GSM not detecting station, USRP N210


I’m having a lot of trouble here while trying to make openBTS work with
my USRP N210
to play with GSMs.
First of all, a little description of my setup:
openbts v5.0
UHD from git
OS: ubuntu 14.04 LTS 64 Bit

My phones cannot find the network, I’m trying with a LG L80 and sony
experia, whereas all indicator led in USRP N210 is on. And
usrp_uhd_probe not trouble.

I would be glad if somebody had an idea where I could look next.

With best regards,