KR101046054B1 - Service switching ping pong prevention device and system in mobile communication system - Google Patents

Abstract

An apparatus, system and method for preventing service switching ping pong in a mobile communication system are provided. An aspect of an ping-pong prevention apparatus for service switching in a mobile communication system of the present invention includes a message receiving unit for receiving a service switching message requesting service switching between a voice mode and a multimedia mode from a first user terminal, and the service switching message. A message transmitter which transmits a service switch rejection message from the second user terminal which has received the message to the first user terminal, and counts the number of service switch denials so that the service switch rejection number is greater than a threshold value from the first user terminal. And a service switcher for blocking a request for service switch of the service.

SCUDIF, service switch, service change, limit

Description

Apparatus and system for preventing ping-pong of service change in mobile communication system

The present invention relates to an apparatus and system for preventing service switching ping-pong in a mobile communication system, and more particularly, to an apparatus and system for reducing loss of network resources due to service switching between voice and multimedia modes in a mobile communication system.

Modern mobile communication systems provide the capability to handle not only voice communications, but also multimedia transmissions such as the transmission of photos, videos, music and the like. Various protocols for integrating multimedia into mobile communication systems are defined in the 3rd Generation Partnership Project (3GPP), which is a joint standardization project of various standardized bodies in Europe, Japan, Korea, the United States, and China. The 3GPP protocol is, for example, a third generation network as configured in accordance with the Universal Wireless Telecommunication Network (UTMS) standard, as well as a second generation wireless communication network as configured according to the Global System for Mobile (GSM) standard. Used in

In previous 3GPP protocols such as 3G.324 of 3GPP R-99, only one of the voice call service and the multimedia call service was available. Therefore, a user who wants to temporarily switch between the voice call service and the multimedia call service needs to end the call and switch the service. To solve this problem, Service Change & Unrestricted Digital Information Fallback (SCUDIF) has been incorporated into 3GPP protocols such as R5 of 3GPP.

SCUDIF not only enables service switching while a call is connected between terminals that support voice call service and multimedia call service, but also supports the case where there is a terminal that supports either voice call service or multimedia call service. To be replaced by a service that

An object of the present invention is to provide an apparatus, a system, and a method for preventing an excessive number of service switching denials in a mobile communication system.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

An aspect of an ping-pong prevention apparatus for service switching in a mobile communication system of the present invention for achieving the above object is to receive a service switching message requesting service switching between a voice mode and a multimedia mode from a first user terminal. A message receiving unit; A message transmitter which transmits a service switch rejection message from a second user terminal receiving the service switch message to the first user terminal; And a service switch processing unit for counting a service switch rejection count to block the request for service switchover from the first user terminal when the service switch rejection count is greater than a threshold.

One aspect of the ping-pong prevention system of service switching in the mobile communication system of the present invention for achieving the above object is a first exchange requesting service switching between the voice mode and multimedia mode from the first user terminal; And a second switch configured to receive a message for receiving service reservation from the first switch, wherein the second changer receives a service switch rejection message from the second user terminal and transmits the message to the first switch. The first exchanger blocks the request for service switchover from the first user terminal by using the service switch rejection count from the second user terminal.

According to an aspect of the present invention, there is provided a method for preventing ping-pong of service switching in a mobile communication system, the method comprising: receiving a service switching message requesting service switching between a voice mode and a multimedia mode from a first user terminal; Receiving a service switch rejection message from a second user terminal receiving the service switch message; And counting a number of service switch denials to block the request for service switch from the first user terminal when the number of service switch denials is greater than a threshold.

According to an embodiment of the present invention, it is possible to prevent ping-pong that repeats service switching in a mobile communication system supporting a SCUDIF call. In addition, the loss of network resources can be reduced by preventing excessive number of service transitions.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Specific details of other embodiments are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a mobile communication system according to an embodiment of the present invention. In this case, the mobile communication system of FIG. 1 may be understood as a Global System for Mobile Communication (GSM) and Universal Mobile Telecommunication System (UMTS) system supporting 3GPP protocol, but is not limited thereto. For example, it can be used not only in UMTS networks but also in IMS networks or other next-generation networks.

1, although there are a number of typical components that make up a mobile communication system in FIG. 1, an originating exchange (O-MSC) and terminating MSC (hereinafter referred to as "O-MSC") for an embodiment of the present invention. A case in which "T-MSC" is illustrated will be described as an example, and a case in which a mobile communication system according to an embodiment of the present invention supports a SCUDIF function or a similar function will be described as an example. .

As shown, the mobile communication system 100 according to an embodiment of the present invention is an originating mobile station (hereinafter referred to as "O-MS") 101, O-MSC 102, T-MSC ( 103) and a terminating mobile station (hereinafter referred to as "T-MS") 104, and the SCUDIF function is O-MS 101, O-MSC 102, T-MSC 103 ) And T-MS 104. The O-MS 101 and the T-MS 104 may be divided into a calling terminal and a called terminal, respectively. In addition, the O-MS 101 and the T-MS 104 may be collectively referred to as user terminals, and one of the O-MS 101 and the T-MS 104 may be referred to as a first user terminal and the other may be referred to as a second user terminal. It may be called a user terminal. The user terminal may include personal digital assistants (PDAs), computers, and the like capable of wireless communication as well as user equipment used for wireless communication. In addition, although not shown in FIG. 1, it is obvious that the mobile communication system 100 of FIG. 1 may include typical components constituting the mobile communication system.

2 is a flowchart illustrating a call processing procedure in the above-described mobile communication system of FIG. 2 illustrates an example of a SCUDIF call processing procedure in a mobile communication system.

As shown, the call processing procedure in the mobile communication system according to an embodiment of the present invention, if the first O-MS 101 wants to use the call service with the T-MS (104), O-MS (101) Transmits a "SETUP" message for setting up the SCUDIF call to the O-MSC 102 (S211). In this case, the "SETUP" message may include information on services supported by the O-MS 101 (eg, multimedia call service or voice call service) and preferred services. For example, as shown in FIG. 2, the "SETUP" message may include information such as a Repeat Indicator (RI), a MultiMedia (MM), and a Speech (SP), indicating that the RI supports the SCUDIF function. A case where the MM indicates a multimedia call service such as a video call and the SP indicates a voice call service will be described. At this time, the preferred service can be known according to the order of services included in the "SETUP" message, in FIG. 2, because the MM is ahead of the SP, the O-MS 101 prefers the MM, and the SP is possible later. It can be understood to represent.

The O-MSC 102 transmits an "IAM (Initial Address Message)" message to the T-MSC 103 based on the "SETUP" message transmitted from the O-MS 101 (S212). In this case, the "IAM" message may include codec information of services supported by the O-MS 101 and a preferred service. In FIG. 2, mm is codec information for a multimedia call service, and AMR (Adaptive Multi Rate) may be understood as codec information for a voice call service. At this time, in the above-described step S211, a message including information about a service is transmitted, and in step S212, a message including information about a codec for a service is transmitted, but this is merely an example for helping understanding of the present invention. It can be understood that both information about the service and codec information for the service are used to indicate the service supported by the O-MS 101.

When the T-MSC 103 transmits an "IAM" message from the O-MSC 102, the T-MSC 103 performs a paging procedure with the T-MS 104 (S213), and sends an "IAM" transmitted from the O-MSC 102. On the basis of the message, the " SETUP " message for setting up the T-MS 104 and the SCUDIF call is transmitted to the T-MS 104 (S214). At this time, the "SETUP" message transmitted from the T-MSC 103 to the T-MS 104 may correspond to the services supported by the O-MS 101 and the preferred service, such as the "SETUP" message of step S211 described above. Information may be included.

The T-MS 104 sends a " CALL CONFIRMED " message containing information on the services supported by the T-MS 104 and the preferred service to the " SETUP " message sent from the T-MSC 103. -Transmit to MSC 103 (S215). In this case, the case where the O-MS 101 and the T-MS 104 support the same services and prefer the same service will be described with reference to FIG. 2. Thus, the T-MS 104 also supports a multimedia call service and a voice call service, and it can be understood that the multimedia call service is preferred.

On the other hand, the service information included in the "CALL CONFIRMED" message of step S215 described above may be understood that the user of the T-MS 104 is set in advance. In other words, the user of the T-MS 104 checks the services supported by the T-MS 104 and sets a preferred service among the supported services in advance. When a call originates, the call can be connected to a preset preferred service.

The T-MSC 103 transmits an "APM (Application transport Message)" message to the O-MSC 102 based on the "CALL CONFIRMED" message transmitted from the T-MS 104 (S216). In this case, since the T-MS 104 also supports a multimedia call service and a voice call service in FIG. 2, and prefers a multimedia call service, mm, which is codec information for the multimedia call service, is selected in the "APM" message. Information may be included.

The O-MSC 102 transmits a "CALL PROCEEDING" message to the O-MS 101 based on the transmitted "APM" message (S217). In this case, the "CALL PROCEEDING" message transmitted to the O-MS 101 may include information on services supported by the T-MS 104 and preferred services. In FIG. 2, the O-MS 101 is described. ) And the T-MS 104 support the same services and prefer the same service (Normal Case), for example, but the service information included in the "CALL PROCEEDING" message supports the same services, but different. A service may be preferred (Reverse Case) or only one of a plurality of services may be supported (Fallback Case). In this case, the fallback case is a case in which the T-MS 104 does not support a specific service among the call services supported by the O-MS 101 or a specific service among the call services supported by the O-MS according to the subscriber setting or network environment. This can happen if it does not support. On the other hand, when the O-MS 101 and the T-MS 104 prefer different call services, call service switching is performed through a service switching process to be described later. Meanwhile, when the O-MS 101 and the T-MS 104 support the same services but switch to another service, the O-MS 101 and the T-MS 104 switch through the service switching process to be described later.

After receiving the "CALL PROCEEDING" message, the O-MS 101 performs a radio resource allocation procedure for service connection between the O-MS 101 and the T-MS 104 (S218), and the O-MSC ( 102 transmits a " COT (Continuity Message) " message indicating the radio resource allocation to the T-MSC 103 (S219).

The T-MSC 103 performs a radio resource allocation procedure with the T-MS 104 (S220), and the T-MS 104 transmits an "ALERTING" message indicating the radio resource allocation to the T-MSC 103. In operation S221, the T-MSC 103 transmits an "ACM (Address Complete Message)" message to the O-MSC 102 in response to the "COT" message of step S219 described above (S222). The MSC 102 transmits an "ALERTING" message to the O-MS 101 (S223). At this time, after the "ALERTING" message is transmitted in step S221 described above, the T-MS 104 rings.

When the user of the T-MS 104 presses a call button or the like, a "CONNECT" message is transmitted to the T-MSC 103 (S224), and the T-MSC 103 sends an "Answer Messgae" message. After transmitting to the O-MSC 102 (S225), the O-MSC 102 transmits a "CONNECT" message to the O-MS 101 (S226) until the O-MS 101 and the T-MS 104 are transmitted. ) Service is connected and the call is available.

Therefore, when a call path is connected between the O-MS 101 and the T-MS 104, the multimedia call service may proceed, and a service change may be possible (S250). Accordingly, the users of the O-MS 101 and the T-MS 104 make a multimedia call along the set multimedia call path, and can change the service to the voice call at any time.

3 is a flowchart of a service change procedure in the mobile communication system of FIG. 1.

Referring to FIG. 3, an example of a service switching to a voice call service while a multimedia call service is in progress between the O-MS 101 and the T-MS 104 is described. On the other hand, it is also possible to switch the service to the multimedia call service while the voice call service is in progress.

First, a multimedia call path is formed between the O-MS 101 and the T-MS 104 (S250). If the user wants to switch to the voice call service while using the multimedia call service while the multimedia call path is formed, the user of the O-MS 101 requests to switch to the voice call service. At this time, the O-MS 101 transmits a "MODIFY" message to the O-MSC 102 (S310), and allocates a radio resource corresponding to service switching (S312). The O-MSC 102 receiving the " MODIFY " message transmits an " APM " message containing information indicating that the O-MS 101 wants to use the voice call service and that the multimedia call service is available later. 103) (S320). The T-MSC 103 transmits a "MODIFY" message to the T-MS 104 based on the transmitted "APM" message (S330). If the T-MS 104 accepts the switch to the multimedia call service, the T-MS 104 transmits a "MODIFY COMPLETE" message to the T-MSC 103 based on the transmitted "MODIFY" message (S355). ). The T-MS 104 allocates radio resources for the voice call service with the T-MSC 103 (S337). When the radio resource for the voice call service is allocated, the T-MSC 103 transmits an "APM" message informing of this to the O-MSC 102 (S340). The O-MSC 102 receives the "APM" message and transmits a "MODIFY COMPLETE" message to the O-MS 10 indicating the completion of service switching (S345).

Therefore, when service switching is completed, a voice call path is formed between the O-MS 101 and the T-MS 104 to perform a voice call service (S350). In addition, the O-MS 101 and the T-MS 104 may be capable of switching to a multimedia call service.

As described above, when there is a service switching request from one of the O-MS 101 and the T-MS 104 in the state where a predetermined call service is being provided, the service switching may be performed by radio resource allocation. However, when the counterpart continuously rejects the service switching request or frequently requests the service switching, the network resource for the service switching may be continuously consumed without establishing a substantial call. For example, if the O-MS 101 continuously requests to switch from the voice call service to the multimedia call service, and the T-MS 104 continuously rejects the service switch request, FIG. The loss of network resources such as In other words, if one of the O-MS 101 and the T-MS 104 continues to request the service switch and the other continues to reject it, a ping-pong phenomenon of the service switch may occur.

4 is a flowchart illustrating a service switching ping pong prevention method in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, for example, ping-pong prevention of service switching to a voice call service while a multimedia call service is in progress between the O-MS 101 and the T-MS 104 will be described. . Meanwhile, in one embodiment of the present invention, a voice call service may be referred to as a "voice mode" and a multimedia call service may be referred to as a "multimedia mode". Accordingly, the "voice mode" refers to a mode in which a voice call service is provided, and the "multimedia mode" refers to a mode in which a multimedia call service is provided. Service switching refers to switching between "voice mode" and "multimedia mode".

First, a multimedia call path is formed between the O-MS 101 and the T-MS 104 and is in a multimedia mode state between the O-MS 101 and the T-MS 104 (S250). In the state in which the call path is formed, the O-MSC 102 specifies the ping-pong count k as '0' in advance and initializes the switching flag f as 'false' (S405). . Here, the ping-pong count indicates the number of times that the service switching request is requested, and the switching flag f indicates whether the service switching request is blocked.

For example, the user of the O-MS 101 may request a service switch from the multimedia mode state to the voice mode. At this time, the O-MS 101 transmits a "MODIFY" message to the O-MSC 102 (S410). The O-MSC 102 may receive the "MODIFY" message, disconnect the call path between the O-MS 101 and the O-MSC 102, and reserve a call path for the switching service (S412).

The O-MSC 102 determines whether the number of service switching is equal to or greater than the threshold value N. Here, the threshold value N is a predetermined value set by the operator of the system or the communication network and refers to the maximum number of times that the loss of network resources can be tolerated. Thus, the O-MSC 102 may automatically block subsequent service switch requests if the requested service switch count from the O-MS 101 is greater than or equal to the threshold value N.

If the number of service transitions is less than the threshold, the O-MSC 102 requests the O-MS 101 to switch to the voice mode and later sends an "APM" message containing information that the multimedia mode is available. Transmit to step 103 (S420). The O-MSC 102 and the T-MSC 103 reserve a bearer modification for service switching to the voice mode to be changed (S424).

The T-MSC 103 transmits a "MODIFY" message to the T-MS 104 based on the transmitted "APM" message (S430).

The T-MS 104 may receive an input using a predetermined UI from the user whether to accept the service switch to the voice mode, or may automatically determine whether to accept the service as previously set (S435). When the T-MS 104 accepts the service switch to the voice mode, the service switch to the voice mode may be performed as shown in FIG. 3.

If the T-MS 104 receives an input that does not accept the service switch to the voice mode, the T-MS 104 transmits a "MODIFY REJECT" message to the T-MSC 103 (S437).

The T-MSC 103 receives the "MODIFY REJECT" message and transmits a "Codec modification failure" message to the O-MSC 102 indicating that no service switchover has been made (S440). At the same time, the T-MSC 103 modifies the bearer for restoring the changes to the call between the O-MSCs 102 (S445). At the same time, the O-MSC 102 increases the ping-pong count k by one (S447).

After receiving the "Codec modification failure" message, the O-MSC 102 transmits the "MODIFY REJECT" message to the O-MS 101 after restoring the changes to the call (S450) and the O-MSC 102 ) And the change is restored to the original between the call and the O-MS 101 (S451).

As described above, when the T-MS 104 rejects the service switch request from the O-MS 101, it may return to the original mode (S460). For example, when the original mode is the multimedia mode, when the T-MS 104 rejects the service switch request, the T-MS 104 may restore the original call and return to the original multimedia mode.

Thereafter, when there is a service switch request from the O-MS 101 again, the O-MSC 102 determines whether the ping-pong count k is greater than or equal to the threshold value N for the service switch request from the O-MS 101. If it is determined whether or not the threshold value is equal to or greater than N, a " MODIFY REJECT " message for automatically rejecting service switching is transmitted to the O-MS 101 (S413 and S415). The O-MSC 102 returns the call path between the O-MS 101 to its original state (S419).

On the other hand, when there is a service switch request from the O-MS 101 and the ping-pong count k is less than the threshold value N, the T-MS 104 rejects the service switch request from the O-MS 101. In this case, the above-described steps may be repeated. Accordingly, the O-MSC 102 continuously increases the ping pong count k by 1 due to the T-MS 104's refusal of service switching. If the value of the ping-pong count k is greater than or equal to the threshold value N, the O-MSC 102 automatically sends a " MODIFY REJECT " message to the service switching request from the O-MS 101. 101). The O-MSC 102 returns the call path between the O-MS 101 to its original state (S419).

In an embodiment of the present invention, the O-MSC 102 may convert the conversion flag f to a "true" value when the ping-pong count k is greater than or equal to the threshold value N. With the switch flag f converted to the value "true", when there is a service switch request from the O-MS 101 later, the O-MSC 102 makes a service switch to the O-MS 101. By sending the rejecting "MODIFY REJECT" message immediately, the progress of the service switch request phase can be blocked, thereby further reducing network resource loss.

In addition, the O-MSC 102 may block the service switch request from the O-MS 101 and transmit a message to the O-MS 101 indicating that the possible number of service switches has been exceeded. Thus, the user of the O-MS 101 can recognize that service switching is not possible in the current state.

On the other hand, when the T-MS 104 accepts the service switch to the voice mode, the T-MS 104 sends a "MODIFY COMPLETE" message to the T-MSC 103 based on the transmitted "MODIFY" message. Transmit (S475). The T-MS 104 allocates radio resources for the voice call service with the T-MSC 103 (S477). When the radio resource for the voice call service is allocated, the T-MSC 103 transmits an "APM" message informing of this to the O-MSC 102 (S480). The O-MSC 102 receives the "APM" message and transmits a "MODIFY COMPLETE" message to the O-MS 10 indicating the completion of service switching (S490). When service switching is completed, a switched call path is formed between the O-MS 101 and the T-MS 104 (S500), for example, when the original mode is the multimedia mode, the T-MS 104. Accepts the service switch request, it may be switched to the voice mode.

As such, on the other hand, if the service change is successfully made when the value of the ping pong counter k is less than the threshold value N, the ping pong count k is initialized to 0 and at the same time the change flag is set to 'false'. It may be set (S485). After the specified time t has passed, the ping pong count k may be initialized to zero, or if k is greater than zero, the value of k may be reduced (for example, k = k−1).

As described above, according to the exemplary embodiment of the present invention, the service switching ping pong phenomenon caused by the T-MS 104 continuously sending a rejection response to the service switching request from the O-MS 101 can be prevented. have. On the other hand, the service switching in one embodiment of the present invention can be requested by any one of the O-MS 101 and T-MS (104), the receiving party can reject. Thus, if either one of the O-MS 101 and the T-MS 104 repeats the denial of service transition above the threshold, the ping-pong counts at one of the O-MSC 102 and the T-MSC 103 ( k) can be used to prevent the ping-pong phenomenon of service switching. In this way, if the number of service switching is limited above the threshold, the service switching is immediately interrupted by one of the O-MSC 102 and the T-MSC 103 to prevent loss of network resources due to excessive ping-pong phenomenon. It can prevent.

5 is a block diagram of an apparatus for preventing service switching ping pong in a mobile communication system according to an exemplary embodiment of the present invention. Referring to FIG. 5, the apparatus 500 for switching service ping pong in a mobile communication system according to an embodiment of the present invention may include a message receiver 510, a message transmitter 520, and a service switch processor 530. have. Although the service switching ping pong prevention apparatus 500 in FIG. 5 will be described in the case of being included in the O-MSC 102 by way of example, it may be configured separately.

The message receiving unit 510 receives a "MODIFY" message requesting service switching from the O-MS 101 and receives an "APM" message from the T-MSC 103. The message receiving unit 510 may receive a call service type to be used in the future by the service switching from the O-MS 101, and may receive a response to the call service switching request from the T-MSC 103.

The message transmitter 520 transmits a message to the O-MS 101 or the T-MSC 103. The message transmitter 520 may transmit an “APM” message for service switching to the T-MSC 103 based on the message received from the O-MS 101. The message transmitter 520 may transmit the success or failure of the service switch request to the O-MS 101 based on the response of the call service switch request from the T-MSC 103, and the service switch. When the number of rejections is greater than or equal to the threshold, the failure message MODIFY REJECT for the call service switch request may be transmitted to the O-MS 101. On the other hand, when the number of service switch denials is less than the threshold, the message transmitter 520 requests the service switch to the T-MS 104 through the T-MSC 103 for the request for service switch from the O-MS 101. You can send a message. The service switch processing unit 530 serves to process a service switch request from the O-MS 101. The service switch processing unit 530 may reserve radio resource modification or radio resource between the O-MSs 101, and may reserve a bearer modification for service switch between the T-MSCs 103.

The service switch processing unit 530 counts the number of service switch rejections of the T-MS 104 in response to the service switch request from the O-MS 101 and stores the number of service switch rejections as the ping-pong count k. The service switch processing unit 530 may immediately block the service switch request from the O-MS 101 when the number of ping-pong counts k is greater than or equal to the threshold. The service switch processing unit 530 may transmit the "MODIFY REJECT" to the O-MS 101 through the message transmitter 520, and may prevent the ping-pong phenomenon of the service switch by performing no further steps for the service switch. have. Therefore, it is possible to reduce the loss of network resources due to excessive service switching. The service switching processor 530 initializes the ping-pong count (k) to 0 and sets the switching flag to 'false' when the SCUDIF call is connected for the first time, or when the switched call path is established due to the successful service change. Can be set. After the specified time t has passed, the ping pong count k may be initialized to zero, or if k is greater than zero, the value of k may be reduced (for example, k = k-1).

In an embodiment of the present invention, the service switch request from the O-MS 101 is described as a reference, but it is obvious that the same applies to the service switch request from the T-MS 104. In the case of the service switching request from the T-MS 104, the ping-pong count k is calculated by the T-MSC 103, and the service switching request from the T-MS 104 immediately if the ping-pong count is greater than or equal to the threshold. Can be blocked.

On the other hand, the components or '~' used in this embodiment is software such as tasks, classes, subroutines, processes, objects, execution threads, programs, or FPGAs (field-) that are performed in a predetermined area on the memory. It may be implemented in hardware such as a programmable gate array or an application-specific integrated circuit (ASIC), or may be a combination of the software and hardware. The component or 'unit' may be included in a computer readable storage medium, or a part of the components may be distributed and distributed to a plurality of computers.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains have various permutations, modifications, and modifications without departing from the spirit or essential features of the present invention. It is to be understood that modifications may be made and other embodiments may be embodied. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a block diagram illustrating a mobile communication system according to an embodiment of the present invention.

2 is a flowchart illustrating a call processing procedure in the above-described mobile communication system of FIG.

3 is a flowchart of a service change procedure in the mobile communication system of FIG. 1.

4 is a flowchart illustrating a service switching ping pong prevention method in a mobile communication system according to an exemplary embodiment of the present invention.

5 is a block diagram of an apparatus for preventing service switching ping pong in a mobile communication system according to an exemplary embodiment of the present invention.

Description of the main parts of the drawing

102: outgoing exchange

103: incoming exchange

510: message receiving unit

520: message transmission unit

530: service switching processing unit

Claims (13)

A message receiver configured to receive a service switch message requesting service switch between a voice mode and a multimedia mode from a first user terminal; A message transmitter which transmits a service switch rejection message from a second user terminal receiving the service switch message to the first user terminal; And And a service switching processing unit for counting a number of service switching denials to block the request for service switching from the first user terminal when the number of service switching denials is greater than a threshold. . The method of claim 1, wherein the service switching processing unit Service switching ping pong in the mobile communication system, when the service switch rejection count is greater than or equal to a threshold, intercepting the request for service switch to send a message switch rejection message of "MODIFY REJECT" to the first user terminal. Prevention device. The method of claim 1, wherein the message transmission unit An apparatus for switching service ping-pong in a mobile communication system, when a service switching rejection number is less than a threshold, transmitting a service switching request message to the second user terminal in response to the request for service switching from the first user terminal. . The method of claim 1, And the second user terminal receives the service switch request message transmitted from the message transmitter, determines whether to accept the service switch, and transmits the service switch to the message receiver. The method of claim 1, wherein the service switching processing unit And counting the number of times of the service change denial and storing the ping-pong flag and comparing the value of the ping-pong flag with the threshold value to determine whether to block the service switch or not. The method of claim 5, wherein the service switching processing unit And change the value of the switch flag to 'true' when the value of the ping pong flag is equal to or greater than the threshold value, thereby blocking the request for the service switch from the first user terminal. The method of claim 1, wherein the message transmission unit, In response to the service switching processor blocking the service switching request of the first user terminal, the service switching ping-pong in the mobile communication system transmits a message indicating that the number of service switching requests has been exceeded. Prevention device. The method of claim 1, wherein the service switching processing unit When receiving the message for allowing the service switch from the second user terminal in the range that the number of service change rejection is less than the threshold value, reset the service change rejection count to '0' and set the value of the ping-pong flag to 'false'. Service switching ping pong preventing device in a mobile communication system. A first exchanger requesting to switch a service between a voice mode and a multimedia mode from the first user terminal; And A second exchange receiving a message for receiving the service changeover from the first exchange, The second exchange receives a service switch rejection message from a second user terminal and delivers it to the first exchange, And the first switch blocks the request for service switchover from the first user terminal using the number of service switch denials from the second user terminal. 10. The apparatus of claim 9, wherein the first exchanger is After the change flag is changed to "true" when the number of times of the service change rejection from the second user terminal is equal to or greater than a threshold, the first user terminal is sent to the first user terminal when there is a request for the service switch from the first user terminal. And a service switchover ping pong prevention system for transmitting the service switch rejection message. delete delete delete

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