Title of Invention	SYSTEM FOR EXECUTING A CALLBACK FOR TELECOMMUNICATIONS
Abstract	The invention discloses a callback method for telecommunications, in which a first participant with a first communication terminal (A) communicates to a telecommunications system that he wishes to communicate with at least one second participant with a second communication terminal (B), whereupon the first participant is temporarily put on hold, a cost-efficient connection to a destination gateway (Point of Presence, POP) (3c) in the vicinity of the second participant is established, and the connection is completed by establishing a local connection (10) from the said gateway (3c) to the second communication terminal (B), characterized in that it comprises the following further steps: initiation of the method through a special message (80) transmitted from the first communication terminal (A) to a service centre (9), determination of the momentarily most cost-efficient destination gateway (3c), which has access to a backbone (1), for the connection (10) of the destination gateway (3c) to the second communication terminal (B) through a callback application (90) in the service centre (9) on the basis of tariff tables stored in a database (91) accessible to the service centre (S), transmission of connection-establishment instructions through the callback application (90) via a communication network to a local gateway (3a) having access to a backbone (1) to establish a connection with the first communication terminal (A) and to the destination gateway (3c) to establish a connection with the second communication terminal (B), establishment of a connection (11) from the local gateway (3a) to the first communication terminal (A), establishment of a connection (10) from the destination gateway (3c) to the second communication terminal  (B),  communication  between  the  first  and  second participants, data being received through the gateways (3a, 3c) from the connected terminal in each case (A, B), the data between the local gateway (3a) and the destination gateway (3c) being transmitted via the backbone (1), and data being received through the gateways (3a, 3c) via the backbone (1) and being sent to the respective connected communication terminal (A, B). Also disclosed is a system for executing a callback method and service center for said system.

Title of Invention

SYSTEM FOR EXECUTING A CALLBACK FOR TELECOMMUNICATIONS

Abstract

The invention discloses a callback method for telecommunications, in which a first participant with a first communication terminal (A) communicates to a telecommunications system that he wishes to communicate with at least one second participant with a second communication terminal (B), whereupon the first participant is temporarily put on hold, a cost-efficient connection to a destination gateway (Point of Presence, POP) (3c) in the vicinity of the second participant is established, and the connection is completed by establishing a local connection (10) from the said gateway (3c) to the second communication terminal (B), characterized in that it comprises the following further steps: initiation of the method through a special message (80) transmitted from the first communication terminal (A) to a service centre (9), determination of the momentarily most cost-efficient destination gateway (3c), which has access to a backbone (1), for the connection (10) of the destination gateway (3c) to the second communication terminal (B) through a callback application (90) in the service centre (9) on the basis of tariff tables stored in a database (91) accessible to the service centre (S), transmission of connection-establishment instructions through the callback application (90) via a communication network to a local gateway (3a) having access to a backbone (1) to establish a connection with the first communication terminal (A) and to the destination gateway (3c) to establish a connection with the second communication terminal (B), establishment of a connection (11) from the local gateway (3a) to the first communication terminal (A), establishment of a connection (10) from the destination gateway (3c) to the second communication terminal  (B),  communication  between  the  first  and  second participants, data being received through the gateways (3a, 3c) from the connected terminal in each case (A, B), the data between the local gateway (3a) and the destination gateway (3c) being transmitted via the backbone (1), and data being received through the gateways (3a, 3c) via the backbone (1) and being sent to the respective connected communication terminal (A, B). Also disclosed is a system for executing a callback method and service center for said system.

Full Text	The present invention relates to a for tetecommunications system for executing a callback Callback methods in which a service provider assigns a special access number to a subscriber are known in telephony. The subscriber dials this number and hangs up. A computer of the service provider calls the subscriber back with a dial-tone to a network with low tariffs. In response, the subscriber may dial the number of his communication partner as usual. Other methods make it possible for the subscriber to pre-define certain destination numbers, such that these numbers are routed automatically by the computer of the service provider to a network with low tariffs. A callback method is known from Digital Long Distance (DLD) Corporation (DLD Mobile Callback, according to www.digitcom.com of December 22, 1997, filed as a US patent application) in which a local network computer (Point-of-Presence, POP) captures the called number and sends digitised call data via the low cost Internet to respective nodes (POP) participating in the method. In this callback method, the POP closest to the destination determines the most cost-effective telephone connection available to complete the call, and establishes the corresponding telephone connection between the destination POP and the local line to the local network computer (local POP). Thereafter, the destination POP completes the circuit with a second local telephone line to the destination end. Besides the low cost for establishing the connection via the Internet, the communication costs are reduced to the costs of the two local connections, as well as to the costs of the long-distance call selected for its low tariffs. It is an object of this invention to propose a new and improved callback method for telecommunications. According to the present invention, this object is achieved particularly through the features of the characterising portion of the independent claims. Moreover, this object is also achieved through the system according to the independent system claim. In addition, further advantageous embodiments follow from the dependent claims and the description. In particular, these objects are achieved according to the invention in that the callback method is implemented such that a connection with the communication terminal of the calling user is established from a local gateway and that a connection with the communication terminal of the called user is established from a destination gateway and that the data transmission from the local gateway to the destination gateway takes place via a backbone. Besides the low costs for establishing the connections from the gateways to the backbone, the communication costs are reduced to the costs of the two local connections to the local gateway and to the destination gateway, as well as to the costs of the data transmission via the backbone, which can turn out to be negligibly low, depending on the embodiment. Preferably, the destination gateway and the local gateway are determined such that the current tariff from the destination gateway to the communication terminal of the called user or from the local gateway to the communication terminal of the calling user, respectively, are the lowest possible. Obviously, the communication costs of the two local connections can thereby be kept optimally low. Preferably, the tariff costs from the local gateway to the communication terminal of the calling user and from the destination gateway to the communication terminal of the called user are subsequently compared with the tariff costs of a direct connection between the communication terminals. If its tariff costs are more favourable, a direct connection between the communication terminals of the calling and the called user is established instead of a connection via the backbone. This approach has the advantage that it ensures that the callback variant with communication via gateways and backbone is only used when it is actually cost beneficial. In the present invention, the current tariffs of the gateways are being monitored for the duration of the connection. If the current tariff of a more cost-effective gateway is by a pre-defined amount lower than the current tariff of the gateway used at the moment, the respective communication terminal is connected to the backbone via the more cost-effective gateway as a result of a connection change. This has the additional advantage that the communication costs can be optimised even for the duration of the connection. Preferably, the callback method of the present invention is initiated through a special message which is prepared and transmitted to a service centre by a SIM-card. This has the additional advantage that a user (or a group of users) may make use, by means of his (their) personal SIM-card, of personal callback services which are transferable to other communication terminals. An embodiment of the present invention is described below by way of example. The embodiment example is illustrated by means of the following appended figure: Fig. 1 shows an overview diagram with a backbone, with which communication networks are connected by means of gateways, and communication terminals which can communicate via the communication networks with the gateways and with a service centre. Reference character A relates to a communication terminal of a calling user, not illustrated, who wishes, for instance, to communicate with a called user, also not illustrated, with a communication terminal B. There are different variants to initiate a callback method for establishing a connection to the called user. For example, the calling user may decide that a callback method should be initiated and he may initiate this explicitly, for instance, by calling a special service number or by selecting a special service of the SIM-card in the communication terminal via the keyboard of the communication terminal. In another variant, a callback method is automatically initiated when the called number corresponds to a number recorded in a special callback list, this list possibly being stored on the SIM-card or in the service centre. In a variant it is also possible that it is sufficient if only the area code of the called number is recorded in this list. Finally, it is also possible that each call, or at least each long-distance call, initiates a callback method. After the decision as to whether or not a callback method should be initiated, the callback method is preferably started by the communication terminal A by transmitting a special callback message 80 as a callback order 8 to a service centre 9. The callback message 80 comprises an identification field 81, identifying the callback service, a field 82, containing the number of the calling user, and a field 83, containing the number of the called user. The callback message is prepared and transmitted by a special callback request application, which is preferably located on a SIM-card. For one skilled in the art it is easy to program the corresponding application, for instance as a Java applet (which can obviously also run outside a SIM-card, for example in a personal computer). The callback request application can transmit the callback message 80, for instance by means of a short message or USSD data, via a communication network 7 to a service centre 9. The communication network 7 is, for example, a mobile radio network, e.g. a GSM-network, and/or a fixed network, via which communication terminals A, such as mobile telephones and/or personal computers, communicate with each other. The callback order 8 is received by a service centre 9; it is recognised as a callback message 80 and passed on to a callback application 90 for further processing of callback orders. For instance, this is implemented such that the service centre 9 comprises a SIM-server, for example a short message service centre (SSC), in which special messages are recognised and handed over to respective special applications for further processing, in this case to the canback application 90, according to the SICAP method described itf EP 0689 368 E^lro'r according to a similar method. The callback application 90 retrieves the number of the calling user 82 and the number of the called user 83 from the callback message 80. Based on tables of tariffs, for example stored in a database 91 accessible to the service centre, the callback application 90 preferably determines the most cost-effective destination gateway 3c with access to a backbone 1, in order to establish a connection with the communication terminal B of the called user. For that purpose, the tables of tariffs in the database 91 contain, for instance, information concerning the geographic location and the different tariffs for different time zones for the available gateways that have access to backbone 1. In a variant, the callback application 90 also determines the most cost-effective local gateway 3a with access to backbone 1, in order to establish a connection 11 with the communication terminal A of the calling user. The tariffs stored in the tables of tariffs of the database 91 can be updated and maintained, for instance by the respective gateways 3a, 3b, 3c themselves, directly via a communication network, preferably by making use of security services, for example TTP-services (trusted third party) or PTP-services (point-to-point). This can take place by means of direct access to the database 91, or to a database server, or by means of special services via the service centre 9. When the two gateways 3a and 3c are determined, the callback application 90 preferably compares the tariff costs for a direct connection, between the two communication terminals A and B, to the total tariff costs of the connection from the local gateway 3a to the communication terminal A and from the destination gateway 3c to the communication terminal B. In the case where the tariff costs are more favourable for the direct connection, the callback application 90 initiates a direct connection between the two communication terminals A, B, which connection can be established in the conventional way known to one skilled in the art. In the case where the total tariff costs for the connection of the local gateway 3a to the communication terminal A and for the connection of the destination gateway 3c to the communication terminal B are more favourable, these connections are established according to the invention such that the calling user can communicate with the called user by means of the communication terminal A via the connection to the local gateway 3a, from there via backbone 1 to the destination gateway 3c, and from there via the connection to the communication terminal B. The connections are established, for instance, by the callback application 90 sending instructions for establishing a connection with the communication terminal A and with the communication terminal B to the local gateway 3a and to the destination gateway 3c, respectively. The instructions for establishing a connection contain information for the identification of the calling user's communication terminal A, of the local gateway 3a, of the called user's communication terminal B, and of the destination gateway 3c. The communication between the service centre 9 and the gateways 3a, 3b, 3c takes place via a communication network, for instance an ATM network, an Intranet or the public Internet. In a variant, the indirect connection via the gateways 3a, 3c, which are interconnected via backbone 1, must be cheaper by a specified minimal amount before it is preferred to the direct connection between the communication terminals A, B. This minimal amount can be set, for instance, such that it corresponds to the tariff costs of the communication via the backbone 1, and may possibly include other extra costs. The backbone 1 is, for instance, an ATM network, an Intranet or the public Internet. The destination gateway 3c receives the instruction to establish a connection from the service centre 9 and establishes a connection 2c to the backbone 1. In a variant, the gateway 3c is permanently connected to the backbone 1. In addition, via the communication network 6, the gateway 3c initiates the synchronised establishment of a connection 10 to the communication terminal B, as will be described in more detail below. Furthermore, the gateway 3c maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal A of the calling user, received via the connection 2c to the backbone 1, are mapped onto the connection 10 to the communication terminal B of the called user, and such that messages for the communication terminal A of the calling user are mapped onto the gateway 3a via the connection 2c to the backbone 1. The communication network 6 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network. The local gateway 3a receives the instruction to establish a connection from the service centre 9, and establishes a connection 2a to the backbone 1. In a variant, the gateway 3a is permanently connected to the backbone 1. In addition, via the communication network 4, the gateway 3a initiates the synchronised establishment of a connection 11 to the communication terminal A, as will be described in more detail below. Furthermore, the gateway 3a maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal B of the called user, received via the connection 2a to the backbone 1, are mapped onto the connection 11 to the communication terminal A of the calling user, and such that messages for the communication terminal B of the called user are mapped onto the gateway 3c via the connection 2a to the backbone 1. The communication network 4 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network. Synchronisation of the establishment of a connection between the local gateway 3a and the communication terminal A with the establishment of a connection between the destination gateway 3c and the communication terminal B takes place, for example, via the backbone 1. For instance, the destination gateway 3c can communicate to the local gateway 3a via the connection 2c, the backbone 1, and the connection 2a that it has initiated the establishment of a connection to the communication terminal B of the called user. In response, the local gateway 3a sends the actual callback 11 to the communication terminal A of the calling user. Thereupon, the communication terminal A can immediately establish the connection to the local gateway 3a and thus await in a transparent fashion, via the connection 11, the connection 2a, the backbone 1, and the connection 2c, the establishment of a connection 10 of the destination gateway 3c to the communication terminal B of the called user. In another variant, control of the synchronisation occurs, for example, through the local gateway 3a sending the actual callback 11 to the communication terminal A of the calling user. Thereupon, the communication terminal A can immediately establish the connection to the local gateway 3a. In response, the local gateway 3a can communicate to the destination gateway 3c via the connection 2a, the backbone 1, and the connection 2c that it has initiated the establishment of a connection to the communication terminal A of the calling user. Thereupon, the destination gateway 3c can initiate the establishment of a connection 10 to the communication terminal B. For a person skilled in the art there are additional embodiments for this establishment of a connection, which will not be discussed any further. When the connections between the local gateway 3a and the communication terminal A and between the destination gateway 3c and the communication terminal B are established, communication between the users may begin. For instance, speech information captured by the communication terminal A are transmitted as data to the local gateway 3a via the communication network 4. Besides mapping the respective connections according to the above-mentioned table, the gateways 3a, 3b, 3c are also taking on the function to execute protocol conversions between the connected communication networks, if necessary. This is achieved, for instance, by retrieving user data from the protocol data units received from a first communication network, for example communication network 4, and embedding them into the corresponding protocol data units of a second communication network, for instance backbone 1, before they are sent via the second communication network, for instance, by means of connection 2a via the backbone 1 to the destination gateway 3c. Mapping of connections and conversion of protocols work in both directions, such that the users can communicate transparently. Preferably, the callback application 90 of the service centre 9, for instance, is monitoring the current tariffs of the gateways 3a, 3b, 3c for the duration of a connection, initiated on its initiative, between two communication terminals A and B via a backbone 1, for instance by means of the tables of tariffs in the database 91. In addition, the callback application 90 maintains for that purpose a table, for instance, where information is stored for the identification of the calling user's communication terminal A, of the local gateway 3a, of the called user's communication terminal B, and of the destination gateway 3c. For a connection to one of the communication terminals A or B, which it is monitoring, the callback application 90 can initiate a change of connection, in the case where it finds a gateway 3b with a current tariff for a current time zone cheaper by at least a pre-defined amount. For instance, this can be implemented such that the callback application 90 sends to the cheaper gateway 3b an instruction to initiate a handover from the more expensive local gateway 3a to the cheaper gateway 3b. The instructions contain, for example, information for the identification of the more expensive gateway to be replaced, of the communication terminal A connected to this gateway, of the gateway 3c involved, and of the communication terminal B connected to this latter gateway. The more cost-effective gateway 3b receives the instruction to initiate a handover from the service centre 9 and establishes a connection to the backbone 1. In a variant, the gateway 3b is permanently connected to the backbone 1. In addition, the gateway 3b forwards the change of connection, for instance through a handover message 12, via the communication network 5 to the communication terminal A, connected to the gateway 3a to be replaced. For instance, the change of connection (handover) can be executed by the communication terminal A to be replaced. This can be done by the communication terminal A, in response to the handover message, releasing the connection to the gateway 3a to be replaced and establishing in its place the connection to the cheaper gateway 3b. The more cost-effective gateway 3b maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal B of the called user, received via the connection 2b to the backbone 1, are mapped onto the connection 12 to the communication terminal A of the calling user, and such that messages for the communication terminal B of the called user are mapped onto the gateway 3c via the connection 2b to the backbone 1. The gateway 3a, replaced as a result of the handover, clears the respective entry in the table for mapping connections, and releases the connection to the backbone 1. In a variant, the connection to the backbone 1 remains. The destination gateway 3c is informed about the change of connection (handover) from gateway 3a to the more cost-effective gateway 3b, for instance by the replaced gateway 3a or by the new gateway 3b. Thus the destination gateway 3c can update, for instance the respective table, with the new information for mapping connections for messages to the communication terminal A of the calling user via the connection 2b to the backbone 1 onto the more cost-effective gateway 3b. The transparent communication between the users via the communication terminals A and B, the gateways 3b and 3c, and the backbone 1 takes place as described above through mapping of connections and conversion of protocols in both directions. The communication network 5 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network. In an additional variant, the synchronisation of the handover and the related distribution of information to the involved gateways can be executed by the callback application 90 of the service centre 9 or alone by the new cost-effective gateway 3b via the backbone 1. For a person skilled in the art there are additional embodiments for the change of connection (handover), which will not be discussed any further. Besides the connection release between a communication terminal A and a gateway 3a, as a result of a connection change (handover), as was described above, there is naturally also a connection release caused by at least one user by means of his communication terminal A, B. This connection release caused by a user is handled, for instance, by the gateway 3a, 3b, 3c connected to the affected communication terminal A, B. The gateway 3a, 3b, 3c detects such a connection release caused by a communication terminal A, B by methods known to one skilled in the art, and forwards a connection release instruction, according to the table with information for mapping of connections, to the gateway 3a, 3b, 3c involved in the connection, clears the entry corresponding to the connection in this table, and terminates the connection 2a, 2b, 2c to the backbone 1. In a variant, the connection 2a, 2b, 2c to the backbone 1 remains. The involved gateway 3a, 3b, 3c receiving the connection release instruction forwards it according to the table with information for mapping of connections by releasing the relevant connection with the corresponding communication terminal A, B. Thereafter, the involved gateway 3a, 3b, 3c clears the entry corresponding to the connection in this table and terminates the connection 2a, 2b, 2c to the backbone 1. In a variant, the connection 2a, 2b, 2c to the backbone 1 remains. The callback application 90 in the service centre 9 is informed about the connection release so that the corresponding entry can be cleared in the table for monitoring connections. For instance, this information can be transmitted to the callback application 90 by an involved gateway 3a, 3b, 3c during the connection release. After termination of a connection, the gateways 3a, 3b, 3c previously involved in the connection can, for instance, calculate the costs of communication for their sections of the connection between the communication terminal A of the calling user and the communication terminal B of the called user based on the measured duration of communication and the corresponding tariffs of the respective gateway 3a, 3b, 3c for the relevant time zones, and charge the calculated costs, for instance, to the calling user, who can be identified by a user identification (for example the international mobile subscriber identity, IMSI). The calculated costs are placed in a billing record, and are transmitted, preferably by making use of security services, for example TTP-services (trusted third party) or PTP-services (point-to-point), to a billing centre, preferably the user's home billing centre. In the billing centre, the costs received from the gateways for their respective sections of the connection are integrated, for instance, into a standard account which is sent to the user. In a variant, the gateways 3a, 3b, 3c dispose of means to charge the calculated costs directly to the calling user, for instance by debiting an amount of money stored on his SIM-card. In order to ensure correctness of the costs transmitted by the gateways 3a, 3b, 3c, the billing centre preferably has means to check the tables of tariffs and the transmitted time values, respectively the clock responsible for the time measurement, in the respective gateways 3a, 3b, 3c. For instance, the gateway 3a can charge the communication costs for the connection 11, between the gateway 3a and the communication terminal A, to the calling user with the communication terminal A. In a variant, gateway 3a can in addition also charge to the user the communication costs for the connection 2a to the backbone 1. In another variant, gateway 3a can further request from the user a contribution for the use of the backbone 1. Direct charging by the gateways has the advantage that the gateways can be financially independent and that they can be managed, for instance, by different operators, which may be independent from network operators, for example. In such cases, a part of the amount charged by the billing centre may be reimbursed to the operators of the gateways. It is important to point out that in a variant the monitoring of current tariffs of the gateways, for the duration of a connection, and the corresponding initiation of a change of connection (handover) can be executed directly from a communication terminal involved in the connection. This is achieved, for example, by way of storing in a SIM-card of the communication terminal a table of tariffs with information about at least certain gateways and by the SIM-card determining a more cost-effective gateway in a fashion similar to the method described above and by directly executing a change of connection (handover) from a gateway 3a to a more cost-effective gateway 3b. In a variant, the SIM-card additionally executes as well determination of the local gateway 3a and of the destination gateway 3c, establishes the connection to the local gateway 3a, and initiates the establishment of a connection between the destination gateway 3c and the communication terminal B. For this variant, the table of tariffs in the SIM-card can be optimised, for example, according to the requirements of its user and/or owner or a group of users/owners. In another variant, the SIM-card can access the table of tariffs, for instance stored in the service centre 9, by means of special services. Personal SIM-cards, capable of initiating a callback method and/or capable of executing the callback method, including determination of gateways, the establishment of connections and/or monitoring of connections with change of connections (handover), may be offered to users or groups of users by a service provider, who, for instance, may also be the operator of the gateways 3a, 3b, 3c and the backbone LSuch cards may be offered as a subscription with periodic billing and payment, or they may be time-limited and can be extended for payment. For example, the SIM-cards may also contain defined amounts (pre-payment), which are debited directly with the tariff costs. Due to the fact that such cards may directly access privileged services, encryption and security methods, such as trusted third party (TIP) or point-to-point encryption, for instance, are employed in order to prevent unauthorised use. WE CLAIM : 1. Callback method for telecommunications, in which a first participant with a first communication terminal (A) communicates to a telecommunications system that he wishes to communicate with at least one second participant with a second communication terminal (B), whereupon the first participant is temporarily put on hold, a cost-efficient connection to a destination gateway (Point of Presence, POP) (3c) in the vicinity of the second participant is established, and the connection is completed by establishing a local connection (10) from the said gateway (3c) to the second communication terminal (B), characterized in that it comprises the following further steps: initiation of the method through a special message (80) transmitted from the first communication terminal (A) to a service centre (9), determination of the momentarily most cost-efficient destination gateway (3c), which has access to a backbone (1), for the connection (10) of the destination gateway (3c) to the second communication terminal (B) through a callback application (90) in the service centre (9) on the basis of tariff tables stored in a database (91) accessible to the service centre (S), transmission of connection-establishment instructions through the callback application (90) via a communication network to a local gateway (3a) having access to a backbone (1) to establish a connection with the first communication terminal (A) and to the destination gateway (3c) to establish a connection with the second communication terminal (B), establishment of a connection (11) from the local gateway (3a) to the first communication terminal (A), establishment of a connection (10) from the destination gateway (3c) to the second communication terminal (B), communication between the first and second participants, data being received through the gateways (3a, 3c) from the connected terminal in each case (A, B), the data between the local gateway (3a) and the destination gateway (3c) being transmitted via the backbone (1), and data being received through the gateways (3a, 3c) via the backbone (1) and being sent to the respective connected communication terminal (A, B). 2. Method as claimed in claim 1, wherein there are the steps of : comparison of the total tariff costs from the local gateway (3a) to the first communication terminal (A) and from the destination gateway (3c) to the second communication terminal (B), with the tariff costs of a direct connection from the first communication terminal (A) to the second communication terminal (B), establishment of a direct connection from the first communication terminal (A) to the second communication terminal (B), if the tariff costs thereof are cheaper. 3. Method as claimed in claim 1 or 2, wherein the local gateway (3a) is determined such that the current communication tariff from the local gateway (3a) to the first communication terminal (A) is as low as possible. 4. Method as claimed in any of the preceding claims wherein the special message (80) identifies callback as a special service (81) and contains the number of the calling participant (82) and the number of the called participant (83). 5. Method as claimed in any of the preceding claims, wherein the special message (80) is transmitted in a SMS short message or by means of USSD data. 6. Method as claimed in any one of the preceding claims, wherein the current tariffs of the gateways (3a, 3b, 3c) are monitored for the duration of the connection (10,11) and if the current tariff of a more cost-efficient gateway (3b) is lower by at least a pre-defined amount than the current tariff of the gateway (3a) used at the moment, a communication terminal (A) is connected to the backbone (1) through a change of connection via the more cost-efficient gateway (3b). 7. Method as claimed in any one of the preceding claims, wherein the monitoring of the tariffs is carried out by the service centre (9). 8. Method as claimed in claims 6 or 7, wherein the change of connection is initiated by the more cost-efficient gateway (3b) through a handover (12). 9. Method as claimed in any one of the preceding claims, wherein at least certain communication terminals (A, B) are mobile radio telephones comprising a SIM-card. 10. Method as claimed in any one of the preceding claims 2 to 9, wherein at least certain gateways (3a, 3b, 3c) store their tariffs in a central database (91). 11. Method as claimed in any one of the preceding claims, wherein there are steps of: calculation of the communication costs for at least certain sections of a connection between the first communication terminal (A) and the second communication terminal (B), by a gateway (3a, 3b, 3c) which is involved in the respective connection, transmission of the calculated communication costs by the said gateway in question (3a, 3b, 3c) to a billing centre for charging to the first participant 12. System for executing a callback method for telecommunications, comprising a plurality of communication terminals (A, B) and a plurality of gateways (3a, 3b, 3c), the gateways (3a, 3b, 3c) being connectible to at least certain of the communication terminals (A, B) via first communication networks (4, 5, 6), and at least one service centre (9), which is set up in such a fashion that it communicates with the gateways (3a, 3b, 3c) via second communication networks and with the at least certain communication terminals (A, B) via the first communication networks (4, 5, 6), characterized in that at least certain of the communication terminals (A, B) comprise means for initiating the callback method through transmission of a special message (80) to the service centre (9), in that the service centre, which has access to a database (91) in which tariff tables are stored, comprises a server and a callback application (90), which callback application (90) comprises means for carrying out the following steps: determination, on the basis of the tariff tables, of the momentarily most cost-efficient destination gateway (3c) for the connection of the destination gateway (3c) to a communication terminal (B) of a called participant, and transmission of connection establishment instructions via one of the second communication networks to a local gateway (3a) to establish a connection to a communication terminal (A) of a calling participant and to a destination gateway (3c) to establish a connection to the communication terminal (B) of the called participant, and in that the gateways (3a, 3b, 3c) have access to a backbone (1) and are set up in such a fashion that they detect and receive the connection-establishment instructions, and establish connections (10, 11) with the respective communication terminals (A, B) in accordance with the connection-establishment instructions, and in that they make possible the communication between the calling and the called participants by receiving data from the respective connected communication terminal (A, B) and transmitting it to the respective remote gateway via the backbone (1), and by receiving data via the backbone (1) and transmitting it to respective connected communication terminal (A, B). 13. System as claimed in claim 12, wherein the callback application (90) comprises means to determine the momentarily most costs-efficient local gateway (3a) for the connection of the local gateway (3c) to the communication terminal (A) of the calling participant. 14. System as claimed in claims 12 or 13, wherein at least certain communication terminals (A, B) are mobile radio telephones, fixed telephones or personal computers comprising a SIM-card that is equipped in such a way that it prepares and transmits the special callback messages (80) which identify callback as a special service (81) and contain the number of the calling participant (82) and the number of the called participant (83). 15. System 'as claimed in claim 14, wherein the SIM-card contains programmed means to prepare callback messages (80) and transmit them to a service centre as short messages or by means of USSD data. 16. System as claimed in any one of the claims 12 to 14, wherein the callback application (90) comprises means for carrying out the following additional steps: monitoring the current tariffs of the gateways (3a, 3b, 3c) for the duration of the communication between the respective communication terminals (A, B), - - transmission of instructions with required data to the respective gateways (3a, 3b, 3c) for initiating a handover (12) if the current tariff of a more cost-efficient gateway (3b) is lower by a predefined amount than the current tariff of the gateway (3a) used at the moment. 17. System as claimed in any of claims 12 to 16, wherein the service centre (9) comprises a short message service centre (SSC). 18. System as claimed in any one of claims 12 to 17, wherein the gateways (3a, 3b, 3c) comprise means for carrying out the following additional steps: detecting a termination of communication on the part of a first communication terminal (A, B), releasing the connection (10,11) with this first communication terminal (A, B), transmitting a connection release instruction via the backbone (1) to the remote gateway with a second communication terminal (A, B) .connected, receiving connection release instructions via the backbone (1), releasing the connection (10,11) with the corresponding connected second communication terminal (A, B). 19. System as claimed in any one of claims 12 to 18, wherein the gateways (3a, 3b, 3c) comprise means for carrying out the following is additional steps: detecting handover instructions, initiating a change of connection in a communication terminal (A) to a more cost-efficient gateway (3b) by means of a handover message (12), informing the involved gateways (3a, 3c) about this change of connection via the backbone (1). 20. System as claimed in any one of claims 12 to 19, wherein the gateways (3a, 3b, 3c) comprise means for carrying out the following additional steps: calculation of the communication costs for at least certain sections of a connection, in which the respective gateway (3a, 3b, 3c) is involved, between a first communication terminal (A) and a second communication terminal (B), transmission of the calculated communication costs to a billing centre for charging the calling participant. 21. System as claimed in any one of claims 12 to 20, wherein the backbone (1) is an ATM network, an intranet and/or the Internet. 22. System as claimed in any one of claims 12 to 21, wherein the first communication networks comprise a mobile radio network (4, 5, 6, 7) and/or a fixed network. 23. System as claimed in any one of claims 13 to 22, wherein the second communication networks comprise an ATM network, an intranet and/or the Internet. 24. Service centre (9) for a system for executing a callback method for telecommunications, which service centre (9) has access to a database (91) in which tariff tables are stored, and which service centre (9) is set up in such a fashion that it communicates with communication terminals (A, B) via first communication networks (4, 5, 6) and with gateways (3a, 3b, 3c), that have access to a backbone (1), via second communication networks, characterized in that the service centre (9) is set up in such a fashion that it detects and receives callback messages (80) from communication terminals (A, B), in that the service centre comprises a server and a callback application (90), which callback application (90) comprises means for carrying out the following steps: determination, on the basis of the tariff tables, of the momentarily most cost-efficient destination gateway (3c) for the connection of the destination gateway (3c) to a communication terminal (6) of a called participant, and transmission of connection establishment instructions via one of the second communication networks to a local gateway (3a) for connection establishment with a communication terminal (A) of a calling participant and to a destination gateway (3c) for connection establishment with the communication terminal (B) of the called participant, so that the communication is made possible between the calling and the called participant, the gateways (3a, 3b, 3c) receiving data from the respective connected communication terminal (A, B) and transmitting it to the respective remote gateway via the backbone (1), and the gateways (3a, 3b, 3C) receiving data via the backbone (1) and transmitting it to the respective connected communication terminal (A, B). 25. Service centre (9) as claimed in claim 24, wherein the callback application (90) comprises means for determining the momentarily most cost-efficient local gateway (3a) for the connection of the local gateway (3c) with the communication terminal (A) of the calling participant. 26. Service centre (9) as claimed in any one of claims 24 to 25, wherein the callback application (90) contains means for carrying out the following steps: monitoring the current tariffs of the gateways (3a, 3b, 3c) for the duration of the communication between the respective communication terminals (A, B), transmission of instructions with required data to the respective gateways (3a, 3b, 3c) for initiating a handover (12) if the current tariff of a more cost-efficient gateway (3b) is lower by a predefined amount than the current tariff of the gateway (3a) used at the moment. 27. Service centre (9) as claimed in any one of claims 24 to 26, wherein the service centre (9) comprises a short message service centre (SSC). 28. Service centre (9) as claimed in any one of claims 24 to 27,wherein the first communication networks comprise a mobile radio network (4, 5, 6, 7) and/or a fixed network. 29. Service centre (9)as claimed in any one of claims 24 to 28, wherein the second networks comprise an ATM network, an intranet and/or the Internet.

Full Text

The present invention relates to a
for tetecommunications
system for executing a callback
Callback methods in which a service provider assigns a special access number to a subscriber are known in telephony. The subscriber dials this number and hangs up. A computer of the service provider calls the subscriber back with a dial-tone to a network with low tariffs. In response, the subscriber may dial the number of his communication partner as usual. Other methods make it possible for the subscriber to pre-define certain destination numbers, such that these numbers are routed automatically by the computer of the service provider to a network with low tariffs.
A callback method is known from Digital Long Distance (DLD) Corporation (DLD Mobile Callback, according to www.digitcom.com of December 22, 1997, filed as a US patent application) in which a local network computer (Point-of-Presence, POP) captures the called number and sends digitised call data via the low cost Internet to respective nodes (POP) participating in the method. In this callback method, the POP closest to the destination determines the most cost-effective telephone connection available to complete the call, and establishes the corresponding telephone connection between the destination POP and the local line to the local network computer (local POP). Thereafter, the destination POP completes the circuit with a second local telephone line to the destination end. Besides the low cost for establishing the connection via the Internet, the communication costs are reduced to the costs of the two local connections, as well as to the costs of the long-distance call selected for its low tariffs.
It is an object of this invention to propose a new and improved callback method for telecommunications.
According to the present invention, this object is achieved particularly through the features of the characterising portion of the independent claims. Moreover, this object is also achieved through the system according to the independent system claim. In addition, further advantageous embodiments follow from the dependent claims and the description.
In particular, these objects are achieved according to the invention in that the callback method is implemented such that a connection with the communication terminal of the calling user is established from a local gateway and that a connection with the communication terminal of the called user is established from a destination gateway and that the data transmission from the local gateway to the destination gateway takes place via a backbone. Besides the low costs for establishing the connections from the gateways to the backbone, the communication costs are reduced to the costs of the two local connections to the local gateway and to the destination gateway, as well as to the costs of the data transmission via the backbone, which can turn out to be negligibly low, depending on the embodiment.
Preferably, the destination gateway and the local gateway are determined such that the current tariff from the destination gateway to the communication terminal of the called user or from the local gateway to the communication terminal of the calling user, respectively, are the lowest possible. Obviously, the communication costs of the two local connections can thereby be kept optimally low.
Preferably, the tariff costs from the local gateway to the communication terminal of the calling user and from the destination gateway to the communication terminal of the called user are subsequently compared with the tariff costs of a direct connection between the communication terminals. If its tariff costs are more favourable, a direct connection between the communication terminals of the calling and the called user is established instead of a connection via the backbone. This approach has the advantage that it ensures that the callback variant with communication via gateways and backbone is only used when it is actually cost beneficial.
In the present invention, the current tariffs of the gateways are being monitored for the duration of the connection. If the current tariff of a more cost-effective gateway is by a pre-defined amount lower than the current tariff of the gateway used at the moment, the respective communication terminal is connected to the backbone via the more cost-effective gateway as a result of a connection change. This has the additional advantage that the communication costs can be optimised even for the duration of the connection.
Preferably, the callback method of the present invention is initiated through a special message which is prepared and transmitted to a service centre by a SIM-card. This has the additional advantage that a user (or a group of users) may make use, by means of his (their) personal SIM-card, of personal callback services which are transferable to other communication terminals.
An embodiment of the present invention is described below by way of example. The embodiment example is illustrated by means of the following appended figure:
Fig. 1 shows an overview diagram with a backbone, with which communication networks are connected by means of gateways, and communication terminals which can communicate via the communication networks with the gateways and with a service centre.
Reference character A relates to a communication terminal of a calling user, not illustrated, who wishes, for instance, to communicate with a called user, also not illustrated, with a communication terminal B. There are different variants to initiate a callback method for establishing a connection to the called user. For example, the calling user may decide that a callback method should be initiated and he may initiate this explicitly, for instance, by calling a special service number or by selecting a special service of the SIM-card in the communication terminal via the keyboard of the communication terminal. In another variant, a callback method is automatically initiated when the called number corresponds to a number recorded in a special callback list, this list possibly being stored on the SIM-card or in the service centre. In a variant it is also possible that it is sufficient if only the area code of the called
number is recorded in this list. Finally, it is also possible that each call, or at least each long-distance call, initiates a callback method.
After the decision as to whether or not a callback method should be initiated, the callback method is preferably started by the communication terminal A by transmitting a special callback message 80 as a callback order 8 to a service centre 9. The callback message 80 comprises an identification field 81, identifying the callback service, a field 82, containing the number of the calling user, and a field 83, containing the number of the called user.
The callback message is prepared and transmitted by a special callback request application, which is preferably located on a SIM-card. For one skilled in the art it is easy to program the corresponding application, for instance as a Java applet (which can obviously also run outside a SIM-card, for example in a personal computer). The callback request application can transmit the callback message 80, for instance by means of a short message or USSD data, via a communication network 7 to a service centre 9. The communication network 7 is, for example, a mobile radio network, e.g. a GSM-network, and/or a fixed network, via which communication terminals A, such as mobile telephones and/or personal computers, communicate with each other.
The callback order 8 is received by a service centre 9; it is recognised as a callback message 80 and passed on to a callback application 90 for further processing of callback orders. For instance, this is implemented such that the service centre 9 comprises a SIM-server, for example a short message service centre (SSC), in which special messages are recognised and handed over to respective special applications for further processing, in this case to the canback application 90, according to the SICAP method described itf EP 0689 368 E^lro'r according to a similar method.
The callback application 90 retrieves the number of the calling user 82 and the number of the called user 83 from the callback message 80. Based on tables of tariffs, for example stored in a database 91 accessible to the service centre, the callback application 90 preferably determines the most cost-effective destination gateway 3c with access to a backbone 1, in order to
establish a connection with the communication terminal B of the called user. For that purpose, the tables of tariffs in the database 91 contain, for instance, information concerning the geographic location and the different tariffs for different time zones for the available gateways that have access to backbone 1.
In a variant, the callback application 90 also determines the most cost-effective local gateway 3a with access to backbone 1, in order to establish a connection 11 with the communication terminal A of the calling user.
The tariffs stored in the tables of tariffs of the database 91 can be updated and maintained, for instance by the respective gateways 3a, 3b, 3c themselves, directly via a communication network, preferably by making use of security services, for example TTP-services (trusted third party) or PTP-services (point-to-point). This can take place by means of direct access to the database 91, or to a database server, or by means of special services via the service centre 9.
When the two gateways 3a and 3c are determined, the callback application 90 preferably compares the tariff costs for a direct connection, between the two communication terminals A and B, to the total tariff costs of the connection from the local gateway 3a to the communication terminal A and from the destination gateway 3c to the communication terminal B. In the case where the tariff costs are more favourable for the direct connection, the callback application 90 initiates a direct connection between the two communication terminals A, B, which connection can be established in the conventional way known to one skilled in the art. In the case where the total tariff costs for the connection of the local gateway 3a to the communication terminal A and for the connection of the destination gateway 3c to the communication terminal B are more favourable, these connections are established according to the invention such that the calling user can communicate with the called user by means of the communication terminal A via the connection to the local gateway 3a, from there via backbone 1 to the destination gateway 3c, and from there via the connection to the communication terminal B. The connections are established, for instance, by the callback application 90 sending instructions for establishing a connection with the communication terminal A and with the communication
terminal B to the local gateway 3a and to the destination gateway 3c, respectively. The instructions for establishing a connection contain information for the identification of the calling user's communication terminal A, of the local gateway 3a, of the called user's communication terminal B, and of the destination gateway 3c. The communication between the service centre 9 and the gateways 3a, 3b, 3c takes place via a communication network, for instance an ATM network, an Intranet or the public Internet.
In a variant, the indirect connection via the gateways 3a, 3c, which are interconnected via backbone 1, must be cheaper by a specified minimal amount before it is preferred to the direct connection between the communication terminals A, B. This minimal amount can be set, for instance, such that it corresponds to the tariff costs of the communication via the backbone 1, and may possibly include other extra costs. The backbone 1 is, for instance, an ATM network, an Intranet or the public Internet.
The destination gateway 3c receives the instruction to establish a connection from the service centre 9 and establishes a connection 2c to the backbone 1. In a variant, the gateway 3c is permanently connected to the backbone 1. In addition, via the communication network 6, the gateway 3c initiates the synchronised establishment of a connection 10 to the communication terminal B, as will be described in more detail below. Furthermore, the gateway 3c maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal A of the calling user, received via the connection 2c to the backbone 1, are mapped onto the connection 10 to the communication terminal B of the called user, and such that messages for the communication terminal A of the calling user are mapped onto the gateway 3a via the connection 2c to the backbone 1. The communication network 6 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network.
The local gateway 3a receives the instruction to establish a connection from the service centre 9, and establishes a connection 2a to the backbone 1. In a variant, the gateway 3a is permanently connected to the backbone 1. In addition, via the communication network 4, the gateway 3a
initiates the synchronised establishment of a connection 11 to the communication terminal A, as will be described in more detail below. Furthermore, the gateway 3a maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal B of the called user, received via the connection 2a to the backbone 1, are mapped onto the connection 11 to the communication terminal A of the calling user, and such that messages for the communication terminal B of the called user are mapped onto the gateway 3c via the connection 2a to the backbone 1. The communication network 4 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network.
Synchronisation of the establishment of a connection between the local gateway 3a and the communication terminal A with the establishment of a connection between the destination gateway 3c and the communication terminal B takes place, for example, via the backbone 1. For instance, the destination gateway 3c can communicate to the local gateway 3a via the connection 2c, the backbone 1, and the connection 2a that it has initiated the establishment of a connection to the communication terminal B of the called user. In response, the local gateway 3a sends the actual callback 11 to the communication terminal A of the calling user. Thereupon, the communication terminal A can immediately establish the connection to the local gateway 3a and thus await in a transparent fashion, via the connection 11, the connection 2a, the backbone 1, and the connection 2c, the establishment of a connection 10 of the destination gateway 3c to the communication terminal B of the called user.
In another variant, control of the synchronisation occurs, for example, through the local gateway 3a sending the actual callback 11 to the communication terminal A of the calling user. Thereupon, the communication terminal A can immediately establish the connection to the local gateway 3a. In response, the local gateway 3a can communicate to the destination gateway 3c via the connection 2a, the backbone 1, and the connection 2c that it has initiated the establishment of a connection to the communication terminal A of the calling user. Thereupon, the destination gateway 3c can initiate the establishment of a connection 10 to the communication terminal B. For a
person skilled in the art there are additional embodiments for this establishment of a connection, which will not be discussed any further.
When the connections between the local gateway 3a and the communication terminal A and between the destination gateway 3c and the communication terminal B are established, communication between the users may begin. For instance, speech information captured by the communication terminal A are transmitted as data to the local gateway 3a via the communication network 4. Besides mapping the respective connections according to the above-mentioned table, the gateways 3a, 3b, 3c are also taking on the function to execute protocol conversions between the connected communication networks, if necessary. This is achieved, for instance, by retrieving user data from the protocol data units received from a first communication network, for example communication network 4, and embedding them into the corresponding protocol data units of a second communication network, for instance backbone 1, before they are sent via the second communication network, for instance, by means of connection 2a via the backbone 1 to the destination gateway 3c. Mapping of connections and conversion of protocols work in both directions, such that the users can communicate transparently.
Preferably, the callback application 90 of the service centre 9, for instance, is monitoring the current tariffs of the gateways 3a, 3b, 3c for the duration of a connection, initiated on its initiative, between two communication terminals A and B via a backbone 1, for instance by means of the tables of tariffs in the database 91. In addition, the callback application 90 maintains for that purpose a table, for instance, where information is stored for the identification of the calling user's communication terminal A, of the local gateway 3a, of the called user's communication terminal B, and of the destination gateway 3c. For a connection to one of the communication terminals A or B, which it is monitoring, the callback application 90 can initiate a change of connection, in the case where it finds a gateway 3b with a current tariff for a current time zone cheaper by at least a pre-defined amount. For instance, this can be implemented such that the callback application 90 sends to the cheaper gateway 3b an instruction to initiate a handover from the more
expensive local gateway 3a to the cheaper gateway 3b. The instructions contain, for example, information for the identification of the more expensive gateway to be replaced, of the communication terminal A connected to this gateway, of the gateway 3c involved, and of the communication terminal B connected to this latter gateway.
The more cost-effective gateway 3b receives the instruction to initiate a handover from the service centre 9 and establishes a connection to the backbone 1. In a variant, the gateway 3b is permanently connected to the backbone 1. In addition, the gateway 3b forwards the change of connection, for instance through a handover message 12, via the communication network 5 to the communication terminal A, connected to the gateway 3a to be replaced. For instance, the change of connection (handover) can be executed by the communication terminal A to be replaced. This can be done by the communication terminal A, in response to the handover message, releasing the connection to the gateway 3a to be replaced and establishing in its place the connection to the cheaper gateway 3b. The more cost-effective gateway 3b maintains, for instance in a table, information for mapping connections, such that messages from the communication terminal B of the called user, received via the connection 2b to the backbone 1, are mapped onto the connection 12 to the communication terminal A of the calling user, and such that messages for the communication terminal B of the called user are mapped onto the gateway 3c via the connection 2b to the backbone 1. The gateway 3a, replaced as a result of the handover, clears the respective entry in the table for mapping connections, and releases the connection to the backbone 1. In a variant, the connection to the backbone 1 remains. The destination gateway 3c is informed about the change of connection (handover) from gateway 3a to the more cost-effective gateway 3b, for instance by the replaced gateway 3a or by the new gateway 3b. Thus the destination gateway 3c can update, for instance the respective table, with the new information for mapping connections for messages to the communication terminal A of the calling user via the connection 2b to the backbone 1 onto the more cost-effective gateway 3b. The transparent communication between the users via the communication terminals A and B, the gateways 3b and 3c, and the backbone 1 takes place as described above through mapping of connections and conversion of protocols
in both directions. The communication network 5 is, for example, a mobile radio network, e.g. a GSM-network, or a fixed network. In an additional variant, the synchronisation of the handover and the related distribution of information to the involved gateways can be executed by the callback application 90 of the service centre 9 or alone by the new cost-effective gateway 3b via the backbone 1. For a person skilled in the art there are additional embodiments for the change of connection (handover), which will not be discussed any further.
Besides the connection release between a communication terminal A and a gateway 3a, as a result of a connection change (handover), as was described above, there is naturally also a connection release caused by at least one user by means of his communication terminal A, B. This connection release caused by a user is handled, for instance, by the gateway 3a, 3b, 3c connected to the affected communication terminal A, B. The gateway 3a, 3b, 3c detects such a connection release caused by a communication terminal A, B by methods known to one skilled in the art, and forwards a connection release instruction, according to the table with information for mapping of connections, to the gateway 3a, 3b, 3c involved in the connection, clears the entry corresponding to the connection in this table, and terminates the connection 2a, 2b, 2c to the backbone 1. In a variant, the connection 2a, 2b, 2c to the backbone 1 remains. The involved gateway 3a, 3b, 3c receiving the connection release instruction forwards it according to the table with information for mapping of connections by releasing the relevant connection with the corresponding communication terminal A, B. Thereafter, the involved gateway 3a, 3b, 3c clears the entry corresponding to the connection in this table and terminates the connection 2a, 2b, 2c to the backbone 1. In a variant, the connection 2a, 2b, 2c to the backbone 1 remains.
The callback application 90 in the service centre 9 is informed about the connection release so that the corresponding entry can be cleared in the table for monitoring connections. For instance, this information can be transmitted to the callback application 90 by an involved gateway 3a, 3b, 3c during the connection release.
After termination of a connection, the gateways 3a, 3b, 3c previously involved in the connection can, for instance, calculate the costs of communication for their sections of the connection between the communication terminal A of the calling user and the communication terminal B of the called user based on the measured duration of communication and the corresponding tariffs of the respective gateway 3a, 3b, 3c for the relevant time zones, and charge the calculated costs, for instance, to the calling user, who can be identified by a user identification (for example the international mobile subscriber identity, IMSI). The calculated costs are placed in a billing record, and are transmitted, preferably by making use of security services, for example TTP-services (trusted third party) or PTP-services (point-to-point), to a billing centre, preferably the user's home billing centre. In the billing centre, the costs received from the gateways for their respective sections of the connection are integrated, for instance, into a standard account which is sent to the user. In a variant, the gateways 3a, 3b, 3c dispose of means to charge the calculated costs directly to the calling user, for instance by debiting an amount of money stored on his SIM-card. In order to ensure correctness of the costs transmitted by the gateways 3a, 3b, 3c, the billing centre preferably has means to check the tables of tariffs and the transmitted time values, respectively the clock responsible for the time measurement, in the respective gateways 3a, 3b, 3c. For instance, the gateway 3a can charge the communication costs for the connection 11, between the gateway 3a and the communication terminal A, to the calling user with the communication terminal A. In a variant, gateway 3a can in addition also charge to the user the communication costs for the connection 2a to the backbone 1. In another variant, gateway 3a can further request from the user a contribution for the use of the backbone 1. Direct charging by the gateways has the advantage that the gateways can be financially independent and that they can be managed, for instance, by different operators, which may be independent from network operators, for example. In such cases, a part of the amount charged by the billing centre may be reimbursed to the operators of the gateways.
It is important to point out that in a variant the monitoring of current tariffs of the gateways, for the duration of a connection, and the corresponding initiation of a change of connection (handover) can be executed directly from a communication terminal involved in the connection. This is achieved, for example, by way of storing in a SIM-card of the communication terminal a table of tariffs with information about at least certain gateways and by the SIM-card determining a more cost-effective gateway in a fashion similar to the method described above and by directly executing a change of connection (handover) from a gateway 3a to a more cost-effective gateway 3b. In a variant, the SIM-card additionally executes as well determination of the local gateway 3a and of the destination gateway 3c, establishes the connection to the local gateway 3a, and initiates the establishment of a connection between the destination gateway 3c and the communication terminal B. For this variant, the table of tariffs in the SIM-card can be optimised, for example, according to the requirements of its user and/or owner or a group of users/owners. In another variant, the SIM-card can access the table of tariffs, for instance stored in the service centre 9, by means of special services.
Personal SIM-cards, capable of initiating a callback method and/or capable of executing the callback method, including determination of gateways, the establishment of connections and/or monitoring of connections with change of connections (handover), may be offered to users or groups of users by a service provider, who, for instance, may also be the operator of the gateways 3a, 3b, 3c and the backbone LSuch cards may be offered as a subscription with periodic billing and payment, or they may be time-limited and can be extended for payment. For example, the SIM-cards may also contain defined amounts (pre-payment), which are debited directly with the tariff costs. Due to the fact that such cards may directly access privileged services, encryption and security methods, such as trusted third party (TIP) or point-to-point encryption, for instance, are employed in order to prevent unauthorised use.

WE CLAIM :
1. Callback method for telecommunications, in which a first participant with a first communication terminal (A) communicates to a telecommunications system that he wishes to communicate with at least one second participant with a second communication terminal (B), whereupon the first participant is temporarily put on hold, a cost-efficient connection to a destination gateway (Point of Presence, POP) (3c) in the vicinity of the second participant is established, and the connection is completed by establishing a local connection (10) from the said gateway (3c) to the second communication terminal (B), characterized in that it comprises the following further steps:
initiation of the method through a special message (80) transmitted from the first communication terminal (A) to a service centre (9),
determination of the momentarily most cost-efficient destination gateway (3c), which has access to a backbone (1), for the connection (10) of the destination gateway (3c) to the second communication terminal (B) through a callback application (90) in the service centre (9) on the basis of tariff tables stored in a database (91) accessible to the service centre (S),
transmission of connection-establishment instructions through the callback application (90) via a communication network to a local gateway (3a) having access to a backbone (1) to establish a connection with the first communication terminal (A) and to the destination gateway (3c) to establish a connection with the second communication terminal (B),
establishment of a connection (11) from the local gateway (3a) to
the first communication terminal (A),
establishment of a connection (10) from the destination gateway (3c) to the second communication terminal (B),
communication between the first and second participants, data being received through the gateways (3a, 3c) from the connected terminal in each case (A, B), the data between the local gateway (3a) and the destination gateway (3c) being transmitted via the backbone (1), and data being received through the gateways (3a, 3c) via the backbone (1) and being sent to the respective connected communication terminal (A, B).
2. Method as claimed in claim 1, wherein there are the steps of :
comparison of the total tariff costs from the local gateway (3a) to the first communication terminal (A) and from the destination gateway (3c) to the second communication terminal (B), with the tariff costs of a direct connection from the first communication terminal (A) to the second communication terminal (B),
establishment of a direct connection from the first communication terminal (A) to the second communication terminal (B), if the tariff costs thereof are cheaper.
3. Method as claimed in claim 1 or 2, wherein the local gateway (3a) is determined such that the current communication tariff from the local gateway (3a) to the first communication terminal (A) is as low as possible.
4. Method as claimed in any of the preceding claims wherein the special
message (80) identifies callback as a special service (81) and contains
the number of the calling participant (82) and the number of the called
participant (83).
5. Method as claimed in any of the preceding claims, wherein the special
message (80) is transmitted in a SMS short message or by means of
USSD data.
6. Method as claimed in any one of the preceding claims, wherein the
current tariffs of the gateways (3a, 3b, 3c) are monitored for the
duration of the connection (10,11) and if the current tariff of a more
cost-efficient gateway (3b) is lower by at least a pre-defined amount
than the current tariff of the gateway (3a) used at the moment, a
communication terminal (A) is connected to the backbone (1) through a
change of connection via the more cost-efficient gateway (3b).
7. Method as claimed in any one of the preceding claims, wherein the
monitoring of the tariffs is carried out by the service centre (9).
8. Method as claimed in claims 6 or 7, wherein the change of connection is
initiated by the more cost-efficient gateway (3b) through a handover
(12).
9. Method as claimed in any one of the preceding claims, wherein at least
certain communication terminals (A, B) are mobile radio telephones
comprising a SIM-card.
10. Method as claimed in any one of the preceding claims 2 to 9, wherein
at least certain gateways (3a, 3b, 3c) store their tariffs in a central
database (91).
11. Method as claimed in any one of the preceding claims, wherein there
are steps of:
calculation of the communication costs for at least certain sections of a connection between the first communication terminal (A) and the second communication terminal (B), by a gateway (3a, 3b, 3c) which is involved in the respective connection,
transmission of the calculated communication costs by the said gateway in question (3a, 3b, 3c) to a billing centre for charging to the first participant
12. System for executing a callback method for telecommunications,
comprising a plurality of communication terminals (A, B) and a plurality
of gateways (3a, 3b, 3c), the gateways (3a, 3b, 3c) being connectible to
at least certain of the communication terminals (A, B) via first
communication networks (4, 5, 6), and at least one service centre (9),
which is set up in such a fashion that it communicates with the
gateways (3a, 3b, 3c) via second communication networks and with the
at least certain communication terminals (A, B) via the first
communication networks (4, 5, 6), characterized in that at least
certain of the communication terminals (A, B) comprise means for
initiating the callback method through transmission of a special
message (80) to the service centre (9), in that the service centre, which
has access to a database (91) in which tariff tables are stored,
comprises a server and a callback application (90), which callback
application (90) comprises means for carrying out the following steps:
determination, on the basis of the tariff tables, of the momentarily most cost-efficient destination gateway (3c) for the connection of the destination gateway (3c) to a communication terminal (B) of a
called participant, and
transmission of connection establishment instructions via one of the second communication networks to a local gateway (3a) to establish a connection to a communication terminal (A) of a calling participant and to a destination gateway (3c) to establish a connection to the communication terminal (B) of the called participant, and in that the gateways (3a, 3b, 3c) have access to a backbone (1) and are set up in such a fashion that they detect and receive the connection-establishment instructions, and establish connections (10, 11) with the respective communication terminals (A, B) in accordance with the connection-establishment instructions, and in that they make possible the communication between the calling and the called participants by receiving data from the respective connected communication terminal (A, B) and transmitting it to the respective remote gateway via the backbone (1), and by receiving data via the backbone (1) and transmitting it to respective connected communication terminal (A, B).
13. System as claimed in claim 12, wherein the callback application (90)
comprises means to determine the momentarily most costs-efficient
local gateway (3a) for the connection of the local gateway (3c) to the
communication terminal (A) of the calling participant.
14. System as claimed in claims 12 or 13, wherein at least certain
communication terminals (A, B) are mobile radio telephones, fixed
telephones or personal computers comprising a SIM-card that is
equipped in such a way that it prepares and transmits the special
callback messages (80) which identify callback as a special service (81)
and contain the number of the calling participant (82) and the number
of the called participant (83).
15. System 'as claimed in claim 14, wherein the SIM-card contains
programmed means to prepare callback messages (80) and transmit
them to a service centre as short messages or by means of USSD data.
16. System as claimed in any one of the claims 12 to 14, wherein the
callback application (90) comprises means for carrying out the following
additional steps:
monitoring the current tariffs of the gateways (3a, 3b, 3c) for the duration of the communication between the respective communication terminals (A, B),
- - transmission of instructions with required data to the respective gateways (3a, 3b, 3c) for initiating a handover (12) if the current tariff of a more cost-efficient gateway (3b) is lower by a predefined amount than the current tariff of the gateway (3a) used at the moment.
17. System as claimed in any of claims 12 to 16, wherein the service centre
(9) comprises a short message service centre (SSC).
18. System as claimed in any one of claims 12 to 17, wherein the gateways
(3a, 3b, 3c) comprise means for carrying out the following additional
steps:
detecting a termination of communication on the part of a first communication terminal (A, B),
releasing the connection (10,11) with this first communication terminal (A, B),
transmitting a connection release instruction via the backbone (1)
to the remote gateway with a second communication terminal (A, B) .connected,
receiving connection release instructions via the backbone (1),
releasing the connection (10,11) with the corresponding connected second communication terminal (A, B).
19. System as claimed in any one of claims 12 to 18, wherein the gateways (3a, 3b, 3c) comprise means for carrying out the following is additional steps:
detecting handover instructions,
initiating a change of connection in a communication terminal (A) to a more cost-efficient gateway (3b) by means of a handover message (12),
informing the involved gateways (3a, 3c) about this change of connection via the backbone (1).
20. System as claimed in any one of claims 12 to 19, wherein the gateways (3a, 3b, 3c) comprise means for carrying out the following additional steps:
calculation of the communication costs for at least certain sections of a connection, in which the respective gateway (3a, 3b, 3c) is involved, between a first communication terminal (A) and a second communication terminal (B),
transmission of the calculated communication costs to a billing
centre for charging the calling participant.
21. System as claimed in any one of claims 12 to 20, wherein the backbone
(1) is an ATM network, an intranet and/or the Internet.
22. System as claimed in any one of claims 12 to 21, wherein the first
communication networks comprise a mobile radio network (4, 5, 6, 7)
and/or a fixed network.
23. System as claimed in any one of claims 13 to 22, wherein the second
communication networks comprise an ATM network, an intranet and/or
the Internet.
24. Service centre (9) for a system for executing a callback method for
telecommunications, which service centre (9) has access to a database
(91) in which tariff tables are stored, and which service centre (9) is set
up in such a fashion that it communicates with communication
terminals (A, B) via first communication networks (4, 5, 6) and with
gateways (3a, 3b, 3c), that have access to a backbone (1), via second
communication networks, characterized in that the service centre (9)
is set up in such a fashion that it detects and receives callback
messages (80) from communication terminals (A, B), in that the service
centre comprises a server and a callback application (90), which
callback application (90) comprises means for carrying out the following
steps:
determination, on the basis of the tariff tables, of the momentarily most cost-efficient destination gateway (3c) for the connection of the destination gateway (3c) to a communication terminal (6) of a called participant, and
transmission of connection establishment instructions via one of the second communication networks to a local gateway (3a) for
connection establishment with a communication terminal (A) of a calling participant and to a destination gateway (3c) for connection establishment with the communication terminal (B) of the called participant, so that the communication is made possible between the calling and the called participant, the gateways (3a, 3b, 3c) receiving data from the respective connected communication terminal (A, B) and transmitting it to the respective remote gateway via the backbone (1), and the gateways (3a, 3b, 3C) receiving data via the backbone (1) and transmitting it to the respective connected communication terminal (A, B).
25. Service centre (9) as claimed in claim 24, wherein the callback
application (90) comprises means for determining the momentarily most
cost-efficient local gateway (3a) for the connection of the local gateway
(3c) with the communication terminal (A) of the calling participant.
26. Service centre (9) as claimed in any one of claims 24 to 25, wherein the
callback application (90) contains means for carrying out the following
steps:
monitoring the current tariffs of the gateways (3a, 3b, 3c) for the duration of the communication between the respective communication terminals (A, B),
transmission of instructions with required data to the respective gateways (3a, 3b, 3c) for initiating a handover (12) if the current tariff of a more cost-efficient gateway (3b) is lower by a predefined amount than the current tariff of the gateway (3a) used at the moment.
27. Service centre (9) as claimed in any one of claims 24 to 26, wherein the
service centre (9) comprises a short message service centre (SSC).
28. Service centre (9) as claimed in any one of claims 24 to 27,wherein the first communication networks comprise a mobile radio network (4, 5, 6, 7) and/or a fixed network.
29. Service centre (9)as claimed in any one of claims 24 to 28, wherein the second networks comprise an ATM network, an intranet and/or the Internet.

Documents:

1268-DEL-1998-Abstract.pdf

1268-DEL-1998-Assignment-(27-01-2010).pdf

1268-del-1998-assignments.pdf

1268-DEL-1998-Claims.pdf

1268-del-1998-complete specification (granted).pdf

1268-del-1998-Correpondence Others-(28-12-2012).pdf

1268-del-1998-Correspondence Others-(20-02-2013).pdf

1268-del-1998-Correspondence Others-(27-12-2012).pdf

1268-del-1998-Correspondence-IPO-(05-11-2012).pdf

1268-DEL-1998-Correspondence-Others (27-01-2010).pdf

1268-del-1998-Correspondence-Others-(27-06-2013).pdf

1268-del-1998-correspondence-others.pdf

1268-del-1998-correspondence-po.pdf

1268-DEL-1998-Description (Complete).pdf

1268-del-1998-drawings.pdf

1268-del-1998-form-1.pdf

1268-del-1998-form-13.pdf

1268-del-1998-form-19.pdf

1268-DEL-1998-Form-2.pdf

1268-del-1998-Form-3-(27-06-2013).pdf

1268-del-1998-form-3.pdf

1268-del-1998-form-4.pdf

1268-del-1998-form-6.pdf

1268-DEL-1998-GPA-(27-01-2010).pdf

1268-del-1998-gpa.pdf

1268-del-1998-pct-409.pdf

1268-del-1998-petition-137.pdf

1268-del-1998-petition-138.pdf

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Patent Number

260011

Indian Patent Application Number

1268/DEL/1998

PG Journal Number

14/2014

Publication Date

04-Apr-2014

Grant Date

31-Mar-2014

Date of Filing

13-May-1998

Name of Patentee

SWISSCOM MOBILE AG

Applicant Address

ALTE TIEFENAUSTRASSE 6, WORBLAUFEN / INTIGEN, 3050 BERN, SWITZERLAND.

Inventors:

#	Inventor's Name	Inventor's Address
1	WALTER HEUTSCHI	JUNGFRAUWEG 8, 3303, JOGENSDORF, SWITZERLAND.
2	RUDOLF RITTER	ROSSWEIDWEG 8, 3051 ZOLLIKOFEN, SWITZERLAND.

PCT International Classification Number

H04M 3/41

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA