A global study about Charging Correlation

The 3GPP standard body has defined the online charging system (OCS) as the central point in the charging architecture and Diameter Ro as the standard interface for enabling online charging in today's converged IP networks. It results in more and more heterogeneous telecom services charged by the online charging system. On top of that, operators want to deliver a consistent rating policy and aggregated billing information to their customers. As a result, there are emerging requirements for correlating lots of charging requests coming from the network into few elements rated at OCS level. This correlation of several charging requests (called ¿Charging Correlation¿) is currently identified in various documents (such as 3GPP TS32.240 or TS32.296). However, up to now, it has never been addressed in detail. For this reason, this document presents the various use cases where ¿charging correlation¿ is needed in IMS (IP multimedia subsystem), EPC (evolved packet core) and Wimax context. Then, the document describes the impact of the use cases at network level and at online charging system level.