6 Sep
2017
6 Sep
'17
4:20 p.m.
Hi Adrian,
I am interested in the sdr_phy work being done
currently
Great to hear that.
I built osmo-trx from the ms branch and implemented a
crude
power measurement command. When running trxcon everything works
fine, I get power indications for channels, and then when the
mobile app is trying to sync to an ARFCN I start having issues.
I have never developed / tested trxcon with OsmoTRX so far.
Currently I am using GR-GSM as a L1 back-end, and the virtual
connection between OsmocomBB and OsmoBTS during development.
In general, trxcon should be able to 'speak' with OsmoTRX,
because one do use classical transceiver UDP interfaces. But
there are some CTRL commands, which aren't implemented in OsmoTRX
yet (such as ECHO and MEASURE).
I had to change the code of trxcon in order for SCH to
work,
because the bit values were inverted (0 was 1 and viceversa).
I am attaching the changes at the end of the message.
Sounds strange. In case of virtual Um-interface (FakeTRX) and
GR-GSM TRX all SCH messages are decoded correctly. I will look
closer to this issue, thanks anyway!
It appears as if the deinterleaving in
gsm0503_xcch_decode
does not work... could be the order of bursts?
The order of bursts should be consistent, I mean frame-by-frame.
You need to make sure that a frame number from SCH burst is being
decoded correctly by OsmoTRX. Every burst coming from OsmoTRX
has a header with frame number, which is used by trxcon to
determine a current frame position within a multiframe.
Probably, the problem is due to incorrect / consistent
frame number values. The internal clock counter (sched_clck.c)
is only used to schedule the UL bursts transmission.
I'd appreciate any help here. I'm also ready
to share the
changes I've made to osmo-trx/ms and trxcon.
For now, have a look at:
- GR-GSM based transceiver:
https://github.com/axilirator/gr-gsm/tree/fixeria/trx
- Virtual Um-interface (brief description):
http://git.osmocom.org/osmocom-bb/tree/src/target/fake_trx/README?h=fixeria…
- The latest version of trxcon (use fixeria/fake_trx branch):
http://git.osmocom.org/osmocom-bb/log/?h=fixeria/fake_trx
You can also join the development process, feel free to mail me.
I will create the wiki page as soon as possible.
With best regards,
Vadim Yanitskiy.
6 Sep
6 Sep
6:40 p.m.
New subject: SDR_PHY question
Hi Vadim,
In general, trxcon should be able to 'speak' with OsmoTRX,
because one do use classical transceiver UDP interfaces. But
there are some CTRL commands, which aren't implemented in OsmoTRX
yet (such as ECHO and MEASURE).
Yes, I implemented both commands, I can share the code with you. My
problem is that Gnuradio (distro version) is built against an
incompatible ABI version of libuhd, so I have to jump through major
hoops just to get both osmo-trx and gnuradio working. So currently all
my tests are using osmo-trx only.
The order of bursts should be consistent, I mean frame-by-frame.
You need to make sure that a frame number from SCH burst is being
decoded correctly by OsmoTRX. Every burst coming from OsmoTRX
has a header with frame number, which is used by trxcon to
determine a current frame position within a multiframe.
Probably, the problem is due to incorrect / consistent
frame number values. The internal clock counter (sched_clck.c)
is only used to schedule the UL bursts transmission.
Yes, the SCH burst has a correct frame number. But the BCCH and CCCH
bursts fail to be decoded. CRC fails in
libosmocore/coding/gsm0503_coding.c
Is your gr-gsm fake-trx able to decode correctly BCCH and CCCH? I
double checked the osmo-trx code and besides some major differences
between the MS branch and master, everything looks correct.
You can also join the development process, feel free to mail me.
I will create the wiki page as soon as possible.
Yes, I'd like that, but for now I just want to get BCCH and CCCH
working and the mobile syncing with the BTS. Then I will be able to
test.
Cheers,
Adrian
7:09 p.m.
New subject: SDR_PHY question
Hi,
Just a quick thing: to get ABI supported version of UHD do not use the Ettus ppa uhd, but
use the one called uhd-lts or something similar. It is compiled with the right ABI version
for the gnuradio distro package.
Cheers,
Domi
2017. szept. 6. dátummal, 17:42 időpontban Adrian Musceac <kantooon(a)gmail.com>
írta:
Hi Vadim,
In general, trxcon should be able to 'speak' with OsmoTRX,
because one do use classical transceiver UDP interfaces. But
there are some CTRL commands, which aren't implemented in OsmoTRX
yet (such as ECHO and MEASURE).
Yes, I implemented both commands, I can share the code with you. My
problem is that Gnuradio (distro version) is built against an
incompatible ABI version of libuhd, so I have to jump through major
hoops just to get both osmo-trx and gnuradio working. So currently all
my tests are using osmo-trx only.
The order of bursts should be consistent, I mean frame-by-frame.
You need to make sure that a frame number from SCH burst is being
decoded correctly by OsmoTRX. Every burst coming from OsmoTRX
has a header with frame number, which is used by trxcon to
determine a current frame position within a multiframe.
Probably, the problem is due to incorrect / consistent
frame number values. The internal clock counter (sched_clck.c)
is only used to schedule the UL bursts transmission.
Yes, the SCH burst has a correct frame number. But the BCCH and CCCH
bursts fail to be decoded. CRC fails in
libosmocore/coding/gsm0503_coding.c
Is your gr-gsm fake-trx able to decode correctly BCCH and CCCH? I
double checked the osmo-trx code and besides some major differences
between the MS branch and master, everything looks correct.
You can also join the development process, feel free to mail me.
I will create the wiki page as soon as possible.
Yes, I'd like that, but for now I just want to get BCCH and CCCH
working and the mobile syncing with the BTS. Then I will be able to
test.
Cheers,
Adrian
7:37 p.m.
New subject: SDR_PHY question
Yes, I implemented both commands, I can share the code
with you.
It would be great. Just send these patches here using git
format-patch / send-email. I'll have a look.
My problem is that Gnuradio (distro version) is built
against an
incompatible ABI version of libuhd, so I have to jump through
major hoops just to get both osmo-trx and gnuradio working.
So currently all my tests are using osmo-trx only.
Ah, just build it yourself. It would be much better.
Distro versions are often pretty dated :(
Excluding Arch Linux and similar ;)
Yes, the SCH burst has a correct frame number.
But the BCCH and CCCH bursts fail to be decoded. CRC fails in
libosmocore/coding/gsm0503_coding.c
Regarding to the 'bits conversation' you mentioned in the first
mail, it's done the same way as in OsmoBTS. It should work as is.
Probably SCH bursts are not actually forwarded from OsmoTRX. Or
being forwarded in a wrong way.
Is your gr-gsm fake-trx able to decode correctly BCCH
and CCCH?
Sure. I am even able to make a voice call.
With best regards,
Vadim Yanitskiy.
2475
days inactive
2475
days old
baseband-devel@lists.osmocom.org
3 comments
3 participants
participants (3)
-
Adrian Musceac -
Tomcsányi, Domonkos -
Vadim Yanitskiy