The present document intends to study the impact of the evolved 3GPP system architecture with respect to charging. The study covers the relevant non-roaming and roaming use cases for both 3GPP and non-3GPP accesses specified in TS 23.401 and TS 23.402. The study aims at producing recommendations for the following aspects:

• 3GPP work item and specification structure;
• charging requirements and principles;
• charging architecture and charging scenarios; and
• charging data and protocols.

The aspect of charging requirements and principles includes the study of the reuse of 3GPP Release 7 charging specifications.