BACKGROUND OF THE INVENTION Telecommunication systems are undergoing con- tinuous development. People and enterprises using telecommunication systems expect and assume that the services provided in conjunction with telecommunica- tion systems will go on improving and growing more varied.

The Internet is a global complex of different telecommunication networks. Its basic idea is global addressing that allows each individual computer con- nected to it to be unambiguously located.

At present, the Internet is very popular and it is growing rapidly. There are Internet services such as electronic mail and the WWW (World Wide Web).

Especially due to its ease of use and its world-wide nature, the WWW has become a global channel for the transmission of information.

The Internet has gathered around it a new channel for advertising and commerce. Various supple- mentary services produced in the Internet may be chargeable. Examples of this are e. g. various net pub- lications, real-time news services, etc. The means of payment used include e. g. credit cards and electronic money. A condition for the implementation of services is that the user of a service be reliably identified

so that the bill for the service is directed to the right party. For these services to gain more wide- spread popularity, security of communication in dif- ferent telecommunication systems must be guaranteed.

An implementation associated with chargeable supple- mentary services is e. g. one in which the services are based on separate systems built in WWW servers in which a registered user of a service is identified on the basis of a user identifier and a personal pass- word. The identifier and password entered by the user are compared with information stored in a user regis- ter, and after successful identification the user is given access to the actual service. The passwords may be either permanent or changeable, being based e. g. on lists of passwords or on agreed algorithms.

In the solution described above, a problem is that the user identification system built in a WWW server requires registration of service users, a sepa- rate database, customer management and password man- agement. The TCP/IP protocol (TCP, Transport Control Protocol; IP, Internet Protocol) is susceptible to in- terception, which means that at least static passwords do not necessarily guarantee security. Moreover, the billing of users for service transactions has to be implemented via a separate billing system or alterna- tively the service has to be integrated with an exist- ing payment system in the Internet.

The object of the present invention is to eliminate the drawbacks referred to above or at least to significantly alleviate them.

A specific object of the invention is to dis- close a new type of procedure and system for providing services requiring reliable user identification for mobile telephone subscribers, preferably GSM subscrib- ers (GSM, Global System for Mobile communications) over the Internet. Further, the invention allows the billing for a service to be integrated with an exist-

ing mobile telephone billing system. This obviates the need for implementing a separate user identification and billing system.

As for the features characteristic of the present invention, reference is made to the claims.

SUBJECT OF THE INVENTION The procedure of the invention concerns iden- tification and billing of a subscriber in conjunction with a service in a telecommunication system. The sys- tem of the invention preferably comprises a first telecommunication network, a first telecommunication terminal connected to the first telecommunication net- work, and a second telecommunication network. Moreo- ver, the system comprises a second telecommunication terminal, which is connected to the second telecommu- nication network. Furthermore, the system of the in- vention comprises a telecommunication server connected to the second telecommunication network and a billing server connected to both the first and the second telecommunication networks.

In the procedure of the invention, using the second telecommunication terminal, a telecommunication connection is established via the telecommunication server to the second telecommunication network. This means e. g. that a connection is set up via any service provider to the second telecommunication network, e. g. the Internet. The telecommunication server is refera- bly a WWW server. By means of the second telecommuni- cation terminal, which is e. g. a computer, the user selects a desired service, a possible second party as- sociated with the service, the mode of service and other parameters relating to the service. This is ac- complished e. g. by selecting a HTML page (HTML, Hyper- Text Markup Language) created for a given service.

From information supplied by the user and from possi- ble attached information, an unambiguous identifier

associated with the service in question is formed. The user sees the identifier e. g. on a new HTML page.

Based on the identifier received, using the first telecommunication terminal, the user sends a message of a given format to the billing server via the first telecommunication network. A short message is sent to a given predetermined short message number.

In practice, this means e. g. that, in the case of a mobile communication network, the short message sent is first passed to a short message service center (SMS-C). The short message service center recognizes by a given part of the short message that it has to be sent further to the billing server. The short message to be sent may also contain other information relating to the service. The first telecommunication terminal is preferably a mobile station and the first telecom- munication network is correspondingly a mobile commu- nication network. If the mobile communication network is a GSM network, then the message to be sent is e. g. a SMS message (SMS, Short Message Service).

The sender of the message and the service se- lected by the sender are identified in the billing server on the basis of the identifier contained in the message sent. The information transmitted in the mes- sage is sufficient for the identification of the user.

The sender of the message is identified e. g. on the basis of the MSISDN number (MSISDN, Mobile Station In- ternational ISDN Number) associated with an SMS mes- sage. The billing for the selected service is part of the business of the first telecommunication network.

According to the invention, the billing is done in ac- cordance with normal subscriber invoicing. If the first telecommunication network is a mobile communica- tion network, then the user of the service is billed in conjunction with a normal mobile communication in- voice.

The sender of the message can be sent a con- firmation of execution of the selected service. The confirmation is sent e. g. as an SMS message or via a WWW connection.

The system comprises means for performing the functions described above.

The present invention has the advantage that chargeable Internet services can be provided for WWW users having a mobile telephone subscription, without their having to register themselves in a separate credit or digital cash system. The billing of service users can be implemented via the billing system of an existing mobile communication network, preferably a GSM network, without a separate user database and cus- tomer management.

LIST OF ILLUSTRATIONS In the following, the invention will be de- scribed in detail by the aid of a few embodiments, wherein Fig. 1 presents a system according to the present invention, and Fig. 2 presents a signalling flow diagram ac- cording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION The system illustrated in Fig. 1 comprises a first telecommunication network 1, a first telecomma- nication terminal 2 connected to the first telecommu- nication network 1, and a second telecommunication network 3. Further, the system of the invention com- prises a telecommunication server 4 connected to the second telecommunication network 3. Moreover, the sys- tem comprises a second telecommunication terminal 5 connected to the second telecommunication network 3

and a billing server 6 connected to both the first 1 and the second 3 telecommunication networks.

The first telecommunication terminal 2 com- prises means 7 for sending a message of a given format on the basis of information contained in an identifier via the first telecommunication network 1 to the bill- ing server 6. The billing server 6 comprises means 8 for identifying the sender of the message and/or the service associated with it in the billing server 6 on the basis of the message and/or its sender and means 9 for billing the sender of the message in accordance with the normal subscriber invoicing practice in the first telecommunication network 1. Moreover, the bill- ing server 6 comprises means 11 for sending to the user of the service a confirmation of successful exe- cution of the selected service in the form of an SMS message and/or over the second telecommunication net- work 3 via the telecommunication server 4 to the sec- ond telecommunication terminal 5 and/or in some other way.

The telecommunication server 4 comprises means 10 for adding to the identifier associated with the selected service a component identifying the serv- ice and/or a unique transaction-specific identifier and/or other information. In addition, the first tele- communication network 1 comprises means 12 for direct- ing a received message to the billing server 6 on the basis of a predetermined identifier contained in the message.

In an embodiment as illustrated in Fig. 1, the user is sending an"electronic postcard". Using a second telecommunication terminal 5 as presented in Fig. 1, the user selects an appropriate HTML page in the WWW, e. g. the HTML page of his own mobile communi- cation network operator. This page presents him the following alternatives: sending an electronic postcard -to a GSM subscriber on the basis of a GSM number,

-as an electronic mail message to a given electronic mail address, -as a printed postcard to the receiver's home ad- dress.

The page also contains a list of service charges. On the next page, the user fills in on the electronic postcard a title, a greeting text and a re- ceiver specification and attaches to the card a de- sired digital picture. Having filled in the informa- tion relating to the postcard, the user confirms the transmission of the electronic postcard by means of a mobile telephone. For the transmission, the WWW server presents a new HTML page to the user. On this page, the user is asked to send a short message of a given format e. g. to the abbreviated number 400. The text message of a given format may contain e. g. a message like"Card 4275". The user sends the above-described message to a certain abbreviated number, which in this example is 400. The short message service center SMS-C of the mobile communication network directs the short message further to a server which handles short mes- sages subject to a special charge; in the present ex- ample, this server is called Netgate. Generally, the text message of a given format contains a component identifying the service (Service ID) and a unique transaction-specific identifier (Transaction ID). The transaction-specific identifier contains possible service options and an unambiguous identifier gener- ated by the server.

Netgate identifies the service in question by the example word"Card" (Service ID) appearing at the beginning of the message and generates a billing ticket concerning use of the service. Based on the billing ticket, the charge for the service is debited directly to the user in his mobile telephone invoice.

Netgate transmits the numeric code"4275" (Transaction ID) and the user's mobile telephone number to an image

server providing a WWW service. Based on these data, the image server activates the transmission of the card.

In the GSM network, the subscriber is identi- fied by an effective authentication mechanism when a telephone containing a SIM card (SIM, Subscriber Iden- tity Module) connects to the GSM network. In the mo- bile originated SMS message, the subscriber MSISDN number, verified by the above-mentioned authentication procedure, is transmitted to the short message service center. In this example, the sender of the message is identified by the MSISDN number.

The user receives an acknowledgement of re- ceipt of the service request in the form of an SMS message. If the transmission of the card is not acti- vated, then the image server will delete unsent cards after a certain delay. If the numeric code in the short message is incorrect, then the user is given an error message, e. g."The card number you sent is in- correct".

Fig. 2 presents a signalling flow diagram ac- cording to the invention. It describes the operation of the system of the invention, illustrating the com- munication between the various components. MS is a mo- bile station and"Netgate"is an example of a server providing chargeable SMS services. The lozenges in Fig. 2 represent internal processes or impulses in the components.

The user supplies the information (20a) re- quired in the service, producing an action request to the WWW server (20). The WWW server interprets the in- formation supplied and generates a unique transaction- specific identifier (Transaction-ID) (21a) from it. At the same time, it sends to the WWW-client a request relating to the service, containing a component iden- tifying the service (Service ID) and a unique transac- tion-specific identifier (Transaction-ID). The request

also contains the short message number to which the user is asked to send a text message.

Next, the user of the mobile station sends a text message to the above-mentioned short message num- ber (22). The text message contains a component iden- tifying the service and a unique transaction-specific identifier. The text message is first sent to the short message service center (SMS-C) (23) of the mo- bile communication network, which again is able to di- rect it to a server taking care of specially charged services. This server, which in this example is called "Netgate", generates a billing ticket (23a) from the service. In this example, the billing for the services is performed in accordance with the normal billing practice of the mobile communication network.

The server"Netgate"sends a notice about the transaction performed to the WWW server (24). The no- tice contains the billed MSISDN number and the trans- action-specific identifier (Transaction-ID). The WWW server recognizes the identifier sent and, based on this, performs the actions (24a) comprised in the service requested. The billing ticket CDR (CDR, Call Detailed Record) generated from the service is sent to the billingsystem (25). A confirmation of the billing transaction can be sent to the mobile station in the form of an SMS message (26). The service user is sent a confirmation of successful execution of the service e. g. via the WWW connection (27) and/or as a SMS mes- sage (28).

The invention is not restricted to the exam- ples of its embodiments described above, but many variations are possible within the scope of the inven- tive idea defined in the claims.