Implementation of a gsm BTS Using USRP

Hi,
I wanna know whether it is possible to implement the GSM BTS on USRP.
Supposing that i am an official of service providers (any cellular
company) and have access to all the information of that particular
Service provider. Can i implement the VIRTUAL BTS using USRP.
If yes, then How?
From where should i start doing that?

Thanks
Gohar