Overview of content tariffs employed by world’s leading mobile operators. Content billing for mobile operators. Standard Internet services. Trends in 2.5/3G network billing.

Tariffs Used by World’s Leading Mobile Operators

Study of tariffs offered by leading operators in Europe and USA singles out several basic approaches to service rating. They are listed below in order of frequency:

• Usage-based rating without traffic differentiation. Applied to charge traffic generated by various services. The scheme is widely used by postpaid operators. The scheme is most common among prepaid European operators. Postpaid tariffs are mainly targeted at corporate customers, while individual customers use prepaid tariffs.
• Event-based rating. Used to charge one-time content download and e-mail services for both prepaid and postpaid customers. Combined with event-based and usage-based options, the scheme is very popular among mobile operators, i.e. downloaded items are charged along with incoming traffic.
• Unlimited rating. Widespread in the USA to charge subscribers for unlimited Internet access.
• Usage-based rating with traffic differentiation. Basically used to separately manage mobile content, e-mail and Internet access tariffs. Less common than the flat rate option, often combined with event-based rating.
• Duration-based rating. Alternative to usage-based rating, this technology is mostly used by European UMTS and WLAN (Wi-Fi) operators.

The information above is summarized in the following table

Tariff	IP Services	Market	Example
Postpaid Usage-based Unified	Internet access e-mail Mobile content	Corporate customers	Europe: O2, T-Mobile, Vodafone
Postpaid Usage-based Flexible	Internet access e-mail Mobile content	Individual customers	Europe: O2, T-Mobile, Vodafone
Postpaid Event-based Flexible	Mobile content e-mail	Individual customers Corporate customers	Europe: O2, T-Mobile, Vodafone
Postpaid Unlimited Flexible	Internet access e-mail Mobile content	Individual customers	USA: T-Mobile
Prepaid Usage-based Flexible	Internet access e-mail Mobile content	Individual customers	Europe: T-Mobile
Postpaid/prepaid Duration-based Uinfied	Internet access e-mail Mobile content	WLAN users	Europe: A1

Classic Internet Services for Mobile Customers

The study shows that both postpaid and prepaid mobile operators tend to use simpler tariffs than their Internet counterparts. Still the question arises whether it is possible to apply flexible tariffs and zone-based rating to telematic services (access to e-mail and game servers) offered by LAN operators, xDSL and home network providers? The answer is “Yes!”

The main drawback of this technology is that mobile subscribers are not assigned static IP addresses in the network; therefore, it requires additional resources to identify network traffic. You can very well allot IP addresses, but supporting them eventually turns out to be quite expensive. The solution is to correlate mobile (MSISDN, IMSI) and IP network data. The picture below shows how to achieve this. In this system traffic is identified by zone or by application. Equipped with such tools, operators can introduce specific tariffs that would individually cover gaming, mail services, etc.

CBOSSip is based on that principle. The solution aggregates details based on analyzed correlation between RADIUS statistics from GGSN/PDSN and Netflow statistics from routers. As a result, mobile operators benefit from the following:

• Postpaid volume-based rating

• Zone-based tariffs

• Statistics details can be stored for further use

Therefore, the solution’s advantages are the following:

• Static and dynamic IP addresses;

• Support of standard features and telecommunication protocols employed by telecommunication equipment.

Modern Approaches to Data Service Rating in 2.5G/3G

Success of any service promotion is directly dependent on flexibility of offered tariffs. In packet data networks where multiple sessions are simultaneously executed via a single customer terminal, rating efficiency and speed requirements are soaring.

Presently, there are two main approaches to build prepaid billing solutions for data transmission service in 2.5G/3G networks.

The first one focuses on the mobile network telecommunication equipment that supports standard protocols (e.g., CAMEL3), the second - implies the use of IP network gateways.

The first approach addresses the main task – packet data transmission in the Prepaid scheme - and supports roaming and various value-added services (SMS, EMS, MMS, USSD). However, if this is a preferred option, the operator is unable to make use of flexible rating or rating by zone and by content. Besides, CAMEL3 is not that simple to obtain and it is usually rather expensive.

In the Proxy gateway technology the traffic is routed via allocated servers. Consequently, rating covers all the traffic both ways (from/to the subscriber). The option is most suitable for data transmission services and allows further extending the set of offered services and introducing content-based services. However, the downsides of the scheme – degraded system performance and scalability, as well as features to align supported standards to a single rating pattern, should not be overlooked.

The results are specified in the table below.

	Camel III	Proxy
Deployment Requirements	Camel Phase III support	High performance Proxy Gateway
Roaming Support	Enabled	Can be implemented on IN platform
Support of special rating protocols (SMS, MMS, USSD, etc.)	Enabled	Restricted
Traffic differentiation	Disabled	Enabled
Content rating differentiation	Disabled	Enabled
Application field	GSM	GSM, CDMA, Wi-Fi, etc.
Implementation costs	Expensive	Cost-effective

We should stress that the specified options are not necessarily to be used cooperatively, but are rather to complement each other. The operator opts for the technology that better suits customer demands and technical equipment parameters.

Content Billing Implementation by Mobile Operators

Content-based services are a promising innovation, which allows the mobile operator to enter into a lucrative segment of the market. Subscribers, too, capitalize on anonymous and transparent access to premium resources with automatic account debiting. Let’s dwell upon how content-based services are implemented and what schemes are used to interact with the content provider.

The easiest solution is, apparently, to sale content based on traffic cost. In this case, with little modification to current networks and billing infrastructures, mobile operators raise their profits and boost the use of basic data services.

This approach addresses the central issue - transparent subscriber authorization. The range of IP addresses for which password authorization should be disabled is disclosed to the content provider. It is obvious, that the scheme is good for cheap content with approximately equal ratio of unit price and traffic volume. That is seen as the main limitation of the scheme.

Characteristics:

• Anonymous access to content resources.

• Charging associated traffic only.

Advantages:

• Profits increased through extended use of basic services

• Current infrastructure employed.

• No specific requirements.

• Transparent settlement scheme.

Disadvantages:

• Can be applied only to cheap content with approximately equal ratio of unit price and traffic volume.

Volume-based rating, apparently, will for long remain an accounting scheme of choice, especially for large volume content (DVD films), since it allows content delivery via low bandwidth channels using various downloading tools. Nevertheless, usage-based rating seems to be more complex than other methods, e.g., small volume content (mp3, mobile game, books) is charged per event, streaming content (TV-and-radio broadcast via the Internet) using time-based rating.

Rating Types and Their Application Areas

• Subscription: information web sites (news, jokes, ratings, etc.)

• Event-based: small volume content (mp3, games, post cards, images)

• Time-based: streaming content (Internet TV/radio)

• Volume-based: non-streaming, large volume content (DVD files, ZIP archives…)

Presently, there are two main approaches to enhance flexibility in content rating: the first one – specified earlier in this report - is to use Proxy gateways, the second – to delegate both controlling and accounting to the service provider.

Let’s consider the both approaches in terms of content rating.

Proxy Gateways

Characteristics

• IP stream identification and classification.

• Content identification.

• Rating event generation.

• Session management.

Advantages:

• Prepaid rating of IP traffic and content

• Flexible IP content and traffic rating

• Double rating (traffic and content) eliminated

• Diverse network access technologies

Disadvantages:

• Not applicable for accounting specialized applications

• Not applicable for encrypted communications channels

Additionally to the content rating, the first approach provides flexible Prepaid rating for data services. Besides, only this scheme cures double charging (for the content and associated traffic, including collateral and advertising information that is usually featured during the content sale).

However, Proxy Gateways can hardly be used to account complicated business transactions operated by specialized applications, e.g., in mobile commerce.

Another way to address the issue, as it was specified earlier in this report, is to delegate control and accounting to the content provider. This implies the provider would interact with the billing system via the standard protocol.

Provider’s Content Accounting Scheme

Advantages

• The content provider is encouraged to lead an independent tariff policy

• Special content transmission protocols are supported

• Capability to transmit content via encrypted channels is enabled

Disadvantages

• Double charging (Double charging for content and traffic)

• Not applicable for streaming services and large volumes

Therefore, it is obvious that each of the specified solutions has certain disadvantages along with advantages. At the same time, the options do not overlap functionally and should be considered not as alternatives, but complementary to each other. CBOSS Association favors every approach its clients may accept and is willing to assist in practically meeting their needs.

© Airat Gumerov, CBOSS
© Edited by Alexey Boyko, Mobile Forum