Content for  TS 32.277  Word version:  18.1.0

For ProSe Direct Discovery and EPC-level Discovery services, as described in TS 32.240, the CTF (an integrated component in each charging relevant ProSe Function) generates charging events and forwards them to the CDF. The CDF, in turn, generates CDRs which are then transferred to the CGF. Finally, the CGF creates CDR files and forwards them to the Billing Domain. If the ProSe Function generating the charging information has an integrated CDF, then the ProSe Function can produce CDRs. The CGF may also be integrated in the ProSe Function, or it may exist as a physically separate entity. If the CGF is external to the ProSe Function, then the CDF forwards the CDRs to the CGF across the Ga interface. In this case, the relationship between ProSe Function/CDF and CGF is m:1. If the CGF is integrated in the ProSe Function, then there is only an internal interface between the CDF and the CGF. In this case, the relationship between ProSe Function/CDF and CGF is 1:1. If the CDF is external to the ProSe Function, the charging events are transferred from the ProSe Function to the CDF via the Rf interface specified in TS 32.299. In this case, the relationship between ProSe Function and CDF is m:1. When an external CGF is used, this CGF may also be used by other, i.e. non-ProSe, network elements, according to network design and operator decision. It should be noted that the CGF may also be an integrated component of the BD - in this case, the Bx interface does not exist and is replaced by a proprietary solution internal to the BD. Figure 4.2.1 depicts the architectural options described above.

For the ProSe Direction Communication Service, the CTF is divided into two functional blocks as described in Annex D of TS 32.240. The Accounting Metrics Collection (AMC) function block is in the UE. The AMC sends usage information collected to the Accounting Data Forwarding (ADF) function block of the CTF in the ProSe Function over the PC3 reference point defined in TS 23.303. The subset of PC3 specific to usage information collection for charging purposes is denoted as PC3ch in Figure 4.2.2.

The PC3 protocol shall allow the following deployment options for the ProSe Function CTF (ADF) for ProSe Direct Communication depicted in Figure 4.2.2:

• The ProSe Function CTF (ADF) for ProSe Direct Communication may be deployed in the same system as any combination of the ProSe Function components defined in clause 4.4.1 of TS 23.303 (i.e. Direct Provisioning Function, Direct Discovery Name Management Function, EPC-level Discovery Function).
• The ProSe Function CTF (ADF) for ProSe Direct Communication may be deployed in a logically or physically separate system from the ProSe Function components defined in clause 4.4.1 of TS 23.303. To support this deployment scenario, the PC3ch subset of the protocol for usage information report delivery shall not require interaction with any other ProSe Function component for successful and complete processing.

The network ensures that the UE can have IP access to its HPLMN ProSe Function, in non-roaming and roaming case, as defined in TS 23.303. When the UE is out of coverage, PC3 reference point is not available. UE will store the logged information and upload to the ProSe Function once the PC3 becomes available and the reporting criteria are met. UE's reporting of usage information is only visible to the ProSe Function. It is mandatory to support at least one of the options Rf, Ga or Bx interfaces from the ProSe Function as described in the specification.

ProSe online charging is based on ProSe function utilizing Ro interface and application towards the OCS as specified in TS 32.299. The Ro reference point covers all online charging functionality required for ProSe.