WO2009124959A2

WO2009124959A2 - Advice of charge service

Info

Publication number: WO2009124959A2
Application number: PCT/EP2009/054195
Authority: WO
Inventors: Martin Farthofer; Gerald Goermer; Georg Kastelewicz
Original assignee: Nokia Siemens Networks Oy
Priority date: 2008-04-10
Filing date: 2009-04-08
Publication date: 2009-10-15
Also published as: WO2009124959A3

Abstract

A charging function (AoC AS) in a communication system is provided, comprising receiving a request for a service of a user, obtaining charging parameters from a subscriber database (HSS/AAA) for the user, and providing charging information for the user based on the obtained charging parameters.

Description

Advice of charge service

Technical field of the invention

The invention relates to a charging entity, a subscriber database, a method and computer program products for providing an advice of charge service to a user.

Background of the invention

Within the IP (Internet Protocol) Multimedia Subsystem (IMS) as defined by 3^rd Generation Partnership Project (3GPP) Session Initiation Protocol (SIP) defined by Internet Engineering Task Force (IETF) is used for controlling communication. SIP is an application-layer control protocol for creating, modifying, and terminating sessions with one or more participants. These sessions may include Internet multimedia conferences, Internet telephone calls, and multimedia distribution. Members in a session can communicate via multicast or via a mesh of unicast relations, or a combination of these.

An Advice of Charge (AoC) supplementary service used in communication systems announces the tariff/rate/cost of the requested service e.g. a phone call to the user, either the expected rate before connecting the call, during the call the cumulated costs, or after the call the total costs. The AoC allows the user to terminate the service before costs emerge to the user. This service is required by many regulators for cost transparency reasons. Currently, in many public switched telephone network (PSTN) and public land mobile network (PLMN) telephony networks the AoC service is offered, for example as announcements for premium rate services "This call costs you 2 Euro a minute...". In the future the regulators can request the AoC service also for voice over internet protocol (VoIP) phone calls either, e.g. calls switched via the IMS or other IMS services. At the time being, the AoC service is requested by many operators in tenders for both user comfort and to fulfil expected regulatory issues.

The object of the invention is to provide the AoC in the IMS also for post paid users.

Summary of the invention

The present invention overcomes the above problem by providing a charging function and a method comprising receiving a request for a service of a user, obtaining charging parameters from a subscriber database for the user, and providing charging information for the user based on the obtained charging parameters.

The invention further provides a subscriber database and a method comprising receiving a request associated with a user, and sending charging parameters for the user in response to the request.

The present invention has the advantage that the AoC service can be provided to users of a communication network. Description of drawings:

Figures 1 - 3 illustrates charging architectures relevant for the invention.

Figure 4 shows interface between relevant network elements .

Figures 5 - 9 illustrate example signaling flows for providing AoC according to embodiments of the invention. Figures 10 explain internal structures of HSS and AoC AS according to embodiments of the invention. Figures 11 and 12 show processes according to embodiments of the invention.

Detailed description of the invention

Different type of network entities and functions exist in the IMS network. Call Session Control Functions (CSCF) implement a session control function in SIP layer. The CSCF can act as Proxy CSCF (P-CSCF), Serving CSCF (S-CSCF) or Interrogating CSCF (I-CSCF) . The P-CSCF is the first contact point for the User Equipment (UE) within the IMS; the S-CSCF actually handles the session states in the network; the I-CSCF is mainly the contact point within an operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator's service area.

The functions performed by the I-CSCF are, for example, assigning an S-CSCF to a user performing SIP registration and routing SIP requests received from another network towards the S-CSCF. The S-CSCF performs the session control services for the UE. It maintains a session state as needed by the network operator for support of the services and may be acting as Registrar, i.e. it accepts registration requests and makes its information available through the location server (e.g. HSS) . The S-CSCF is the central point to users that are hosted by this S-CSCF. The S-CSCF provides services to registered and unregistered users when it is assigned to these users. This assignment is stored in the Home Subscriber Server (HSS) .

The HSS is the master database for a given user. It is the entity containing the subscription-related information to support the network entities actually handling calls/sessions. As an example, the HSS provides support to the call control servers (CSCFs) in order to complete the routing/roaming procedures by solving authentication, authorisation, naming/addressing resolution, location dependencies, etc. The HSS is responsible for holding the following user related information:

User Identification, Numbering and addressing information

User Security information: Network access control information for authentication and authorization, such as password information

User Location information at inter-system level: the HSS supports the user registration, and stores inter-system location information, etc. User profile information.

Cx reference point or Cx interface is an interface between a CSCF and a HSS, supporting the transfer of data between them. The Cx reference point is based on the diameter protocol with 3GPP standard diameter applications. Sh interface is a corresponding interface between the HSS and an AS. Diameter is an authentication, authorisation, and accounting (AAA) protocol defined by the IETF and used for network access services, such as dial-up and mobile IP.

An Application Server (AS) is offering value added IP multimedia (IM) services to users of the IMS network and resides either in the IMS user's home network or in a third party location. The third party could be a network or simply a stand-alone AS. The AS may host and execute various services and can influence and impact a SIP session on behalf of the services. The IP multimedia Subsystem Service Control Interface (ISC) interface is between the S-CSCF and the service platforms (i.e. Ass) . The ISC interface offers extended services to subscribers. ASs that are connected to the IMS are controlled via ISC interface. The protocol used on the ISC interface is the SIP.

An HSS can communicate with an application server over Sh interface. The Sh interface enables data handling procedures, for example, download of data from the HSS to an AS, or update of data in the HSS. An AS can subscribe to receive notifications from the HSS of changes in data. The HSS can notify an AS of changes in data for which the AS previously had subscribed. Diameter protocol can be used in Sh interface .

A media gateway control function (MGCF) acts as an interworking point between a circuit switched (CS) network and an IP network in the control plane of the network. The MGCF controls the parts of the call state related to connection control for media channels in a media gateway (MGW) , communicates with call state control, and performs protocol conversion between the call control protocols, such as SIP and ISUP.

Charging is a function within the telecommunications network and the associated charging elements whereby information related to a chargeable event is collected, formatted, transferred and evaluated in order to make it possible to determine usage for which the charged party may be billed (offline charging) or the subscribers account balance may be debited (online charging) .

An online charging is a charging mechanism where charging information can affect, in real-time, the service rendered and therefore a direct interaction of the charging mechanism with session/service control is required. An offline charging is a charging mechanism where charging information does not affect, in real- time, the service rendered. A tariff is a set of parameters defining the network utilization charges for the use of a particular bearer, session and/or service

An online charging system (OCS) can support mechanisms for:

• online bearer charging towards access / core network entities (e.g. SGSN, GGSN, IP Flow Handler, WLAN) . Online charging interfaces to be supported can be Ro and CAP; • online charging of applications/services that are provided to subscribers via service nodes (outside the core network) e.g. MMS and LCS. The online charging interface to be supported can be Ro; • IMS online charging. Online charging interface to be supported can be Ro;

• account balance management towards external account management servers e.g. recharge server, hot billing server;

• generation of charging data records (CDRs) and their transfer to the operator's post-processing system.

• correlation of bearer, service and IMS charging.

To support these requirements, the following functions can be implemented by the OCS:

Rating can take place before and/or after service consumption and rating can comprise unit determination, for example, calculation and reservation of a number of session-related non-monetary units (service units, data volume, time and events) . A price determination, for example, calculation of monetary units (price) for a given number of non-monetary units and determination of tariff information based on the subscribers contractual terms and service being requested (e.g. e-parameters for AoC) can belong to rating, as well as getting and/or setting counters applicable for rating

A subscriber account balance management can include checking account balance, account balance update (credit/debit) , account balance reservation, get/set counters, and get/set expiry date of the (prepaid) account (optional) .

A charging transaction control can include performing charging control on request basis for bearer and events/services, immediate charging and charging with reservation, generation of charging information/CDR per charging transaction, and/or support the correlation requirements, the functions listed below are possible in the OCS.

The correlation function can include context handling of bearer, service and IMS charging events related to a given subscriber and/or generation of a combined multiple event and session requests to the rating function .

A Rating Function (RF) can perform both monetary and non-monetary unit determination (rating) , and can provides the following functionalities:

• Rating for network- and external services and applications (session, service, event) before and after service delivery;

• Cross-product and cross-channel discounts, benefits and allowances.

The Rating Function can be able to handle a wide variety of rateable instances, such as:

• Rating of volume (in terms of granted units or money, e.g. based on charging initiated by an access network entity) ;

• Rating of time (in terms of granted units or money, e.g. based on charging initiated by a SIP application);

• Rating of events (e.g. based on charging of web content or MMS) .

Figure 1 presents an architecture of OCS relevant for this invention. Reference point Re can be online charging reference point towards the Rating Function (RF) . An online charging reference point Rr can be arranged towards an external account recharging server. An online charging reference point Ro can be arranged towards the online charging functions (EBCF, SBCF)

Three AOC services exist: a) Charging information at communication set-up time (AOC-S)

The AOC-S service enables a user to receive information about the charging rates at communication set-up time and also to receive further information during the communication if there is a change of charging rates. b) Charging information during the communication (AOC- D)

The AOC-D service enables a user to receive information on the recorded charges for a communication during the active phase of the communication. c) Charging information at the end of the communication (AOC-E)

The AOC-E service enables a user to receive information on the recorded charges for a communication when the communication is terminated.

An AoC architecture for the IMS is shown in figure 2. UE gets AoC information by a SIP message from an AoC Function running as a SIP application server (AS) . The AoC Function can obtain charging related information either from entities of the own IMS network, or from another network if services from the other network are used.

In embodiments of the invention, rating/cost related information is stored in a subscriber database, such as an AAA server or a HSS, and the AoC function retrieves the tariff information for the generation of AoC Information. The AAA server is a server that handles user requests for access to computer resources and provides authentication, authorisation, and accounting services. The AAA server can interact with network access and gateway servers and with databases and directories that contain user information. Devices and applications typically communicate with an AAA server by using the remote authentication dial-in user service (RADIUS) .

A connection can exists between a AoC service function, running as a SIP AS, and an Online Charging System (OCS) . The advantage of this is that the Rating Function (RF) of the OCS can be used for determining the rate which has to be announced to the user. However, the problems arise if there is post-paid charging in the network (billing systems are usually not real-time capable) and that there is no interface between the OCS and the SIP AS which would ensure an inter-operator compatibility.

Embodiments of the invention provide another architecture which avoids the above mentioned problems.

According to first embodiment of the invention the architecture is provided in which the AoC function generates the AoC information based on local configured or received tariff information from a subscriber database (AAA server, HSS) for example via the standardized Sh interface. In one aspect of the invention the tariff information can either be stored at the subscriber database and/or can be retrieved by the subscriber database directly from an OCS or a rating function, if available. The embodiment enables an operator to provide the user with the AoC information before connecting a session (expected rate, AoC-S) , during the session (cumulated costs, AoC-D) and/or after the session (total cost, AoC- E) . An example architecture of the invention is shown in Figure 3. The AoC function server is connected as a SIP AS via the ISC interface to the S-CSCF and via Sh interface to the HSS.

The information transfer is shown in figure 4.

According to SIP handling, the S-CSCF can pass SIP messages during the session setup, during the session and after the session, to the AoC function server. The AoC function server can add to SIP message (s) relating to this SIP message exchange or SIP session AoC related information. To provide AoC-S, AoC-D and AoC-E information, the messages shown in Figures 5-9 can be used to add the relevant AoC information.

In one aspect of the invention, at the AoC function server can be configured which of the AoC information shall be added (e.g. to fulfill local regulatory requirements, implementation of just AoC-S can be sufficient) . The AoC function server can retrieve the tariff information via the standardized Sh interface from the HSS. The AoC function server can then apply the tariff/rates and to set up the AoC information.

An example configuration of an embodiment of the invention is here described. AoC related information, for example different tariff/rates, can be stored by an operator at the subscribe database (e.g. AAA server, HSS) for example for every subscriber. The rates can be stored and administered at the AoC function server, while at the HSS for every subscriber the applicable tariff type (tariff, e.g. "Flatrate", "business user", "basic tariff", "friends & family for the numbers xxx and yyy") are stored. The centrally stored rates/tariff can also be used by other charging and billing related function of the network operator, such as the billing system or the OCS which can access the subscriber database (HSS) via the Re/Rr interface.

Alternatively, the subscriber database can retrieve AoC related information from the OCS or from another rating function (RF) , for example, via the Re/Rr interface. This can happen either every time or only for special tariffs like bonus systems to ease the implementation of the rating functionality at the AoC server. This aspect of the invention allows storing part of AoC related information in other network elements which the subscriber database can access if needed.

Embodiments of the invention provide the solution which can work for both post-paid and pre-paid subscribers. In particular it can be relevant for operators which do not have any pre-paid system or not real time capable billing system. In some embodiments only standardised interfaces are used which can allow easy implementation. The solution can be implemented in the IMS core (CSCF, HSS) .

Fig 10 shows an internal structure of a charging function, such as AoC AS, according to an embodiment of the invention. The AoC AS can comprise a receiving unit 101 configured to receiving a request for a service of a user. The request can be SIP request received from an S- CSCF. The AoC AS can include an obtaining unit 102 to obtain charging parameters from a subscriber database 9, such as AAA server or HSS, for the user. The obtaining unit 102 can obtain the charging parameters via Sh interface of the IMS, and can be obtained as part of a user profile download operation, for example using Diameter or Radius protocols. The AoC AS can have providing unit 103 configured to provide charging information for the user based on the obtained charging parameters. The providing unit 103 can be configured to provide the charging information in SIP signaling messages and may be configured to provide an advice of charge supplementary service. The charging information can comprise information relating to costs associated with the service. The AoC AS can comprise a transmitting unit 104 to transmit the received request for the service further in the communication network for providing the service, for example to the S-CSCF.

The AoC AS can comprise a storing unit 105 configured to store charging data and the providing unit 103 can be configured to use the charging data based on the obtained charging parameters when providing the charging information for the user. The charging parameters can comprise a rate or tariff, and/or an indication of an applicable rate or tariff, and/or a type of tariff, and/or a subscriber class. The storing unit 105 can store information relating plurality of tariffs, and the obtaining charging parameters by obtaining unit 102 can comprise obtaining an indication of an applicable tariff or rate. Hence, only an indication of tariff/rate to be used can be obtained, but the actual tariff/rate can be stored in the storing unit 105. Fig 10 also shows an internal structure of a subscriber database, such as AAA server or HSS, according to an embodiment of the invention. The subscriber database can comprise a receiving unit 111 configured to receive a request associated with a user, and a sending unit 112 to send charging parameters for the user in response to the request, which units can be configured to receive the request and send the charging parameters via Sh interface of the IMS, for example to/from an advice of charge application server. The charging parameters comprise at least one of rate, tariff, an indication of an applicable rate or tariff, a type of tariff, a subscriber class. The subscriber database can also have a storing unit 113 for storing charging related information and/or an obtaining unit 114 configured to obtain the charging related information from a server, for example from an online charging server or a rating function, and the obtaining the charging related information happens via Re or Rf interface specified by the 3GPP. Sending the charging parameters by the sending unit 112 can comprise sending the charging parameters as part of a user profile download operation. The subscriber database can comprise a providing unit 115 for providing charging information stored in the storing unit 113 to a billing system.

All units described above may be implemented for example using microprocessors and/or other electrical components and/or by software.

A charging function and a subscriber database may be physically implemented in a switch, router, server or other hardware platform or electronic equipment which can support data transmission and processing tasks, or can be implemented as a component of other existing device .

Figure 11 presents a method of providing charging related information in a communication system according to an embodiment of the invention. The method includes receiving 1001 a request for a service of a user, obtaining 1002 charging parameters from a subscriber database for the user, and providing 1003 charging information for the user based on the obtained charging parameters .

Figure 12 presents another method of providing charging related information in a communication system according to an embodiment of the invention. The method includes receiving 2001 a request associated with a user, and sending 2002 charging parameters for the user in response to the request.

The invention is not limited to the IMS, but can also be applied in other type of networks providing AoC and having similar type of subscriber entity as in the IMS. In particular the invention is applicable also to fixed networks and fixed mobile convergence (FMC) networks, as well as next generation networks (NGN) Therefore, the HSS/AAA, the AoC AS, are only used here as examples network elements. Functions of a charging function and a subscriber database described above may be implemented by code means, as software, and loaded into memory of a computer .

Claims

1. A charging function (8) in a communication system, comprising: receiving means (101) for receiving a request for a service associated with a user, obtaining means (102) for obtaining charging parameters from a subscriber database for the user, providing means (103) for providing charging information for the user based on the obtained charging parameters .

2. The charging function (8) of any of preceding claims wherein the obtaining means (102) is configured to obtain the charging parameters via Sh interface of an internet protocol multimedia subsystem.

3. The charging function (8) of any of preceding claims wherein the obtaining means (102) is configured to obtain the charging parameters as part of a user profile download operation.

4. The charging function (8) of any of preceding claims wherein the charging function comprises an advice of charge application server of an internet protocol multimedia subsystem.

5. The charging function (8) of any of preceding claims wherein the obtaining means (102) is configured to obtaining the charging parameters from a home subscriber server of an internet protocol multimedia subsystem or from an authentication, authorisation, and accounting server.

6. The charging function (8) of any of preceding claims wherein the receiving means (102) is configured to receive the request for the service according to session initiation protocol.

7. The charging function (8) of any of preceding claims wherein the providing means (103) is configured to provide the charging information in session initiation protocol signaling messages.

8. The charging function (8) of any of preceding claims wherein the charging information comprises information relating to costs associated with the service .

9. The charging function (8) of any of preceding claims wherein the providing means (103) is configured to provide an advice of charge supplementary service.

10. The charging function (8) of any of preceding claims, further comprising transmitting means (104) for transmitting the received request for the service further in the communication network for providing the service .

11. The charging function (8) of any of preceding claims, further comprising storing means (105) for storing charging data and wherein the providing means (103) is configured to use the charging data based on the obtained charging parameters when providing the charging information for the user.

12. The charging function (8) of any of preceding claims wherein the charging parameters comprise at least one of rate, tariff, an indication of an applicable rate or tariff, a type of tariff, a subscriber class.

13. The charging function (8) of any of preceding claims, wherein the storing charging data comprises storing information relating plurality of tariffs, and wherein the obtaining charging parameters comprises obtaining an indication of an applicable tariff.

14. A subscriber database (9) in a communication system, comprising:

- receiving means (111) for receiving a request associated with a user,

- sending means (112) for sending charging parameters for the user in response to the request.

15. The subscriber database (9) of claim 14 wherein the charging parameters comprise at least one of rate, tariff, an indication of an applicable rate or tariff, a type of tariff, a subscriber class.

16. The subscriber database (9) of any claims 14 or 15, further comprising obtaining means (114) for obtaining the charging related information from a server.

17. The subscriber database (9) of any of claims 14 - 16, wherein the obtaining means (114) is configured to obtain the charging related information from an online charging server or a rating function, and the obtaining the charging related information happens via Re or Rf interface of the 3GPP.

18. The subscriber database (9) of any of claims 14-17, wherein the subscriber database (9) comprises a home subscriber server of an internet protocol multimedia subsystem or an authentication, authorisation, and accounting server.

19. The subscriber database (9) of any of claims 14-18, wherein the receiving means (111) and the sending means (112) are configured to receive the request and send the charging parameters via Sh interface of an internet protocol multimedia subsystem.

20. The subscriber database (9) of any of claims 14-19, wherein the receiving means (111) and the sending means

(112) are configured to receive the request and send the charging parameters to/from an advice of charge application server.

21. The subscriber database (9) of any of claims 14-20, wherein the sending the charging parameters comprise sending charging parameters as part of a user profile download operation.

22. The subscriber database (9) of any of claims 14 - 21, further comprising storing means (113) for storing charging related information,

23. The subscriber database (9) of any of claims 14-22

, further comprising providing means (115) for providing charging information stored in the storing means (113) to a billing system.

24. A method of providing charging related information in a communication system, comprising: receiving a request for a service associated with a user, obtaining charging parameters from a subscriber database for the user, and providing charging information for the user based on the obtained charging parameters.

25. The method of claim 24 wherein the obtaining comprises obtaining the charging parameters via Sh interface of an internet protocol multimedia subsystem.

26. The method of claim 24 or 25 wherein the obtaining comprises obtaining the charging parameters as part of a user profile download operation.

27. The method of claim 24 to 26 wherein the obtaining comproses obtaining the charging parameters from a home subscriber server of an internet protocol multimedia subsystem or from an authentication, authorisation, and accounting server.

28. The method of claim 24 to 27 wherein the receiving comprises receiving the request for the service according to session initiation protocol and wherein the providing comprises provide the charging information in session initiation protocol signaling messages.

29. The method of claim 24 to 28 wherein the charging information comprises information relating to costs associated with the service.

30. The method of claim 24 to 29 wherein the providing comprises providing an advice of charge supplementary service .

31. The method of claim 24 to 30 further comprising transmitting the received request for the service further in the communication network for providing the service .

32. The method of claim 24 to 31 further comprising storing charging data and wherein the providing comprises to use the charging data based on the obtained charging parameters when providing the charging information for the user.

33. The method of claim 24 to 32 wherein the charging parameters comprise at least one of rate, tariff, an indication of an applicable rate or tariff, a type of tariff, a subscriber class.

34. The method of claim 24 to 33 wherein the storing charging data comprises storing information relating plurality of tariffs, and wherein the obtaining charging parameters comprises obtaining an indication of an applicable tariff.

35. A method of providing charging related parameters in a communication system, comprising: receiving a request associated with a user, and sending charging parameters for the user in response to the request.

36. The method of claim 35 further comprising storing charging related information.

37. The method of claim 35 or 36 wherein the charging parameters comprise at least one of rate, tariff, an indication of an applicable rate or tariff, a type of tariff, a subscriber class.

38. The method of any of claims 35 or 37 further obtaining the charging related information from a server .

39. The method of any of claims 35 or 38, wherein the comprises obtaining the charging related information from an online charging server or a rating function, and the obtaining the charging related information happens via Re or Rf interface of the 3GPP.

40. The method of any of claims 35 or 39, wherein the receiving and the sending comprises to receive the request and send the charging parameters via Sh interface of an internet protocol multimedia subsystem.

41. The method of any of claims 35 or 40, wherein the receiving and the sending comprises to receive the request and send the charging parameters to/from an advice of charge application server.

42. The method of any of claims 35 or 41, wherein, wherein the sending the charging parameters comprise sending charging parameters as part of a user profile download operation.

43. The method of any of claims 35 or 42, further comprising for providing stored I charging information to a billing system.

44. A computer program product comprising code means adapted to produce the steps of any one of claims 24 to 43 when loaded into the memory of a computer.

45. A communication system comprising the charging function according to any of claims 1 - 13 and the subscriber database of any of claims 14-23