TODO: OsmocomBB to continually iterate over all cells and dump SI

Jason osmocom at
Wed Dec 22 18:01:37 UTC 2010

On 12/22/2010 05:23 PM, Steve Markgraf wrote:
> Hi all,
> On 22.12.2010 17:58, Harald Welte wrote:
>> A number of people want to do some long-term evaluation of their cellular
>> environment and would be interested in an 'app' for OsmocomBB that
>> continuously
>> scans the spectrum and dumps the cell parameters such as
>> * ARFCN, Signal Level, SNR
>> * frequency synch offset
>> * SCH info (BCC/NCC)
>> * SI (at least 1-4) from BCCH
>> * optional logging of GPS coordinates from a GPS receiver
> Just to avoid any duplicate of work as well: most of this is already
> done by cell_log (layer23/src/misc). It iterates over the whole spectrum
> and tries to get an Immediate Assignment by sending a RACH to every cell.
> It stores SI1-4, GPS position and the TA in a logfile, and using the
> gsmmap utility you can create a *.kml map of the calculated cell
> positions for Google Earth.

Funny, I was just looking at this last night.  Would you mind if I added 
gpsd support to cell_log?

> So what's missing is really only the PCAP support...

would you want libpcap (a lot of unnecessary code), or just use the file 
and packet headers?

> ...and a command line
> switch to turn off the "active" scanning by sending no RACHs.

Since I'm just learning GSM, I've only compiled with TX disabled.  My 
results have been pretty poor.  Is there something I could add to handle 
passive scanning better?  I've been getting nothing from cell_log, 
layer23, or mobile on lo (although I do see other loopback network 
traffic).  I just started working on this a few days ago, so I'm not 
surprised.  I'll dig into it more.  The Getting Started guide was a 
great help!



More information about the baseband-devel mailing list