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

Jason osmocom at lakedaemon.net
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!

thx,

Jason.




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