-------'Range' network is not detected-------

GNU Radio
1

Hi all,

I have recently installed OpenBTS-2.8 on a Banana-Pi (Processor: ARMv7)
board for USRP N210 functioning. All the prerequisites including
GNURadio,
UHD were successfully built on the board prior to OpenBTS installation.
With all configurations done, still there is a problem in the USRP
connection.
I have configured MCC, MNC and ethernet IP connection. “ping
192.168.10.2”
works fine. Once the ethernet connection is established and until
“./OpenBTS” is executed, “uhd_find_devices” and “uhd_usrp_probe” detect
USRP. After the execution of “./OpenBTS”, surprisingly
“uhd_find_devices”
and “uhd_usrp_probe” do not detect the device and say “No device
found…”
(‘ping’ is still working though). The strangest thing is even at this
stage, “./OpenBTS” works fine even at a re-run.
After all these drama, no (‘range’) network is detected by a properly
configured mobile phone. (Note: We have successfully placed calls and
SMS
with almost same procedure using a PC instead of B-Pi).
I am bit confused here whether this is a deal of OpenBTS or GNURadio.
Does
the processor speed come in to play in this scenario?
Any valuable suggestions would be highly appreciated.

Thank you.

Zamrath N.

2

First of all, it is normal that the USRP is not detected anymore with
the uhd tools when it is claimed by OpenBTS. So this looks not alarming.

Are you able to verify if RF is transmitted? Is there some spectrum
analyzer available, or a receiver that can tune into the used GSM
frequency, best is AM mode and open squelch, to see if a carrier is
present? This way you can find out if it transmits at all, and if so, it
must be continously, uninterruptes, without stuttering.

I assume your successful tests used the very same USRP, so the frequency
should not be off too far?!

Ralph.

From: Zamrath N. [mailto:[email protected]]
Sent: Tuesday, March 24, 2015 5:33 AM
To: [email protected]; GNURadio D.ion List
Subject: [Openbts-discuss] -------‘Range’ network is not detected-------

Hi all,

I have recently installed OpenBTS-2.8 on a Banana-Pi (Processor: ARMv7)
board for USRP N210 functioning. All the prerequisites including
GNURadio, UHD were successfully built on the board prior to OpenBTS
installation. With all configurations done, still there is a problem in
the USRP connection.

I have configured MCC, MNC and ethernet IP connection. “ping
192.168.10.2” works fine. Once the ethernet connection is established
and until “./OpenBTS” is executed, “uhd_find_devices” and
“uhd_usrp_probe” detect USRP. After the execution of “./OpenBTS”,
surprisingly “uhd_find_devices” and “uhd_usrp_probe” do not detect the
device and say “No device found…” (‘ping’ is still working though).
The strangest thing is even at this stage, “./OpenBTS” works fine even
at a re-run.

After all these drama, no (‘range’) network is detected by a properly
configured mobile phone. (Note: We have successfully placed calls and
SMS with almost same procedure using a PC instead of B-Pi).

I am bit confused here whether this is a deal of OpenBTS or GNURadio.
Does the processor speed come in to play in this scenario?

Any valuable suggestions would be highly appreciated.

Thank you.

Zamrath N.

3

Thanks for the early reply Ralph.

First of all, it is normal that the USRP is not detected anymore with
the uhd tools when it is claimed by OpenBTS. So this looks not alarming.

Note that our successful implementation did not have any issue with
UHD-USRP connection. It worked as it was before OpenBTS claims it. Hope
this is ‘actually normal’ without interrupting the main intended
functions.
Right? Could I know the reason for USRP connection loss?

Are you able to verify if RF is transmitted? Is there some spectrum
analyzer available, or a receiver that can tune into the used GSM
frequency, best is AM mode and open squelch, to see if a carrier is
present? This way you can find out if it transmits at all, and if so, it
must be continously, uninterruptes, without stuttering.

Yes. Oh no! Surely transmission LED (labeled A) is not working. Which
means
that there is a RF transmission problem in our build. Reading through
several threads on similar problem, I don’t think it is a hardware
issue,
rather software compatibility issue. What would be the remedy for this?

I assume your successful tests used the very same USRP, so the
frequency should not be off too far?!

Yes. The similar N210 version was tried with the same set of software.

Could you please address above issues.

Best,
Zamrath N.

On Tue, Mar 24, 2015 at 12:16 PM, Ralph A. Schmid, dk5ras
[email protected]

4

Hi Zamrath,

Could I know the reason for USRP connection loss?
there’s no connection loss – the USRP is just now talking to the
OpenBTS application, and won’t talk to other applications, including
uhd_usrp_probe.

Surely transmission LED (labeled A) is not working.
Ok, that means the USRP is not configured to receive samples, ie. the
software (OpenBTS) has not yet started to talk to it, possibly because
something went wrong. Since we already constantly cross-post with the
OpenBTS list (hi, people!), I recommend going through the output of
OpenBTS, and talking to the OpenBTS community about these messages.
I am bit confused here whether this is a deal of OpenBTS or GNURadio.
GNU Radio is completely unrelated to this problem – it’s not a part of
OpenBTS.
Does the processor speed come in to play in this scenario?
At this point, probably not. Even with a lot of Under-/Overflows, which
would be typical for a case of CPU bottleneck, the A LED should be
shining.

Greetings,
Marcus

5

Hi Marcus, Thanks for the instant tips. One question. As I aware the
latest
bug free UHD package is uhd-master. Though my last build was related
with
uhd-master, since I have tried different ways of GNURadio and UHD
installations (pybombs option, download-unzip-build option, debian
download),* I suspect a uhd version mismatch and thereby hindering the
USRP
transmission?* (Please pardon me for my lack of knowledge in this field.
And I am pretty sure that there should not be duplicate versions
though).

Hi Openbts,

  1. Please address the issues specified in previous threads.

  2. According to the link [1], once after OpenBTS build, should run,

ln -s …/Transceiver52M/transceiver .

whereas in another link [2], the executions are,

ln -s …/TransceiverRAD1/transceiver .
ln -s …/TransceiverRAD1/ezusb.ihx .
ln -s …/TransceiverRAD1/fpga.rbf .

Does this confuse the OpenBTS same as me? Does this have an impact on
the
issues given in 1)?

Thanks.

[1]
http://opensource.telkomspeedy.com/wiki/index.php/OpenBTS:_N210_Instalasi_OpenBTS
[2] https://wush.net/trac/rangepublic/wiki/BuildInstallRun

On Tue, Mar 24, 2015 at 8:59 PM, Marcus Müller
[email protected]