The Evaluation of the Efficient Prepaid Scheme TICA for All-IP Networks and Internet Services Abstract—Future all-IP networks will support a variety of high- value IP-based services including the upcoming integration of today’s non-IP services offered by mobile telecommunication pro- viders. Besides postpaid charging, prepaid charging will play an important role in all-IP environments due to the financial control of providers and customers, thus determining effective economic management means for Internet services. Since existing prepaid charging solutions do not meet imposed all-IP requirements, a novel approach—TICA (Time Interval Calculation Algorithm)— with three variants has been presented recently in [14, 16]. To prove its optimized performance for many service mixes fore- seen, this paper performs a thorough evaluation based on differ- ent scenarios. Additionally, comparing TICA’s overall perfor- mance with existing online charging solutions shows TICA’s promising results in terms of way smaller quantity of credit checks required and smaller financial risks for providers to be achieved. Finally, the three TICA variants reveal a clear sensitiv- ity to defined input parameters. These findings indicate that a numbers of suitable settings can be used by service providers. Keywords: Prepaid Charging, Economic Management, Perfor- mance Evaluations, All-IP Networks, Internet Services I. INTRODUCTION Prior to the introduction of the World Wide Web (WWW), the Internet had the status of a scientific and non-commercial network. The commercialization of IP-based services shifted this status and today the Internet is an important global eco- nomic domain. However, the IP-based Internet is not (yet) the basis for all communication networks—especially for mobile environments, where non-IP mobile telecommunication net- works represent an anti pole to the IP-world. As opposed to the Internet, mobile telecommunication networks were always eco- nomic driven, which led to a dense global penetration [3]. Typically, service providers were used to set the focus for offering their services in either of these two domains. However, since a small number of years, this situation is changing and service providers start to serve both domains. But for service providers this coexistence of non-IP and IP-based networks causes many technical and economic issues. A concept to har- monize these two worlds is the so-called “All-IP Approach”, [19, 6]. Although all-IP sounds like wrapping the IP-world around the non-IP, instead from a conceptual point of view all- IP means to merge the most sophisticated features and func- tionalities from both worlds [20]. One particular and wide- spread feature of non-IP mobile telecommunication networks is that service providers aim to port their services to IP and apply economically important charging schemes, especially prepaid charging. Since its introduction in 1995, Mobile Network Op- erators (MNO) apply the prepaid charging option widely for their circuit-switched services and the global average penetra- tion has reached more than 50% in 2005 [3]. The customer de- mand for the prepaid charging option will also be present in an all-IP environment. Therefore, a flexible and efficient prepaid charging solution is a precondition to enter all-IP markets for service providers. For the classical circuit-switched services, the telecommu- nication market is already close to complete saturation. The only way to stabilize or even increase the Average Revenue Per User (ARPU), is for MNOs to increase the revenue made with packet-switched—i.e. IP-based—services. The customers’ fa- vor for prepaid charging will carry over to IP-based services. Therefore, in the telecommunications market, MNOs must of- fer the prepaid charging option for IP services in order to satis- fy and serve the prepaid customer market segment. To increase the added value, future IP services will be more sophisticated than simple “Internet Access”. However, existing prepaid charging systems in IP-based networks and particularly prepaid charging systems for traditional non-IP mobile telecommunica- tion services give too few support to high-value and QoS-en- abled IP-services. Therefore, the novel approach TICA has been proposed [14]. While current prepaid approaches suffer from a large over- head of credit checks, the first of the key advantages of TICA is the reduction of real-time credit checks during prepaid service consumption. Every real-time credit check consumes resources of the provider’s network and represents a considerable cost- driver of the total service costs. Traditional prepaid systems re- duce the number of credit checks at the cost of an increased risk of revenue loss due to overuse of credits. However with TICA, the number of credit checks is reduced, while minimizing the risk of revenue loss. In order to prove TICA’s applicability in all-IP environments, this paper performs thorough evaluations based on different scenarios. The second key advantage is TICA’s support for sophisti- cated and flexible tariff functions. A flexible and user-incentive pricing is an important instrument allowing MNOs to maxi- mize their ARPU and to differentiate from competitors. Such novel pricing schemes are also important to minimize churn: Pascal Kurtansky 1 , Peter Reichl 2 , Burkhard Stiller 1,3 1 Computer Engineering and Networks Laboratory TIK, ETH Zurich, 8092 Zurich, Switzerland 2 Telecommunications Research Center, ftw. Vienna, Austria 3 Department of Informatics IFI, University of Zurich, Binzmühlestrasse 14, 8050 Zürich, Switzerland E-mail: Kurtansky@tik.ee.ethz.ch, Peter.Reichl@ftw.at, Stiller@ifi.unizh.ch