METHOD FOR BILLING λ COMMUNICATION SERVICE AND TELECOMMUNICATION SYSTEM

1. Field of the Invention

The invention relates to a method for establishing a communication connection between a first mobile terminal of a calling user and a second mobile terminal of a called user according to the preamble of claim 1 and to a service control device according to the preamble of claim 6.

2. Background of the Invention

The invention relates to the provision of community services for registered users in telecommunication networks. Such community services may include discounts for connections between users belonging to the same community. Such communities may include members of a certain enterprise, alumni of particular universities, families, clubs or the like. The discounts granted to the members of these communities for communication connections within the communities may be negotiated between the providers of the telecommunication network and representatives of the communities and may include discounts on basic fees as well as discount on volume-dependent fees.

Further, prepaid communication services have become very widespread in telecommunication systems. In such prepaid services, a user has an account with a prepaid amount of fees and the expended fees for using the prepaid telecommunication services are subtracted more or less instantaneously from the account during the use of the services. If e.g. a voice call service is billed on a minute basis, a certain amount of

money is subtracted from the account every minute while the user is speaking.

In general, the account belonging to one user is managed at a particular Service Control Point (SCP-A) , wherein one telecommunication network typically comprises multiple service control points associated to different groups of users. In order to execute its accounting function, the service control point has to be informed of the services to be paid by the user and of any discount granted to the user.

In a scenario where multiple communities take advantage of different discounts and wherein the account information relating to the different users are managed by different service control points, it may be difficult upon establishing a communication connection to decide whether or not the two users belong to the same community and are therefore entitled to a discount granted for the community. An obvious solution for this problem would be to provide each of the service control points with a data base for determining the community membership of every possible colleague. However, this solution is clearly not practicable in the case where large communities and a high number of service control points are provided since it would require a large amount of resources for maintaining and updating the databases in a synchronized way.

3. Summary of the Invention

In view of the above problems, it is one object of the invention to provide a method for establishing a communication connection between mobile terminals of different users in which it is possible to account for the community memberships of the participating users even if the

subscription and accounting information of these users are managed in different service control points. A further object of the invention is to provide a method for establishing a communication connection allowing for the management of large communities in a resource saving way.

The invention starts from a method for billing a communication service to be established between at least two user equipment devices in a telecommunication network in which a part of the users is member of at least one community. The method comprises in particular the steps of deciding if the two user equipment device is participating in a communication service are registered for users being members of the same community and of using a tariff specific for the community for billing the communication service if both users are members of the same community.

According to one aspect of the invention, it is proposed that the step of deciding if the users are members of the same community includes sending a request to a centralized community server holding the community membership information of all users . Accordingly, the membership information can be maintained and updated in a centralized way and no databases containing the membership information have to be provided in the service control points responsible for billing the communication service. Since the membership information is managed in the centralized server, the updating of the membership information is easy to perform, even if a large amount of users belong to the community under consideration.

A further aspect of the ^' invention relates to a telecommunication system including plural service control points for billing a telecommunication service to be established and between at least two user equipment devices

in a telecommunication network in which at least a part of the users is member of at least one community. Accounting information of each user is managed by one of the service control points which is associated to the user.

It is proposed that the telecommunication system further comprises a centralized community server holding the community membership information of the users, wherein the centralized community server is configured to answer requests for deciding if the two user equipment devices participating in the communication service are registered for users being members of the same community or not. The service control point associated to a calling user is configured to use a tariff specific for the common community for billing the communication service if both users are members of the same community.

The telecommunication system according to the invention allows accounting for the discounts for calls between members of the same community in a resource saving way. By centralizing the community membership information, these information may be easily updated, which is particularly favourable in the case where at least some of the communities have a large number of members .

The following description of further characterizing features of the invention and the advantages thereof applies equally to both the method according to the invention and the telecommunication system according to the invention.

Since the billing on a real-time basis is particularly advantageous in the case where the communication service invoked by a user that has subscribed to a prepaid service and/or where the calling user has prepaid contract such that

billing is performed by charging a prepaid account as on a service control point associated to the calling user, the invention is preferably applied to this type of service.

Although in principle the request to the centralized community server could be transmitted using other communication channels such as e.g. the Internet, it is preferred that the request is transmitted to the centralized community server via a core network of the telecommunication network, such that a secure communication may be guaranteed even if the other communication channels are out of order. In particular, the request may be transmitted using a standardized Intelligent Network Application Part (INAP) or CAMEL Application Part (CAP) according to the 3GPP Standards.

In particular, the request may be generated by a service control point associated to the calling user and the request may be triggered by adding a corresponding prefix to a mobile subscriber ISDN number (MSISDN-B) of the called user in a connect message. If a connect message includes such a prefix is received by a mobile switching centre of the telecommunication network, the mobile switching centre may redirect the connect message to the centralized community server which can determine the community status of the called user by reading the MSISDN. The mobile switching centre may exchange and/or remove the prefix.

According to one embodiment of the invention, the centralized community server may answer to the request by transmitting ReleaseCause (RC) Message via the core network of the telecommunication network. The final leg of the communication service may be set up by the service control point (SCP-A) associated to the calling user after the reception of such a Release Cause Message from the centralized community server.

If this procedure is followed, the communication connection is set up only after having settled the tariff issues.

According to a further embodiment, the final leg of the communication service is set up by the centralized community server after the reception of the request, wherein the centralized community server transmits a connect message to the called user equipment device, wherein the connect message comprises information relating to the community relationship of the two users and wherein the called user equipment device inserts this information in an answer message (ISUP) in order to allow a service control point (SCP-A) associated to the calling user to perform a proper charging taking this information into account. If this procedure is followed, the establishment of the communication connection can be accelerated in comparison to the first embodiment of the invention.

Further characterizing features of the invention and the advantages thereof will become apparent from the following description of embodiments of the invention. The embodiments show particular combinations of the characterizing features of the invention and are not meant to limit the scope of the appended claims. The skilled person will easily be able to find other combinations or subcombinations of the characterizing features matching the requirements of particular applications.

4. Brief Description of the Drawings

Fig. 1 is a schematic representation of a telecommunication system of an initial part of a method for setting up the communication service between two user equipment devices .

Fig.2 is a schematic representation of a second part of a method for setting up the communication service according to Fig. 1.

Fig. 3 is a schematic representation of a telecommunication system and of a method for setting up a communication service between two user equipment devices according to a further embodiment of the invention.

Fig. 4 is a second part of the method for setting up a communication service according to the embodiment of Fig. 3.

5. Detailed Description of the Embodiments

Fig. 1 is a schematic representation of a telecommunication system suitable for providing a communication service between a first user equipment device A and a second user equipment device B. A mobile switching centre (VMSC-A) is located within the range of the first user equipment device A and is part of a Home Public Land Mobile Network (HPLMN) providing various types of community services. The second user equipment device B is located within the range of a further mobile switching centre (MSC/VLR) of a visited home public land mobile network (HPLMN) .

Both user equipment devices A and B belong to users having subscribed to a prepaid service. Each of the users possesses an account with a prepaid amount of fees which is managed by a prepaid subscription service (PPS) by means of a PPS control logic implemented in a service control point (SCP-A) associated to the user. The service control point (SCP- A) responsible for managing the accounting information for the first user equipment device A is shown in Fig. 1, whereas the

accounting information of the second user equipment device B may be managed by the same SCP or by a different SCP.

Further, the telecommunication system includes a centralized community server SCP-C, i.e. a service control point SCP with a centralized community service implemented. This centralized community server SCP-C is illustrated on the upper left-hand side of Fig. 1.

If the user possessing the user equipment device A wants to set up a communication service, in particular a voice call to the user equipment device B, he dials the number of the second user equipment device B. Then the first user equipment device generates a mobile originating call (MOC) message including the mobile subscriber ISDN number (MSISDN-B) of the second user equipment device B as the parameter defining the called party CdPa.

The prepaid subscription service (PPS) is triggered as usual in the HPLMN due to the PPS subscription and the VMSC-A sends a request comprising the mobile subscriber ISDN number

(MSISDN-B) of the called party to the service control point

(SCP-A) controlling the A-party PPS service. This message further contains a request to the A-party SCP used to decide whether a sufficient amount of fees is available on the prepaid account of the user A.

This service is triggered based on the user information (0- CSI) stored in the visitor location register VLR of the VMS. The SCP associated to the calling user then detects whether or not the calling user has a community subscription. If this is the case, the SCP associated to the calling user generates a modified connect message (CON) including a prefix and the MSISDN of the called user as the destination routing address .

The VMSC-A detects the prefix and removes this prefix. The presence of this prefix triggers a particular community service including sending a message comprising the MSISDN of both the calling party and the called party to the centralized community server SCP-C holding the community membership information for the users .

The centralized community server SCP-C decides whether or not the called user and the calling user belong to a common community and generates a release cause (RC) message to the VMSC-A signalling the result. In the RC message, the parameter is set to "release cause" or "cause" dependent on the result. In further embodiments, this message may further comprise an identifier of the community of the two users.

It is noted that the above described implementation uses only standardized messaging of an intelligent network application part (INAP) such as the CAMEL application part (CAP) .

Fig. 2 shows the further proceeding according to the method of the invention.

After having transmitted the release cause (RC) message, the centralized community server SCP-C has not further tasks and terminates therefore. The termination of the RC message is the calling party mobile switching centre VMSC-A. VMSC-A signals the value of the RC message to the service control point SCP associated to the calling party and to the prepaid subscription service PPS thereof using the EventReportBCSM message and the O_route select failure event. The special value of the release cause message is delivered as an additional information as well.

The PPC logic implemented in the SCP of the calling party- uses this information in order to determine a tariff specific for the community for billing the communication service if both users are members of the same community. Finally, the PPS service in the SCP associated to the calling party will setup a final call leg for establishing the communication service connection to the called party B.

As already mentioned above, this solution can be easily integrated into the existing prepaid services. No new protocol or protocol version has to be developed. The community data base of the centralized community server SCP-C can be placed at a central point in the network such that there are no synchronization tasks for updating plural PPS systems. The connection between the PPS service and the centralized community server SCP-C is done via the core network which is more reliable than IP connections in some countries. The end users will be satisfied since the calling party and the called party can use the community feature and can take advantage of the granted discounts even if both are supported by different PPS systems. The network has to update only one intelligent network system (the centralized community server SCP-C) with the newest community subscription and membership data.

Figs. 3 and 4 show a further embodiment of the invention. In the following description, the focus is put on differences between the embodiment illustrated in Figs . 3 and 4 and the embodiment illustrated in Figs. 1 and 2. With regard to similar features, we refer to the above description of the embodiments of Figs. 1 and 2 in order to avoid repetitions.

In contrast to the embodiment of Figs. 1 and 2, the embodiments of Figs . 3 and 4 use an implementation based on

the Siemens Intelligent Network Application Part (SINAP) in the version SINAP7m+. While the first steps of the method for billing the communication service and for establishing a communication service are similar to the first steps illustrated in Figs. 1 and 2, in the embodiment of Figs. 3 and 4, the centralized community server SCP-C does not generate a release cause (RC) message, but generates a connect (CON) message establishing the final leg to the called user B.

According to SINAP7m+, the connect message comprises a parameter with the name "ExtensionBackwardUserUser" which is used by the centralized community server SCP-C for signalling the result of the determination of the community status of the calling user and the called user to the mobile switching centre VMSC-A associated to the calling user A.

If the called party B answers the call, the "ExtensionBackwardUserUser" information is automatically included into the event report ECSM (0_answer) part of the PPS service. As shown in Fig. 4, the EstensionBackwardUserUser parameter is included in the answer message (ISUP) by the called user equipment device and forwarded to the SCP associated to the calling party, such that the PPC logic implemented in this SCP may perform a proper charging taking the community status of the two users into account .