exec -ti test-osmocombb-trx /bin/bash Thanks for this great addition to OsmocomBB & GR-GSM! On Sun, Jul 16, 2017 at 7:00 PM, Vadim Yanitskiy <axilirator at gmail.com> wrote: > Hi Piotr, > > > I'm very happy to hear from you again. > > Glad to see you too! > > > It's great that you figured it out. I'm more than interested > > to help you to push this topic forward. Will you be able to tell > > me how to compile and run the software so I will be able to test > > it on my side? > > Thanks! I definitely need to create a page on wiki about that. > This is a brief guideline how to run OsmocomBB on SDR: > > 1) You will need to clone a fork of GR-GSM from GitHub: > https://github.com/axilirator/gr-gsm/tree/fixeria/trx > I am going to send a pull request, as soon as I finish > some things and clean up the code according to your > requirements. > > 2) Build GR-GSM as usually, and you will see a new GNURadio > block named 'TRX Interface' in gnuradio-companion. > > 3) Clone my branch of OsmocomBB: > git clone git://git.osmocom.org/osmocom-bb -b fixeria/sdr_phy > > 4) Make sure you have a fresh version of libosmocore, and build > OsmocomBB without firmware (we don't need it anymore): > > cd osmocom-bb/src/ > make nofirmware > > 5) Go to the 'apps/trx/' directory, and launch the 'grgsm_trx.py' > application. One will init a simple follow graph and actual > TRX interface. > > 6) Go to the 'osmocom-bb/src/host/trxcon/' directory, and run > the 'trxcon' application, which is used to connect OsmocomBB > L2&3 applications with transceiver application. > > ./trxcon -d DAPP:DL1C:DSCH > > 7) Go to the 'osmocom-bb/src/host/layer23/src/misc/' directory > and run the 'ccch_scan' application, and you will see how > it actually works ;) > > ./ccch_scan -a ARFCN -i 127.0.0.1 > > > To answer this I will need to know more about what hardware you plan to > > use to receive and transmit. With i.e. USRP on a hardware level you have > > the synchronization. If you plan to use RTL-SDR + some transmitter then > > we will probably need some way to provide synchronization at a hardware > > level too. As for GSM Receiver - it sends bursts together with GSMTAP > > header which contains frame number. So you can identify bursts. > > I think, exactly devices like USRP should be our primary hardware > platform. I use UmTRX - USRP based board, designed exactly for mobile > networks. At the same time, I would prefer to keep in mind further > possibility to use the project with separate RX and TX hardware. > > > We will need to write some modulator for bursts. We can adapt the code > > from osmo-trx or use portion of the code from GMSK Mod block. Using GMSK > > Mod block might not be a good idea because of 8.25 symbols long guard > > periods between bursts. The quater bit long shifts might be a problem. > > Yeah, I had a little discussion on #gnuradio IRC, and some guy > consulted me a bit. One problem, we will probably deal with, is > GNURadio scheduling engine and block buffers. At the same time, the > trxcon application can send TX bursts in advance. As much frames before > as it's required to normal TX operation. This is how OsmoBTS does. > > He also described an exemplary algorithm of TX operation: > > 1) Take in your bits (burst) > 2) Up sample > 3) Pulse shape with an interpolating fir filter with a Gaussian response > 4) Feed that into a frequency modulation operation with the correct gain > 5) Then channel filter those with an FFT filter > 6) Use a frequency rotator of you need to freq shift the signal within > your DSP bandwidth > 7) And perform a final up sampling and antialias filter before TX. > > What do you think? > > > Can you tell me what you would like to do on OsmocomBB side and what to > > do on the GNU Radio side? I'm asking because have some idea how to make > > a low level part of GSM TRX in GNU Radio. > > OsmocomBB's side does all burst transcoding operations itself, > so we only need to modulate and send requested bursts in time. > We will also need to perform power measurements, but let's focus > on TX for now. > > > What hardware you want to use (RTL-SDR to receive and Calypso > > phone to transmit)? > > No, we need to build a Calypso independent PHY for OsmocomBB. > See my answer above. > > With best regards, > Vadim Yanitskiy. > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/baseband-devel/attachments/20170716/1cc54bf8/attachment.htm>