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

Harald Welte laforge at
Wed Dec 22 16:58:09 UTC 2010


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

I would love to do it, but I simply don't have the time.  I thought maybe
somebody on this list is looking for a relatively simple task and has some
time.  I think this is a great project to work with OsmocomBB without having
to go into the details.

The algorithm would look something like

STATE 1: Power Scan
	* do power measurement over all supported bands
	* pick strongest N carriers and iterate over them
STATE 2: FCCH/SCH acquisition
	* try to get lock on the carrier
	* if not, go back to next carrier from power scan
	* if yes, continue with STATE 3
STATE 3: Wait until all relevant SI have been received
	* generate GSMTAP output for the SI messages (or timeout)
	* go back to STATE 2 for next strongest ARFCN
	* after last ARFCN, re-start from STATE 1

This is basically the initial step of the GSM 03.22 cell (re)selection
that we already have as part of the 'mobile' program.

So all the code is there, but what's needed is a separate rady-made app,
not requiring any user interaction.  It should also include some e.g. shell
script that automatically generates a new pcap file every N minutes/hours,
and make sure to never overwrite any existing PCAP file.

In the end, having this running for an extended period of time should simply
produce a large number of PCAP files without any manual interaction.  Lock-ups
in any state should be detected  by timers, singalling a proper L1_RESET
to make sure it continues.  Unplugging / re-plugging the phone should also
not require any re-start of the program.

Optional extensions:
	* software to aggregate info from the pcap files (remove duplicate
	  entries, e.g.)
	* optional logging of GPS coordinates from a GPS receiver

If anyone has some time to give this some work, I'd most appreciate it. Please
inform the mailing list to ensure no duplicate work is created.

- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)

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