offline charging system (OFCS)
The Offline Charging System (OFCS) is a component of the Policy Control and Charging(PCC) of LTE networks.
Offline Charging uses the information about the connections and the mobile services used that it receives from the Policy and Charging Enforcement Function( PCEF) to calculate the costs that the billing system charges to the subscriber. The billing file is called the Charging Data Record( CDR) in mobile networks. The offline charging system is connected to the PECF component via a G interface (Gz).