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Convergence - Intelligent System, Mobile Data Charging and PCRF

Abstract – My last post created some typical requests from regular readers about simplifying the post as most of the reader mentioned it was too technical and difficult to understand, PCRF the Liberator for Mobile Data Charging. So I am making my every effort to take care of their feedback and writing this as extended version of last one with much more simple language and example from real life. It's a learning for me like providers learning to Interface, with subscribers of different segments is not like a drag-and-drop GUI (Even though this will be difficult for some). Customers are 1st priority hence should be dealt like P1 service quality.

At present when MNO’s across the globe are hard-pressed for their revenues & pushed to increase service quality and increase new service portfolios. At the same time MNO’s are choosing a disruptive technologies and approach to serve digital services to consumers. Focus on Mobile data users who are on rise in multiple folds. Data charging is the amount charged to a mobile phone account for data access, which in most cases refers to Internet-based data.

Data charging usually follow either of two models i.e Pay-As-You-Use(Less then 1% contribution from my own experience) or Pre-Set(Bundles etc which is close to 99%). With the rise of smartphones, tablet PCs and the subsequent demand for web-based services, carriers have been trying to compete with each other with more attractive data charging schemes. With the pay-as-you-use data charging scheme, subscribers are charged based on either the total amount of hours used or the total amount of data downloaded.

Introduction - MNO’s are on progress with great speed to ensure and answer them self on how they can create a digital experience that their customers are shouting about or asking for. MNO’s working hard to ensure service control points remain at their side but present in a way to give experience of self control to consumers and provide services including call access and signalling control, service logic management, Basic data operation and processing. The general front-end processor or handset is mainly used to exchange data between other communication entities, for example, the message transfer between the handset and the pre-delivery service agent or business rules in providers system.

Any Online Charging System (OCS) or any typical IN system, which is a uniform charging platform that helps mno’s to charge voice, data, and multimedia services of fixed, mobile, and data networks. The charging & billing system helps mno’s to conform to the complicated operation environment, new services, different cooperators, and detailed customer types.

The charging & billing system can run on the Global System of Mobile Telephone (GSM) network, Code Division Multiple Access (CDMA) network, Time Division Multiple Access (TDMA) network, Session Initiation Protocol (SIP) network and Next Generation Network (NGN). In addition, the system can precisely realize the credit control to subscribers at a maximum. In this way, the risk of arrears can be reduced, and the revenue loss of carriers can be reduced accordingly for most of services. Sadly for data services it lacks behind for need of today’s time so here comes PCRF to compliment & fix all the potholes for mobile data charging.

Policy and Charging Rules Function i.e pcrf; that supports service data flow detection, policy enforcement and flow-based charging. PCRF is the part of the evolved packet core (EPC) and kind of saviour for provider so that it can satisfy more policy control use cases, faster, on policy enforcement infrastructure. 

Main Story - Convergence of - Intelligent System, Mobile Data Charging and PCRF was the biggest break through & reason for big smile on providers face. The IN (Charging and Billing System) system provides the functions such as Product management, Resource management, Rating and billing, credit control, recharge center, Call control and Customer care. The IN system is of good expandability and convergence. Through the convergence with external charging system, the IN system can provide a uniform charging platform, a uniform service management platform and a uniform customer care platform for prepaid subscribers, postpaid subscribers. The IN system provides a uniform charging platform and flexible charging policies for multiple telecommunication services, such as voice, short message, and data services used by prepaid and postpaid subscribers.

The IN system supports telecommunication services, such as voice service, short message service, data service, ring back tone service, and recharging services.  The web browsing service provides the online service through the web protocols. Mobile subscriber accesses an application server through a internet gateway to obtain information. Subscribers browses web pages, news, music, videos and pictures through a mobile terminal The IN system supports the charging and rental of a subscriber based on the contents, traffic, and duration of the web browsing service in conjunction with business rules defined under pcrf.

The IN system provides accurate and flexible charging methods, such as prepaid charging, postpaid charging, and credit-based postpaid charging. Issues that critically assesses the vulnerability of 3G/4G charging system. Discovery of loopholes in policy practice and weakness in charging system architecture was fixed with pcrf. As a result revenues moved in correct directions. Tight control of service quality is critical for operators to establish new business models and monetized services.

Attacks or fraudulent injections on charging & billing systems i.e the toll-free data access attack; attackers can access any data service from the mobile phone for any period of time free of charge. It exploits the policy loopholes when the operator allows for certain free services. In the stealth spam attack, attackers will inject arbitrarily large volume of spam data into the victim device, even after the target device has terminated its data service, thus fully unaware of such a spam. This attack exploits the architecture weakness of not using feedback from the user when making charging decisions, as well as features of Internet instant messaging applications (e.g., Skype or what’s app etc). Prototypes showed that both attacks were feasible and simple enough to launch over the operational 3G networks. In some experiments on two 3G networks from two US carriers showed that, the undercharge or overcharge traffic volume can go unbounded.

Pay as you go and pre-set are two different models and serves 2 different segments of customers. Pre-set model (data bundling) is based on the size of the Web page or downloaded data, in kilobytes or megabytes. Thus, pages with only text are less expensive than pages with images.With the pre-set charging scheme, subscribers are given a maximum download limit (data volume or quantity of data) per month. For example data plan features 10 GB of data access per month. Users can access the Internet as often as they desire until hitting the 10 GB limit. However, there are no extra charges for exceeding the limit. But, the user's download speed is curtailed until the next billing cycle (post-paid users) or disconnection of data services as soon as user runs out of his limit (pre-paid users) unless user recharge again. Pay-as-you-use is the cheaper data charging scheme for users only occasionally going online. Users who are frequently checking and wants to be on facebook , what’s app, tweeter, other messengers, browsing the web, watching YouTube and so on, this option turns to be killing expensive. Data bundles are best for this category.

Quality control enables operators to employ fair-use policies that limit subscriber service abuse and maintains network performance during peak traffic times. Undisputed & uninterrupted services in best-of-breed network policy control and class should be motive or actually is the motive for every service provider. The policy engine empowers hundreds of communications channels which are based on fair-use policies, congestion free management solutions, quota-based plans, and wildly innovative prepaid and postpaid subscriber services. Before commenting heavy capex of billions dollars on equipment and deployments, forward-thinking operators will carefully evaluate vendors and proactively measure the quality of service and policy management functions of their network devices. Validating mobile data service quality requires saturating the network with a high load of real-world mobile subscriber traffic, and measuring key performance indicators that identify quality of experience. The rapid growth in mobile broadband has been a great success story, but one that has left in its wake many challenges, as well as opportunities, for mobile operators. 

Rise and adoption of smartphones are major triggers for service providers to move in this direction. Smart devices in many markets now account for over half of new devices and total subscriber base, and extensive availability of applications and services, with video accounting for over half the traffic, has created a surge in the data load on the networks. Accommodating the increased traffic volume can be an expensive proposition for mobile operators, and yet discouraging subscriber use limits the opportunity for revenue growth. Tomorrow’s hot app or new service request can show up without warning, and service provider need to be able to move quickly to take advantage of new opportunities and respond to competitive threats. As subscriber will demand same service on same day. Its very impatient, service demanding at lower cost and always ready for new things market out there. By productizing policy control and making service definition accessible, mno’s needs to act when its required to act right now and now now. With the service delivery engines, launching any new service should swift and does not require any waiting. 

Fair charging, transparent charging should be motive of any service provider at all times. Marketing communication, educating your customer on price plans and usage policy should be the clear agenda and ready to avail information. I gave this example in my post in last year. for an instance if you move your network from 2G to 3G or from 3G to 4G and tell your customer to use the faster connection and enjoy speedy data next day customer will complain that you (Service provider) stolen his money and would never realise that his/her data now would not last for 30 days due to speed it may vanish in 15 days as package bought was on the total data amount not unlimited data under time bound package. When customer use 1GB data on 2G network it may take 30 days (Just for argument sake) and on 3G it might vanish in 22 days and on 4G it might take just 10 days to be consumed and customer says what!!!, where is my data!!, and accuse provider for stealing his data / money. When we advertise something like Limitless Possibilities and its very Easy To Use, this marketing language needs to be explained to customers in their own easy way as this looks very deceptively simple to use but impressively difficult for some 

Conclusion - Deep packet inspection (DPI) to gain actionable intelligence on traffic flows. Policy rules to define how to manage traffic based on information gathered through DPI, network resources, subscriber profiles, and offered services. Policy enforcement to implement policy at a granular level in real-time across the network, applying policy rules to DPI data. The joint implementation of DPI and Policy enables operators to optimize network resource allocation, to segment their subscriber-ship effectively, and to create value-based, personalized services. This in turn may lead to improved network performance and utilization, a higher perceived value for the service, lower churn, and expanded revenue opportunities. When service provider launch a super service that gives unlimited usage of the latest app, or just update fair-use policy, this needs time and clear communication.

The tight interdependency between DPI, policy rules and policy enforcement presents a strong case for integration, to enable mobile operators to leverage DPI data in defining and enforcing policy, while keeping complexity under control and enabling a fast time-to-market deployment. With PCRF capabilities and mno’s service delivery engine this is feasible. By leveraging prepackaged building blocks and setting own conditions and values, can design and deploy a new service in minutes, without worrying about what’s happening behind-the-scenes. The PCEF (Policy and Charging Enforcement Function) select a PCC rule for each received packet by evaluating received packets against service data flow filters of PCC rules in the order of the precedence of the PCC rules. When a packet matches a service data flow filter, the packet matching process for that packet is completed, and PCC rule for that filter shall be applied.


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