Background Art Prepaid mobile telephone service denotes a service in which users can use a mobile telephone within the limit of deposit money. In order to provide this prepaid mobile telephone service, a prepaid service (PPS) server for managing a prepaid mobile telephone subscriber database is introduced. A prepaid mobile telephone server supports users to make mobile telephone calls within the limits of their deposit money.

The prepaid mobile telephone service is generally provided by a destination number dialing method. In order to provide prepaid mobile telephone service using a destination number dialing method, the prepaid mobile telephone deposit money and the mobile identification numbers (MINs) of mobile telephone subscribers registered for prepaid mobile telephone service are maintained in the prepaid mobile telephone subscriber database. The MINs are usually general mobile telephone numbers of mobile communication terminals. In the destination number dialing method, all mobile telephone calls attempted through mobile communication terminals having registered MINs are considered as prepaid mobile telephone calls, and they are connected to the prepaid mobile telephone server and are allowed within the limits of deposit money through the interface between a mobile switching center and the prepaid mobile telephone server. From the standpoint of users, prepaid mobile telephone calls made in this way are similar to general mobile telephone calls. The prepaid mobile telephone service provided by this destination number dialing method is limited to the case when mobile communication terminals having registered MINs are used, so that a separate user authentication

However, in the prepaid mobile telephone service provided by a conventional destination number dialing method, mobile communication terminals having registered MINs can be exclusively used as prepaid mobile telephones and cannot be used as general mobile telephones. That is, a single mobile communication terminal cannot make both general mobile telephone calls and prepaid mobile telephone calls. Also, there is an essential limit in that dialing itself is impossible when deposit money for registered MINs is completely consumed.

Prepaid mobile telephone service can also be provided by a feature code using method or particular number connection method in which users are connected to a prepaid mobile telephone server through a feature code or a particular number, undergo a user authentication procedure, and finally make prepaid mobile telephone calls. According to these methods, users can selectively make general mobile telephone calls or prepaid mobile telephone calls using a single mobile communication terminal.

However, these methods have users feel inconvenience since users always must connect to a prepaid mobile telephone server, perform user authentication through their MINs and passwords, and finally input destination numbers in order to get prepaid mobile telephone service. Also, these methods have a fundamental problem in that there is a possibility that others can make fraudulent use of the MINs and passwords of subscribers.

Disclosure of the Invention To solve the above problems, an objective of the present invention is to provide a method of providing a selective prepaid mobile telephone service using a destination number dialing method, and a system for providing a selective prepaid mobile telephone service.

The above objective of the present invention is achieved by a method of providing selective prepaid mobile telephone service, according to an aspect of the present invention, in prepaid mobile telephone service system including a switching center for relaying a mobile telephone call, a home location register connected to the switching center via a mobile

telephone subscribers, and a prepaid service (PPS) server connected to the switching center and the home location register via a mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money. This method includes steps (a) through (c).

In step (a), a selective prepaid mobile telephone service field which can be set to be one of at least three state values, namely a not-registered state value representing that a user is not registered for selective prepaid mobile telephone service to selectively provide prepaid mobile telephone service, a registered-but-not-activated state value representing that a user does not activate prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, and a registered-and-activated state value representing that a user has activated prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, is included in a subscriber profile that is managed by the home location register. In step (b), a mobile telephone call including a destination number is received. In step (c), the mobile telephone call received in step (b) is processed. The step (c) includes : (c1) treating the mobile telephone call received in step (b) as a general mobile telephone call if the selective prepaid mobile telephone service field in the subscriber profile of a mobile telephone subscriber who has made the mobile telephone call is set to be the not-registered state value or registered-but-not-activated state value ; and (c2) treating the mobile telephone call received in step (b) as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed, if the selective prepaid mobile telephone service field is set to be the registered-and-activated state value.

Preferably, in step (c1), the mobile telephone call received in step (b) is treated as a general mobile telephone call because specific origination triggers are not armed for the selective prepaid mobile telephone service, in a visitor profile that is managed by a visitor location

within a predetermined zone and that is referred to to process the mobile telephone call by the switching center, and in step (c2), the mobile telephone call is treated as a prepaid mobile telephone call based on a destination number dialing method by signaling between the switching center and the hole location register because the specific origination triggers in the visitor profile are armed for the selective prepaid mobile telephone service.

It is also preferable that the step (a) further comprises (a1) changing the state value of the selective prepaid mobile telephone service field in the subscriber profile of the corresponding subscriber between the registered- but-not-activated state value and the registered-and-activated state value at the request of a mobile telephone subscriber registered for the selective prepaid mobile telephone service.

Preferably, the step (a1) includes: (a11) the home location register making a request to the visitor location register that specific origination triggers in the visitor profile of a corresponding visitor are armed for the selective prepaid mobile telephone service, when the state value of the selective prepaid mobile telephone service field is changed from the registered-but-not-activated state value to the registered-and-activated state value ; and (a12) the home location register making a request to the visitor location register that the specific origination triggers in the visitor profile of a corresponding visitor are disarmed for the selective prepaid mobile telephone service, when the state value of the selective prepaid mobile telephone service field is changed from the registered-and-activated state value to the registered-but-not-activated state value.

The above objective of the present invention is achieved by a method of providing a selective prepaid mobile telephone service, according to another aspect of the present invention, in prepaid mobile telephone service system including a switching center for relaying a mobile telephone call, a home location register connected to the switching center via a mobile communication network for managing the subscriber profiles of mobile telephone subscribers, and a prepaid service (PPS) server

mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money, the method including : (a) preparing a selective prepaid mobile telephone service field, which can be set to be one of at least three state values, namely a not-registered state value representing that a user is not registered for a selective prepaid mobile telephone service to selectively provide prepaid mobile telephone service and a registered state value representing that a user is registered for the selective prepaid mobile telephone service, in a subscriber profile that is managed by the home location register; (b) receiving a mobile telephone call including a destination number from a mobile telephone subscriber registered for the selective prepaid mobile telephone service; and (c) treating the mobile telephone call received in step (b) as a general mobile telephone call if there is no positive balance of deposit money in the account of the mobile telephone subscriber who makes the mobile telephone call received in the step (b) in a prepaid mobile telephone subscriber database that is managed by the PPS server, and treating the mobile telephone call received in step (b) as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed, if there is a positive balance of deposit money.

Preferably, the step (c) includes (c1) the switching center transmitting an origination request with respect to the mobile telephone call received in step (b) to the home location register if specific origination triggers are armed for the selective prepaid mobile telephone service, in the visitor profile that is managed by a visitor location register which manages information on each mobile telephone subscriber located within a predetermined zone and that is referred to in order to process the mobile telephone call received in step (b); (c2) the home location register inquiring of the PPS server about the balance of deposit money in the account of the corresponding prepaid mobile telephone subscriber in order to process the

transmitting to the switching center a reply message to the origination request that orders the switching center to treat the received mobile telephone call as a prepaid mobile telephone call based on the destination number dialing method when the PPS server informs the home location register that there is a positive balance of deposit money in the corresponding account or orders the switching center to treat the received mobile telephone call as a general mobile telephone call if the PPS server informs the home location register that there is no positive balance of deposit money in the corresponding account; and (c4) the switching center processing the received mobile telephone call according to the reply message received in step (c3).

Also, preferably, the step (a) further includes (a1) setting the selective prepaid mobile telephone service field to be the registered state value if a mobile telephone subscriber registers for the selective prepaid mobile telephone service ; and (a2) the home location register making a request to the visitor location register that specific origination triggers in the visitor profile of a corresponding visitor are armed for the selective prepaid mobile telephone service.

The above objective of the present invention is achieved by a method of providing selective prepaid mobile telephone service, according to still another aspect of the present invention, in prepaid mobile telephone service system including a switching center for relaying a mobile telephone call, a home location register connected to the switching center via a mobile communication network for managing subscriber profiles of mobile telephone subscribers, and a prepaid service (PPS) server connected to the switching center and the home location register via a mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money. This method includes steps (a) through (d).

In step (a), a selective prepaid mobile telephone service field which can be set to be one of at least three state values, namely a not-registered state

telephone service to selectively provide prepaid mobile telephone service, a registered-but-not-activated state value representing that a user does not activate prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, and a registered-and-activated state value representing that a user has activated prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, is included in a subscriber profile that is managed by the home location register. In step (b), the state value of the selective prepaid mobile telephone service field in the subscriber profile of a subscriber registered for the selective prepaid mobile telephone service, is set depending on the state of the balance of deposit money in the account of the corresponding subscribers in a prepaid mobile telephone subscriber database that is managed by the PPS server. In step (c), a mobile telephone call including a destination number is received. In step (d), the mobile telephone call received in step (c) is processed. The step (d) includes : (d1) treating the mobile telephone call received in step (c) as a general mobile telephone call if the selective prepaid mobile telephone service field in the subscriber profile of a mobile telephone subscriber who has made the mobile telephone call is set to be the not-registered state value or registered-but- not-activated state value; and (d2) treating the mobile telephone call received in step (c) as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed, if the selective prepaid mobile telephone service field is set to be the registered-and-activated state value.

In the step (b), when the balance of deposit money in the account of a subscriber registered for the prepaid mobile telephone service in the prepaid mobile telephone subscriber database that is managed by the PPS server is exhausted, the PPS server transmits a message informing the occurrence of the first event to the home location register, and the home location register sets the selective prepaid mobile telephone service field of the corresponding subscriber to be the registered-but-not-activated state value, and when the balance of deposit money in the account of the

money, the PPS server transmits a message informing the occurrence of the second event to the home location register, and the home location register sets the selective prepaid mobile telephone service field of the corresponding subscriber to be the registered-and-activated state value.

Preferably, the step (b) includes : (b1) the home location register making a request to the visitor location register that specific origination triggers in the visitor profile of a corresponding visitor are armed for the selective prepaid mobile telephone service, when the state value of the selective prepaid mobile telephone service field is changed from the registered-but-not- activated state value to the registered-and-activated state value; and (b2) the home location register making a request to the visitor location register that the specific origination triggers in the visitor profile of a corresponding visitor are disarmed for the selective prepaid mobile telephone service, when the state value of the selective prepaid mobile telephone service field is changed from the registered-and-activated state value to the registered- but-not-activated state value.

Also, preferably, deposit money capable of being used for the selective prepaid mobile telephone service according to the present invention can be accumulated using compensation acquired from web servers on the Internet.

The above objective of the present invention is achieved by a selective prepaid mobile telephone service system, according to an aspect of the present invention, including: a switching center for relaying a mobile telephone call ; a home location register connected to the switching center via a mobile communication network for managing the subscriber profiles of mobile telephone subscribers; and a prepaid service (PPS) server connected to the switching center and the home location register via a mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money. The subscriber profile in the home location register includes a selective prepaid mobile telephone service field which

state value representing that a user is not registered for selective prepaid mobile telephone service to selectively provide prepaid mobile telephone service, a registered-but-not-activated state value representing that a user does not activate prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, and a registered-and- activated state value representing that a user has activated prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service. The switching center which has received a mobile telephone call including a destination number treats the mobile telephone call as a general mobile telephone call if the selective prepaid mobile telephone service field in the subscriber profile of a mobile telephone subscriber who has made the mobile telephone call is set to be the not- registered state value or registered-but-not-activated state value, or treats the received mobile telephone call as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed, if the selective prepaid mobile telephone service field is set to be the registered-and- activated state value.

The above objective of the present invention is achieved by a selective prepaid mobile telephone service system, according to another aspect of the present invention, including a switching center for relaying a mobile telephone call, a home location register connected to the switching center via a mobile communication network for managing the subscriber profiles of mobile telephone subscribers, and a prepaid service (PPS) server connected to the switching center and the home location register via a mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money. In this system, a subscriber profile that is managed by the home location register includes a selective prepaid mobile telephone service field which can be set to be one of at least three state values, namely a not-registered state value representing that a user is not

provide prepaid mobile telephone service and a registered state value representing that a user is registered for the selective prepaid mobile telephone service. When the switching center receives a mobile telephone call including a destination number from a mobile telephone subscriber registered for the selective prepaid mobile telephone service, if there is no positive balance of deposit money in the account of the mobile telephone subscriber who makes the received mobile telephone call in a prepaid mobile telephone subscriber database that is managed by the PPS server, the received mobile telephone call is treated as a general mobile telephone call. If there is a positive balance of deposit money, the received mobile telephone call is treated as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed.

The above objective of the present invention is achieved by a selective prepaid mobile telephone service system, according to still another aspect of the present invention, including : a switching center for relaying a mobile telephone call ; a home location register connected to the switching center via a mobile communication network for managing the subscriber profiles of mobile telephone subscribers ; and a prepaid service (PPS) server connected to the switching center and the home location register via a mobile communication network for managing the database for subscribers registered for prepaid mobile telephone service, in which a certain amount of money is deposited and then mobile telephone service is provided within the limits of the deposit money. The subscriber profile in the home location register includes a selective prepaid mobile telephone service field which can be set to be one of at least three state values, namely a not-registered state value representing that a user is not registered for selective prepaid mobile telephone service to selectively provide prepaid mobile telephone service, a registered-but-not-activated state value representing that a user does not activate prepaid mobile telephone service while being registered for the selective prepaid mobile telephone service, and a registered-and-activated state value representing

registered for the selective prepaid mobile telephone service. The state value of the selective prepaid mobile telephone service field in the subscriber profile of a mobile telephone subscriber registered for the selective prepaid mobile telephone service is set depending on the state of the balance of deposit money in the account of a corresponding subscriber in the prepaid mobile telephone subscriber database that is managed by the PPS server. The switching center which has received a mobile telephone call including a destination number treats the mobile telephone call as a general mobile telephone call if the selective prepaid mobile telephone service field in the subscriber profile of a mobile telephone subscriber who has made the mobile telephone call is set to be the not- registered state value or registered-but-not-activated state value, or treats the received mobile telephone call as a prepaid mobile telephone call based on a destination number dialing method where authentication of prepaid mobile telephone subscribers is not performed, if the selective prepaid mobile telephone service field is set to be the registered-and- activated state value.

Brief Description of the Drawings FIG. 1 schematically shows the configuration of a system for providing prepaid mobile telephone service in a mobile communication network ; FIG. 2 is a flowchart illustrating a method of providing selective prepaid mobile telephone service in prepaid mobile telephone service system, according to a first embodiment of the present invention ; FIG. 3 is a flowchart illustrating a method of providing selective prepaid mobile telephone service in prepaid mobile telephone service system, according to a second embodiment of the present invention ; and FIG. 4 is a flowchart illustrating a method of providing a selective prepaid mobile telephone service in prepaid mobile telephone service system, according to a third embodiment of the present invention.

Referring to FIG. 1, base station transceiver subsystems (BTSs ; hereinafter, referred to as base stations), mobile switching centers (MSCs) 110a and 11 Ob, visitor location registers (VLRs) 120a and 120b and a home location register (HLR) 130 are fundamental for providing mobile communication service. Generally, signaling on a mobile communication network which connects the MSCs 110a and 11 Ob, the VLRs 120a and 120b and the HLR 130 is performed via a signaling system number 7 (SS7) network. Also, a base station control (BSC ; not shown) may be installed between a base station and an MSC.

The MSCs 110a and 11 Ob receive a mobile telephone call from a mobile communication terminal via base stations and relay the received mobile telephone call to a destination MSC by communicating with the HLR 130.

The HLR 130 manages various subscriber information in the form of subscriber profiles. Essentially, the HLR 130 provides information on the current location of a destination mobile station (that is, a mobile communication terminal) to an originating MSC through communicating with the VLRs 120a and 120b, so that it supports a call to be routed to an appropriate destination MSC and an appropriate base station. Also, the HLR 130 processes a feature code (which denotes a code which starts with special characters such as * or # and is used for a special purpose) from the call originating MSC and a call, origination triggers for which are armed.

The origination triggers will be described in detail later.

The VLRs 120a and 120b manage subscriber profiles which contain information on mobile telephone subscribers (more accurately, mobile communication terminals) currently located within a predetermined zone.

Hereinafter, the subscriber profiles which are managed by the VLR are referred to as visitor profiles. When a mobile telephone subscriber enters in the predetermined zone, the subscriber profile (including origination triggers) is transmitted from the HLR 130 to the VLRs 120a and 120b. The VLRs 120a and 120b provide information on the origination triggers of originating calls to originating MSCs. Therefore, even when information on

registration or cancellation of a special service by the corresponding subscriber, the profile of the corresponding subscriber is transmitted from the HLR 130 to the VLRs 120a and 120b.

The VLRs 120a and 120b are generally located within the MSCs 110a and 110b. In FIG. 1, the VLRs 120a and 120b are connected to the MSCs 11 Oa and 11 Ob, respectively. Also, the VLRs 120a and 120b can be installed in computer systems that are the same as the MSCs 110a and 110b. In this case, communication between the MSCs 110a and 110b and the VLRs 120a and 120b is inter-process communication (IPC). However, one VLR can provide information to a plurality of MSCs, or one MSC can receive information from a plurality of HLRs.

Processing of general mobile telephone calls will now be described on the basis of the above-described content. A general mobile telephone call made by an originating mobile station is transmitted to an origination MSC via an origination base station. Then, the origination MSC acquires information on origination triggers through communications with a VLR, obtains information on a destination MSC through communications with the HLR 130 with reference to the information on the origination triggers and a destination number, and connects the corresponding call to a destination mobile station via the destination MSC and a destination base station.

In order to provide prepaid mobile telephone service, a prepaid service (PPS) server 150 for managing a prepaid mobile telephone subscriber database is introduced in a mobile communications network. As described above, the prepaid mobile telephone subscriber database stores the identification numbers of prepaid mobile telephone service subscribers and prepaid mobile telephone deposit money (hereinafter, referred to as deposit money). Here, the mobile identification numbers (MINs) of mobile communication terminals registered for the prepaid mobile telephone service are generally used as the subscriber identification numbers.

However, in the prepaid mobile telephone service provided by the feature code using method or particular number connection method, the number of a prepaid mobile telephone card can be used as the subscriber

As shown in FIG. 1, the PPS server 150 is connected to the MSCs 110a and 11 Ob and the HLR 130 via the SS7 network. Generally, a separate communications channel used for transmission of audio information or other functions is established between the PPS server 150 and the MSC 110b. Also, prepaid mobile telephone service is generally provided via a service control point (SCP) in a mobile communications network. In this case, the PPS server 150 exists within the SCP. That is, the PPS server and the SCP are realized in the same computer system.

In the following, a method of providing prepaid mobile telephone service using prepaid mobile telephone service system including the PPS server 150 will be described. As described above, prepaid mobile telephone service is generally provided by the destination number dialing method, and alternatively can be provided by the feature code method or particular number connection method in some cases.

First, prepaid mobile telephone service provided by the particular number connection method will be described. In the particular number connection method, a user directly dials the particular connection number of the PSS server 150 to be connected to the PSS server 150. Next, the user undergoes authentication by inputting his/her own prepaid mobile telephone account number (which denotes a subscriber identification number) and his/her own password, and makes a mobile telephone call by inputting a desired destination number, so that he or she can get mobile telephone service within the limits of deposit money. A detailed method of providing prepaid mobile telephone service using a particular number connection method (including a feature code method and a destination number dialing method to be described later) may vary depending on the type of international standard and the requirements of application. Here, a standard of the interim standard 41 E (IS41 E) family, which has been proposed by the Telecommunication Industry Association/Electronic Industries Association (TIA/EIA), is taken as an example.

A particular number representing the PPS server 150 can be a destination number capable of being directly discerned by the MSCs 11 Oa

destination number which is recognized as a general destination number by the MSC 11 Ob. When the particular number representing the PPS server 150 is a destination number capable of being discerned by the MSC 110b, users can be directly connected to the PPS server 150 without performing a destination location inquiry of the HLR 130 to ascertain the destination path of the corresponding destination number. Here, it is assumed that the MSC 11 Ob treats the particular number for prepaid mobile telephone service a general destination number.

When the MSC HOB receives a mobile telephone call including a destination number from a user via a base station, it primarily performs communications with the VLR 120b to acquire information on the origination triggers of the user. If particular origination triggers in the subscriber profile of the corresponding user are armed, a separate process is performed when a corresponding trigger event is detected. However, in general, there are no origination triggers separately armed in order to provide prepaid mobile telephone service using the particular number connection method.

Hereinafter, when there is no origination triggers separately armed for prepaid mobile telephone service, the step of communicating with the VLR 120b to acquire information on the origination triggers will be excluded.

Next, the MSC 11 Ob transmits a Location Request Invoke message to the HLR 130 in order to ascertain the destination path of the corresponding destination number. To be exact, the destination path denotes an actual destination number including information on the destination path. Hereinafter, destination address will be used instead of the destination path to be distinguished from a destination number received from a user via a mobile telephone call.

The HLR 130 which has received the Location Request Invoke message transmits the destination address for the particular number of the PPS server 150 to the MSC 11 Ob in reply to the location request invoke.

In order to do this, the HLR 130 must have information for matching the particular number of the PPS server 150 with the destination address of the PPS server 150.

PPS server 150 recognizes that the corresponding destination address is of the PPS server 150, and performs prepaid mobile telephone service process. In order to achieve the prepaid mobile telephone service, the MSC 11 Ob transmits an analyzed information invoke to the PSS server 150.

The PPS server 150 which has received the analyzed information invoke provides an announcement to a user via an information peripheral for providing the output of an audio signal, receives the usent subscriber identification number and password, and then performs a user authentication process. After the user authentication process is completed, the PPS server 150 receives a destination number from the user.

After processes according to the analyzed information invoke are completed, the PPS server 150 informs the MSC 110b of a call enable time depending on deposit money and the destination number received from the user. Then, the MSC 110b provides a mobile telephone service within the limits of the call enable time depending on deposit money. After a call is finished, the MSC 11 Ob transmits information on the call time to the PPS server 150 to allow the PPS server 150 to reduce the deposit money of the corresponding user.

Up to now, an example of processing a particular number connection method has been described, but, as noted above, there may be different embodiments of the particular number connection method. Also, provision of prepaid mobile telephone service through signaling on the intelligent network has been basically described above. However, it will be understood by one of ordinary skill in the art to which the present invention pertains that, in applications, prepaid mobile telephone service can be provided in a state where a mobile telephone call made by a particular number is connected directly to the PPS server 150, and the mobile telephone call to the PPS server 150 has been set.

The feature code method will now be described. When a mobile telephone subscriber dials a specific feature code (for example, *11 **), the MSC 11 Ob connects the subscriber ca ! ! to the PPS server 150 through communications with the HLR 130. Next, the PPS server 150

number and password, receives a destination number from the subscriber, and then allows the subscriber to get mobile telephone service within the limits of deposit money. The particular number connection method has a drawback in that it is difficult for users to remember the particular number for prepaid mobile telephone service. However, according to the feature code method, users can get prepaid mobile telephone service using a specific feature code that users can easily remember instead of a particular number. That is, a feature code for prepaid mobile telephone service, for example, *11, can be remembered much more easily than a particular number, for example, 200-4949.

Processing of the feature code method is similar to that of the particular number connection method. The MSC 11 Ob which has received a feature code from a user transmits a feature request invoke to the HLR 130 in order to process the feature code.

The HLR 130 which has received the feature request invoke recognizes the meaning of the corresponding feature code and transmits the destination address of the PPS server 150 to the MSC 110b in reply to the feature request invoke. In order to do this, the HLR 130 must have information for processing the feature code for prepaid mobile telephone service. A process after the MSC 11 Ob receives the destination address of the PPS server 150 is the same as that for the case of the particular number connection method.

Finally, the destination number dialing method, which is the most widely used for prepaid mobile telephone service, will now be described.

In the destination number dialing method, all calls attempted by mobile telephone subscribers are considered as prepaid mobile telephone calls and are connected to the PPS server 150. Then, calls corresponding to deposit money are allowed through communications between the MSC 110b and the PPS server 150. Thus, the destination number dialing method requires no user authentication processes.

In order to provide prepaid mobile telephone service using the destination number dialing method, a code for discerning prepaid mobile

the identification numbers of subscribers registered for prepaid mobile telephone service) is set in the subscriber profile managed by the HLR 130.

When the HLR 130 transmits a subscriber profile message, for example, a qualification directive invoke, to the VLR 120b upon subscriber location registration or subscriber information change for subscribers registered for prepaid mobile telephone service based on the destination number dialing method, it is requested that specific origination triggers are armed for prepaid mobile telephone service based on the destination number dialing method.

Origination triggers are referred to by the MSC 110b to process an originating call. The MSC 11 Ob acquires information on the origination triggers for an originating call from the VLR 120b. The origination triggers include every call triggers, K-digit triggers (for example, 1-digit triggers, 2- digit triggers, 3-digit triggers, or the like), international call triggers, general call triggers, revertive call triggers, feature code related triggers (for example, * call triggers, ** call triggers, # call triggers or the like), and the like. Here, a revertive call denotes a call made to the caller own number.

The aforementioned triggers correspond to the bit fields of origination triggers. When an armed trigger event is detected from an originating call, the MSC 11 Ob transmits an origination request invoke to the HLR 130 instead of directly processing the originating call, and processes the originating call in accordance with a reply of the HLR 130 to the origination request invoke.

The type of origination triggers and event interpretation of each origination trigger can vary depending on the type of specification and implementation method. Also, origination triggers to be used for prepaid mobile telephone service can vary depending on the policy of businesses.

In principle, triggers capable of detecting all calls which are charged must be used as origination triggers for prepaid mobile telephone service. For example, every call triggers can be used for prepaid mobile telephone service, or K-digit triggers can be used.

The MSC 110b primarily acquires information on the origination

originating call, and checks the corresponding armed trigger event. In the case of users registered for prepaid mobile telephone service, specific origination triggers are armed for prepaid mobile telephone service, as described above. Thus, when the MSC 110b senses an event related to the armed triggers for prepaid mobile telephone service, it sends an origination request invoke to the HLR 130. The origination request invoke includes information on the sensed origination triggers, a subscriber identification number (hereinafter, referred to as an MIN), an electronic serial number (ESN) that is the unique identification code of a mobile communication terminal, and the destination number of a mobile telephone call.

When the HLR 130 identifies a corresponding subscriber as prepaid mobile telephone service subscriber by reference to a subscriber profile using the MIN and ESN in the origination request invoke, it transmits an Origination Request Result message including the destination address to the PPS server, and the destination number of a mobile telephone call to the MSC 11 Ob.

The MSC 110b which has received the destination address of the PPS server 150 recognizes the received call as a prepaid mobile telephone call, and transmits an analyzed information invoke including the MIN and the destination number of a mobile telephone call to the PPS server 150.

When the PPS server 150 receives the analyzed information invoke including the destination number of a mobile telephone call, a user authentication process using the identification number and password of a subscriber is not performed on the assumption that the user authentication process has been completed by the HLR 130. However, an announcement about the current positive balance of deposit money is generally provided to users.

After processes according to the analyzed information invoke are completed, the PPS server 150 informs the MSC 11 Ob of the call enable time depending on deposit money and the destination number of a mobile telephone call. Then, as described above, the MSC 110b provides mobile

depending on deposit money. After a call is finished, the MSC 11 Ob transmits information on tie call time to the PPS server 11 Ob to allow the PPS server 110b to reduce the deposit money of the corresponding subscriber. The above-described method of providing prepaid mobile telephone service using a destination number dialing method is an example. As described above, there may be different embodiments of the method of providing prepaid mobile telephone service.

Up to now, methods for providing prepaid mobile telephone service using the particular number connection method, the feature code method and the destination number dialing method have been described. In the following, a method of providing a selective prepaid mobile telephone service according to a preferred embodiment of the present invention will be described.

The present invention proposes the selective use of a prepaid mobile telephone using the destination number dialing method in which users do not undergo a user authentication process. A method of selecting a prepaid mobile telephone call or a general mobile telephone call according to the request of a user, that is, a method of determining the use or non-use of prepaid mobile telephone service according to the user-T request, is referred to as a manual conversion method (which corresponds to the first embodiment). A method of providing prepaid mobile telephone service when there is a positive balance of deposit money in the account of a subscriber on the prepaid mobile telephone subscriber database managed by a PPS server, and automatically providing a general mobile telephone service when there is no positive balance is referred to as an automatic conversion method (which corresponds to the second and third embodiments). A selective prepaid mobile telephone service system according to embodiments of the present invention can be configured by applying the function performed in each step for method embodiments of the present invention to the constituent members of the prepaid mobile telephone system of FIG. 1. Hereinafter, the method embodiments will be primarily described.

illustrating a method of providing a selective prepaid mobile telephone service in prepaid mobile telephone service system, according to a first embodiment of the present invention. The HLR of FIG. 1 has several additional functions to support the first embodiment. However, the first embodiment can be compatibly performed with an existing prepaid mobile telephone system.

First, a selective prepaid service (SPPS) field is included in a subscriber profile managed by the HLR, in step 210. The SPPS field can be a separate field added to support the first embodiment of the present invention in which prepaid mobile telephone service is selectively provided, or a field already existing in the subscriber profile can be utilized for the SPPS field in the embodiment of the present invention. This is the same in the second and third embodiments to be described later.

The SPPS field can be set to be three basic state values of a not- registered state value, a registered-but-not-activated state value and a registered-and-activated state value, and can also be set to be additional state values for the purpose of management and the like. Here, the not- registered state value represents that a user is not registered for a selective prepaid mobile telephone service according to an embodiment of the present invention. The registered-but-not-activated state value represents that a user does not activate prepaid mobile telephone service (that is, a state where a general telephone call is used) while being registered for selective prepaid mobile telephone service according to an embodiment of the present invention. The registered-and-activated state value represents that a user has activated prepaid mobile telephone service (that is, a state where a prepaid mobile telephone call is used) while being registered for selective prepaid mobile telephone service according to an embodiment of the present invention. That is, the SPPS field in the first embodiment can be set to be an activated state value or a not-activated value of prepaid mobile telephone service, while a user is being registered for selective prepaid mobile telephone service according to an embodiment of the present invention.

field in its subscriber profile, and the initial value of the SPPS field is set to be the not-registered state value. When a mobile telephone subscriber registers for selective prepaid mobile telephone service according to an embodiment of the present invention, the SPPS field is set to be the registered-but-not-activated state value or the registered-and-activated state value at the user% ! request. Registration for selective prepaid mobile telephone service according to an embodiment of the present invention can be made in various ways such as manual registration through an operator, registration through an automatic answering machine, registration through a home page on the Internet, and registration using a feature code.

In order to register for a selective prepaid mobile telephone service according to an embodiment of the present invention, basically, the account of a user, that is, the subscriber identification number of a user, must be registered in the prepaid mobile telephone subscriber database managed by a PPS server.

In step 220, a subscriber registered for selective prepaid mobile telephone service according to an embodiment of the present invention can change the state value (that is, the activated or not-activated state value) of the SPPS field by request. The request for the change of the state value of the SPPS field can be made by various methods as in the registration for selective prepaid mobile telephone service. Preferably, the state value of the SPPS field can be changed into an activated or not-activated state value using a specific feature code. For example, a feature code *12 can be used for activation, and a feature code *13 can be used for deactivation.

When the state value of the SPPS field is changed at userS request, the HLR makes a request to the VLR that specific origination triggers in the visitor profile of a corresponding subscriber are armed or disarmed for a selective prepaid mobile telephone service according to an embodiment of the present invention, in step 230. That is, when the state value of the SPPS field is changed from the registered-but-not-activated state value to the registered-and-activated state value, the HLR makes a request to the VLR that specific origination triggers in the visitor profile of

prepaid mobile telephone service according to an embodiment of the present invention. On the other hand, when the state value of the SPPS field is changed from the registered-and-activated state value to the registered-but-not-activated state value, the HLR makes a request to the VLR that specific origination triggers in the visitor profile of a corresponding subscriber are disarmed for a selective prepaid mobile telephone service according to an embodiment of the present invention.

Preferably, the request for arming and disarming specific origination triggers is made by a subscriber profile message, for example, qualification directive invoke, which is transmitted from the HLR to the VLR upon registration or cancellation of a specific service or registration of a new location. Also, for compatibility, it is preferable that the same triggers are used for origination triggers armed for a conventional prepaid mobile telephone service based on a destination number dialing method and origination triggers armed for a selective prepaid mobile telephone service according to an embodiment of the present invention.

Next, a switching center receives a mobile telephone call including a destination number from a mobile telephone subscriber via a base station, in step 240. A method of processing the mobile telephone call is determined depending on the state value of the SPPS field, in steps 250 through 270.

That is, if the state value of the SPPS field of a corresponding mobile telephone subscriber is set to be the not-registered state value or the registered-but-not-activated state value, the mobile telephone call received in step 240 is processed as a general mobile telephone call, in step 260.

If the state value of the SPPS field of a corresponding mobile telephone subscriber is set to be the registered-and-activated state value, the mobile telephone call received in step 240 is processed as a prepaid mobile telephone call based on a destination number dialing method in which user authentication is not performed, in step 270.

Here, the switching center operates, through communications with the VLR, with reference to origination triggers that are set according to the

profile managed by the HLR. To be more exact, the switching center operates with respect tc only the origination triggers, regardless of a selective prepaid mobile telephone service according to an embodiment of the present invention, in step 250. That is, when the state value of the SPPS field is set to be the not-registered state value or the registered-but- not-activated state value, there are no triggers armed for a selective prepaid mobile telephone service according to an embodiment of the present invention, so that the mobile telephone call received in step 240 is treated as a general mobile telephone call, in step 260. When the state value of the SPPS field is set to be the registered-and-activated state value, specific origination triggers are armed for a selective prepaid mobile telephone service according to an embodiment of the present invention, so that the switching center transmits an origination request invoke to the HLR, and treats the mobile telephone call received in step 240 as a prepaid mobile telephone call in reply of the HLR, in step 270. When the state value of the SPPS field is set to be the registered-and-activated state value, the HLR orders the switching center to treat the received call as a prepaid mobile telephone call. Undoubtedly, origination triggers armed for a service unrelated to selective prepaid mobile telephone service according to an embodiment of the present invention is processed by a general processing method, regardless of the embodiment of the present invention.

In FIG. 1, the steps 220 and 230 are shown ahead of the step 240 for convenience of explanation. However, it will be understood by one of ordinary skill in the art to which the present invention pertains that the change of the state value of the SPPS field can be performed at any point in time, and that the step 240 can be performed without performing the step 220 and/or step 230 according to circumstances.

As described above, a selective prepaid mobile telephone service system according to an embodiment of the present invention can be configured by applying the operation of each of the steps for the first embodiment to the constituent members of the prepaid mobile telephone system of FIG. 1.

who wants to make a prepaid mobile call using deposit money reserved in his or her prepaid mobile telephone service account, activates the SPPS field and then can make a prepaid mobile call in the same way as the conventional way of making a prepaid mobile call based using a destination number dialing method. On the other hand, a subscriber, whose deposit money in his or her account is completely consumed, or who wants to stop making a prepaid mobile call for some other reason, inactivates the SPPS field and then can make a general mobile call.

Also, the selective prepaid mobile telephone service according to an embodiment of the present invention can be extended to a business model on the Internet. In order to achieve this, it is preferable to support accumulation of compensation acquired from a web server on the Internet in the form of deposit money to be used to get a selective prepaid mobile telephone service according to an embodiment of the present invention, through interworking between a web server on the Internet and a prepaid mobile telephone server on the mobile network.

A second embodiment, which is an automatic conversion method, will be described below. FIG. 3 is a flowchart illustrating a method of providing a selective prepaid mobile telephone service in prepaid mobile telephone service system, according to the second embodiment of the present invention.

In the second embodiment, an HLR sets up a communication channel with a PPS server. When the HLR receives a mobile telephone call from a subscriber registered for selective prepaid mobile telephone service according to an embodiment of the present invention, the HLR inquires of the PPS server about the balance of deposit money. If there is a positive balance in the account of a corresponding subscriber in a prepaid mobile telephone subscriber database managed by the PPS server, the received call is treated as a prepaid mobile call based on a destination number dialing method. On the other hand, if there is no positive balance in the account, the received call is treated as a general mobile call. That is, in the second embodiment, a service providing way is automatically

account for a prepaid mobile telephone call.

The second embodiment can also be achieved by adding several functions to the HLR and the PPS server, and can be performed compatibly with the constituent members of an existing prepaid mobile telephone system. The second embodiment will now be described.

First, an SPPS field is included in a subscriber profile that is managed by an HLR, in step 310. The SPPS field in the second embodiment can be set to be one of two basic state values, namely a not- registered state value and a registered state value, in contrast to the first embodiment, and can also be set to be additional state values for the purpose of management and the like. Here, the not-registered state value represents that a user is not registered for selective prepaid mobile telephone service according to an embodiment of the present invention, and the registered state value represents that a user is registered for selective prepaid mobile telephone service according to an embodiment of the present invention.

In order to achieve the second embodiment, the HLR includes the SPPS field in the subscriber profile, and the initial value of the SPPS field is set to be the not-registered state value. When a mobile telephone subscriber registers for selective prepaid mobile telephone service according to an embodiment of the present invention, the SPPS field is set to be the registered state value. Registration for selective prepaid mobile telephone service according to the second embodiment of the present invention can be made in a way similar to a way for the first embodiment.

When a mobile telephone subscriber is registered for selective prepaid mobile telephone service according to the second embodiment of the present invention, and thus the SPPS field in the subscriber profile of the corresponding subscriber is set to be the registered state value, the HLR makes a request to the VLR that specific origination triggers in the visitor profile of the corresponding subscriber are armed for selective prepaid mobile telephone service according to the second embodiment of the present invention, in step 320. As described above, preferably, the

profile message, which is transmitted from the HLR to the VLR upon registration or cancellation of a specific service or a new location registration. Also, for compatibility, it is preferable that origination triggers armed for selective prepaid mobile telephone service according to the second embodiment of the present invention are the same as origination triggers armed for a conventional prepaid mobile telephone service based on a destination number dialing method.

Next, a switching center receives a mobile telephone call including a destination number from a mobile telephone subscriber via a base station, in step 330. When there is a positive balance of deposit money in the account of the corresponding subscriber in a prepaid mobile telephone subscriber database that is managed by a PPS server, the received call is treated as a prepaid mobile call based on the destination number dialing method, and, when the balance of deposit money is completely consumed, the received call is treated as a general mobile call, in steps 340 through 370.

To be more specific, first, the switching center which has received a mobile telephone call acquires information on the origination triggers in the visitor profile of the corresponding subscriber by communications with the VLR in order to process the received call. If the corresponding subscriber has been registered for the selective prepaid mobile telephone service according to the second embodiment of the present invention, specific origination triggers in the visitor profile of the VLR has been armed, in step 320. Accordingly, the switching center transmits an origination request invoke with respect to the origination call received in step 330 to the HLR, in step 340.

The HLR which has received the origination request invoke inquires of the PPS server about the balance of deposit money in the prepaid mobile call account of the corresponding subscriber through a communication channel when an originator of the corresponding call is a subscriber for selective prepaid mobile telephone service according to the second embodiment of the present invention (that is, when the SPPS field is set to

communication network, for exampte, an SS7 network, can be used for the communication channel for an inquiry about the balance of deposit money between an HLR and a ;'PS server, or a separate data communication channel through the Internet or Intrant can be used.

The HLR which has received information on the balance of deposit money in the corresponding account from the PPS server transmits the destination address of the PPS server and the destination number of the mobile telephone call to the switching center in reply to the origination request invoke if there is a positive balance in the corresponding account in the PPS server, in order to direct the switching center to treat the corresponding call as a prepaid mobile telephone call based on the destination number dialing method, in step 360. If there is no positive balance in the corresponding account in the PPS server, the HLR transmits only the destination address for the destination number of the mobile telephone call to the switching center in reply to the origination request invoke in order to direct the switching center to treat the corresponding call as a general mobile telephone call, in step 360.

The switching center processes the received mobile telephone call according to the result of processing the origination request invoke, in step 370. As described above, in the second embodiment, the switching center also acquires information on the origination triggers from the VLR and operates in accordance with the result of processing of the origination request invoke by the HLR, regardless of the selective prepaid mobile telephone service according to the second embodiment of the present invention.

As in the first embodiment, selective prepaid mobile telephone service system according to the second embodiment of the present invention can be configured by applying the operations of the steps of the second embodiment of a method of providing selective prepaid mobile telephone service to the constituent members of the prepaid mobile telephone system of FIG. 1. As described above, the selective prepaid mobile telephone service according to the second embodiment of the

Internet.

Below, a third embodiment, which is another automatic conversion method, will be described. FIG. 4 is a flowchart illustrating a method of providing selective prepaid mobile telephone service in prepaid mobile telephone service system, according to a third embodiment of the present invention. The third embodiment can be performed by adding several functions to an HLR and a PPS server, and prepaid mobile telephone service system according to the third embodiment can operate compatibly with an existing prepaid mobile telephone system.

In the second embodiment, in order to process an origination call from a subscriber registered for selective prepaid mobile telephone service, even when there is no positive balance of deposit money in the account of the corresponding subscriber, a switching center always transmits an origination request to an HLR, and the HLR transmits a balance inquiry to a PPS server. In the third embodiment, in order to eliminate redundant communication processes in the second embodiment, a switching center transmits an origination request invoke to an HLR only when prepaid mobile telephone service is actually provided in case that there is a positive balance of deposit money. The HLR does not inquire about the state of the balance of the PPS server. On the contrary, the PPS server informs the HLR of the existence or non-existence of a positive balance of deposit money of a subscriber registered for the selective prepaid mobile telephone service according to the third embodiment of the present invention (which are the cases where the positive balance exists and then becomes zero and where an amount of deposit money is newly accumulated to make a positive balance), so that the HLR can adjust the origination triggers of the corresponding subscriber in the subscriber profile.

In the operation of the third embodiment, first, a selective prepaid service (SPPS) field is included in a subscriber profile managed by the HLR, in step 410. As in the first embodiment, the SPPS field can be set to be one of three basic state values, namely a not-registered state value, a registered-but-not-activated state value and a registered-and-activated

purpose of management and the like. However, in contrast to the first embodiment in which the state value of the SPPS field is set to be the registered-and-activated state value or the registered-but-not-activated state value at a userS request, the state value of the SPPS field is automatically determined depending on the state of the balance of deposit money in the corresponding subscriber account existing in the PPS server.

In order to achieve the third embodiment, the HLR includes the SPPS field in its subscriber profile, and the initial value of the SPPS field is set to be the not-registered state value. When a mobile telephone subscriber registers for selective prepaid mobile telephone service according to the third embodiment of the present invention, the SPPS field is set to be the registered-but-not-activated state value or the registered- and-activated state value according to the request of synchronization between the HLR and the PPS server. For example, at the time of registration, the HLR sends a synchronization request to the PPS server, and the state value of the SPPS field is set depending on the reply of the PPS server to the synchronization request. It will be understood by one of ordinary skill in the art to which the present invention pertains that synchronization between the HLR and the PPS server can be achieved by various methods. Also, the registration for the selective prepaid mobile telephone service according to the third embodiment of the present invention can be made in a way similar to the way for the first or second embodiment.

In contrast with the first embodiment, the state value of the SPPS field is automatically determined depending on the state of the positive balance of deposit money in the account of a subscriber registered for selective prepaid mobile telephone service in the prepaid mobile telephone subscriber database which is managed by the PPS server, in step 420.

In order to perform the step 420, when the balance of deposit money in the account of a subscriber registered for the prepaid mobile telephone service according to the third embodiment is completely consumed

informs the HLR that the first event has occurred. On the other hand, when the balance of deposit money in the account of the corresponding subscriber has become positive by accumulation of new deposit money (hereinafter, this case is referred to as the second event), the PPS server informs the HLR that the second event has occurred. In order for the PPS server to inform the HLR that the first or second event has occurred, the PPS server needs to manage information by which an HLR to manage the profile of prepaid mobile telephone service subscriber can be extracted from the identification number of the corresponding subscriber, or a mediation server for mediating communications between the PPS server and the HLR needs to be introduced.

When the first event is reported, the HLR sets the SPPS field of the corresponding subscriber to be the not-activated state value, and disarms origination triggers for the selective prepaid mobile telephone service according to the third embodiment from the subscriber profile of the HLR.

When the second event is reported, the HLR sets the SPPS field of the corresponding subscriber to be the activated state value, and arms specific origination triggers in the subscriber profile for the selective prepaid mobile telephone service according to the third embodiment.

When the state value of the SPPS field is changed according to the first or second event reported by the PPS server, the HLR makes a request to the VLR that origination triggers in the visitor profile of a corresponding subscriber are armed or disarmed for the selective prepaid mobile telephone service according to the third embodiment of the present invention, in step 430. That is, when the state value of the SPPS field is changed from the registered-and-activated state value to the registered-but- not-activated state value, the HLR makes a request to the VLR that the specific origination triggers in the visitor profile of a corresponding subscriber are disarmed for selective prepaid mobile telephone service according to the third embodiment of the present invention. This prevents the switching center from transmitting an origination request invoke to the HLR to make a request to the HLR for prepaid mobile telephone service.

the registered-but-not-act vated state value to the registered-and-activated state value, the HLR makes a request to the VLR that specific origination triggers in the visitor profile of a corresponding subscriber are armed for selective prepaid mobile telephone service according to the third embodiment of the present invention. This allows the switching center to transmit an origination request invoke to the HLR to provide prepaid mobile telephone service.

Preferably, the request for arming and disarming the specific origination triggers is made by a subscriber profile message, which is transmitted from the HLR to the VLR upon receipt of a message reporting the occurrence of the first or second event, upon registration or cancellation of the other services or upon registration of a new location. Also, as described above, it is preferable that the same triggers are used for origination triggers armed for a conventional prepaid mobile telephone service based on a destination number dialing method and origination triggers armed for selective prepaid mobile telephone service according to the third embodiment of the present invention to achieve compatibility.

Next, a switching center receives a mobile telephone call including a destination number from a mobile telephone subscriber via a base station, in step 440. In this case, similar to the first embodiment, a method of processing the mobile telephone call received in step 440 is determined depending on the state value of the SPPS field, in steps 450 through 470.

To be more specific, if the state value of the SPPS field in the subscriber profile of a corresponding mobile telephone subscriber is set to be the not-registered state value or the registered-but-not-activated state value, there are no triggers armed for selective prepaid mobile telephone service according to the third embodiment of the present invention, so that the mobile telephone call received in step 440 is treated as a general mobile telephone call, in step 460. When the state value of the SPPS field is set to be the registered-and-activated state value, specific origination triggers are armed for selective prepaid mobile telephone service according to the third embodiment of the present invention, so that the switching

mobile telephone call received in step 440 as a prepaid mobile telephone call based on the destination number dialing method where user authentication is not performed, in reply of the HLR, in step 470. When the state value of the SPPS field is set to be the registered-and-activated state value, the HLR orders the switching center to treat the received call as a prepaid mobile telephone call.

As in the first and second embodiments, selective prepaid mobile telephone service system according to the third embodiment of the present invention can be configured by applying the operations of the steps of the third embodiment of a method of providing selective prepaid mobile telephone service to the constituent members of the prepaid mobile telephone system of FIG. 1. As described above, the selective prepaid mobile telephone service according to the third embodiment of the present invention can also be extended to a business model on the Internet.

The method embodiments of the present invention can be written in a program that can be executed on a computer system. Also, this program can be read from a recording medium and executed by a general digital computer system. The recording medium may be a magnetic storage medium (for example, ROM, floppy discs, hard discs, etc.), an optical reading medium (for example, CD-ROM, DVD, etc.), or a carrier wave (for example, transmission through the Internet).

Up to now, preferred embodiments of the present invention have been described. It will be understood by those skilled in the art, to which the present invention pertains, that various modifications to the present invention may be made without departing from the essential characteristics of the present invention. Thus, the described embodiments must be considered not from a standpoint of restriction but from a standpoint of explanation. The true technical protection scope of the present invention must be determined not by the above description but by the attached claims, and all differences within the equivalent range must be interpreted to be included in the present invention.

According to the present invention, users can selectively get prepaid mobile telephone service based on a destination number dialing method where user authentication is not performed or a general mobile telephone service using a single mobile communication terminal. That is, users can expediently get selective prepaid mobile telephone service using a destination number dialing method instead of a feature code method or a particular number connection method in which subscriber authentication is performed. Also, the prepaid mobile telephone service and the general mobile telephone service can be converted into each other depending on the state of the positive balance of deposit money for prepaid mobile telephone service. When the balance of deposit money is exhausted, users can get general mobile telephone service by converting the mode of a mobile telephone terminal into the mode of a general mobile telephone.

Also, according to the present invention, selective prepaid mobile telephone service can be provided while maintaining compatibility with a conventional prepaid mobile telephone service.