WO2008068121A2

WO2008068121A2 - Online charging in roaming cases

Info

Publication number: WO2008068121A2
Application number: PCT/EP2007/061866
Authority: WO
Inventors: Kari RONKÄ; Anne NÄrhi; David Banjo; Juha-Pekka Koskinen; Sanna MÄENPÄÄ; Benni Alexander
Original assignee: Nokia Corporation
Priority date: 2006-12-05
Filing date: 2007-11-05
Publication date: 2008-06-12
Also published as: WO2008068121A3

Abstract

The invention relates to online charging in roaming cases. A credit control request for a visiting subscriber is sent to a gateway charging control unit in a visited network. A corresponding credit control request is sent from the gateway charging control unit to a network entry node of a home network of the subscriber and forwarded to a charging control unit of the subscriber's home network. Credit control is executed for the roaming subscriber by the charging control unit of the subscriber's home network, and a corresponding response is sent back in reply to the credit control requests.

Description

ONLINE CHARGING IN ROAMING CASES

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a mechanism usable for charging control in roaming cases. In particular, the present invention is related to a framework with which roaming subscribers can be charged online for the use of services delivered by a network node in a visited network.

For the purpose of the present invention to be described herein below, it should be noted that

- a user equipment may for example be any device by means of which a subscriber may access a communication network; this implies mobile as well as non-mobile devices and networks, independent of the technology platform on which they are based; only as an example, it is noted that communication equipments operated according to principles standardized by the 3^rd Generation Partnership Project 3GPP and known for example as UMTS terminals are particularly suitable for being used in connection with the present invention;

- contents of services requested by the subscriber as used in the present invention may include any service, such as, for example, multimedia services for communicating data of at least one of audio data, video data, image data, text data, and meta data descriptive of attributes of the audio, video, image and/or text data, any combination thereof or even, alternatively or additionally, other data such as, as a further example, program code of an application program to be accessed/downloaded; - method steps likely to be implemented as software code portions and being run using a processor at one of the entities described herein below are software code independent and can be specified using any known or future developed programming language;

- method steps and/or devices likely to be implemented as hardware components at one of the entities are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS, CMOS, BiCMOS, ECL, TTL, etc, using for example ASIC components or DSP components, as an example;

- generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the present invention; - devices or units can be implemented as individual devices or units, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the functionality of the device/unit is preserved.

Related prior art

In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) communication networks like the Universal Mobile Telecommunications System (UMTS) , cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM) , the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolutions (EDGE) , Worldwide Interoperability for Microwave Access (Wimax) or other wireless communication system, such as the Wireless Local Area Network (WLAN) , took place all over the world. Various organizations, such as the 3^rd Generation Partnership Project (3GPP) , the International

Telecommunication Union (ITU), 3^rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), and the like are working on standards for telecommunication network and multiple access environments.

In general, the system structure of a communication network is such that one party, e.g. a subscriber's communication equipment, such as a mobile station, a mobile phone, a fixed phone, a personal computer (PC) , a laptop, a personal digital assistant (PDA) or the like, is connected via transceivers and interfaces, such as an air interface, a wired interface or the like, to an access network subsystem. The access network subsystem controls the communication connection to and from the communication equipment and is connected via an interface to a corresponding core or backbone network subsystem. The core (or backbone) network subsystem switches the data transmitted via the communication connection to a destination party, such as another communication equipment, a service provider (like a server/proxy), or another communication network. It is to be noted that the core network subsystem may be connected to a plurality of access network subsystems. Depending on the used communication network, the actual network structure may vary, as known for those skilled in the art and defined in respective specifications, for example, for UMTS, GSM and the like.

Generally, for properly establishing and handling a communication connection between network elements such as the user equipment (or subscriber terminal) and another communication equipment or terminal, a database, a server, etc., one or more intermediate network elements, such as network control elements, support nodes or service nodes are involved. Network control elements, such as a Mobile

Switching Center (MSC), a Serving GPRS Support Node (SGSN), gateway nodes, such as a Gateway GPRS Support Node (GGSN) , or the like, are responsible for controlling the call establishment, call control, call termination, and the like.

In current telecommunication systems, such as cellular telecommunication systems, mechanisms are provided that enable a user to be authorised to use services provided within his or her home network. There are also known certain mechanisms that authorise network access in home and visited networks.

However, in telecommunications systems, a generic, service- based mechanism is needed to authorise the use of services offered by a network to visiting subscribers. Such a mechanism would need to obtain certain subscriber attributes from the home network in order to perform authorisation, for example, for the usage of a service offered by a visited network. This authorisation can be partially provided by mechanisms such as AAA

(Authentication, Authorisation and Accounting) , or VPLMN (Visited Public Land Mobile Network) access attributes defined in the GSM/GPRS HLR (Home Location Register) . The 3GPP standards define various control mechanisms and parameters (e.g. in 3GPP TS 23.060) that are stored within an HLR dictating whether a subscriber may utilise visited network services, and what charging characteristics (e.g. normal, prepaid, flat-rate, and/or hot billing subscription) apply to the subscriber or PDP context. These mechanisms are bearer specific and do not support per- service charging well. In particular, these mechanisms do not support on a per-service basis for a given subscriber determination of service authorisation, charging method or charging system address. Further, certain authentication protocols such as RADIUS and Diameter are typically used for network access authorisation .

In document WO2006/067265, a method for providing charging attributes is disclosed. In detail, a method is described for authorizing services for visiting subscribers and for obtaining the necessary charging profile information from the subscribers' home network on a per-service basis. For providing charging attributes in a communication system, a service authorization request is sent to a service authorization node in a visited network and a charging attribute request is transmitted to a request receiver in another network, such as the home network of the subscriber. Here, it is determined which charging attribute storage node can satisfy the charging attribute request. Then, charging attribute information are transmitted from the corresponding charging attribute storage node. On the basis of this information, a service authorization reply is sent by the service authorization node. Thus, a visiting subscriber is enabled to use a specific service, it is possible to resolve how the subscriber should be charged, and to resolve the charging server or the balance server to which credit control messages should be directed.

However, there is a problem when a roaming subscriber requests access to a service in a visited network and is to be charged online for the use of such services which are delivered, for example, by a network node like a gateway node in the visited network. In such cases the subscriber's account balance is kept in his/her home network, while the subscriber needs to be authorised (for credit control) for the use of the services in the visited network. Thus, it is necessary that the visited network, which is capable of rating its local services, and the requesting subscriber's home network, which is capable of controlling the subscriber's account balance, interact with each other.

However, current solutions do not provide a standardised framework providing such an interaction possibility that could be used for charging online a roaming subscriber in such cases.

SUMMARY OF THE INVENTION

Thus, it is an object of the invention to provide an improved mechanism for online charging control in roaming cases. In particular, it is an object of the invention to provide a mechanism usable for charging a subscriber requesting a service in a visited network by means of providing a suitable method and framework allowing interaction between the visited network which is capable of rating its local services and the subscriber's home network which is capable of controlling the subscriber' s account balance .

This object is achieved by the measures defined in the attached claims.

In particular, according to one aspect of the proposed solution, there is provided, for example, a method comprising sending a first credit control request for online charging for a visiting subscriber to a gateway charging control unit in a visited network, sending a second credit control request from the gateway charging control unit to a network entry node of a home network of the subscriber, forwarding the second credit control request from the network entry node to a charging control unit of the subscriber's home network, performing credit control processing for online charging for the subscriber by the charging control unit of the subscriber's home network, and responding to the first and second credit control requests on the basis of a result of the credit control processing.

Furthermore, according to one aspect of the proposed solution, there is provided, for example, a charging control device configured to receive from a network control node a first credit control request for online charging for a subscriber visiting a network, and to send a second credit control request to a network entry node of a home network of the subscriber.

Moreover, according to one aspect of the proposed solution, there is provided, for example, a network entry node configured to receive, from a charging control unit of a network visited by a subscriber of the network entry node's network, a credit control request for online charging for a service requested by the subscriber from the visited network, and to forward the credit control request to a charging control unit of the subscriber's home network.

In addition, according to one aspect of the proposed solution, there is provided, for example, a charging control device configured to receive a credit control request from a network entry node for online charging for a service requested by a subscriber of the charging control device's network in a network visited by the subscriber, to perform credit control processing for the subscriber, and to send a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

Furthermore, according to one aspect of the proposed solution, there is provided, for example, a charging control device comprising receiver means for receiving from a network control node a first credit control request for online charging for a subscriber visiting a network, sending means for sending a second credit control request to a network entry node of a home network of the subscriber .

Moreover, according to one aspect of the proposed solution, there is provided, for example, a network entry node comprising receiver means for receiving, from a charging control unit of a network visited by a subscriber of the network entry node's network, a credit control request for online charging for a service requested by the subscriber from the visited network, and sending means for forwarding the credit control request to a charging control unit of the subscriber's home network.

In addition, according to one aspect of the proposed solution, there is provided, for example, a charging control device comprising receiver means for receiving a credit control request from a network entry node for online charging for a service requested by a subscriber of the charging control device's network in a network visited by the subscriber, processor means for performing credit control processing for the subscriber, and sending means for sending a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

Furthermore, according to one aspect of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a charging control unit, wherein the computer program product is configured to execute steps of receiving from a network control node a first credit control request for online charging for a subscriber visiting a network, and sending a second credit control request to a network entry node of a home network of the subscriber.

In addition, according to one aspect of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a network entry unit, wherein the computer program product is configured to execute steps of receive, from a charging control unit of a network visited by a subscriber, a credit control request for online charging for a service requested by the subscriber from the visited network, and to forward the credit control request to a charging control unit of the subscriber's home network.

Moreover, according to one aspect of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a charging control unit, wherein the computer program product is configured to execute steps of receiving a credit control request from a network entry node for online charging for a service requested by a subscriber in a network visited by the subscriber, performing credit control processing for the subscriber, and sending a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

According to further refinements, the proposed solution may comprise one or more of the following features:

- in the first credit control request service information for a service requested by the subscriber in the visited network may be received, then rating information on the basis of the received service information may be requested, and initial rating parameters may be allocated to the service requested by the subscriber;

- in the second credit control request the initial rating parameters may be included;

- in the credit control processing, a re-rating processing for the subscriber may be performed on the basis of the initial rating parameters and of subscriber specific information, then rating parameters resulting from the re- rating processing may be included in a response to the first and second credit control request;

- in the gateway charging control unit at least one of a mapping processing and a translation processing of information received by the first credit control request may be performed, and the second credit control request (or a response in the opposite direction) may be generated on the basis of the results of the at least one of the mapping processing and the translation processing.

By virtue of the proposed solutions, the following advantages can be achieved.

It is possible that the visited network being capable of rating its local services and the home network being capable of controlling the subscriber's account balance interact with each other in such a manner that the subscriber can gain access to services offered in a visited network and being charged correctly on the basis of a credit control performed in and subscriber and charging information obtained from his/her home network. This is possible by providing a specific charging control entity, such as a gateway Online Charging System (GW OCS) within the visited network. This specific charging control entity is adapted to request, for example, rating in the visited network, and to send a credit control request to the subscriber's home network. As an entry point to the subscriber' s home network, a specific network node such as a charging address function is provided to which the GW OCS sends the credit control request. This network entry node forwards, for example, the credit control request to a credit control entity of the subscriber' s home network, such as a corresponding OCS that is responsible for controlling the subscriber's account balance.

As a further advantage of optionally performing a (initial) rating in the charging control entity in the visited network, a correct rating of the service is possible since only the visited network has full knowledge of the services offered in this particular network, and is thus capable of rating the services.

As a further advantage of optionally performing re-rating in the home network charging control entity like an OCS, it is possible to consider specific subscriber information in the credit control process, like to have control over e.g. roaming premiums, discounts, etc.

As a further advantage of providing a specific network entry node to the home network for the request of the GW OCS, for example, by the use of the charging address function, it is possible for the home network operator to hide more easily the actual network architecture and to avoid direct contacts from foreign networks towards the actual charging system controlling the subscribers' accounts. Thus, network security is improved.

The above and still further objects, features and advantages of the invention will become more apparent upon referring to the description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a diagram for illustrating a network structure according to an embodiment of the invention.

Fig. 2 shows a block circuit diagram for illustrating further details of network elements according to an embodiment of the invention.

Fig. 3 shows a signalling diagram for illustrating a charging procedure according to an embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, embodiments of the present invention is described with reference to the drawings. For illustrating the present invention, the preferred embodiments will be described in a network environment comprising mobile access network subsystem and core network subsystem components, for example, according to the 3GPP specifications and/or in an IMS network environment. However, it is to be noted that the present invention is not limited to an application in such a network environments but is also generally applicable in other network types.

In Fig. 1, a schematic diagram of a network structure of a communication network is shown in which the present invention is applicable. It is to be noted that the structure according to Fig. 1 represents only a simplified example of an architecture of a communication network in which the present invention is applicable. As known by those skilled in the art, there are provided several additional network elements and signalling links or interfaces used for a communication connection. However, for the sake of simplicity, only those elements are depicted which are necessary for describing the invention. Furthermore, the network elements and their functions described herein may be implemented by software, e.g. by a computer program product for a computer, or by hardware. In any case, for executing their respective functions, correspondingly used devices, such as a communication equipment, core network control element like a gateway node and associated functions, an access network subsystem element like Radio Access Network RAN element, a charging control unit or entity, such as an OCS or GW OCS, and the like comprise several means and components (not shown) which are required for control, processing and communication/signalling functionality. Such means may comprise, for example, a processor unit for executing instructions, programs and for processing data, memory means for storing instructions, programs and data, for serving as a work area of the processor and the like (e.g. ROM, RAM, EEPROM, and the like) , input means for inputting data and instructions by software (e.g. floppy diskette, CD-ROM, EEPROM, and the like) , user interface means for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), interface means for establishing links and/or connections under the control of the processor unit (e.g. wired and wireless interface means, an antenna, etc.) and the like.

In Fig. 1, reference sign 10 denotes a user equipment or the like of a subscriber roaming into a network B (also referred to as visited network) . Reference sign 20 denotes a network control node, such as a gateway node (GW) , of the visited network with which the roaming subscriber 10 is communicating. Reference sign 25 denotes a charging control unit, such as an OCS, of the visited network B, which is connected via a corresponding interface to the visited GW 20. It is to be noted that the network B may comprise a plurality of different charging control units, such as one or more OCSs for online charging, or charging control units for offline charging, and the like. However, for the sake of simplicity, only OCS 25 is shown in Fig. 1. Reference sign 30 denotes a specific further charging control unit or device which is also referred to hereinafter as a gateway charging control unit or gateway OCS (GW OCS) . The GW OCS 30 is connected to the visited GW 20 via corresponding interface. The specific further charging control unit may be a physically separated entity or may be part of one or more of the other charging control units of network B (for example, a GW OCS entity 30 may be part of at least one other OCS node of network B) . Reference sign 35 denotes a rating unit or entity which provides data and parameters for rating local requests offered in network B, for example. The rating unit 35 is connected to the GW OCS 30 via corresponding interface, for example.

Furthermore, in Fig. 1, reference sign 40 denotes a network entry node for a home network A of the subscriber 10 via which the network B's nodes can communicate with the network A. The network entry node 40 is also referred to hereinafter as a charging address function (CAF) . The GW OCS 30 is able to communicate with the CAF 40 through a correspondingly established communication link, for example. Reference sign 50 denotes a charging control unit or device, such as an OCS, in the home network A of subscriber 10. It is to be noted that the network A may also comprise a plurality of different charging control units, such as one or more OCSs for online charging, or charging control units for offline charging, and the like. However, for the sake of simplicity, only OCS 50 is shown in Fig. 1. The OCS 50 is connected to the CAF 40 by means of corresponding interface, for example. Furthermore, the OCS 50 is connected via interface or the like to an account balance entity Generally, the charging procedure according to an example of the present invention is executed in the following manner. When a visiting (i.e. roaming) subscriber 10, who is to be charged online, requests some local service from the visited network B, e.g. from the visited GW 20, and a corresponding request is received by the visited GW 20, the visited GW 20 sends a (first) credit control request to the specific charging control unit 30 (i.e. the GW OCS) in the visited network B. The GW OCS 30 requests rating, for example for a currency value, for the service from the rating entity 35 in the visited network. Then, the GW OCS 30 sends a (second) credit control request to the subscriber's home network A, i.e. to the network entry node (the charging address function) 40, which serves as the entry point to the home network A of the subscriber. By means of this network entry node 40, it is possible to hide the actual (charging) network topology within the home network A (in other words, it is possible to hide the network architecture and to avoid direct contacts from foreign networks towards the actual charging system

(including one or more charging control units like OCSs and the like) controlling the subscribers' accounts). The charging address function 40 forwards the (second) credit control request to the OCS 50 in the subscriber's home network A, which OCS 50 being responsible for controlling the subscriber's account balance. The OCS (or target OCS) 50 in the subscriber's home network A performs now the credit control which may include a re-rating in comparison to the (initial) rating performed by the GW OCS 30, if necessary) against the subscriber's account. For this, the account balance entity 55 is contacted by the OCS 50. The result of the credit control (including possible re-rating) is responded back to the visited GW 20 along the same communication path, i.e. from the OCS 50 via the network entry node 40 and the GW OCS 30. In Fig. 2, a more detailed illustration of the specific charging control unit (or GW OCS) 30 of the visited network B, the network entry node (or charging address function) 40 of the subscriber's home network A and the charging control unit (or OCS) 50 of the subscriber's home network A as well as their connections with each other based on the network structure shown in Fig. 1 is given.

In the example according to Fig. 2, the GW OCS 30 as an example of the specific charging control unit of the visited network B comprises senders and receivers (in the following combined in a respective interface (I/F) unit; however, also separate receiver and sender functional entities may be provided) for connecting it with the visited GW 20 (via I/F 31), the rating entity or unit 35 (via I/F 33) and the network entry node 40 of the home network A (via I/F 34) . The I/Fs 31, 33 and 34 are each connected to a processor 32 (comprising, for example, a CPU, a memory and the like (not shown) ) which performs processing on a received (first) credit control request, (initial) rating for the service requested by the subscriber (with rating unit 35) , mapping and/or translating processing between first and second credit control request format (in dependence on the respective network systems used for networks A and B, for example) , generating (on the basis of the mapping/translating processing, for example) a second credit control request or first credit control response, and the like. This means that the specific credit control unit 30 may create a mapping between the two credit control sessions: the one from the visited GW 20 to the GW OCS 30 and the one from the gateway OCS 30 to the network entry node 40 (i.e. the charging address function) . Further details of the processing performed by the processor 32 are described below. The charging address function 40 as an example for the network entry node to the home network A comprises senders and receivers (i.e. interfaces) I/F 41 for communicating with the specific charging control unit of the visited network B (i.e. the GW OCS 30) and I/F 43 for communicating with the charging control unit (OCS) 50 of the subscriber's home network A. The I/Fs 41 and 43 are connected to a processor 42 (comprising, for example, a CPU, a memory and the like (not shown) ) for performing processing of the received credit control request from the GW OCS 30, for example, and a corresponding response from the OCS 50 as well as for forwarding them to the GW OCS 30 and the OCS 50, respectively. Furthermore, a memory 44 or the like is connected to the processor 42 for retrieving information related to the subscriber, such as an address of the OCS 50 responsible for credit control of the subscriber which is stored in the home network A. The memory 44 may be also provided in a separate network element in the home network A, such as a database or the like.

The credit control unit (OCS) 50 of the subscriber's home network A is provided with senders and receivers (i.e. interfaces) I/F 51 for communicating with the network entry node 40 and I/F 53 for communicating with an account balance entity 55 in the network A. The I/Fs 51, 53 are connected to a processor 52 (comprising, for example, a CPU, a memory and the like (not shown) ) for performing processing of the received credit control request from the network entry node, for executing the credit control for the subscriber, for example by communicating with the account balance entity 55, for re-rating the subscriber for using the service requested, and the like. Furthermore, a memory 54 may be provided storing subscriber specific information necessary for performing the credit control. Now, referring to Fig. 3, a further detailed example of the usage of the charging method according to the present invention is described.

Fig. 3 shows a signalling diagram for illustrating a charging procedure according to an example of an embodiment of the present invention. In Fig. 3, a GW OCS is employed as the specific charging control unit of the visited network, a charging address function (CAF) is employed as the network entry node of the home network A, and an OCS is employed as the charging control unit of the home network A.

Assuming a case where a subscriber (subscriber 10 of Fig. 1), whose home network is a network A, is roaming into a network B. In step Sl the subscriber requests in the network B, for example by contacting the visited GW, a local service in the network B. For the usage of this service, it is assumed in this example that the subscriber is to be charged online.

The visited GW processes the service request from the subscriber and resolves that the subscriber is to be charged online and is a visiting subscriber. This means that it is recognized that not the network B's OCS (like

OCS 25 in Fig. 1) is responsible for credit control but an OCS of the home network A of the subscriber (which can be contacted via the network B' s GW OCS entity (which may or may not be physically separated from the network B's other charging control units like OCS nodes) ) . Furthermore, as a further option, the visited GW resolves also the subscriber's home network (i.e. network A) identity. The visited GW may also resolve the address of the network entry node (i.e. the charging address function) into the subscriber's home network. Examples for mechanisms used for resolving these information, i.e. that, for example, the subscriber is to be charged online (or offline) , or that he/she is a visiting subscriber, or the address of the network entry node are given below. However, it is to be noted that the present invention is not restricted to the following mechanisms described below. There may be other existing or future mechanisms which can be equivalently used for resolving the necessary information for executing the charging procedure described.

A first example for resolving the necessary information in the visited network, for example, the address of the network entry node, that the subscriber is a visiting subscriber and how he/she is to be charged (online/offline, prepaid, postpaid and the like) is that disclosed in document WO2006/067265. After a roaming subscriber has initiated the use of a service provided by the visited network, the network node providing the service (e.g. a service flow aware GGSN network node), which may or may not know that the user is a visiting subscriber from another network, requests authorisation for the use of the specific service by the visiting subscriber. For example, it may be established that the subscriber is a visiting subscriber by means of a IMSI (International Mobile Subscriber Identity) analysis, and also the network to which the subscriber belongs. A service authorization node transmits a charging attribute request to a charging attribute request receiver node in the subscriber's home network, such as an External Profile Gateway. The requested profile attributes may for example include service authorisation, subscriber' s charging method, and charging server or control unit address (es) . The network address of the charging attribute request receiver node may for example be statically configured between cooperating networks, or may for example be dynamically discovered e.g. using a mechanism such as the mechanism known to a man skilled in the art as Liberty

Discovery. The charging attribute request receiver node determines which charging attribute storage node (or nodes) can satisfy the request received, and transmits the request to that storage node. The charging attribute storage node returns the results of the request, i.e. charging attribute information back to the attribute request receiver node, which transmits the charging attribute information back to the service authorization node. Finally, the service authorization node returns a service authorisation response to the network node providing the requested service. The service authorisation response may advantageously include the charging method (such as online or offline) applicable to the subscriber and service and, if required due to online charging, the address of the charging server or charging control unit or of the network entry node (the charging address function) to which further credit control requests should be directed.

As a second example for resolving the necessary information in the visited network, for example, the address of the network entry node, that the subscriber is a visiting subscriber and how he/she is to be charged (online/offline, prepaid, postpaid and the like) , access specific solutions are applicable, such as GPRS SGSN HLR query with information to the GW via GTP (GPRS Tunneling Protocol) signalling .

Returning to Fig. 3, since the visited GW has recognized that the subscriber requesting the service is a visiting subscriber, it knows that the specific charging control unit (i.e. the GW OCS) is to be used as being responsible for credit control concerning visiting subscribers roaming from other networks. As mentioned above, the GW OCS may be a physically separate entity of network B or being part (by providing corresponding hardware and/or software portions) of other network B's charging control units (like the OCS

25, not shown in Fig. 1) . Thus, in S2, the visited GW sends a (first) credit control request to the specific charging control unit, like a specific OCS called Gateway (GW) OCS, in network B. The (first) credit control request may be sent, for example, by using a predetermined protocol, such as Diameter (e.g. Diameter Credit Control). However, it is to be noted that the format of the credit control request is not limited thereto, but also another signalling type could be used, for example depending on the network structure. It is to be noted that the GW OCS may be a separate element or be a function implemented within a standard OCS (i.e. no separate network element is required) . In the (first) credit control request sent in S2, the visited GW may include a rating group and a service identification or other service information for the service requested. For example, in case the service to be charged is an IMS service, the visited GW may include the ICID (IMS Charging Identifier) to the (first) credit control request.

In S3, the GW OCS processes the received (first) credit control request. For example, the GW OCS resolves the identity of the subscriber' s home network (network A) . The identity of the subscriber' s home network may be indicated by the visited GW in the credit control request or analysed by the GW OCS itself. For example, the visited GW may know the network identity (e.g. by analysing the Mobile Country Code MCC or the Mobile Network Code (MNC) received a registration or in the request of the subscriber) of the visiting subscriber's owning network, and provide this in the credit control message. As a further possibility, when the visited GW does not provide this information, the GW OCS performs an own analysis for achieving the identity of the subscriber's home network, for example, by doing a lookup and match based on information present in the credit control message (for example, the IMSI can be used for this analysis) and locally maintained lookup tables. However, it is to be noted that there may be also other existing and future ways of achieving this information, and the present invention is not limited to the examples given here which serve only for illustrative purposes.

Similar to the way of determining the identity of the subscriber' s home network (network A) , the GW OCS may also resolve the address of the network entry node (the charging address function) in the subscriber's home network (network A) . For example, the GW OCS may maintain a routing table where the addresses of corresponding network entry nodes for associated networks can be found by using the network identity, or the address information may be transmitted from the visited GW (e.g. carried over a Gy interface) . In other words, the address of the network entry node (the charging address function) in the subscriber' s home network may be indicated by the visited GW in the credit control request or analysed by the GW OCS itself. For example, the visited GW may derive the address of the network entry node (the charging address function) in the subscriber's home network from the network identity (e.g. by analysing the Mobile Country Code MCC or the Mobile Network Code (MNC) received a registration or in the request of the subscriber) of the visiting subscriber's owning network, and provide this in the credit control message. As a further possibility, when the visited GW does not provide this information, the GW OCS performs an own analysis for achieving the address of the network entry node (the charging address function) in the subscriber's home network for example, by doing a lookup and match based on information present in the credit control message (for example, the network identity of the subscriber's home network, or IMSI can be used for this analysis) and locally maintained lookup tables. However, it is to be noted that there may be also other existing and future ways of achieving this information, and the present invention is not limited to the examples given here which serve only for illustrative purposes.

Further in S3, based on the credit control request received from the visited GW, the GW OCS may perform an initial rating for the service. This is done by communicating with a rating unit or entity of the network B which provides corresponding rating information for the service requested. For example, the rating may be done for a currency value to be used.

In addition, in S3, the GW OCS may perform translations/mappings on the information it has to send towards the subscriber's home network. The mapping/translation processing is based, for example, on the identity of the home network so that protocols and/or messages are used in the further transmission being understandable by the home network elements.

When the processing on S3 is completed, the GW OCS sends in S4 a (second) credit control request to the network entry node (e.g. the charging address function) of the subscriber's home network (network A) . For example, the (second) credit control request may be based on a predetermined protocol like Diameter (using e.g. Diameter Credit Control) . The content and format of the (second) credit control request is based, for example, on the results of the mapping/translation processing performed by the GW OCS (i.e. the second credit control request is generated by the GW OCS) . In addition, the (second) credit control request may comprise to the result of the (initial) rating, as well as further information received or determined in the processing, such as the rating group, a charging rule, and/or service charging information. If the charged service is an IMS service, the request may also comprise the ICID.

It is to be noted that the Gateway OCS executes the mapping/translation processing, if it is to be performed, also in the opposite direction when receiving a response from the network entry node of network A, which is to be forwarded to the visited GW. In other words, the GW OCS is adapted to perform mapping between two credit control sessions: the one from the visited GW to the GW OCS and the one from the GW OCS to the network entry node (the CAF) .

Furthermore, it is to be noted that network B and network A may use different currency for charging (for example when located in different countries or continents) . Therefore, one or more currency conversions may be necessary between the two networks in order to ensure that the charging is done correctly. The currency conversion (s) may be done in the visited network (network B) to the subscriber' s home network (network A) currency, or in the subscriber's home network (network A) from the visited network' s (network B's) currency to the home network's currency. As an example for executing such a currency conversion, various exchange rate information which is freely available, for example, via the Internet can be used. Or, it may be assumed for that the operators of the networks A and B mutually agree which currency is to be used and where to use it.

After receiving the (second) credit control request in S4, the network entry node (CAF) resolves the address of the home network (network A) OCS that is responsible for account handling for the subscriber (i.e. the address of the home OCS) . This may be done, for example, by a lookup within an operators own network, as defined in current standards of telecommunication networks known to those skilled in the art. Then, the network entry node CAF forwards in S5 the (second) credit control request received from the Gateway OCS to the determined home OCS .

In S6, the home OCS processes the received (second) credit control request and executes credit control for the subscriber. For example, it validates the credit control request and performs the required action (s) towards the subscriber' s account balance handling entity which provides necessary charging and credit information for executing the credit control. Furthermore, based on subscriber information and the (initial) rating information included by the GW OCS, the home OCS may also perform re-rating. For example, it may calculate a so-called 'roaming premium' or calculate any discounts, bonuses etc. that may apply for the subscriber. The subscriber's account balance handling entity responds to the action (s) of the home OCS by providing, for example, an authorisation or denial for the use of the service, and/or other information, for example an indication that the balance is approaching depletion or the like.

Then, in S7, the home OCS responds to the (second) credit control request it received from the CAF with a (second) credit control response including the information from subscriber's account balance handling entity as well as the results of the credit control.

The CAF forwards the (second) credit control response to the GW OCS in S8.

When receiving the (second) credit control response, the GW OCS processes it in S9, for example, as described above, by performing mapping/translation on the information it receives from the subscriber' s home network, based on the identity of the home network. Then, in SlO, the GW OCS responds to the original (first) credit control request it received from the visited GW, for example by generating a (first) credit control response based on the mapping/translation processing. In the (first) credit control response, the visited GW is provided with the information from the subscriber' s account balance handling and the results of the credit control.

In SIl, the visited GW reacts according to the information from the subscriber's account balance handling, for example, by providing or denying the service requested.

As described above, the invention relates to online charging in roaming cases. A credit control request for a visiting subscriber is sent to a gateway charging control unit in a visited network. A corresponding credit control request is sent from the gateway charging control unit to a network entry node of a home network of the subscriber and forwarded to a charging control unit of the subscriber's home network. Credit control is executed for the roaming subscriber by the charging control unit of the subscriber's home network, and a corresponding response is sent back in reply to the credit control requests.

It should be understood that the above description and accompanying figures are merely intended to illustrate the present invention by way of example only. The preferred embodiments of the present invention may thus vary within the scope of the attached claims.

Claims

1. A method comprising sending a first credit control request for online charging for a visiting subscriber to a gateway charging control unit in a visited network, sending a second credit control request from the gateway charging control unit to a network entry node of a home network of the subscriber, forwarding the second credit control request from the network entry node to a charging control unit of the subscriber's home network, performing credit control processing for online charging for the subscriber by the charging control unit of the subscriber's home network, and responding to the first and second credit control requests on the basis of a result of the credit control processing.

2. The method according to claim 1, further comprising receiving in the first credit control request service information for a service requested by the subscriber in the visited network, requesting rating information on the basis of the received service information, and allocating initial rating parameters to the service requested by the subscriber.

3. The method according to claim 2, further comprising including in the second credit control request the initial rating parameters.

4. The method according to claim 3, further comprising performing, in the credit control processing, a re- rating processing for the subscriber on the basis of the initial rating parameters and of subscriber specific information, including rating parameters resulting from the re- rating processing in a response to the first and second credit control request.

5. The method according to claim 1, further comprising performing in the gateway charging control unit at least one of a mapping processing and a translation processing of information received by the first credit control request, and generating the second credit control request on the basis of the results of the at least one of the mapping processing and the translation processing.

6. A charging control device configured to receive from a network control node a first credit control request for online charging for a subscriber visiting a network, and to send a second credit control request to a network entry node of a home network of the subscriber.

7. The charging control device according to claim 6, configured to receive a response to the second credit control request from the network entry node of the home network of the subscriber, and to send a response to the first credit control request to the network control node on the basis of the received response on the second credit control request.

8. The charging control device according to claim 6, configured to receive in the first credit control request service information for a service requested by the subscriber from the visited network, to request rating information on the basis of the received service information, and to allocate initial rating parameters to the service requested by the subscriber.

9. The charging control device according to claim 8, configured to include in the second credit control request the initial rating parameters.

10. The charging control device according to claim 6, configured to perform at least one of a mapping processing and a translation processing of information received by the first credit control request, and to generate the second credit control request on the basis of the results of the at least one of the mapping processing and the translation processing.

11. A network entry node configured to receive, from a charging control unit of a network visited by a subscriber of the network entry node's network, a credit control request for online charging for a service requested by the subscriber from the visited network, and to forward the credit control request to a charging control unit of the subscriber's home network.

12. The network entry node according to claim 11, configured to receive a response to the credit control request from the charging control unit of the subscriber's home network, and to forward the response to the credit control request to the charging control unit of the visited network.

13. The network entry node according to claim 11, wherein the network entry node is a charging address control function .

14. A charging control device configured to receive a credit control request from a network entry node for online charging for a service requested by a subscriber of the charging control device's network in a network visited by the subscriber, to perform credit control processing for the subscriber, and to send a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

15. The charging control device according to claim 14, configured to receive in the credit control request initial rating parameters allocated by a network element of the visited network, to perform, in the credit control processing, a re- rating processing for the subscriber on the basis of the initial rating parameters and of subscriber specific information, and to include rating parameters resulting from the re- rating processing in a response to the credit control request .

16. A charging control device comprising receiver means for receiving from a network control node a first credit control request for online charging for a subscriber visiting a network, sending means for sending a second credit control request to a network entry node of a home network of the subscriber.

17. The charging control device according to claim 16, further comprising receiver means for receiving a response to the second credit control request from the network entry node of the home network of the subscriber, and sending means for sending a response to the first credit control request to the network control node on the basis of the received response on the second credit control request .

18. The charging control device according to claim 16, further comprising receiver means for receiving in the first credit control request service information for a service requested by the subscriber from the visited network, requesting means for requesting rating information on the basis of the received service information, and allocating means for allocating initial rating parameters to the service requested by the subscriber.

19. The charging control device according to claim 18, further comprising processor means for including in the second credit control request the initial rating parameters.

20. The charging control device according to claim 16, further comprising processor means for performing at least one of a mapping processing and a translation processing of information received by the first credit control request, and for generating the second credit control request on the basis of the results of the at least one of the mapping processing and the translation processing.

21. A network entry node comprising receiver means for receiving, from a charging control unit of a network visited by a subscriber of the network entry node's network, a credit control request for online charging for a service requested by the subscriber from the visited network, and sending means for forwarding the credit control request to a charging control unit of the subscriber's home network .

22. The network entry node according to claim 11, further comprising receiver means for receiving a response to the credit control request from the charging control unit of the subscriber's home network, and sending means for forwarding the response to the credit control request to the charging control unit of the visited network.

23. The network entry node according to claim 21, wherein the network entry node is a charging address control function .

24. A charging control device comprising receiver means for receiving a credit control request from a network entry node for online charging for a service requested by a subscriber of the charging control device's network in a network visited by the subscriber, processor means for performing credit control processing for the subscriber, and sending means for sending a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

25. The charging control device according to claim 24, further comprising receiver means for receiving in the credit control request initial rating parameters allocated by a network element of the visited network, and processor means for performing, in the credit control processing, a re-rating processing for the subscriber on the basis of the initial rating parameters and of subscriber specific information, and for including rating parameters resulting from the re-rating processing in a response to the credit control request.

26. A computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a charging control unit, wherein the computer program product is configured to execute steps of receiving from a network control node a first credit control request for online charging for a subscriber visiting a network, and sending a second credit control request to a network entry node of a home network of the subscriber.

27. The computer program product according to claim 26, further configured to execute steps of receiving a response to the second credit control request from the network entry node of the home network of the subscriber, and sending a response to the first credit control request to the network control node on the basis of the received response on the second credit control request.

28. The computer program product according to claim 26, further configured to execute steps of receiving in the first credit control request service information for a service requested by the subscriber from the visited network, requesting rating information on the basis of the received service information, and allocating initial rating parameters to the service requested by the subscriber.

29. The computer program product according to claim 28, further configured to execute steps of including in the second credit control request the initial rating parameters.

30. The computer program product according to claim 26, further configured to execute steps of performing at least one of a mapping processing and a translation processing of information received by the first credit control request, and generating the second credit control request on the basis of the results of the at least one of the mapping processing and the translation processing.

31. A computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a network entry unit, wherein the computer program product is configured to execute steps of receive, from a charging control unit of a network visited by a subscriber, a credit control request for online charging for a service requested by the subscriber from the visited network, and to forward the credit control request to a charging control unit of the subscriber's home network.

32. The computer program product according to claim 31, further configured to execute steps of receiving a response to the credit control request from the charging control unit of the subscriber's home network, and to forward the response to the credit control request to the charging control unit of the visited network

33. A computer program product for a computer, comprising software code portions for making, when said product is run on the computer, said computer to function as a charging control unit, wherein the computer program product is configured to execute steps of receiving a credit control request from a network entry node for online charging for a service requested by a subscriber in a network visited by the subscriber, performing credit control processing for the subscriber, and sending a response to the credit control request to the network entry node on the basis of a result of the credit control processing.

34. The computer program product according to claim 33, further configured to execute steps of receiving in the credit control request initial rating parameters allocated by a network element of the visited network, performing, in the credit control processing, a re- rating processing for the subscriber on the basis of the initial rating parameters and of subscriber specific information, and including rating parameters resulting from the re- rating processing in a response to the credit control request .