Capture of gprs packets through usrp 2

Hi I'm using USRP kit to deploy a gsm network and then integrate gprs service into it to later capture gprs packtets. For now just the gsm network has been deployed and i began to capture its packets but unfortunately, i can not find any method to capeter my communication. I found out that wireshark is dependent on OS. I'm working on Linux 12.04. Any help would be appreciated.