GB2383230A

GB2383230A - Telecommunication payment system

Info

Publication number: GB2383230A
Application number: GB0125905A
Authority: GB
Inventors: Philip Ginzboorg; Yoshikatsu Nakagawa
Original assignee: Nokia Oyj; Nokia Inc
Current assignee: Nokia Oyj; Nokia Inc
Priority date: 2001-09-14
Filing date: 2001-10-29
Publication date: 2003-06-18
Anticipated expiration: 2021-10-29
Also published as: GB0125905D0; GB2383230B

Abstract

A method for charging in a communication system comprising an access control unit capable of controlling access by terminals to network resources for communication sessions and a database storing a balance for each subscriber of the system, the method comprising: receiving at the access control unit a request to establish a communication session to be charged to a subscriber; reducing the balance for the subscriber stored in the database by a deposit amount; storing the deposit amount as a deposit at the access control unit; determining at the access control unit the cost of services used in the session and reducing the deposit stored at the access control unit by the cost of services used; and increasing the credit for the subscriber stored in the database by the amount of the deposit stored at the access control unit after the session has ended.

Description

TELECOMMUNICATION PAYMENT SYSTEM This invention relates to a system for arranging payments in a telecommunications network.

Subscribers are normally charged for telecommunications services on one of two bases. In a post-paid or credit based system, the services used by a user are metered and at the end of each billing period the appropriate subscriber (frequently the user himself) is billed by the service provider for the services that were used during that billing period. In a pre-paid system, the subscriber makes an initial payment to the service provider and as services are used the subscriber's credit is decreased accordingly. The subscriber's credit is decreased periodically during the call, based on the usage made of the system during the call, and when the subscriber's credit has diminished to zero he is barred from using more services until he has made another payment.

In some telecommunications networks, especially older networks, there can be a significant delay in the calculation of the charge for use of the system. The delay can be an hour or more between a user having made use of a service and the network updating its database with the corresponding charges for that service. This does not hinder post-paid charging, because the subscriber can still be charged correctly provided the charges for the billing period have been calculated by the time the bills are sent out. However, significant delays in calculating charges do hinder the operation of current forms of pre-paid system. If there were a delay in calculating the charge for an ongoing communication session then the session could be continued after the cost of the session had exceeded the subscriber's remaining credit. The session would only be terminated when the charge had been calculated and compared to the subscriber's remaining credit. If the delay was an hour then the user could have used services amounting to a substantial value during the intervening period.

Pre-paid services are attractive to network operators because they avoid the risk that users will not pay their bills, and because the network receives payment for the services earlier than in a post-paid system and can then make use of the monies received in advance. However, operators of older networks may have problems implementing current forms of pre-paid systems because their networks may not be able to calculate and attribute charges quickly enough.

There is therefore a need for an improved pre-paid charging system that can allow pre-paid charging to be operated in a network in which there is a significant delay between a charge being incurred for a service and the charge being calculated and applied against a user's account.

According to the present invention from one aspect there is provided a method for charging in a communication system comprising an access control unit capable of controlling access by terminals to network resources for communication sessions and a database storing a balance for each subscriber of the system, the method comprising: receiving at the access control unit a request to establish a communication session to be charged to a subscriber; reducing the balance for the subscriber stored in the database by a deposit amount; storing the deposit amount as a deposit at the access control unit; determining at the access control unit the cost of services used in the session and reducing the deposit stored at the access control unit by the cost of services used; and increasing the credit for the subscriber stored in the database by the amount of the deposit stored at the access control unit after the session has ended.

According to the present invention from another aspect there is provided a communication system comprising: an access control unit capable of controlling access by terminals to network resources for communication sessions; and a database storing a balance for each subscriber of the system; wherein the access control unit is arranged to: receive a request to establish a communication session to be charged to a subscriber, and in response request the balance for the subscriber stored in the database to be reduced by a deposit amount; if that request

is successful store the deposit amount as a deposit; determine the cost of services used in the session and reduce the deposit stored by the cost of services used; and cause credit for the subscriber stored in the database to be increased by the amount of the deposit stored after the session has ended.

There may be a typical deposit amount defined in the system. The typical deposit amount would be the amount that is normally to be taken from the user's account in the database. This could equate to what has been determined to be the cost of an average session. The actual deposit amount could be the typical deposit amount or could be less, for instance if the subscriber has less than the typical deposit amount in his account.

Suitably the method comprises the steps prior to the reducing step of: determining whether the balance for the subscriber stored in the database is less than the deposit amount; and if the balance for the subscriber stored in the database is less than the deposit amount barring establishment of the session. Preferably the request specifies the type of the session, and the method comprises determining the deposit amount based on the type of the session. The deposit amount may be determined to be an average cost for a session of the specified type. An alternative system would be to take what is left from the account (even if it is less than the deposit amount) and let the user consume services as long as the taken amount lasts. This would be useful in session-based communications. For example, to get access to a game server the access control unit might normally takes $1 from the database and then reduces it 10c each minute, so that the user may play for 10 minutes. But if there are only 20c in the database, then the access control unit could takes 20c as the deposit amount and the user could then play for 2 minutes. If the requested deposit amount is greater than the balance of the user's account then the full balance of the user's account may be debited instead of the deposit amount.

Suitably the method comprises the step of, if the amount of the deposit stored in the access control unit reaches a predetermined level before the session has ended: determining whether the balance for the subscriber stored in the database is at least

equal to a deposit amount; and if the balance for the subscriber stored in the database is at least equal to the deposit amount, reducing the balance for the subscriber stored in the access control unit by the deposit amount and increasing the amount of the deposit stored in the access unit by the deposit amount; and otherwise terminating the session. The deposit amount could be a fixed amount or could be variable depending on the type of the session and/or the balance stored for the subscriber in the database. The predetermined amount could be zero or greater than zero.

The method suitably comprises the step prior to the reducing step of determining whether the subscriber is a pre-paid subscriber, and implementing the subsequent said steps only if the subscriber is a pre-paid subscriber.

The communication system is suitably a radio communication system, for example a mobile telephone system. The access control unit is suitably a gateway, for example an t-mode gateway.

The session could be a voice or data session.

The database is advantageously implemented as two or more storage units each of which stores a balance for only a subset of the subscribers. The storage units could be network units or could be located at terminals of the system. Conveniently the database is implemented by the storage at each terminal of a balance for a subscriber associated with that terminal. The balance for a subscriber associated with a terminal is preferably stored on a removable module in that terminal. The module is suitably a subscriber information module. The balance for a subscriber associated with a terminal is conveniently stored in encrypted and/or otherwise secured form at that terminal.

The present invention will now be described by way of example with reference to the drawings.

In the drawings: figure 1 is a schematic diagram of a telecommunications system; figure 2 shows a set of steps performed during the handling of a post-paid connection in the system of figure 1; and figure 3 shows a set of steps performed during the handling of a pre-paid connection in the system of figure 1.

In figure 1 mobile phones 1 and 2 can communicate with a mobile phone network 6 over radio links 5 and via a base station 4. The mobile phone network 6 is connected to other communications networks such as a fixed line phone network 9, to which fixed line phone 7 is connected, and data network 10 (which could, for mobile instance, be the internet), to which data terminal 8 is connected. The phones 1 and 2 can communicate via the network 6 with each other or with the terminals 7 and 8 that are connected to the other networks.

The network 6 comprises a routing arrangement 11, which routes connections within the network (e. g. for connections between phones 1 and 2) and between the network and the other networks 9,10 to which it is connected. Attempts to establish connections that pass through the routing arrangement are validated by an access control unit 14. The access control unit also monitors existing connections and can terminate them and determine the level of charge to a subscriber that is accrued in each connection. The access control unit could be a gateway, such as an i-mode gateway. In practice, more than one l-mode gateway could be used.

The network also includes a charging controller 12 by means of which the control unit 14 can communicate with a charging database 13.

The term call as used herein refers to any kind of session, whether circuit-switched or packet switched.

Figure 2 illustrates the steps in handling a post-paid call in the system of figure 1.

Terminal 1 initiates the call, which is directed to telephone 7, by transmitting to the

routing arrangement 11 a message requesting the call to be set up. (21). The message includes information concerning the type of the call, the identity of the terminal to which the call is directed, and information by which the subscriber who is to be charged for the call can be identified. In this example, the charging arrangement is such that the subscriber of mobile station 1 is to bear the cost of the call. It is normal for the subscriber of the terminal that initiates a call to be charged for the call, but other systems can be adopted.

At the routing arrangement 11 the message is handled by access control unit 14. The routing arrangement determines where the charging records for the subscriber who is to be charged for the call are stored. (22). In this case it is assumed that the subscriber is a subscriber of network 6 and that his records are stored in database 13, but in a roaming situation the records may be stored at another network and the routing arrangement would make contact with the charging database of that network instead of with database 13 in the subsequent steps.

The access control unit then contacts the appropriate charging database, in this example database 13, to determine the type of billing (post-paid or pre-paid) to be used for that subscriber. (23). In this example it is assumed that the billing is to be post-paid.

Since the billing is to be post-paid, the access control unit permits the call to be set up. (24). As the call progresses it is monitored by the access control unit. The access control unit logs the chargeable units (e. g. duration of connection or amount of data carried) used in the call. (25). The access control unit stores a tariff. At intervals the access control unit periodically applies the tariff to the amount of chargeable units used since the tariff was last applied to the call to determine the cost due to the call in the last charging interval. (26). Charging intervals will typically be brief-for example less than a few seconds. Then the access control unit generates a charging message indicating at least the identity of the subscriber who is to be charged for the call and the cost due for the last billing period. That message is sent to the charging controller 12, (27) which updates the subscriber's

billing data as stored in the database 13 so as to increase the amount that the subscriber owes by the cost due. (28). This is repeated each charging interval until the call ends.

Instead of sending multiple charging messages to the charging controller, as described above, the access control unit 14 could be configured to collect all the charges for the call and then send a single charging message to the charging controller indicating at least the subscriber's identity and the total cost of the call.

The process for handling post-paid calls is thus somewhat like that applied in conventional systems.

Figure 3 illustrates the steps in handling a pre-paid call in the system of figure 1.

Steps 31 to 33 are the same steps 21 to 23 in the post-paid method. However, in this case the subscriber is determined to be a pre-paid subscriber.

To help overcome problems of potential delay between charging messages being sent from the access control unit 14 and the corresponding charges being applied in the database 13, the access control unit implements a different charging method for pre-paid subscribers. On determining that the subscriber who is to be charged for the call is a pre-paid subscriber the access control unit sends a deposit request message to the charging controller 12. (34). The deposit request message indicates the subscriber's identity and an amount. The amount could be fixed, or could be determined based on the type of call that is to be set up. For example it could be an expected average charge for the call. Thus, if the call were a data call that was to be charged at a rate of 1.6 JPY/kB and the average amount of data transferred in a call had been found to be 25 kB then the amount could conveniently be 40 JPY. On receiving the deposit request message the charging controller checks whether the subscriber's pre-paid account is in credit by the amount or more. If it is not, then the charging controller returns to the access control unit a deposit reject message, indicating that the request for a deposit has been rejected, and in response to that message the access control unit returns a reject message to

terminal 1 to indicate that the call cannot be set up (36). Alternatively, if the subscriber's account is sufficiently in credit then the charging controller decreases the amount of credit stored for the subscriber in the charging database 13 by the amount (35) and returns to the access control unit a deposit accept message, indicating that the request for a deposit has been accepted. On receiving the deposit accept message the access control unit stores a record of the amount of the deposit in connection with the call (36) and permits the call to be set up. (37).

The taking of a deposit amount also allows the number of database hits to be reduced, because the access unit goes to access the database only when a quota (e. g. of 40 JPY) has been used up by the subscriber. But if the amount remaining in the database is 20 JPY, i. e. less than the 40 JPY, then the access unit should take the remaining 20 JPY and let the subscriber use the service for as long as those 20 JPY last.

As the call progresses it is monitored by the access control unit, which logs the chargeable units used in the call. (38). At intervals the access control unit periodically applies the tariff to the amount of chargeable units used since the tariff was last applied to the call to determine the cost due to the call in the last charging interval. (39). Then, instead of generating a charging message the access control unit reduces the deposit stored in connection with the call by cost due. (40). This is repeated each charging interval as the call progresses.

As the call progresses, the deposit stored at the access control unit in connection with the call may be reduced to zero. In that case the access control unit requests another deposit in the same way as described above. If the charging controller returns a deposit reject message then the call is terminated.

If the call terminates normally then the deposit stored at the access control unit may be greater than zero. In that case the access control unit signals the charging controller to re-credit the remaining deposit to the subscriber's account. (41). This may be done by way of a dedicated deposit return message, or by means of a

charging message, as used in post-paid billing, in which the amount indicates the credit corresponding to the returned deposit as a negative value. For example, if the deposit stored in the access unit when call terminates is 5 JPY, then the amount in the charging message will be-5 JPY.

The method of figure 3 allows pre-paid billing to be implemented with greatly fewer hits on the charging database 13. By reducing the load on the database its performance can be enhanced. Thus the method of figure 3 provides a means by which pre-paid billing can be implemented in systems in which there is a significant delay between charging messages being sent by the access control unit and the corresponding changes to the charging database being made by the charging controller.

Other measures may also be taken to improve the performance of the database 13.

1. The subscriber accounts can be distributed between two or more databases. For example the details of subscribers in the lower half of the range of subscriber IDs that are in use could be stored in one database, and those in the upper half stored in another database. Charging messages will be actioned by addressing the appropriate database on the basis of the subscriber 10 that they specify. This spreads the load between the databases so throughput can be increased. The split between the databases could be made on the basis of other factors, such as where in the alphabet the subscriber's name falls, or a hashed function of the user 10.

2. The entire charging database could be replicated and the load could be shared between the replicated databases. The databases would be synchronised regularly.

Again, this spreads the load between the databases so throughput can be increased.

3. The charging database could be embodied in a special way so as to increase its speed of operation. One option is to distribute the database between user identification modules located individual phones. In many phone systems, phones

are equipped with user identification modules, such as the subscriber identification modules (StMs) used in GSM. (Module 3 in figure 1). A user's charging details, including his current credit, could be stored in the user's identification module. This avoids the need for a central charging database to be accessed during a connection; instead the access control unit withdraws the deposit and re-credits unused deposit directly to or from the credit stored on the SIM in an analogous way to that described above. Since the user has physical access to the identification module the charging information stored on the identification module should be stored in secure, e. g. encrypted, form. Charging data stored on a SIM could be replicated with a central charging database-for instance after each call-to ensure that it is kept correct.

The applicant draws attention to the fact that the present invention may include any feature or combination of features disclosed herein either implicitly or explicitly or any generalisation thereof, without limitation to the scope of any definitions set out above. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

1. A method for charging in a communication system comprising an access control unit capable of controlling access by terminals to network resources for communication sessions and a database storing a balance for each subscriber of the system, the method comprising: receiving at the access control unit a request to establish a communication session to be charged to a subscriber; reducing the balance for the subscriber stored in the database by a deposit amount; storing the deposit amount as a deposit at the access control unit; determining at the access control unit the cost of services used in the session and reducing the deposit stored at the access control unit by the cost of services used; and increasing the credit for the subscriber stored in the database by the amount of the deposit stored at the access control unit after the session has ended.

2. A method as claimed in claim 1, comprising the steps prior to the reducing step of : determining whether the balance for the subscriber stored in the database is less than the deposit amount; and if the balance for the subscriber stored in the database is less than the deposit amount barring establishment of the session.

3. A method as claimed in any preceding claim, wherein the request specifies the type of the session, and the method comprises determining the deposit amount based on the type of the session.

4. A method as claimed in any preceding claim, comprising the step of, if the amount of the deposit stored in the access control unit reaches a predetermined level before the session has ended:

determining whether the balance for the subscriber stored in the database is at least equal to a deposit amount; and if the balance for the subscriber stored in the database is at least equal to the deposit amount, reducing the balance for the subscriber stored in the database by the deposit amount and increasing the amount of the deposit stored in the access control unit by the deposit amount; and otherwise terminating the session.

5. A method as claimed in claim 4, wherein the predetermined amount is zero.

6. A method as claimed in claim 5, wherein the predetermined amount is greater than zero.

7. A method as claimed in any preceding claim, comprising the step prior to the reducing step of determining whether the subscriber is a pre-paid subscriber, and implementing the subsequent said steps only if the subscriber is a pre-paid subscriber.

8. A method as claimed in any preceding claim, wherein the communication system is a radio communication system.

9. A method as claimed in any preceding claim, wherein the access control unit is a gateway.

10. A method as claimed in any preceding claim, wherein the session is a data session.

11. A method as claimed in any preceding claim, wherein the database is implemented as two or more storage units each of which stores a balance for only a subset of the subscribers.

12. A method as claimed in claim 11, wherein the database is implemented by the storage at each terminal of a balance for a subscriber associated with that terminal.

13. A method as claimed in claim 12, wherein the balance for a subscriber associated with a terminal is stored on a removable module in that terminal.

14. A method as claimed in claim 13, wherein the module is a subscriber information module.

15. A method as claimed in any of claims 12 to 14, wherein the balance for a subscriber associated with a terminal is stored in encrypted form at that terminal.

16. A method as claimed in any preceding claim, wherein the step of determining at the access control unit the cost of services used in the session and reducing the deposit stored at the access control unit by the cost of services used is performed periodically.

17. A communication system comprising: an access control unit capable of controlling access by terminals to network resources for communication sessions; and a database storing a balance for each subscriber of the system; wherein the access control unit is arranged to: receive a request to establish a communication session to be charged to a subscriber, and in response request the balance for the subscriber stored in the database to be reduced by a deposit amount; if that request is successful store the deposit amount as a deposit; determine the cost of services used in the session and reduce the deposit stored by the cost of services used; and cause credit for the subscriber stored in the database to be increased by the amount of the deposit stored after the session has ended.

18. A method for charging in a communication system substantially as herein described with reference to figures 1 to 3.

19. A communication system substantially as herein described with reference to figures 1 to 3.