Charging in Mobile Telecommunication Networks

Background

Although UMTS introduced lately and the charging protocol hasn’t changed significantly since GPRS (General Packet Radio Service) was introduced somewhere at the end of the 20th century, different phases of the standard are still under development. 3GPP (3^rd Generation Partnership Project) specifies guidelines and recommendations for the network elements, and the standards are detailing two different types of charging methods: offline and online charging (3GPP, 2004).

An actual service request might be pre-paid or post-paid, depending on whether the price of the requested service is paid before, or after the consumed service. Most telecommunication company groups their subscribers into two sets. Pre-paid subscribers may only require services in pre-paid mode, so they have to top up some amount of money to their balance, and may only require services until their balance covers the price of those requests. Post-paid users may gain services anytime (at least until their un-paid balance does not exceeds a given security threshold), and may pay the prices of those services in predefined periods. However, these subscribers types are straightforward and most common, telecommunication companies may introduce novel subscriber types and may set up or dismiss restrictions regarding the type of services and payment mode. The connection between the payment mode (pre-paid and post-paid) and charging method (offline and online) are detailed later.