Efficient Prepaid Charging for the 3gpp Ip Multimedia Subsystem (ims)

Over the last years, prepaid charging has become an essential option for the billing of telecommunication services. However, the evolution toward QoS-enabled AllIP networks, like the 3GPP IP-Multimedia Subsystem (IMS) and corresponding Next Generation Network (NGN) services, is posing increasingly complex requirements to the real-time capabilities of such a charging mechanism. In order to cope with those arising difficulties, it has been proposed recently to reduce the complexity of the credit checking procedure for multiservice environments by mapping all relevant variables into a scalar parameter, which can be interpreted as timeuntil-next-check. In this paper, the resulting TICA mechanism (Time Interval Calculation Algorithm) is adapted and enhanced in the context of a prototypical IMS test-bed. Thus, the solution-oriented billing framework, using statistical models and different prepaid use cases, is discussed and evaluated. A reality-driven parameter optimization for this promising approach is derived, both in terms of technical overhead and economic efficiency.