1. Introduction

In the previous PCC document [1], our main focus in discussing PCC rules was on QoS rules. Now, this document puts more focus on charging rules, specifically offline charging rules.

In LTE networks, services are charged at a bearer (e.g. EPC), subsystem (e.g. IMS) or service level (e.g. MMS), either by online or offline [2].
In online charging, when a user requests network resources, the network runs an account query and decides whether to grant permission or not before it actually let the user use the requested network resources. In this case, the network resource usage by the user is measured in real time, and thus charging information has a real time effect on service provision. This method is used for prepaid plans.

On the other hand, in offline charging, a user is charged for the network resources that he already used. That is, the network reports the resource usage by the particular user by forwarding his CDR (Charging Data Record) to its billing domain. Information on the user’s usage is collected on a regular basis, or at the end of each session. Hence charging information does not have a real time effect on service provision.

In general, online charging is used in prepaid plans while offline charging is used in postpaid plans. For example, most mobile users in Korea are postpaid plan holders¹, and thus subject to offline charging policies. Holders with this type of plan use services (e.g. Internet or voice service) first, and their operators charge them later for their usage monthly. Globally, there are more prepaid plan holders than postpaid plan holders. Prepaid plan holders pay in advance and thus their quotas are secured. Once their quotas are exceeded, active service sessions are terminated.

This document will discuss a charging procedure used when applying offline charging policies at a bearer level to a postpaid plan holder using the Internet service.

This document is organized as follows:

Chapter 2 provides an overview of charging-related interfaces and how offline charging works and

Chapter 3 explains the offline charging procedure.

Chapter 4 summarizes CDR parameters, offline charging parameters.