KR100925980B1 - Method and system for providing prepaid presence service in ims network - Google Patents

Abstract

The present invention relates to a method and a system for providing a prepaid presence service in an IMS network. A method for providing a prepaid presence service for providing a prepaid service to a prepaid subscriber in an IP multimedia subsystem (IMS) network according to the present invention is a subscriber. Receiving a service request message from a terminal; Providing and executing the requested service to the subscriber station; Determining whether the subscriber is a prepaid subscriber; If a prepaid subscriber, subtracting a fee for executing the service from the prepaid balance of the subscriber; And restoring the pre-executed service to its previous state when the prepaid balance is insufficient. Therefore, traffic congestion of the IMS network is prevented so that stable service can be provided.

IMS, Prepaid, Presence, Balance, Traffic, Congestion

Description

Method and system for providing prepaid presence service in IMS network {METHOD AND SYSTEM FOR PROVIDING PREPAID PRESENCE SERVICE IN IMS NETWORK}

1 is a diagram illustrating a configuration of a system for providing a presence service to a prepaid subscriber in an IMS network according to an embodiment of the present invention.

2 is a flowchart illustrating a method of providing a presence service to a prepaid subscriber in an IMS network according to an embodiment of the present invention.

3 is a flowchart illustrating a method of providing a presence service of a prepaid subscriber in a presence server according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of a presence server and a subscriber state information server according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: subscriber terminal 120: presence server

130: subscriber status information server 140: billing server

The present invention relates to a prepaid mobile communication service, and more particularly to a prepaid mobile communication service in an IMS network.

Voice, audio and video based on IP protocol due to the development of mobile communication network. Commercialization of IMS (IP Multimedia Subsystem) which provides a multimedia etc. complexly is progressing. IMS is compatible with other communication networks, can provide various contents at the same time, and is easy to scale. Mobile operators are researching and developing VoIP and video telephony services, presence services, and multi-party video conferencing services based on IMS networks. In addition, the mobile operators are in the process of research and development to convert the current service to the IMS base. There is a prepaid fee service for these R & D services.

Looking at an example of an IMS network-based prepaid fee service, a subscriber station requests a request for status information of another subscriber station through a call session control function (CSCF), requests to change its own status information, adds a buddy list, and the like. do. The presence server receiving the service request requests the debit server to deduct the prepaid fee. Then, the billing server subtracts the fee for using the service of the subscriber terminal from the prepaid balance and transmits the related information to the presence server. At this time, when the prepaid balance is insufficient, the charging server transmits authentication failure information to the presence server.

When the presence server receives the authentication success information from the billing server, the subscriber server performs the service requested by the subscriber. When the presence server receives the authentication failure information from the billing server, the presence server notifies the subscriber of the service impossible information.

However, due to the nature of the Session Initiation Protocol (SIP) message used for communication in the IMS network, the subscriber station re-requests the service if it does not receive a response from the presence server for a certain time (response service result response or prepaid balance response). . That is, the subscriber station retransmits the SIP message and re-requests the service. As a result, network traffic between the presence server and the subscriber station is increased.

In addition, when communication between the presence server and the billing server is not smooth, and the receipt of billing deduction information from the billing server is delayed (that is, a request timeout occurs), the presence server is not OK to the subscriber terminal due to the policy of the SIP message. It will send a message. Then, the subscriber station retransmits the SIP message to request the service again.

As such, SIP message transmission of a subscriber station-> delay in processing a service due to increased network traffic of a subscriber station and a presence server-> retransmission of SIP messages of a subscriber station not receiving a response from the presence server-> network of the subscriber station and the presence server Traffic increase-> Service delay due to congestion-> SIP message resend of subscriber station ...

As a result, when the subscriber station does not receive a response to the service request from the presence server within a certain time, a vicious cycle of increasing traffic occurs, and the subscriber is late to receive the requested service.

The present invention has been proposed to solve the above problems, and provides a method and system for providing a presence service for the prepaid subscriber in the IMS network that provides a presence service without delay to the prepaid subscriber by preventing traffic congestion of the IMS network Its purpose is to.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

According to a first aspect of the present invention for achieving the above object, a method of providing a prepaid presence service for providing a presence service to a prepaid subscriber in an IP Multimedia Subsystem (IMS) network, receiving a service request message from a subscriber station ; Providing and executing the requested service to the subscriber station; Determining whether the subscriber is a prepaid subscriber; If a prepaid subscriber, subtracting a fee for executing the service from the prepaid balance of the subscriber; And restoring the pre-executed service to its previous state when the prepaid balance is insufficient.

In addition, according to a second aspect of the present invention for achieving the above object, a method for providing a prepaid presence service of a presence server interworking with a subscriber status information server for storing and managing subscriber status information in an IMS network is provided by a subscriber station. Pre-sending a service to the subscriber status information server upon receiving a request message; Receiving a service response result from the subscriber status information server and transmitting the service response result to the subscriber station; Determining whether a user of the subscriber station is a prepaid subscriber; If a prepaid subscriber, requesting a prepaid balance deduction according to service use to a billing server and receiving a response result accordingly; And requesting restoration of the pre-executed service to the subscriber status information server when the prepaid balance deduction response result is insufficient of the prepaid balance.

In addition, according to a third aspect of the present invention, a system for providing a presence service to a prepaid subscriber in an IMS network comprises: subscriber status information management means for storing subscriber status information and buddy list information; Charging processing means for storing and charging the billing information of the subscriber; And after executing the subscriber's service request in advance with the subscriber status information management means, if the subscriber is a prepaid subscriber, the fee for using the service is deducted from the prepaid balance in conjunction with the billing processing means. Presence service means for requesting restoration of the pre-executed service to the subscriber state information management means when the prepaid balance is insufficient.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a configuration of a system for providing a presence service to a prepaid subscriber in an IMS network according to an embodiment of the present invention.

As shown in FIG. 1, the system for providing a presence service of a prepaid subscriber according to the present invention includes a subscriber station 110, a presence server 120, a subscriber status information server 130, and a charging server 140.

Each of these components is connected via a mobile communication network (150). Herein, the mobile communication network 150 provides an IP-based multimedia service. The mobile communication network 150 includes a base station NodeB and a base station controller RNC in charge of accessing the subscriber station 110 through a wireless section. It includes SGSN, GGSN, and the like, which are responsible for transferring user packet data between the network or IMS domain, and provide mobility management and PDP context activation services of the subscriber station 110. In addition, the mobile communication network 150 is an IMS domain, which has a call session control function (CSCF) that handles registration and multimedia call processing using a SIP (Session Initiation Protocol) protocol, and an IP address of a home location register (HLR) function of an existing network. Home Subscriber Server (HSS), which integrates functions for mobility management and authentication of multimedia users.

The subscriber station 110 receives an IP-based multimedia service through the mobile communication network 150. The subscriber station 110 requests the presence server 120 to change its own state information, requests the state information of another subscriber station, or requests the addition and deletion of a buddy list and receives a result response accordingly.

In addition, the subscriber station 110 may request notification of the balance change to the subscriber status information server 130. If the subscriber is a prepaid subscriber and the prepaid balance is exhausted, the subscriber station 110 may receive the balance shortage information from the subscriber status information server 130.

The presence server 120 collects and manages the subscriber's status information. That is, the presence server 120 collects and manages information such as the buddy list of the subscriber and the current state of the subscriber (happy, depressed, callable, busy, power on / off, meeting, etc.). In addition, the presence server 120 receives the service request from the subscriber to provide the service. For example, when the presence server 120 receives the request for changing the status information from the subscriber station 110, the presence server 120 requests the subscriber status information server 130 to change the status information of the corresponding subscriber and receives a response accordingly. The presence server 120 transmits the changed information to the subscriber station 110. At this time, even if the subscriber is a prepaid subscriber, the presence server 120 preferentially provides a service requested by the subscriber regardless of the prepaid balance.

Meanwhile, the presence server 120 determines whether the subscriber is a prepaid subscriber after providing the service requested by the subscriber. In the case of a prepaid subscriber, the presence server 120 requests the accounting server 140 to deduct the balance and receives the result (deduction success or deduction failure). When receiving the deduction success information from the billing server 140, the presence server 120 maintains without changing the service of the prepaid subscriber performed, and when receiving the deduction failure information from the billing server 140, the presence server 120 The subscriber status information server 130 transmits remaining subscriber shortage information to request restoration of the previously executed service.

The subscriber status information server 130 stores the balance information of the prepaid subscriber, the status information of the subscriber, the buddy list of the subscriber, and the like in the form of presence information data format (PDF). In particular, the subscriber state information server 130 may store the subscriber information in the form of Rich Presence Information Data Format (RPID) or Contact Information for Presence Information Data Format (CIPID) with the extended PIDF function. When the subscriber status information server 130 receives the request for changing the subscriber status information from the presence server 120, the subscriber status information server 130 changes the status information of the corresponding subscriber and transmits the changed result to the presence server 120.

In addition, the subscriber status information server 130 receives a request for adding a buddy list from the presence server 120, adds a buddy list of the corresponding subscriber, and transmits a result thereof to the presence server 120. In addition, the receiver receives the status information transmission request of the other subscriber from the presence server 120 and transmits the corresponding information to the presence server 120. In addition, when the subscriber status information server 130 receives the remaining balance shortage information of the subscriber who provided the service from the presence server 120, the subscriber state information server 130 restores the service of the subscriber. In other words, the service provided to the subscriber whose prepaid balance is insufficient is returned to the state before execution. At this time, the subscriber status information server 130 notifies the subscriber terminal 110 of the remaining balance.

The billing server 140 stores and manages billing information of the subscriber. In particular, the billing server 140 stores the prepaid fee of the prepaid subscriber and deducts the fee according to the subscriber's use of the service from the prepaid fee. In addition, the billing server 140 receives the balance deduction request of the prepaid subscriber from the presence server 120 and transmits the balance deduction success or failure information to the presence server 120.

2 is a flowchart illustrating a method of providing a presence service to a prepaid subscriber in an IMS network according to an embodiment of the present invention.

Referring to FIG. 2, the subscriber station 110 requests the presence server 120 to change its state information (S201). In this case, the service is requested from the subscriber station 110 to the presence server 120 in a PUBLISH message, which is a kind of SIP message. The CSCF of the IMS domain analyzes the PUBISH message transmitted from the subscriber station 110 and routes the PUBISH message to the presence server 120 (S203). At this time, the CSCF requests the profile of the subscriber who requested the service to the HSS and checks whether the subscriber who requested the service is a prepaid subscriber. In the case of a prepaid subscriber, the CSCF inserts a prepaid fee identifier into a specific field of the PUBLISH message and transmits it to the presence server 120.

The presence server 120 receiving the service request from the CSCF executes the service with or without a prepaid fee identifier (ie, whether the subscriber is a prepaid subscriber). That is, the presence server 120 requests the subscriber state information server 130 to change the state information of the subscriber (S205). Then, the subscriber status information server 130 changes the status information of the corresponding subscriber, and simultaneously stores the subscriber status information before the change (S207).

Subsequently, the subscriber status information server 130 transmits the changed subscriber status information to the presence server 120 (S209), and the presence server 120 transmits the changed subscriber status information to the subscriber terminal 110 ( S211, S213). At this time, an OK message, which is a kind of SIP message, is transmitted from the presence server 120 to the CSCF, and the CSCF transmits an OK message to the subscriber terminal 110.

In this way, after providing the service regardless of whether the subscriber who requested the service is a prepaid subscriber, the presence server 120 determines whether the prepaid fee identifier is inserted into the PUBLISH message received in step S203 (S215). If the prepaid fee identifier does not exist, the presence server 120 requests the billing server 140 to charge for the service used by the subscriber.

On the other hand, if the prepaid fee identifier exists, the presence server 120 requests the billing server 140 to deduct the prepaid fee for the use of the service of the subscriber (S217). The billing server 140 subtracts the service fee from the subscriber's prepaid balance. However, if the subscriber's balance is insufficient, the billing server 140 transmits the balance deduction failure information to the presence server 120 (S219).

Upon receiving the balance deduction failure information from the charging server 140, the presence server 120 transmits the balance shortage information to the subscriber status information server 130 and requests the restoration of the previously executed service (S221). The subscriber state information server 130 receiving the balance shortage information extracts the subscriber state information before the change previously stored and restores the state information of the subscriber to the state information before the change (S223). Turn.

Subsequently, the subscriber status information server 130 transmits a message for service recovery to the subscriber station 110. At the same time, the subscriber status information server 130 transmits a notification message notifying the subscriber terminal 110 that the balance is exhausted (S225, S227). The message indicating that the recovery message and the balance are exhausted is transmitted as a NOTIFY message, which is a kind of SIP message. That is, the NOTIFY message, which is a kind of SIP message, is transmitted from the subscriber state information server 130 to the CSCF, and the CSCF analyzes the NOTIFY message and transmits the NOTIFY message to the subscriber station 110. The subscriber station 110 restores information that has been updated according to service execution to a previous state.

Table 1 shows a Presence Information Data Format (PDFF) of the subscriber station 110 stored in the subscriber status information server 130 according to an embodiment of the present invention.

<? xml version = "1.0" enconding = "UTF-8"?><presence xmlns = "urn: ietf: params: xml: ns: pidf" entity = "sip: 30102312@ktf.com"><tuple id = "86"><status><basic> open </ basic><credit> valid </ credit></status><contact priority = "0.00"> sip: 192.168.151.111: 7072 </ contact></tuple><person><mood> happy </ mood><pre-mood> melancholy </ pre-mood></person></presence>

Referring to Table 1, if there is a prepaid balance of the subscriber station 110, the subscriber status information server 130 is displayed as "valid" in the <credit> element of the PIDF, the subscriber terminal 110 If the prepaid balance is exhausted, the <credit> element is marked as "invalid". In addition, the subscriber state information server 150 displays the emotional state information (happy, depressed, etc.) of the subscriber in the <mood> element. The <pre-mood> element represents the emotional state information of the subscriber before the service.

For example, suppose a subscriber changes his or her emotional state from "depressed" to "happy." Then, the presence server 120 requests the subscriber status information server 130 to change the status of the subscriber regardless of the subscriber's prepaid balance. Then, the subscriber state information server 130 stores "melancholy" information, which is a state before service execution, in the <pre-mood> element, and the <mood> element indicating the current emotional state information of the subscriber. Change (element) to "happy".

However, when the subscriber status information server 130 receives the balance shortage information from the presence server 120, the subscriber state information server 130 changes the <credit> element to "invalid" indicating the balance shortage. At the same time, the subscriber status information server 130 changes the &quot; mood &quot; element to &quot; melancholy &quot; marked on the &lt; pre-mood &gt; element representing the subscriber status before service execution.

Table 2 below shows the PIDF of the subscriber station 110 restored to the state before the service execution due to the lack of the prepaid balance.

<? xml version = "1.0" enconding = "UTF-8"?><presence xmlns = "urn: ietf: params: xml: ns: pidf" entity = "sip: 30102312@ktf.com"><tuple id = "86"><status><basic> open </ basic><credit> invalid </ credit></status><contact priority = "0.00"> sip: 192.168.151.111: 7072 </ contact></tuple><person><mood> melancholy </ mood><pre-mood> melancholy </ pre-mood></person></presence>

On the other hand, the subscriber state information server 130 receiving the request to change the subscriber state information from the presence server 120, if "invalid" is extracted from the <credit> element of the PIDF corresponding to the subscriber, step 207 It is preferable to transmit the service execution impossible information to the presence server 120 and to notify the subscriber terminal 110 of the remaining balance information without performing the subscriber state change. Then, the presence server 120 transmits a Not OK message indicating that the service execution is impossible to the subscriber terminal (110).

Thereafter, the subscriber status information server 130 may receive the charge information of the subscriber from the billing server 140 when the subscriber whose balance is exhausted charges the balance. Then, the subscriber status information server 130 changes the information of the <credit> element from "invalid" to "valid" and notifies the subscriber terminal 110 that the fee has been charged. The subscriber status information server 130 performs the service requested by the subscriber in the method of FIG. 2.

As described above, the presence service system according to the present invention provides the service requested by the subscriber even when the subscriber is a prepaid subscriber and the prepaid balance is insufficient. If it is confirmed that the subscriber's prepaid balance is insufficient, the service provided to the subscriber is restored to the previous state, and the subscriber is notified of the balance shortage notification. Accordingly, in the presence service system, traffic congestion can be prevented to provide a stable service.

On the other hand, in the embodiment with reference to Figure 2 has been described as a service for changing the status information of the subscriber as an example, it will be clear that the present invention can be applied to the addition of the subscriber's buddy list, requesting the status information of other subscribers.

3 is a flowchart illustrating a method of providing a presence service of a prepaid subscriber in a presence server according to an embodiment of the present invention.

Referring to FIG. 3, the presence server 120 receives a service providing request of changing its state information, adding a buddy list, etc. from the subscriber station 110 (S301). At this time, the presence server 120 receives the service request as a SIP message.

The presence server 120 executes the service with or without a prepaid fee identifier (ie, with or without a prepaid subscriber) (S303). That is, the presence server 120 requests the subscriber state information server 130 to change the state information of the subscriber station 110 or add a buddy list. Subsequently, the presence server 120 transmits a service response message (OK message) to the subscriber station 110 (S305).

Next, the presence server 120 determines whether a prepaid fee identifier is inserted in the service request message received in step S301 (S307). That is, the presence server 120 determines whether the subscriber who requested the service is a prepaid subscriber. If there is a prepaid fee identifier, the presence server 120 requests the billing server 140 to deduct the fee due to the use of the service of the subscriber and receives a response according to the above (S309).

However, when the response from the charging server 140 is the balance deduction failure, the presence server 120 restores the executed subscriber's service to the previous state (S313). That is, the presence server 120 notifies the subscriber status information server 130 of the subscriber's balance shortage information, thereby causing the subscriber status information server 130 to return the status information to the state before the service execution.

On the other hand, if the prepaid fee identifier is not included in the service request message received in step S301, the presence server 120 requests the billing server 140 to charge for the subscriber's service (S315). The billing server 140 bills the subscriber's service usage fee after payment.

On the other hand, with respect to the subscriber station 110 succeeded in deducting the balance in step S311, the presence server 120 does not request the service recovery information to the subscriber state information server 130, and maintains the executed service state.

4 is a diagram illustrating a configuration of a presence server and a subscriber state information server according to an embodiment of the present invention.

First, as shown in FIG. 4, the presence server 120 includes a transceiver 401, a subscriber determiner 403, and an authenticator 405.

The transceiver 401 of the presence server 120 receives a service request such as a request for changing subscriber status information, a request for adding a buddy list, or a request for other subscriber status information from the subscriber terminal 110, and provides information change and information accordingly. The request is sent to the subscriber status information server 140.

In addition, the transceiver 401 of the presence server 120 receives a result (subscriber status information, status information of another subscriber, etc.) for the service request from the subscriber status information server 140 to the subscriber terminal 110. to provide.

Meanwhile, the subscriber determination unit 403 of the presence server 120 determines whether the subscriber who requested the presence service is a prepaid subscriber. That is, the subscriber determiner 403 determines whether the subscriber is a prepaid subscriber by checking whether the prepaid fee identifier is included in the service request message received by the transceiver 401. The subscriber determination unit 403 transmits a subscriber determination result signal to the authentication unit 405.

The authenticator 405 of the presence server 120 requests the charging server 140 to charge the service according to the subscriber determination result signal transmitted from the subscriber determination unit 403 and receives a response accordingly. If the subscriber is not a prepaid subscriber, the authentication unit 405 requests a general charge to the billing server 140, and if the subscriber is a prepaid subscriber, requests the balance deduction to the billing server 140. If the subscriber is a prepaid subscriber but the prepaid balance is insufficient, the authentication unit 405 receives the balance deduction failure information from the billing server 140, and the subscriber to the subscriber status information server 130 through the transceiver 401. The terminal 110 transmits the balance shortage information together with the identification information to request the restoration of the previously executed service.

Next, as shown in FIG. 4, the subscriber status information server 130 includes a transceiver 407, a storage 409, an information manager 411, and a balance notifying unit 413.

The transceiver 407 of the subscriber status information server 130 receives a request for adding a buddy list, a request for changing subscriber status information, a request for transmitting status information of another subscriber, and the like from the presence server 120. In addition, the transceiver 407 receives a subscriber's remaining balance shortage information and a pre-executed service recovery request from the presence server 120.

The storage unit 409 stores status information, a buddy list, and the like for each subscriber in the form of a PIDF. In particular, the subscriber status information server 130 may store subscriber status information, a buddy list, and the like in the form of RPID or CIPID with extended PIDF function.

The information manager 411 of the subscriber status information server 130 changes and manages the subscriber's status information and the buddy list stored in the storage 409. That is, when the transceiver 407 receives the subscriber state information change request from the presence server 120, the information manager 411 changes the subscriber state information in the storage unit 409 in response to the request.

In addition, when the transceiver 407 receives the balance shortage information including the identification information of the subscriber station 110 from the presence server 120, the information manager 411 receives the state of the subscriber before executing the service in the storage unit 409. Extract the information and return to the state before the change.

When the information management unit 411 restores the subscriber's status information, the balance notifying unit 413 notifies the subscriber of the remaining balance information through a popup window. In addition, the balance notification unit 413 prepares a message for returning the application screen of the subscriber station 110 to the screen state before the service request, and transmits it to the subscriber station 110.

In the above-described embodiment of the present invention, the presence server 120 and the subscriber state information server 130 have been described as being implemented and operated independently, but the present invention is not limited thereto and may be implemented as an integrated system to operate as a system. Make it clear.

According to the present invention as described above, even if the subscriber requesting the service is a prepaid subscriber but the balance is insufficient, the IMS network provides the requested service regardless of the balance. Accordingly, the terminal 110 of the subscriber does not receive a response to the service request and thus does not retransmit the service request message, thereby preventing traffic congestion in the IMS network. In addition, the IMS network provides the service to the prepaid subscribers regardless of the prepaid balance in advance, but immediately checks the prepaid balance of the prepaid subscriber and restores the service provided to the original state when the prepaid balance is insufficient. Resolve the problem of providing a service.

The method of the present invention as described above may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, by preventing the traffic congestion of the IMS network can smoothly provide the presence service to the prepaid subscribers without delay to increase the subscriber satisfaction.

Claims (9)

A method of providing a prepaid presence service that provides a presence service to a prepaid subscriber in an IMS (IP Multimedia Subsystem) network, (a) receiving a service request message from a subscriber station; (b) pre-executing the requested service to provide the subscriber terminal; (c) determining whether the subscriber is a prepaid subscriber; (d) in the case of a prepaid subscriber, subtracting a fee for executing the service from the prepaid balance of the subscriber; And (e) restoring the pre-executed service to a state before the service is executed when the prepaid balance is insufficient. The method of claim 1, When the prepaid balance is insufficient, sending a balance shortage notification message to the subscriber terminal; Prepaid presence service providing method further comprising. The method according to claim 1 or 2, Step (c) is, And if the prepaid service identifier is included in the service request message, determining the subscriber as a prepaid subscriber. The method of claim 3, wherein The service request message, Method of providing a prepaid presence service, characterized in that any one of its own state change request message, buddy list add request message, other subscriber status information request message. A prepaid presence service providing method of a presence server interworking with a subscriber status information server storing and managing subscriber status information in an IMS network, (a) requesting a service to the subscriber state information server in advance upon receiving a service request message from a subscriber station; (b) receiving a service response result from the subscriber status information server and transmitting the service response result to the subscriber station; (c) determining whether a user of the subscriber station is a prepaid subscriber; (d) in the case of a prepaid subscriber, requesting a prepaid balance deduction according to the use of the service to a billing server and receiving a response result accordingly; And (e) requesting restoration of the pre-executed service from the pre-executed service to a state before the service is executed if the prepaid balance deduction response result is insufficient of the prepaid balance; How to provide type presence service. A system for providing a presence service to a prepaid subscriber in an IMS network, Subscriber status information management means for storing subscriber status information and buddy list information; Charging processing means for storing and charging the billing information of the subscriber; And After executing the subscriber's service request in advance with the subscriber status information management means, if the subscriber is a prepaid subscriber, the fee for using the service is deducted from the prepaid balance in conjunction with the billing processing means. And a presence service means for requesting, by the subscriber state information management means, to restore the original state from the pre-executed service to the state before the service is executed when the balance is insufficient. The method of claim 6, The subscriber state information management means, A prepaid presence service system, characterized by transmitting a prepaid balance shortage notification message to the subscriber. The method according to claim 6 or 7, The presence service means, And if the prepaid service identifier is included in the service request message received from the subscriber, determining the subscriber as a prepaid subscriber. The method of claim 8, The service request message, A prepaid presence service system, characterized in that any one of a state change request message, a buddy list add request message, other subscriber status information request message.

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