Ashraf -

Once your phone shows a "real" network, it will almost certainly not camp to your test BTS.  The real network is much more appealing.

You main problem is probably a clock offset error.  There was a posting about that on this lis a few weeks ago.  Search the archives and I'm sure you'll find it.

The best way to avoid this problem is to get handset that supports GSM850 and test in that band.  That way, the GSM850 handset will not see any BTS but yours.  Failing that, you will just need to reset the phone (power off and remove/replace the battery and SIM) and keep trying until the phone stumbles onto your signal before it sees the real network.

The spectrum survey was prudent.  Do a similar survey before trying the 850 band, too.  That said, I am not familiar with the regulations in Egypt nor with your testing facility and nothing here constitutes legal advice.  (You'd think that'd be obvious, but...)

Of course, none of this explains the lack of signal on the spectrum analyzer.  How was the USRP connected to the analyzer?

-- David


On Jun 16, 2009, at 12:18 PM, Ashraf Gouda wrote:

Dear David,

I have tried again till reach "uptime 484 seconds" so maybe what i've done to register on the OpenBTS using Nokia 3310 was wrong . well, i am using "manual" from "Network selection" and wait to search for GSM network, is that right? 

  • I am operating in Egypt.
  • I have already performed a spectrum survey using usrp_fft.py to avoid frequency in use e.g " ARFCN 57 , 44, 49, 51 "
  • Carriers are " Vodafone, Mobinil and Etisalat "
  • I am using a SIM of one of those carriers " Mobinil " ... however i've used different frequency , does that make a difference?
  • Astersik is running and zoiper registered.
  • Yes the handset shows "Mobinil" when i am trying to search for a new GSM network.
OpenBTS.config changed to be
  1.  MCC=001 and MNC=01.
  2. ARFCN 975
the daughterboards are well-seated.

about spectrum analyzer , i set ARFCN 25 and tuned the SA to 940M but i didn't detect activity there.

Thanks
Best Regards,
Ashraf 



David A. Burgess
Kestrel Signal Processing, Inc.