Check for proper clock of the USRP. My experience with a TCXO is, when watching the system while heating up and settling its frequency, more and more phones start finding the BCCH. Some older Motorolas and Nokias even then hardly find the signal. They were known for this already in the 90ies, so I do not see there a problem of OpenBTS. Those phones lock their internal clock too strict to the commercial carriers they find, so the slightest variation of your USRP clock makes your signal invisible to them. In a shielded environment, when your BTS is the one and only BTS and nothing else can be found by the phone, usually there are no problems to register.

 

Ralph.

 

From: Daniel Melo [mailto:danielr.films@gmail.com]
Sent: Friday, 14 September, 2012 05:23
To: openbts-discuss@lists.sourceforge.net
Subject: [Openbts-discuss] Question

 

Hello,

My configuration for OpenBTS is:

1- USRP1 with one daughterboard RFX900
2- OpenBTS 2.8
3-GNURadio 3.4.2
4-Asterisk 1.4
5-Ubuntu 10.04
6-Clock Tamer GPS 1.2

I have two phones Nokia 1100 and BlackBerry , OpenBTS it works , Nokia 1100 take the Network (00101) but Blackberry doesn't .
OpenBTS doesn't errors. Why some Phone take the network and the another dont?.

thanks for your colaboration