21 Aug
2012
21 Aug
'12
10:44 p.m.
I just released an LTE cell scanner based on the rtlsdr library. If
you're interested, the code is available on github:
https://github.com/Evrytania/LTE-Cell-Scanner
This code will search for all the LTE cells in your area and will also
report the frequency error of your dongle.
BR,
James
P.S. Many thanks for the rtlsdr library!
--
Integrity is a binary state - either you have it or you don’t. - John Doerr
22 Aug
22 Aug
12:39 a.m.
Hi James,
I just released an LTE cell scanner based on the
rtlsdr library. If
you're interested, the code is available on github:
https://github.com/Evrytania/LTE-Cell-Scanner
This is exciting stuff, thank you for sharing! I had to change few lines
(patch attached) for it to compile on my system, not sure it is the proper
way, though.
This code will search for all the LTE cells in your
area and will also
report the frequency error of your dongle.
Works for me, found one carrier so far.
Best regards,
Dimitri
8:37 a.m.
New subject: ACARS decoder for rtl-sdr
I have just uploaded to
http://jmfriedt.free.fr/gr-acars.tar.gz
the first version of the ACARS message decoder I have written for gnuradio operating with
RTL-compatible dongles. I have included an example directory with a WAV file for testing
the
decoder, and the log of last night's reception.
The decoder is far from perfect, but I think it behaves no worse than the sound-card based
decoder I have used (e.g kracars and wacars). It is also, to the best of my knowledge,
the
only opensource ACARS decoder since acarsdec does not seem functional (at least not with
the
provided example file), so someone might find it useful, and maybe even inspiring for
improvement.
I hope to learn by next week to add parameter passing from grc to the C++ program so that
two parameters -- the log file which is currently hardcoded to be located in
/tmp/log_file.txt,
and a threshold value which is currently hardcoded but should be user-tunable (or ideally
automagically adapted to received power levels, but so far such attempts have failed) --
can be
provided through the gnuradio-companion interface. This will provide a minor update of the
archive.
This is my very first attempt at grc block programming, so any feedback is welcome. I
have
updated the manuscript describing the development method -- still in French
unfortunately,
hoping to translate to English sometimes in the coming month -- and uploaded the PDF
document at http://jmfriedt.free.fr/lm_sdr.pdf for any French speaking audience to comment
on.
Jean-Michel
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 32 av. observatoire, 25044 Besancon,
France
8:15 a.m.
Hi James,
Very interesting code. I have to try to run it here - I know we have
few LTE carriers around.
Have you seen this project which is going in a similar direction?
http://sourceforge.net/p/openlte/home/Home/
On Wed, Aug 22, 2012 at 12:44 AM, James Peroulas <james(a)peroulas.com> wrote:
I just released an LTE cell scanner based on the
rtlsdr library. If
you're interested, the code is available on github:
https://github.com/Evrytania/LTE-Cell-Scanner
This code will search for all the LTE cells in your area and will also
report the frequency error of your dongle.
BR,
James
P.S. Many thanks for the rtlsdr library!
--
Integrity is a binary state - either you have it or you don’t. - John Doerr
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
3:15 p.m.
Thanks everyone for all the initial comments and feedback! I've
updated the code to fix the two small problems that were reported to
me.
Have you seen this project which is going in a similar
direction?
http://sourceforge.net/p/openlte/home/Home/
Actually, I've exchanged a few emails with Ben and his code helped me
with several parts of my code. I've now added a link back to his
project in the README.
BR,
James
24 Aug
24 Aug
6:11 p.m.
I was able to build it on Ubuntu 9.04 (Jaunty Jackalope) with a little
upgrading of some dependencies.
CellSearch is now crashing in the static initializer for the
ROM_TABLES object. *sigh*
Would anyone have an idea what may be is causing it?
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb773b910 (LWP 21087)]
0x00f743fe in itpp::Vec<std::complex<double> >::set_size () from
/usr/local/lib/libitpp.so.7
Current language: auto; currently asm
(gdb) where
#0 0x00f743fe in itpp::Vec<std::complex<double> >::set_size () from
/usr/local/lib/libitpp.so.7
#1 0x00f74ada in itpp::Vec<std::complex<double> >::operator= () from
/usr/local/lib/libitpp.so.7
#2 0x0808b0cd in PSS_fd::PSS_fd ()
#3 0x08094444 in global constructors keyed to ROM_TABLES ()
Christian
27 Aug
27 Aug
10:54 a.m.
Maybe this is a n00b question, but what am I doing wrong when I try to
access the git repository?
git clone https://github.com/Evrytania/LTE-Cell-Scanner.git
Initialized empty Git repository in
/home/buchner/lte_scan/LTE-Cell-Scanner/.git/
fatal: https://github.com/Evrytania/LTE-Cell-Scanner.git/info/refs
download error - The requested URL returned error: 403
Fortunately I can download the tarball as well, but it's more work to
keep in sync with the repository.
Christian
11:10 a.m.
Now I am really close, the latest fix for ROM_TABLES did the trick!
I am having an issue with tuning the frequency, following the PLL not
locked messages.
Is this also happening to anyone else? The rtl_test tool also shows
the same messages,
but I also see other people's forum postings who run the rtl-sdr
software successfully, even
with this kind of error message appearing.
# CellSearch --freq-start 791e6 --freq-end 821e6
LTE CellSearch v0.1.0 (release) beginning
Search frequency range: 791-821 MHz
PPM: 100
correction: 1
Found Elonics E4000 tuner
[E4K] PLL not locked for 791000000 Hz!
Error: unable to set center frequency
# rtl_test -t
Found 1 device(s):
0: Terratec T Stick PLUS
Using device 0: Terratec T Stick PLUS
Found Elonics E4000 tuner
Supported gain values (14): -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0
21.5 24.0 29.0 34.0 42.0
Benchmarking E4000 PLL...
[E4K] PLL not locked for 51000000 Hz!
[E4K] PLL not locked for 2175000000 Hz!
[E4K] PLL not locked for 1088000000 Hz!
[E4K] PLL not locked for 1232000000 Hz!
E4K range: 52 to 2174 MHz
E4K L-band gap: 1088 to 1232 MHz
12:27 p.m.
For some reason, your CellSearch software worked the second time I ran
it. Here's the result for a scan in Munich. The two frequencies found
correspond to the operators O2 and Vodafone. Deutsche Telekom is
either not using the 800 MHz band here, or I happen to be out of the
reception range for this dongle.
Detected the following cells:
C: CP type ; P: PHICH duration ; PR: PHICH resource type
CID fc foff RXPWR C nRB P PR CrystalCorrectionFactor
449 796M -13.2k -47.7 N 50 N one 0.99998344473785039099
372 806M -13.2k -43.7 N 50 N one 0.99998362964129883235
This software project is way cool! I am surprised how precise my crystal is.
Now who's willing to extend the code to combine several dongles to
scan the full 10 MHz band and to analyze the allocated resources
signalled on the PDCCH so we can generate statistics on cell load and
number of UEs served?
Christian
28 Aug
28 Aug
12:18 p.m.
A couple of suggestions for improvement of this tool:
- detect and report number of Tx antennas used by each cell (1,2 or
4). This should be detectable from the CRC part of the MIB.
- report whether the LTE system uses TDD or FDD.
I am surprised that today I find 4 cells on 796 MHz and 5 cells on 806
MHz. I did not expect this dongle to be so sensitive.
Detected the following cells:
C: CP type ; P: PHICH duration ; PR: PHICH resource type
CID fc foff RXPWR C nRB P PR CrystalCorrectionFactor
388 796M 369h -44 N 50 N one 0.99998386356929225283
449 796M 349h -48 N 50 N one 0.9999838380560712725
389 796M 358h -48.3 N 50 N one 0.99998384936395678935
52 796M 359h -49.2 N 50 N one 0.99998385073518580857
Detected the following cells:
C: CP type ; P: PHICH duration ; PR: PHICH resource type
CID fc foff RXPWR C nRB P PR CrystalCorrectionFactor
108 806M 359h -42.3 N 50 N one 0.999983844979292269
372 806M 255h -42.9 N 50 N one 0.99998371629218352208
109 806M 215h -44.1 N 50 N one 0.99998366727140031163
235 806M 244h -44.6 N 50 N one 0.9999837021424591299
365 806M 849h -48 N 50 N one 0.99998445366580002158
I would now like to log the received power for each cell ID in a log
file, and later plot it. I am interested how this power changes over
time, especially under varying weather conditions.
Christian
4269
days inactive
4276
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9 comments
5 participants
participants (5)
-
Alexander Chemeris -
Christian Buchner -
Dimitri Stolnikov -
friedtj -
James Peroulas