Hi! I just released a major update to the LTE code. There's a new program called LTE-Tracker that camps on a certain frequency and tracks, any LTE cells that it finds.
Interesting features (all are in realtime):
- You can see cells popping in and dropping off as the receiver is moved around the coverage area of the different cells. - You can see the actual transfer function of the wireless channel plotted on the screen.
I've also made a small change to CellSearch so that now, it also displays the number of antennas (ports) on the basestation.
Please let me know of any comments or suggestions!
http://www.evrytania.com/lte-tools/lte-tracker
James
Hi James,
On Sun, 18 Nov 2012 05:40:55 +0100, James Peroulas james@peroulas.com wrote:
Hi! I just released a major update to the LTE code. There's a new program called LTE-Tracker that camps on a certain frequency and tracks, any LTE cells that it finds.
Interesting features (all are in realtime):
- You can see cells popping in and dropping off as the receiver is
moved around the coverage area of the different cells.
- You can see the actual transfer function of the wireless channel
plotted on the screen.
I've also made a small change to CellSearch so that now, it also displays the number of antennas (ports) on the basestation.
Cool!
Please let me know of any comments or suggestions!
I had to apply the attached patch for it to compile on my machine.
Unfortunately i wasn't able to test the tools, as both of them segfaulted in xc_peak_freq? Backtrace fragment attached.
LTE Tracker v1.0.0 (release) beginning Search frequency: 1815 MHz PPM: 120 correction: 1 Found Elonics E4000 tuner Calibrating local oscillator. Segmentation fault
LTE CellSearch v1.0.0 (release) beginning Search frequency: 1815 MHz PPM: 120 correction: 1 Found Elonics E4000 tuner Examining center frequency 1815 MHz ... Segmentation fault
The old copy of commit ef8474ed5d9213c494e8e17b8436208a04844b1a works just fine at the same time:
C: CP type ; P: PHICH duration ; PR: PHICH resource type CID fc foff RXPWR C nRB P PR CrystalCorrectionFactor 262 1815M 595h -24.6 N 100 N one 1.0000447970890209426 263 1815M 595h -25.3 N 100 N one 1.0000447969528891701
Also, i noticed that you calculate the expected tuning frequency for e4k tuners in order to make your calculations more exact. Can you tell us which tuning errors you get from the e4k driver usually and how this affects your application?
Nice documentation & videos! Linked the page on the rtl-sdr wiki.
Best regards,
Dimitri
On Sun, Nov 18, 2012 at 3:05 AM, Dimitri Stolnikov horiz0n@gmx.net wrote:
I had to apply the attached patch for it to compile on my machine.
Thanks for the patch! cmake is something very new to me :)
Unfortunately i wasn't able to test the tools, as both of them segfaulted in xc_peak_freq? Backtrace fragment attached.
Fixed (and pushed)! That was an easy bug to find and was related to the fact that LTE cells in your area were at such a high frequency (1.8GHz). The one's I've worked on were in the 700MHz band.
Also, i noticed that you calculate the expected tuning frequency for e4k tuners in order to make your calculations more exact. Can you tell us which tuning errors you get from the e4k driver usually and how this affects your application?
Well, it's like this. Since the LO and sampling clock are derived from the same reference, if I can figure out the frequency error of the LO, I will know the frequency error of the ADC and I can use the frequency error of the ADC to predict where I should be sampling the data. That way, in LTE-Tracker, when the dongle's chrystal output stabilizes, the time offset of the tracked basestations should not change (as long as the dongle itself is not moving). I needed to calculate the actual LO and sampling frequencies used by the dongle in order to remove the small time offset drift I was observing.
As a new feature request, it would be nice for the library to return the actual frequency that was programmed into the dongle in floating point (fractions of a Hz sometimes matter). So, if I request 739,000,000Hz, the library would be able to tell me that the actual programmed frequency was 739000025.5123... Hz. Similarly for the sampling rate.
http://www.evrytania.com/lte-**tools/lte-trackerhttp://www.evrytania.com/lte-tools/lte-tracker
Nice documentation & videos! Linked the page on the rtl-sdr wiki.
Thanks for the comments and the link!
James
Hi James,
Looks like a great software!
Do you plan to support UHD to support USRPs? In my area (Moscow) we have LTE in 2500/2600 FDD band and I can't tune to that frequency with rtl-sdr.
On Sun, Nov 18, 2012 at 8:40 AM, James Peroulas james@peroulas.com wrote:
Hi! I just released a major update to the LTE code. There's a new program called LTE-Tracker that camps on a certain frequency and tracks, any LTE cells that it finds.
Interesting features (all are in realtime):
You can see cells popping in and dropping off as the receiver is moved around the coverage area of the different cells. You can see the actual transfer function of the wireless channel plotted on the screen.
I've also made a small change to CellSearch so that now, it also displays the number of antennas (ports) on the basestation.
Please let me know of any comments or suggestions!
http://www.evrytania.com/lte-tools/lte-tracker
James
-- Integrity is a binary state - either you have it or you don’t. - John Doerr
On Mon, Nov 19, 2012 at 3:22 AM, Alexander Chemeris < alexander.chemeris@gmail.com> wrote:
Do you plan to support UHD to support USRPs? In my area (Moscow) we have LTE in 2500/2600 FDD band and I can't tune to that frequency with rtl-sdr.
Well, it's 'planned', but I don't have any specific schedule for it... I don't even have a USRP yet :)
James
On Tue, Nov 20, 2012 at 7:03 AM, James Peroulas james@peroulas.com wrote:
On Mon, Nov 19, 2012 at 3:22 AM, Alexander Chemeris alexander.chemeris@gmail.com wrote:
Do you plan to support UHD to support USRPs? In my area (Moscow) we have LTE in 2500/2600 FDD band and I can't tune to that frequency with rtl-sdr.
Well, it's 'planned', but I don't have any specific schedule for it... I don't even have a USRP yet :)
Fair enough :)
-- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru
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Alexander Chemeris -
Dimitri Stolnikov -
James Peroulas