I tried to install CalypsoBTS have libosmocore installed, osmo-bts osmobsc,
libosmo-netif, libosmo-abis, ortp, trx, libosmo-dsp everything went without
errors, following the instructions I created: touch ~/.osmocom/open-bsc.cfg
, then when you run : osmo-nitb -c ~/.osmocom/open-bsc.cfg-l
~/.osmocom/hlr.sqlite3-P-C --debug=DRLL:CC:MM:RR:RSL:NM shows me:<0005>
bsc_init.c:498 Failed to parse the config file:
'/root/.osmocom/open-bsc.cfg' file tried to create as administrator but
without success , pleas help me
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Hi,
We have been working on the handover feature in OsmocomBB and have
managed to make some progress including SB/BSIC detection in dedicated mode
which was not previously being successfully done in firmware. I wanted to
share it and seek guidance on the last bit of handover implementation on
which we are stuck. I hope someone would be able to help us or make use of
our work.
We took code related to handover from the osmocom-bb jolly branch by
manually adding/deleting stuff in the master branch as updating to the
latest copy was giving us issues. We added code from the “Safely change TPU
offset on TS change or sync change” commit till the “Use only sel_si for
information about the current cell” commit. Using the handover code in the
jolly branch and after making the changes explained below we were able to
obtain the handover command from the BTS. The synchronized handover case
works sometimes though still not every time, however the non-synchronized
case doesn't work at all as we are not able to get the physical information
command from the new cell. I'll explain the changes/additions we made to
achieve this.
Firstly, we noted that in dedicated mode SB burst was not being detected.
Changes were required at three main places in order to correctly perform
FB/SB detection:
- It was seen that the results for SB were being read from DSP API location
dsp_api.db_r->a_sch which is for the idle mode. The results had to be read
from the dsp_api.ndb->a_sch26 location for the dedicated case if
TCH_SB_DSP_TASK is used.
- After reading the FB we needed to update the quarter-bit offset of the
TPU using the TOA of the FB to sync it with the start of frame of the
neighbour cell in order to catch the SB (by changing the vaule of
l1s.tpu_offset using the TOA of the FB).
- Frequency compensation needed to be performed using the afc_correct
function before reading the SB.
* We actually kind of cheated a bit by adding 3 frames to the original idle
frame in order to give us more time to perform FB/SB detection including
the synchronizations mentioned above. This was because we weren't that
proficient with the code and someone with more understanding could do this
better. The call did not get dropped. We used the initial added “idle”
frame to perform the quarter-bit and frequency compensation which was
reversed in the idle frame with the response function to tune back to the
serving cell.
These things, when added to the code did the trick and BSIC of the
neighbours was obtained.
Once the BSICs were decoded the measurement report sent to the BTS became
meaningful and the handover command was received. Upon receiving handover
command, access bursts needed to be sent on the new channel which again was
not currently being implemented properly as in order to tune to the new
cell we needed to know its quarter-bit offset for start of frame, frequency
compensation and absolute frame number which were not previously being
obtained. Now that we were able to detect FB and SB these values were
stored for the neighbours following detection of these bursts and were used
to tune to a neighbour cell in case of a handover to it before the sending
of access bursts. However, here is where we are stuck. We were expecting a
physical information message following the access bursts but were not able
to receive it due to which the handover failed. If only that could be
achieved we believe handover should be successful.
Either we are not syncing properly to the new cell or we might not be
following GSM protocol properly. We also might not be reading the FACCH
properly for physical information message after tuning to the new cell as
we couldn't really understand that bit very well. We wanted someone
expertise on this matter and were hoping our work could be of use. We were
more interested in getting the work done first up.
Best Regards,
M. Awais Aslam
== OsmoCon 2018 ==
OsmoCon (Osmocom Conference) 2018 is the technical conference for
Osmocom users, operators and developers!
We are happy to announce the date of OsmoCon 2018. It has been scheduled
on October 18 + 19, 2018 and will happen in Berlin, Germany.
For the second time, the Osmocom Conference brings together users,
operators and developers of the Osmocom Open Source cellular
infrastructure projects, such as OsmoBTS, OsmoBSC, OsmoSGSN, OpenGGSN
and others.
Join us for two days of presentations and discussions with the main
developers behind Open Source Mobile Communications, as well as
commercial and non-profit users of the Osmocom cellular infrastructure
software.
You can find some initial information in our wiki at
http://osmocom.org/projects/osmo-dev-con/wiki/OsmoCon2018
which will be updated as more information becomes available.
== Call for Participation ==
We're also at the same time announcing the Call for Participation and
call on everyone with experiences to share around the Osmocom member
projects to submit talks, workshops, discussions or other proposals.
You can find the CfP at https://pretalx.sysmocom.de/osmocon2018/cfp
We are particularly looking for contributions about:
* updates on features/functionality/status of individual Osmocom projects
* success stories on how Osmocom projects are deployed in practice
* migration from OsmoNITB to the post-NITB architecture
* tutorials / workshops on how to setup / analyze Osmocom projects
* statistics, reporting, operations aspects of Osmocom projects
* third-party open source utilities to be used with Osmocom projects
Looking forward to meeting many existing and new Osmocom users at OsmCon
this October!
Regards,
Harald Welte
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
Hi all,
Gr-gsm's receiver currently relies on having SCH channel to keep
synchronization. I want to remove that requirement so it'll be more
usable in an SDR based burst transceiver for OsmocomBB.
To do this it would be great to know how normal mobile phones maintain
synchronization, something I don't know currently. Especially:
1. How often mobile station (MS) checks if the synchronization is kept?
2. What is usually used to check if synchronization is kept, especially
when a MS is on a traffic channel?
3. How MS regains synchronization? Does it always do full FCCH+SCH scan?
Thanks in advance,
Piotr Krysik
