OsmocomGMR main author Sylvain Munaut has given a presentation about the GMR-1 standard and the OsmocomGMR software at the 2011 annual CCC conference (28C3).
It is a great introduction into the topic, and a recommended read/view for everyone wanting to experiment with our OsmocomGMR software.
The slides are available from http://events.ccc.de/congress/2011/Fahrplan/attachments/2027_28c3_introducing_osmocom_gmr.pdf
The video is available from http://mirror.fem-net.de/CCC/28C3/mp4-h264-HQ/28c3-4688-en-introducing_osmo_gmr_h264.mp4
I've merged the DECT tree with the Linux 3.1 release and pushed out experimental support for P640j (Wideband) in the MAC/DLC/NWK layers. Besides the kernel, libnl and libdect need to be rebuilt (Build_instructions).
Asterisk wideband support is still unfinished and chan_dect will currently not build cleanly, only update if you intend to work on chan_dect yourself or want to play with wideband using the libdect example code.
As some of the readers may already know, a couple of Osmocom developers have been working on a new sub-project: OsmocomGMR.
The primary goal of this project is to provide a reusable and clean implementation of the various layers of GMR-1.
What is GMR-1 ? Well, it stands for "GEO Mobile Radio" and it's a set of specifications describing a satellite based mobile phone network heavily inspired from GSM. One of the major commercial operators of GMR-1 technology is "Thuraya", providing coverage over Europe/Africa/Asia/Australia?.
So far the implementation focused on the lowest layers:
- Physical layer with FCCH sync and demodulation support for pi4-CBPSK and pi4-CQPSK bursts.
- Channel coding layer (scrambling/puncturing/convolutional coding/crc/interleaving/...)
And some ancillary tools to exploit those:
- A good capture tool to listen to particular ARFCN and channelize them properly
- Wireshark support (BCCH only so far)
The first 'demo application' using all of the above provides functionalities similar to what airprobe is for GSM: An air interface protocol analyzer that goes all the way from capturing data off-the-air to sending packets to wireshark for analysis. Limited to BCCH only currently but this will evolve with time.
Development was mainly done by Sylvain Munaut, with help from Dimitri Stolnikov (early signal captures and his great capture tool), Harald Welte (initiating the project) and Steve Markgraf (testing different setup and antenna ideas).
If you'd like to know more, you are encourated to read the wiki and join the mailing list
I've pushed out P640j/wideband support, so far only for the 1442x firmware, the upper layers still need a bit of work. P640j can only be enabled if the PCMCIA driver is deselected and requires a firmware rebuild. I'd appreciate feedback whether things are still working properly on the PCMCIA devices.
I've merged the DECT tree with the Linux 3.0 release. P640j/Wideband support will also be pushed out soon
For quite some time we've been hacking away on a project called osmo-bts.
You can find it source code as usual on git.osmocom.org, for occasional web browsing we offer cgit access.
osmo-bts is a BTS-side Layer3 and Layer2 protocol implementation, including Abis/IP, TS 08.58 RSL, TS 12.21 OML, TS 04.06 LAPDm and various other bits and pieces required to run a BTS.
Specifcally, it does not include a GSM Um Layer1. Rather, the idea is to port osmo-bts to a variety of L1 implementations.
So far, hardware support only exists for an upcoming BTS product which is not available yet, the sysmocom femtobts. However, there is active work being done un hacking some OsmocomBB phones into using them as a BTS, as well as support for other L1/hardware, too.
We are also planning to implement a 'virtual layer1', that can be used to run a BTS without any radio layer, interfacing the OsmocomBB stack via TCP/IP for netwokr simulation and software testing.
Today, a Chaosradio Express (CRE) about TETRA has been released at http://chaosradio.ccc.de/cre183.html
OsmocomTETRA founder Harald Welte was interviewed by Tim Pritlove, maker of the popular German language technology podcast Chaosradio Express.
The 2 hours and 20 minutes long interview covers the historic evolution from analog radio, trunked radio to digital trunked radion and TETRA. It also covers users, security issues and the OsmocomTETRA project.
Please note: CRE is a German language publication.
I've merged with Linus' current tree, due to a newly assigned netlink family, the NETLINK_DECT value has changed. Both the libnl and libdect trees need to be updated as well and recompiled against the current set of kernel headers (specifically, using the current include/linux/netlink.h file).
Refer to the Build_instructions if in doubt.
Thanks to laforge, the git problems should be fixed now. Apparently OpenVZ by default limits the amount of sockets per instance to 1% of the global limit. Git is forking wildly, creating lots of orphaned sockets until it hits the limit.
