KR101606213B1 - Method for preventing undesired call forwarding if out of reach and providing an immediate ring-back tone in mVoIP network - Google Patents

Abstract

The present invention relates to a method for preventing an unnecessary shadow call forwarding in a mVoIP network and a method for providing a fast ring back tone in the mVoIP network. In providing an mVoIP service in a portable Internet network, the present invention determines a current state of a called terminal subscribed to a shadow- (Ring back tone or coloring) without delay to the calling terminal when the called terminal is currently in an idle state or in an awake state or the like, And to provide a method for preventing unnecessary shadow call forwarding and providing quick ring back tone in an mVoIP network.
To this end, according to the present invention, there is provided a method for preventing shadow call forwarding, comprising: a status checking step of, when a call control server receives a call connection request message, acquiring a current status of a called terminal and confirming whether or not the call is available; Performing, as a result of the checking of the status checking step, a 'shadow call forwarding service', which is a service of 'forwarding to another telephone number set by a subscriber in advance, if the current state of the called terminal is unreachable; If it is determined that the current state of the called terminal is an incoming call, the call control server transmits a first callable message to the calling terminal in response to the call connection request message on behalf of the called terminal So that a ring back tone is provided; And requesting connection of the incoming call after the call control server prevents shadowing of the incoming call.

Description

[0001] The present invention relates to a mVoIP network, and more particularly, to a mVoIP network, which avoids unnecessary shadow call forwarding and provides a quick ring back tone,

The present invention relates to a method for preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network. More particularly, the present invention relates to a mVoIP service for providing a mVoIP service in a wireless network, It is possible to prevent the call from being shadowed when the called terminal is able to receive an incoming call, such as an idle state, and additionally, to the calling terminal without receiving a normal ringback tone Coloring) in a mVoIP network, and to a method for providing fast ring back tones.

The mVoIP terminal according to an exemplary embodiment of the present invention may be a mVoIP terminal capable of accessing a portable Internet network or a WiMAX network as well as a mobile Internet network or a WiMAX network, Mode mVoIP terminal or tri-mode mVoIP terminal that can be connected to a base station (e.g., CDMA or W-CDMA or a next-generation wireless communication network).

In an embodiment of the present invention, when an mVoIP destination terminal can not receive an incoming call, the call is forwarded to another telephone number (a telephone number of another call access network of the same terminal or a telephone number of another terminal) set by a subscriber in advance Will be referred to as "shadow call forwarding service ".

In the existing technology, when the mVoIP terminal normally registered in the CSCF (Call Session Control Function) moves to the shadow area, when there is an incoming request to the mVoIP terminal, the CSCF sends a call connection request message (INVITE message) to the mVoIP terminal send.

However, since the mVoIP terminating terminal is located in the shadow area, the mVoIP terminating terminal fails to receive the call connection request (INVITE) message, and accordingly, the CSCF determines that there is no response from the corresponding mVoIP terminating terminal And releases the call request.

Accordingly, even if the call forwarding service is registered in advance with respect to the mVoIP terminal, the call forwarding service is not activated and the call forwarding for the call forwarding request is not performed. This phenomenon occurs when the conventional conditional call forwarding service does not receive a response from the user of the called terminal (i.e., a "No Answer" situation in which there is a signal but does not receive a call) When there is no response signal from the terminal, it is judged as an error and the call is released.

In order to solve this problem, in the conventional shadow call forwarding service, an IP Multimedia Subsystem (IMS) server (referred to as an application server in the embodiment as a call control server) or a WiMAX VoIP Service (WVS server) If there is no response from the called terminal with respect to the call request message (INVITE) transmitted to the called terminal in the area (or the modem is turned off), the other telephone number (the other telephone access network telephone number of the same terminal Or the telephone number of the other terminal).

That is, in the prior art, when the mVoIP terminating terminal is located in the shadow area, the portable Internet modem is idle, the mVoIP terminating terminal is powered off, or the call connection request message is delayed, When the mVoIP receiving terminal can not receive the call within a predetermined time period, the shadow call forwarding service is driven and the other phone number (the telephone number of another call access network of the same terminal or the other terminal Telephone number) and forwarded the call to connect the call.

However, in a wireless network, even if the called terminal is within the coverage of the wireless communication network, the terminal is in an idle state when it does not communicate for a certain period of time. In this case, the called terminal awakes in an awake state through a paging process There is a considerable time delay after sending a response to the call connection request. In this case, the following two problems arise.

The first problem is that the IMS server (application server) or the WVS server (call control server) proceeds to the shadow call forwarding processing if the called terminal does not respond within the response waiting time set by the shadow call forwarding service, An unwanted call forwarding occurs for the called terminal. In particular, as the paging cycle becomes longer, the time delay increases and the frequency of occurrence of the first problem increases. For reference, the wait time for shadow call forwarding in the portable Internet network developed by "KT Co., Ltd." is 5 seconds, and the paging cycle of the portable Internet network is about 5.2 seconds.

The second problem is that the caller does not hear ring back tones, such as ring back tone or coloring, for a period of time during which the response to the call connection request is delayed. This may cause the caller to misunderstand the device and terminate the call connection request.

As described above, in the above-mentioned related art, when a receiving terminal subscribed to a shadow call forwarding service is available in an mVoIP network but the response to a call connection request is delayed due to an idle state at present, (Ringback tone or coloring) during the time delayed in response to the call connection request, and the call connection request is terminated. At least one of the problems It is an object of the present invention to solve one problem.

Accordingly, the present invention provides an mVoIP service in a portable Internet network, in which the mVoIP network determines the current state of a called terminal subscribed to a shadow call forwarding service, and when the called terminal is in an idle state, And an object of the present invention is to provide a method for preventing shadow call forwarding in an mVoIP network.

In addition, the present invention provides a mVoIP service in a portable Internet network, wherein the mVoIP network determines a current state of a called terminal subscribed to a shadow call forwarding service in a mVoIP network, and when the called terminal is in an idle state, Another object of the present invention is to provide a method of preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network in order to prevent calls from being shadowed and to provide a normal ringback tone (ringback tone or coloring) without delay to the calling terminal .

In addition, the present invention provides an mVoIP service in a portable Internet network, wherein the mVoIP network determines a current state of a called terminal subscribed to a shadow call forwarding service, and when the called terminal is in an idle state, Another object is to provide a method for providing a fast ring back tone in an mVoIP network to provide a normal ring back tone (ring back tone or coloring) without delay to the terminal.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to another aspect of the present invention, there is provided a method of preventing shadow call forwarding, the method comprising: receiving a call connection request message from a call control server; receiving a current status of a called terminal, ; Performing, as a result of the checking of the status checking step, a 'shadow call forwarding service', which is a service of 'forwarding to another telephone number set by a subscriber in advance, if the current state of the called terminal is unreachable; If it is determined that the current state of the called terminal is an incoming call, the call control server transmits a first callable message to the calling terminal in response to the call connection request message on behalf of the called terminal So that a ring back tone is provided; And requesting connection of the incoming call after the call control server prevents shadowing of the incoming call.

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According to another aspect of the present invention, the call control server further includes discarding a second callable message received from the called terminal through the called CSCF.

According to another aspect of the present invention, there is provided a method for providing a ring back tone, the method comprising the steps of: when a call control server receives a call connection request message, acquiring a current state of the called terminal, A status checking step; Performing, as a result of the checking of the status checking step, a 'shadow call forwarding service', which is a service of 'forwarding to another telephone number set by a subscriber in advance, if the current state of the called terminal is unreachable; And if it is determined that the current state of the called terminal is a callable state, the call control server sends a first callable message to a calling terminal in response to the call connection request message on behalf of the called terminal So that a ring back tone is provided.

According to still another aspect of the present invention, the call control server further includes discarding a second callable message received from the called terminal through the called CSCF.

According to another aspect of the present invention, there is provided a method of preventing shadow call forwarding, the method comprising: a status checking step of, when a call control server receives a call connection request message, acquiring and checking a current status of a called terminal; Processing the incoming call if the current state of the called terminal is ACTIVE as a result of the checking of the state; If it is determined that the current state of the called terminal is not in service (NOT-IN-SERVICE) as a result of the checking of the status, it is determined that the incoming call is terminated or " a service for switching to another telephone number Performing a call forwarding service; And if the current state of the called terminal is an IDLE state or an IN-SERVICE state as a result of the state checking step, the call control server adjusts a call connection request transaction timeout so that the incoming call is shaded And processing the incoming call after preventing the call forwarding.

According to another aspect of the present invention, there is provided a method for controlling a call control server, the method comprising the steps of: if the current state of the called terminal is an idle state, And transmitting the first callable message to the calling terminal in response to the call connection request message so that a ring back tone is provided.

According to another aspect of the present invention, there is provided a method of controlling a call control server, the method comprising: discarding a second callable message received from the called terminal by the call control server.

According to still another aspect of the present invention, there is provided a method for controlling a call control server, the method comprising the steps of: if the current state of the called terminal is in an IN-SERVICE state, And transmitting the first callable message to the calling terminal in response to the call connection request message so that a ring back tone is provided.

According to another aspect of the present invention, there is provided a method for providing a ring back tone, the method comprising: a status checking step of, when a call control server receives a call connection request message, acquiring and confirming a current status of the called terminal; Processing the incoming call if the current state of the called terminal is ACTIVE as a result of the checking of the state; If it is determined that the current state of the called terminal is not in service (NOT-IN-SERVICE) as a result of the checking of the status, it is determined that the incoming call is terminated or " a service for switching to another telephone number Performing a call forwarding service; And if the current state of the called terminal is an idle state as a result of the checking of the state, the call control server sends a first callable message in response to the call connection request message on behalf of the called terminal And transmitting the ring back tone to the terminal.

According to still another aspect of the present invention, the call control server further includes discarding a second callable message received from the called terminal.

According to still another aspect of the present invention, there is provided a method for controlling a call in which a call control server transmits an incoming call to an incoming call, And transmitting the first callable message to the calling terminal in response to the call connection request message on behalf of the terminal so that a ring back tone is provided.

As described above, according to the present invention, in a mVoIP network, when a called terminal that is subscribed to a shadow call forwarding service is in a callable state but the response to a call connection request is delayed due to an idle state at present, The present state of the called terminal is judged to prevent the incoming call connection request from being subjected to the shadow call forwarding processing and additionally provides a normal ringback tone (ringback tone or coloring) to the calling terminal without delay.

According to the present invention as described above, in providing mVoIP service in a wireless network, when a current state of a called terminal subscribed to a shadow call forwarding service is determined in an mVoIP network and the called terminal can receive an incoming call such as an idle state It is possible to prevent the call from being forwarded to the shadow.

That is, in providing mVoIP service in a wireless network, the mVoIP network does not misidentify that the called terminal that subscribes to the shadow call forwarding service is out of coverage of the wireless communication network (in the shadow area) Can be provided.

In addition, the present invention provides mVoIP service in a wireless network, wherein the mVoIP network determines the current state of a called terminal subscribed to a shadow call forwarding service, and when the called terminal is in an idle state, Can provide a normal ringback tone (ringback tone or coloring) without delay.

That is, the present invention enables a caller to listen to a ring back tone (ring back tone or coloring) without delay even when the called terminal joining the shadow call forwarding service in the mVoIP network is currently in an idle state, Allows you to wait with confidence without ending the request.

Accordingly, the present invention can improve the call success rate, thereby improving the convenience of the subscriber and increasing the mVoIP call income of the communication service provider.

In addition, when the called terminal is not registered in the shadow call forwarding service, the incoming WVS server immediately sends an error message to the originating network without waiting for a SIP INVITE transaction timeout, The call can be terminated.

1 is an example of an IMS-based mVoIP network to which the present invention is applied,
2 is a flowchart showing an example of a signal processing procedure in a case where a called terminal registered in a shadow call forwarding service normally responds to an incoming call;
FIG. 3 is a flowchart showing an embodiment of a signal processing procedure in a case where a called terminal registered in a shadow call forwarding service is a non-response to an incoming call;
4 is a flowchart showing an example of a signal processing procedure in a case where a called terminal registered in a shadow call forwarding service is in a deregistered state or a call is temporarily impossible;
FIG. 5 is a flowchart illustrating an exemplary signal processing procedure in a case where a called terminal registered in a shadow call forwarding service according to the present invention is in an idle state at present;
FIG. 6 is a flowchart illustrating a method for preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network according to the present invention.
FIG. 7 is a flowchart of another embodiment showing a call connection procedure to a called terminal disconnected from a network;
FIG. 8 is a flowchart showing another embodiment of a call connection processing procedure in a called network when a called terminal subscribed to a shadow call forwarding service is in an idle mode;
9 is a flowchart illustrating a call connection procedure in a case where a called terminal according to the present invention is not in service in an mVoIP network;
FIG. 10 is a flowchart showing another embodiment of a call connection processing procedure in a case where a called terminal according to the present invention is in an idle mode;
11 is a flowchart illustrating another embodiment of a method for preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It can be easily carried out. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

And throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between. Also, when a component is referred to as " comprising "or" comprising ", it does not exclude other components unless specifically stated to the contrary .

1 is an example of an IMS-based mVoIP network to which the present invention is applied.

As shown in FIG. 1, the IMS-based mVoIP network to which the present invention is applied is composed of a WiBro network and an IMS network. The IMS-based mVoIP network connects an IMS network with a portable Internet network, A VoIP-based call service (e.g., voice call service, video call service) can be provided to the terminal.

At this time, the portable Internet network includes an AAA (Authentication, Authentication, Authorization, and so on) for performing an mVoIP terminal, a Radio Access Station (RAS), an Access Control Router (ACR) (I-CSCF), and an S-CSCF (Serving-CSCF). The IMS network includes a Proxy-Call Session Control Function (P-CSCF), an Interrogating- A Policy and Charging Rule Function (PCRF), a QoS Manager (QM), an Application Server (AS) for providing IMS application services, and a Media Gateway Control Function (MGCF).

And an MGW for interworking with the IMS network and other networks (mobile communication network, wired telephone network). Although not shown in the figure, the IMS network includes an HSS (Home Subscriber Server) for voice service authentication, HDS (Home Digital Service), and the like.

And an MSC, a BSC, a BTS, a mobile communication terminal and the like on a mobile communication network (WCDMA, CDMA, GSM) interworking with an IMS network, and includes an exchange, a wired telephone and the like on a wired telephone network (PSTN).

Next, each of the above components will be described in more detail as follows.

The Call Session Control Function (CSCF) is a system that handles the part related to call processing among the functions of the IMS. The Call Control Function (CSCF) includes a call control function ).

Here, ICGW (Incoming Call GateWay) acts as the first entry point and performs routing for the incoming call. ICGW also performs service triggering on input calls such as call screening and forwarding, queries for address handling (AH), and communicates with the HSS (Home Subscriber Server).

The Call Control Function (CCF) is responsible for call setup and termination, state / event management, interactions with MRF (Multimedia Resource Function) for multi-party services, call event reporting for billing, reception and processing of application level registration .

The SPD (Serving Profile Database) communicates with the HSS of the home domain to manage the user profile information, and performs a function similar to the Visitor Location Register (VLR) of the existing network for notifying the home domain at the first access of the user.

Address handling (AH) performs address translation, translation, and modification, and provides address mobility.

CSCF (Proxy-CSCF), I-CSCF (Interrogating CSCF), and S-CSCF are based on the location and role of CSCF (Call Session Control Function) CSCF (Serving CSCF). For example, the function of guaranteeing quality of service (QoS) in conjunction with PCRF is performed in the P-CSCF.

Policy and Charging Rule Function (PCRF) is a service-based quality of service (QoS) policy setting function and flow-based charging management function. Collects service basic information, verifies the authorization of the service according to the policy decision of the network operator, and transmits a quality assurance (QoS) policy and a billing policy for network bandwidth allocation to the network access system.

Meanwhile, an access control router (ACR) is a component that controls an mVoIP terminal and a base station (RAS) in a portable Internet network and routes IP packets.

From the viewpoint of data traffic, the base station controller (ACR) can be regarded as a router (access control router), and a plurality of base stations (RAS) are managed thereunder.

The base station controller (ACR) processes radio interface control signals and bearer service traffic between a base station (RAS) and a core network (Core Network).

In addition, the base station controller (ACR) includes an interworking function with a base station (RAS), a call connection setting function, a location management (mobility management) function of a wireless terminal (mVoIP terminal), an authentication and security function, Information generation and notification functions, and IP QoS management functions.

Meanwhile, a base station (RAS: Radio Access Station) refers to a component of a portable Internet network that terminates a wired network and performs transmission / reception with a wireless terminal (mVoIP terminal) through a wireless interface.

The Serving RAS is a base station to which a mobile terminal currently receives service, and is a base station that has recently registered a mobile terminal (mVoIP terminal). The target RAS is a target base station to which a mobile terminal (mVoIP terminal) handover is a base station to which a mobile terminal (mVoIP terminal) registers in the last process of handover. The neighbor RAS refers to a base station adjacent to the serving base station. In addition, there are a detected RAS, a selected RAS, and the like.

In addition, the base station RAS has functions of transmitting and receiving a radio signal, a modulation and demodulation signal processing function, a packet retransmission function, a packet scheduling function, a radio bandwidth allocation function, a ranging function, a connection control function such as setting / Over control function.

The main requirements of the base station (RAS) are frequency efficiency, transmission speed in terms of service, QoS parameters (jitter, delay time, packet loss rate, transmission rate, etc.), and handover.

Meanwhile, a media gateway (MGW) refers to a device that performs processing and conversion of media between a circuit switching network and a packet switching network. That is, the media gateway MGW converts a voice signal in the form of a packet (IP packet or the like) created in the Internet into a PCM or the like used in a public telephone network (wired telephone network) or vice versa.

In addition, the media gateway (MGW) has a function of compressing a voice for packetizing a voice signal or vice versa, a function of echo cancellation of voice generated by delay, a function of receiving a digit and transmitting a fax , And the function of converting TDM-based traffic to IP or ATM packet.

The media gateway is interlocked with the soft switch and control protocol for call control between the media gateways.

The access media gateway supports access to a packet-switched network such as VoIP in a private exchange network. The trunk media gateway connects the circuit-switched network and the packet-switched network. The Residential Media Gateway also allows access to the packet network through the analogue line in the home.

Meanwhile, MGCF (Media Gateway Control Function) is a network element that controls several media gateways so that intelligent call control can be performed.

In order to implement this, the call processing with the existing circuit network is connected with the MGCF through the SGW (Signaling Gateway) to perform the call processing control function, and the MGCF translates the call number to control the media gateway (MGW) And allocates an IP address / UDP port (User Datagram Protocol Port) to be connected between the media gateways, and manages corresponding resources such as a compression function necessary for forming an IP packet between ends, thereby interconnecting the voice traffic delivered to the media gateway.

The MGCF is also called the Softswitch or Call Agent, which separates the signal network and the transport network by the No.7 structure like the existing PSTN / N-ISDN on the Internet.

2 is a flowchart showing an example of a signal processing procedure in a case where a called terminal registered in a shadow call forwarding service normally responds to an incoming call.

First, the calling terminal A sends a call connection request (INVITE B) message to connect to the calling terminal B (terminal registered in the shadow forwarding service) to the calling CSCF (201), and in response thereto, 100 Trying < / RTI > message is received (202).

In the calling CSCF, the called terminal B acquires the received incoming CSCF and delivers a call connection request (INVITE B) message to the incoming calling CSCF (203), and receives a 100 Trying message from the incoming CSCF in response thereto (204).

Then, the called CSCF confirms that the called terminal B is a subscriber registered in the shadow call forwarding service, and transmits a call connection request (INVITE B) message to the application server (AS: Application Server, call control server for controlling the shadow call forwarding call) (205), and receives a 100 Trying message (206) from the application server (AS) in response thereto.

Then, the application server AS drives a shadow call forwarding timer and transmits a call connection request (INVITE B) message to the incoming CSCF (207), and receives a 100 Trying message from the incoming CSCF in response thereto (208).

Then, the called CSCF transfers the INVITE B message received from the application server AS to the called terminal B 209, and the called terminal B rings a ring and sends a 180 Ringing message (Call enabled message) to the incoming CSCF (210).

The incoming CSCF then forwards the 180 Ringing message to the application server AS and the application server AS then forwards the 180 Ringing message back to the incoming CSCF 212, . At this time, the application server AS determines whether a 180 Ringing message is received in response to a call connection request (INVITE B) message within a predetermined response waiting time (within the response waiting time set in the shadow call forwarding timer) And confirms whether or not the called terminal B responds. At this time, if there is a response from the called terminal B within the predetermined response waiting time, the application server AS judges that the called terminal B can be called.

The terminating CSCF then forwards the 180 Ringing message to the originating CSCF if the terminating terminal B is capable of receiving 213 and the Originating CSCF then forwards the 180 Ringing message to the originating terminal A 214 ).

When the called subscriber B receives the call, the called terminal B transmits a call connection response (200 OK) message to the incoming CSCF in response to the [Hook-Off] call connection request (INVITE B) message (215).

The incoming CSCF then forwards the call connection response (200 OK) message to the application server (AS) (216) and the application server (AS) then forwards the call connection response (200 OK) message back to the incoming CSCF 217). The terminating CSCF then forwards the call connection response (200 OK) message to the originating CSCF (218) and the originating CSCF forwards the call connection response (200 OK) message to originating terminal A (219).

Accordingly, a call is established between the calling terminal A and the called terminal B to make a call (220).

3 is a flowchart illustrating an exemplary signal processing procedure in a case where the called terminal registered in the shadow call forwarding service is not responding to an incoming call.

First, the calling terminal A transmits (301) a call connection request (INVITE B) message for connecting a call to the called terminal B (terminal registered in the shadow transfer service) to the calling CSCF (301) 100 Trying < / RTI > message is received (302).

In the calling CSCF, the called terminal B acquires the called CSCF and delivers a call connection request (INVITE B) message to the called CSCF (303), and receives a 100 Trying message from the incoming CSCF in response thereto (304).

Then, the called CSCF confirms that the called terminal B is a subscriber registered in the shadow call forwarding service, and transmits a call connection request (INVITE B) message to an application server (AS) (305) (100) Trying message from the AS.

Then, the application server AS drives the shadow call forwarding timer and transmits a call connection request (INVITE B) message to the incoming CSCF (307), and receives a 100 Trying message from the incoming CSCF in response thereto (308).

Then, the incoming CSCF forwards the call connection request (INVITE B) message received from the application server (AS) to the called terminal B, and the call connection request (INVITE) message is transmitted to the called terminal B (309). Accordingly, the called CSCF does not receive the 180 Ringing message from the called terminal B and fails to transmit the 180 Ringing message to the application server AS.

On the other hand, the application server AS receives a call connection request (INVITE B) message from the incoming CSCF within the predetermined response waiting time (within the response waiting time set in the shadow call forwarding timer) (180 Ringing) message is received in response to the INVITE B message. At this time, if there is no response from the called terminal B during the predetermined response waiting time, the application server AS judges that the called terminal B can not receive the call in the shadow area or the like. Accordingly, the application server AS drives the shadow call forwarding service 310 to forward the message " 181 Call is being forwarded to the forwarding telephone number "to the incoming CSCF 311, The CSCF forwards the "181 Call is being forwarded" message to the originating CSCF (312), thereby causing the originating CSCF to send a "181 Call is being forwarded Quot; message "to the calling terminal A (313). As a result, the calling subscriber waits without hanging up the telephone. However, since the caller does not hear any sound during the response wait time set in the shadow call forwarding timer at this time, the response waiting time of the shadow call forward timer is generally set to be short as 5 seconds.

When the called terminal B is in a non-response state in the shadow area or the like as described above, the application server AS transmits a call connection to the incoming CSCF to forward the call to the terminal (called terminal C) registered in the shadow-tone call transition service in advance (314) an INVITE C message and receives a 100 Trying message from the incoming CSCF in response thereto (315).

Then, the called CSCF confirms the system (MGCF, other CSCF, etc.) in which the called terminal C is accommodated and transmits a call connection request (INVITE C) message to the called terminal C through the corresponding system (316). Accordingly, the called terminal C rings a ring and transmits a 180 Ringing message (callable message) to the incoming CSCF (not shown).

When the called subscriber C receives the call, the called terminal C transmits a call connection response (200 OK) message to the incoming CSCF in response to the [Hook-Off] INVITE C message (317).

The incoming CSCF then forwards the call connection response (200 OK) message to the application server (AS) (318) and the application server (AS) then forwards the call connection response (200 OK) message back to the incoming CSCF 319). The terminating CSCF then forwards the call connection response (200 OK) message to the originating CSCF (320), and accordingly the originating CSCF forwards the call connection response (200 OK) message to originating terminal A (321).

Accordingly, a call is established between the calling terminal A and the called terminal C to make a call (322).

4 is a flowchart showing an example of a signal processing procedure in the case where the called terminal registered in the shadow call forwarding service is in the deregistered state or temporarily disabled.

First, the calling terminal A sends a call connection request (INVITE B) message to the calling terminal B (terminal registered in the shadow forwarding service) to the calling CSCF (401), and in response thereto, 100 Trying < / RTI > message is received (402).

In the calling CSCF, the called terminal B acquires the called CSCF and transmits a call connection request (INVITE B) message to the corresponding incoming CSCF (403), and receives a 100 Trying message from the incoming CSCF in response thereto (404).

Then, the called CSCF confirms that the called terminal B is a subscriber registered in the shadow call forwarding service, and transmits a call connection request (INVITE B) message to the application server (AS) (405) (100 Trying) message from the AS (406).

Then, the application server AS drives the shadow call forwarding timer and transmits a call connection request (INVITE B) message to the incoming CSCF (407).

Then, the called CSCF having received the call connection request (INVITE B) message from the application server (AS) confirms the current state of the called terminal B, and if the called terminal B is judged to be temporarily unable to make a call, 480 Temporarily Unavailable) message to the application server (408). Here, a state in which the called terminal B can not make a call temporarily includes the case where the called terminal B is located in the shaded area and the registration is canceled in the CSCF, or the calling terminal B can not make a call for other reasons.

When the application server AS receives the 480 Temporarily Unavailable message in response to the INVITE B message in step 407, the application server AS drives the shadow call forwarding service in step 409, Quot; 181 Call is being forwarded "message to the incoming CSCF (410) and the incoming CSCF accordingly sends a " 181 Call is being forwarded " message to the incoming CSCF CSCF 411, and the originating CSCF accordingly delivers a "181 Call is being forwarded" message to the calling terminal A 412. As a result, the calling subscriber waits without hanging up the telephone.

In the application server AS, when the called terminal B is in the temporary call disabled state in the shadow area or the like, the called terminal CS is notified in advance to the incoming CSCF (413) a call connection request (INVITE C) message to the called CSCF in response thereto, and receives a 100 Trying message from the incoming CSCF (414).

Then, the called CSCF confirms the system (MGCF, other CSCF, etc.) in which the called terminal C is accommodated and transmits a call connection request (INVITE C) message to the called terminal C through the corresponding system (415). Accordingly, the called terminal C rings a ring and transmits a 180 Ringing message (callable message) to the incoming CSCF (not shown).

When the called subscriber receives the call, the called terminal C transmits a call connection response (200 OK) message to the incoming CSCF in response to the [Hook-Off] INVITE C message (416).

The incoming CSCF then forwards the call connection response (200 OK) message to the application server (AS) (417) and the application server (AS) then forwards the call connection response (200 OK) message back to the incoming CSCF 418). The incoming CSCF then forwards the call connection response (200 OK) message to the originating CSCF (419), and the originating CSCF forwards the call connection response (200 OK) message to originating terminal A (420).

Thereby, a call is established between the calling terminal A and the called terminal C to make a call (421).

As described above, in the shadow call forwarding service, when the mVoIP terminating terminal is located in the shadow area, or when the portable internet modem is idle, or when the power of the mVoIP terminating terminal is turned off, When the mVoIP destination terminal is unable to receive an incoming call, such as when the mVoIP destination terminal is delayed, the shadow call forwarding service is driven and the other telephone number (the telephone number of another call access network of the same terminal or the like The telephone number of the terminal) to forward the call to connect the call.

However, in the above-described shadow call forwarding service, if the called terminal which subscribes to the shadow call forwarding service is available in the mVoIP network but the response to the call connection request is delayed due to the current idle state or the like, And the caller terminates the call connection request because the caller can not hear the ring back tone (coloring) during the delay time of the response to the call connection request.

Accordingly, there is a need for a method of preventing a shadow call from being switched and providing a ring back tone when a called terminal that has subscribed to the shadow call forwarding service is currently in an idle state or in an awake state such as an awake state. This will be described in detail with reference to FIGS. 5 and 6. FIG.

5 is a flowchart illustrating an exemplary signal processing procedure in a case where the called terminal registered in the shadow call forwarding service according to the present invention is in an idle state or the like.

First, the calling terminal A transmits a call connection request (INVITE B) message to the called terminal B (terminal registered in the shadow call forwarding service) to the calling CSCF (501), and in response thereto, 100 Trying < / RTI > message is received (502).

In the calling CSCF, the called terminal B obtains the called CSCF and transmits a call connection request (INVITE B) message to the incoming CSCF (503), and receives a 100 Trying message from the incoming CSCF in response thereto (504).

Then, the called CSCF confirms that the called terminal B is a subscriber registered in the shadow call forwarding service, and transmits a call connection request (INVITE B) message to the application server (AS) (505) (100 Trying) message from the AS (506).

The application server AS acquires (inquires) the current state of the called terminal B (507). In other words, the application server AS interworks with a system (e.g., a base station controller (ACR), an LBS server, an AAA server, a USI server, a QM server, etc.) that knows the current state of the terminal in the portable Internet network, (Inquiry) 507 the state (the awake state, the idle state, the unconnected state, etc.).

Then, the application server AS again transmits a call connection request (INVITE B) message to the incoming CSCF (508) and receives a 100 Trying message from the incoming CSCF in response thereto (509).

The called CSCF transmits an INVITE B message received from the application server AS to the called terminal B 510. When the called terminal B is in the idle state at present, (180 Ringing) message to the incoming CSCF. Accordingly, the called CSCF can not receive the 180 Ringing message from the called terminal B for a certain period of time, and can not deliver the 180 Ringing message to the application server for a predetermined time.

Therefore, in the application server AS, if the result of acquiring the current state of the called terminal B is 507, if the called terminal B is in the idle state at present (511), a response to the call connection request (180 Ringing) message to the incoming CSCF (512). Here, even when the called terminal B is awake now, it can be implemented to transmit a 180 Ringing message to the incoming call CSCF in response to the call connection request instead of the called terminal B, (180 Ringing) message to the incoming CSCF instead of sending the message to the called CSCF.

The terminating CSCF then forwards the 180 Ringing message to the originating CSCF 513 and the originating CSCF forwards the 180 Ringing message to originating terminal A 514. Accordingly, a ringback tone or coloring occurs in the calling subscriber, so that the calling subscriber stands by without interrupting the telephone call.

That is, even if the called terminal B is subscribed to the shadow call forwarding service, if the called terminal B can receive an incoming call such as an idle state or an awake state, it is not in the shaded area, ) Message is delayed, the call is not subjected to the shadow call forwarding process, and additionally, a normal ringback tone (ringback tone or coloring) is provided to the calling terminal without delay.

On the other hand, after the called terminal B awakes in the idle state or the like, a ring is ringed in response to the INVITE B message of the "510" process and a 180 Ringing message Message to the incoming CSCF (515). Then, the incoming CSCF transmits a 180 Ringing message to the application server (AS) (516). In step 512, the application server (AS) ) Message to the incoming CSCF, the mobile terminal discards the 180 ringing message (callable message) received in the step 516. [

Then, the called terminal B transmits a call connection response (200 OK) message to the incoming CSCF in response to the [Hook-Off] call connection request (INVITE B) message when the called subscriber receives the call (517).

The incoming CSCF then forwards the call connection response (200 OK) message to the application server (AS) (518) and the application server (AS) then forwards the call connection response (200 OK) message back to the called CSCF 519). The terminating CSCF then forwards the call connection response (200 OK) message to the originating CSCF (520) and the originating CSCF forwards the call connection response (200 OK) message to originating terminal A (521).

Thus, a call is established between the calling terminal A and the called terminal B to make a call (522).

Meanwhile, the application server AS transmits a call connection request (INVITE B) message to the incoming CSCF (508), drives the shadow call forwarding timer (T1), and waits for a response within a predetermined time. This is because the state of the called terminal B may continuously change, and therefore there may be no response when the connection is instantaneously terminated in the idle state. However, in general, if the calling terminal B is in the awake state, the waiting time (for example, 10 seconds) is longer than the conventional shadowing call forward timer because it knows to give a response immediately or wake up if it was idle. Can be set to wait for a response. And since you have already sent the 180 Ringing message instead, the caller can also wait. If there is no response within a predetermined time set in the shadow forwarding timer T1, the shadow forwarding service is driven (see FIG. 6 described later).

6 is a flowchart illustrating a method for preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network according to an embodiment of the present invention.

First, when the called CSCF receives a call connection request (INVITE B) message for connecting a call to the called terminal B (terminal registered in the shadow forwarding service) through the calling CSCF from the calling terminal A (601), the HSS (602), and confirms whether the called number is a number registered in the shadow-tone call forwarding service (shadow call forwarding registration number) (603).

If the called number is not the number registered in the shadow call forwarding service, the call processing is performed according to a known existing method (604). If the called number is the number registered in the shadow-tone call forwarding service, The application server AS transmits an INVITE B message to the AS server 605 and receives an INVITE B message from the incoming CSCF in step 606.

Then, the application server (AS) acquires (inquires) the current state of the called terminal B (607) and confirms the current state of the called terminal B (608) (when receiving the call connection request message from the incoming CSCF). In other words, the application server AS interworks with a system (e.g., a base station controller (ACR), an LBS server, an AAA server, a USI server, a QM server, etc.) that knows the current state of the terminal in the portable Internet network, (Inquiry) (state 607), and confirms the current state of the called terminal B (608) by acquiring a state (an awake state, an idle state, an unconnected state, and the like).

If the current state of the called terminal B is in the awake state, the terminal transmits a call connection request (INVITE B) message to the called CSCF (609), drives a shadow call forwarding timer (T1: (610) if the 180 Ringing message is received from the incoming CSCF within a predetermined response waiting time (i.e., if there is a response within the response waiting time specified previously from the terminating terminal B for an incoming call) The call terminating timer T1 is terminated and the call is routed between the calling terminal A and the called terminal B by transmitting a 180 Ringing message to the called CSCF 611.

If the current state of the called terminal B is unconnected (that is, the called terminal B is in the deregistered state or temporarily unable to make a call) as a result of the check (608), the application server (AS) (612) and transmits a " 181 Call is being forwarded " message to the incoming CSCF (613). Then, in the application server AS, in order to call forward the call to the terminal (called terminal C) registered in the shadow-tone call forwarding service, the shaded call forwarding telephone number (telephone number of the called terminal C) (614), and transmits a call connection request (INVITE C) message to the incoming CSCF (615) for making a call to the searched forwarding telephone number (615), and proceeds call processing between the calling terminal A and the called terminal C 616).

If the current state of the called terminal B is idle, the application server AS transmits a call connection request (INVITE B) message to the called CSCF (617), and transmits a shadow call forwarding timer (180 Ringing) message to the called CSCF in response to the call connection request immediately on behalf of the called terminal B and transmits 180 Ringing (180 Ringing) message received from the called terminal B through the incoming CSCF ) Message (618). Then, the application server AS stops the shadow call forwarding timer T1 according to a call connection response (200 OK) message from the incoming CSCF and advances the call processing between the calling terminal A and the called terminal B (619).

That is, even if the called terminal B is subscribed to the shadow call forwarding service, if the called terminal B can receive an incoming call such as an idle state or an awake state, it is not in the shaded area, ) Message is delayed, the call is not subjected to the shadow call forwarding process, and additionally, a normal ringback tone (ringback tone or coloring) is provided to the calling terminal without delay.

1 to 6) illustrate an application example in the mVoIP service based on the IMS, and an application example in the non-IMS based mVoIP service will be described in another embodiment described later. Here, in another embodiment, a home AAA server (home-AAA server) is utilized to inquire the network connection state of the called terminal B (the current state of the called terminal) as an example, and a wireless network includes WiMAX WiMAX) network as an example, but the present invention is not limited thereto.

For reference, one of the differences between the non-IMS network and the IMS network is that the basic call processing in the IMS network is handled in the CSCF divided into P-CSCF, S-CSCF and I-CSCF, (Application server, call control server for controlling shadowed telephone calls) to perform call processing, but all operations are performed in the non-IMS network (Session Initiation Protocol) server (meaning a WVS server of another embodiment described later).

Next, an example of a conventional call connection process procedure in which state information of the UE is not utilized will be described with reference to FIG. 7 and FIG. 8. FIG.

7 is a flow chart of another embodiment showing a call connection processing procedure to a terminating terminal whose network connection is disconnected.

A network connection termination procedure may be performed on the grounds that the calling terminal B leaves the service coverage without the SIP registration deregistered in the SIP registration state 701 to the incoming WVS server (SIP server), an abnormal termination or an unexpected restart of the base station 702). FIG. 7 exemplarily shows a call connection procedure in a non-IMS-based VoIP network when the network connection is disconnected as described above.

First, the calling terminal A transmits a SIP INVITE Request message for connecting a call to the calling terminal B (703) to the calling WVS server to which the calling terminal A is registered.

Then, the calling WVS server transmits a SIP 100 (Trying) Provisional Response message to the calling terminal A in response to the SIP INVITE Request message (704) .

The originating WVS server acquires the incoming WVS server accommodating the called terminal B and transmits the SIP INVITE Request message to the incoming WVS server (705).

The incoming WVS server then sends a SIP 100 (Trying) Provisional Response message to the calling WVS server in response to the SIP INVITE Request message (706) .

Then, the incoming WVS server transmits the SIP INVITE Request message to the called terminal B (707) and drives the SIP timer A (T1 = 500 ms). For example, in the SIP standard [RFC 3261], SIP timer A is used for retransmitting a SIP INVITE Request message, and a T1 value (500 ms) corresponding to the round trip time (RTT) is set as an initial value . However, the SIP INVITE Request message is delivered only to the radio access network 2 (ASN / A-PCEF2) because the called terminal B is not connected to the network, and is not received to the called terminal B. If the called terminal B is in the idle state, the ASN / A-PCEF2 will perform a paging procedure so that the called terminal B enters the network again.

Meanwhile, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B (708) and drives the SIP timer A (T1 * 2) when the SIP timer A (T1 = 500 ms) expires.

Then, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B 709 and drives the SIP timer A (T1 * 4) when the SIP timer A (T1 * 2) expires again. This process is repeated until SIP timer B expires. Here, the SIP timer B is set to T1 * 64 and means a SIP INVITE transaction timeout timer.

Meanwhile, the incoming WVS server transmits a SIP 408 Request Timeout Response message to the originating WVS server 710 when the SIP timer B (T1 * 64) expires.

Then, the calling WVS server transmits the SIP 408 Request Timeout Response message to the calling terminal A (711).

Then, the calling terminal A transmits a SIP ACK Request message to the calling WVS server in response to the SIP 408 Request Timeout Response message (712).

The originating WVS server then transmits the SIP response (SIP ACK Request) message to the incoming WVS server (713).

At this time, between the steps " 704 " and "711 ", the user of the calling terminal A may disconnect the telephone because it can not hear the ringback tone (coloring). The ring back tone is reproduced only when the calling terminal A receives a SIP 180 (ringing) provisional response (SIP 180 (Ringing) Provisional Response) message (callable message). Since the timeout value of the SIP timer B is too long based on the initial value of the timer in the SIP standard [RFC 3261], in actual implementation, the maximum number of retransmission of the SIP INVITE Request message is limited or the call connection request By defining and using a separate short timer for the SIP INVITE transaction time out, it is determined more quickly whether to terminate the incoming call or proceed. For example, the retransmission may be interrupted immediately after the retransmission of the SIP INVITE Request message two or three times, and the called terminal B may be out of coverage of the wireless communication network (e.g., WiMAX network) ) And processes the call. If the called terminal B is subscribed to the shadow call forwarding service, the incoming call is forwarded to another telephone number (a telephone number of another call access network of the same terminal or a telephone number of the other terminal) previously set (registered) by the subscriber The call is forwarded and the call is connected. Such a shadow call forwarding scenario is shown in FIG. 8, and FIG. 8 shows a case where the called terminal B is in an idle state.

FIG. 8 is a flowchart illustrating another example of a call connection procedure in a called network when a called terminal subscribed to a shadow call forwarding service is in an idle mode.

First, the called terminal B subscribed to the shadow call forwarding service is in an idle mode (801).

At this time, the incoming WVS server receives a SIP INVITE Request message from the originating network to connect the call to the called terminal B (terminal registered in the shadow forwarding service) (802).

The incoming WVS server transmits a SIP 100 (Trying) Provisional Response message to the originating network in response to the SIP INVITE Request message (803).

Then, the incoming WVS server transmits the SIP INVITE Request message to the called terminal B (804) and drives the SIP timer A (T1 = 500 ms). The incoming WVS server confirms that the called terminal B is subscribed to the shadow call forwarding service and drives the SIP timer CF1 (for example, 3 to 5 sec). At this time, when the radio access network 2 receives the downstream packet directed to the destination terminal B, that is, the SIP INVITE Request message of the "804" process, the destination terminal B is in the current idle state 801, And performs a paging procedure to return to the active mode.

Meanwhile, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B (805) when the SIP timer A (T1 = 500 ms, call connection request message retransmission timer) expires, * 2).

When the SIP timer A (T1 * 2) again expires, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B (806).

On the other hand, if the incoming WVS server confirms that the SIP timer CF1 has expired, the WVS server transmits a "SIP 181 Call is being forwarded" message to the originating network with the forwarding telephone number (807).

Then, the incoming WVS server simultaneously transmits a SIP INVITE Request message to the terminal (called terminal C) registered in the shadow-tone call forwarding service of the called terminal B in advance, To the called terminal C (808).

Then, the called terminal C transmits a SIP 180 (Ringing) Provisional Response message (callable message) to the incoming WVS server in response to the SIP INVITE Request message (809).

The destination WVS server then transmits the SIP 180 (Ringing) Provisional Response message (callable message) to the originating network (810).

Meanwhile, the called terminal C includes its own media stream information in the SIP 200 OK Response message and transmits it to the incoming WVS server (811).

The incoming WVS server then transmits the SIP 200 OK Response message to the originating network (812).

The incoming WVS server receives a SIP ACK Request message from the originating network in response to the SIP 200 OK Response message (813).

The incoming WVS server then transmits the SIP response (SIP ACK Request) message to the called terminal C (814).

Accordingly, a WVS session is established between the calling terminal of the calling network and the called terminal C to make a call (815).

On the other hand, when the paging is successfully completed between the radio access network 2 and the called terminal B according to the SIP INVITE Request message of the '804' process, the called terminal B reenters the wireless network and enters an active mode 816 ). Accordingly, the called terminal B sends a SIP 180 (Ringing) Provisional Response message (callable message) in response to the SIP INVITE Request message transmitted from the originating network To the incoming WVS server (817). However, the SIP 180 (Ringing) Provisional Response message from the terminating terminal B (the SIP 180 (Ringing) Provisional Response) message (the callable message) is not received because the session has already been terminated by a SIP INVITE transaction timeout ) Is ignored in the incoming WVS server.

If the calling / called terminal is in idle mode, it must re-enter the wireless network to make a call. That is, it must exit the idle state and become active. In this case, the originating terminal may transmit a SIP INVITE Request message to the called terminal after first starting the idle state termination procedure. However, in the case of the called terminal, the switch to the active state is started after the call connection is started. In order for the called terminal to exit the idle state, the wireless network (base station) must perform paging with the called terminal. This paging procedure may take several seconds because the UE in the idle state checks the wireless network only during PLI (Paging Listen Interval) and performs retry due to paging failure or multi-stage paging in different paging groups As well. Therefore, to prevent unwanted call forwarding or call termination, the timer value for the SIP INVITE transaction timeout should be carefully set.

Next, an example of a call connection procedure according to the present invention using state information of the UE will be described with reference to FIGS. 9 and 10. FIG.

9 is a flowchart illustrating a call connection procedure in a case where a called terminal according to the present invention is not in service in an mVoIP network.

The network connection termination procedure may be performed on the grounds that the calling terminal B leaves the service coverage without the SIP registration deregistration in the SIP registration state 901 to the incoming WVS server (SIP server), the abnormal termination, or the unexpected restart of the base station 902).

At this time, the incoming WVS server receives a SIP INVITE Request message for connecting the call to the called terminal B from the originating network (903).

The incoming WVS server transmits a SIP 100 (Trying) Provisional Response message to the originating network in response to the SIP INVITE Request message (904).

The incoming WVS server transmits a MS State Query Request message to a home AAA server (e.g., AAA authentication server) of the corresponding WiMAX network to request the current state of the called terminal B (905).

Then, the home AAA server transmits a MS State Query Response message to the incoming WVS server in response to the MS State Query Request message to determine the current state of the called terminal B (e.g., NOT -IN-SERVICE state) (906). Accordingly, the incoming WVS server confirms that the called terminal B is not currently in service (NOT-IN-SERVICE), and does not forward the SIP INVITE Request message to the called terminal B any more.

On the other hand, the incoming WVS server refers to a service to which the called terminal B has subscribed in a subscriber database (DB) or the like, and when all the incoming calls are to be forwarded to the called terminal C (907). At this time, the already registered shade forwarding telephone number (the telephone number of the called terminal C) is also obtained. If the called terminal B is not registered in the shadow-tone call diversion service, the incoming WVS server immediately issues an error message (e.g., Temporarily Disable SIP 480 Temporarily) without waiting for a SIP INVITE transaction timeout Unavailable message) to the originating network to terminate the call. The non-receivable state may be a loss on a network link, a network disconnection, a loss of coverage, a power shutdown, and the like.

On the other hand, the incoming WVS server confirming the subscription of the shadow terminal B to the calling terminal B transmits the "SIP 181 Call is being forwarded" message to the originating network (908).

The incoming WVS server simultaneously transmits a SIP INVITE Request message to the terminal (called terminal C) registered in the shadow call forwarding service of the called terminal B in advance, To the called terminal C (909).

Then, the called terminal C transmits a SIP 180 (Ringing) Provisional Response message (callable message) to the incoming WVS server in response to the SIP INVITE Request message (910).

The destination WVS server then sends the SIP 180 (Ringing) Provisional Response message (callable message) to the originating network (911).

Meanwhile, the called terminal C includes its own media stream information in the SIP 200 OK Response message and transmits it to the incoming WVS server (912).

The incoming WVS server then transmits the SIP 200 OK Response message to the originating network (913).

The incoming WVS server receives a SIP ACK Request message from the originating network in response to the SIP 200 OK Response message (914).

Then, the incoming WVS server transmits the SIP response (SIP ACK Request) message to the called terminal C (915).

Accordingly, a WVS session is established between the calling terminal of the calling network and the called terminal C to make a call (916).

As described above, in the shadow call forwarding service, when the mVoIP destination terminal is located in the shadow area, the wireless modem is idle, or the mVoIP destination terminal is powered off, or the call connection request message When the mVoIP destination terminal can not receive the call, for example, when the mVoIP destination terminal is delayed, the shadow call forwarding service is driven and the other telephone number (the telephone number of another call access network of the same terminal or the other terminal The call is forwarded to the called party and the call is connected.

However, in the above-described shadow call forwarding service, if the called terminal which subscribes to the shadow call forwarding service is available in the mVoIP network but the response to the call connection request is delayed due to the current idle state or the like, And the caller terminates the call connection request because the caller can not hear the ring back tone (coloring) during the delay time of the response to the call connection request.

Accordingly, there is a need to provide a method for preventing a shadow call from being switched and providing a ring back tone when a called terminal that has subscribed to a shadow call forwarding service is in a state where an incoming call is possible, such as an idle state or an in-service state . This will be described in detail with reference to FIG.

FIG. 10 is a flowchart of another embodiment of a call connection procedure in a case where a called terminal according to the present invention is in an idle mode.

First, the called terminal B subscribed to the shadow call forwarding service is in an idle mode (1001).

At this time, the incoming WVS server receives a SIP INVITE Request message from the originating network to connect the call to the called terminal B (terminal registered in the shadow forwarding service) (1002).

The incoming WVS server transmits a SIP 100 (Trying) Provisional Response message to the originating network in response to the SIP INVITE Request message (1003).

The incoming WVS server then sends a MS State Query Request message to the home AAA server (e.g., AAA authentication server) of the corresponding WiMAX network to request the current state of the called terminal B (1004).

Then, the home AAA server transmits a MS State Query Response message to the incoming WVS server in response to the MS State Query Request message and transmits the current state of the called terminal B (for example, IDLE (1005).

The incoming WVS server accordingly adjusts the SIP timer value for the SIP INVITE transaction timeout to ensure that the terminating terminal B is idle and has sufficient time to complete paging (1006). Of course, there is a probability that the called terminal B in the idle state terminates the network connection at this point of time and paging fails.

Then, the incoming WVS server transmits the SIP INVITE Request message to the called terminal B (1007) and drives the SIP timer A (T1 = 500 ms). Then, the SIP INVITE Request message of the step " 1007 " triggers the paging. That is, when the radio access network 2 receives the SIP INVITE Request message of the "1007" process directed to the called terminal B, the called terminal B enters the wireless network again because it is in the idle state 1001, active mode in order to return to the active mode.

Meanwhile, the called WVS server transmits a SIP 180 (Ringing) Provisional Response message (callable message) to the calling network on behalf of the called terminal B (1008). Through the operation of the "1008 " process, the caller can hear ring back tone (ring back tone or coloring).

The incoming WVS server then retransmits the SIP INVITE Request message to the terminating terminal B (1009) and sends a SIP INVITE Request message to the SIP timer A (T1 *) when the SIP timer A (T1 = 500 ms, call connection request message retransmission timer) 2).

Then, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B 1010 and drives the SIP timer A (T1 * 4) when the SIP timer A (T1 * 2) expires again.

When the SIP timer A (T1 * 4) is again expired, the incoming WVS server retransmits the SIP INVITE Request message to the called terminal B (1011).

If the called terminal B completes the paging procedure and reenters the network (that is, becomes active) (step 1012), the called WVS server sends a SIP 180 (ringing) message in response to the SIP INVITE Request message. And receives a provisional response (SIP 180 (Ringing) Provisional Response) message (callable message) from the called terminal B (1013). However, since the incoming WVS server has already transmitted a SIP 180 (Ringing) Provisional Response message (callable message) to the originating network in step 1008 in place of the terminating terminal B , The SIP 180 (Ringing) Provisional Response message (talkable message) actually received from the called terminal B in the above step 1013 is ignored.

Meanwhile, the called terminal B includes the media stream information of its own in the SIP 200 OK Response message and transmits it to the incoming WVS server (1014).

The incoming WVS server then transmits the SIP 200 OK Response message to the originating network (1015).

The incoming WVS server receives a SIP ACK Request message from the originating network in response to the SIP 200 OK Response message (1016).

Then, the incoming WVS server transmits the SIP response (SIP ACK Request) message to the called terminal B (1017).

Accordingly, a WVS session is established between the calling terminal of the originating network and the called terminal B to make a call (1018).

11 is a flowchart illustrating another embodiment of a method for preventing unnecessary shadow call forwarding and providing a fast ring back tone in an mVoIP network according to the present invention.

First, the incoming WVS server (incoming call control server) receives a SIP INVITE Request message directed to the called terminal B (terminal registered in the shadow forwarding service) from the originating network (1101) (1102) a current state of the called terminal B to a corresponding home AAA (Authentication, Authorization, Accounting) server of the WiMAX network through an MS State Query Request message.

At this time, if there is no terminal state reporting function, the home AAA server (for example, AAA authentication server) transmits a response indicating that the terminal state reporting function is not supported through the MS State Query Response message to the incoming WVS server . On the other hand, if the home AAA server has the terminal state reporting function, the state of the called terminal B is "ACTIVE" state, "IDLE" state, "service" state via the MS State Query Response message, IN-SERVICE "state, or a" NOT-IN-SERVICE "state to the destination WVS server.

Accordingly, the incoming WVS server receiving the MS State Query Response message confirms whether the home AAA server has the terminal status reporting function (1103).

If the home AAA server does not have the terminal status reporting function, the incoming WVS server independently processes the received SIP INVITE Request message without interworking with the home AAA server (1104). As described above, an example of a conventional call connection process procedure in which the status information of the UE is not utilized is as described above with reference to FIG. 7 and FIG.

If the home AAA server has a terminal state reporting function, the state of the called terminal B is "ACTIVE", "IDLE", "IN-SERVICE" , Or "NOT-IN-SERVICE" (1105).

Here, the "ACTIVE" state means that the called terminal B is in an active mode and has at least one IP address for WVS (WiMAX VoIP Service). The "IDLE" state means that the called terminal B is in idle mode and has at least one IP address for WVS. The "IN-SERVICE" state means that the home AAA server does not know whether the called terminal B is active or idle, but has at least one IP address for WVS. The "NOT-IN-SERVICE" state means that the home AAA server does not have a valid IP address for WVS with respect to the called terminal B.

If the confirmation result 1105 confirms that the called terminal B is in the "ACTIVE" state, the incoming WVS server sends a SIP response message from the called terminal B, namely a SIP 180 (Ringing) ) Response message (callable message) (1106), and proceeds to call processing between the calling terminal and the called terminal B according to a known conventional method (1107).

If the confirmation result (1105) indicates that the called terminal B is in the "NOT-IN-SERVICE" state, the incoming WVS server starts the shadow call forwarding service (1108) (A terminal registered in the shadow-tone call diversion service in step 1109). That is, if the shadow call forwarding service is set for the corresponding subscriber and another available device is registered, the incoming WVS server delivers a SIP INVITE Request message to the other available device. Otherwise, the incoming WVS server responds with a SIP response message (eg, a SIP 480 Temporarily Unavailable message) informing the calling terminal of its status. An example of the call connection procedure when the called terminal B is not in service in the network is as described above with reference to FIG.

If the acknowledgment result (1105) indicates that the called terminal B is in the "IDLE" state or the "IN-SERVICE" state, the incoming WVS server sends a SIP INVITE transaction timeout (I.e., the timer A and / or the timer B shown in FIG. 7) associated with the SIP message to secure sufficient time for paging to be completed, and transmits the SIP INVITE Request message To the called terminal B (1110).

The incoming WVS server then sends the SIP 180 (ringing) message directly before receiving the SIP response message, i.e., the actual SIP 180 (Ringing) Provisional Response message (callable message) And responds to the originating terminal A with a provisional response (SIP 180 (Ringing) Provisional Response) message (callable message) (1111). At this time, the incoming WVS server may be implemented to send the SIP 180 (Ringing) Provisional Response message (callable message) only when the called terminal B is in the " IDLE & have. If the incoming WVS server has already responded with a SIP 180 (Ringing) Provisional Response message (callable message), then the actual SIP 180 (ringing) provisional response from the terminating terminal B (SIP 180 (Ringing) Provisional Response) message (callable message), the call is discarded without transmitting it to the calling terminal A (1111).

The incoming WVS server then proceeds to call processing between the calling terminal and the called terminal B (1112).

If the incoming WVS server does not receive any SIP response message from the called terminal B until the SIP timers expire, a SIP response message (e.g., SIP 480 Temporarily Unavailable) indicating a status (status) Message to the calling terminal A. An example of the call connection procedure when the called terminal B is in the idle mode is described above with reference to FIG.

Meanwhile, in the mVoIP network according to the present invention, the method of preventing unnecessary shadow call forwarding and providing a fast ring back tone may be implemented in the form of a program command which can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. The medium may be a transmission medium such as an optical or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a data structure, or the like. Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various permutations, modifications and variations are possible without departing from the spirit of the invention.

Therefore, the scope of the present invention should not be construed as being limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

The present invention can be used in the mVoIP network to prevent shadow call forwarding when a called terminal can be called, and to prevent a call connection request from being terminated by a calling subscriber due to a response delay.

Claims (20)

delete A method for preventing shadow call forwarding,
A state checking step of, when the call control server receives the call connection request message, acquiring the current state of the called terminal and confirming whether or not the call is available;
Performing, as a result of the checking of the status checking step, a 'shadow call forwarding service', which is a service of 'forwarding to another telephone number set by a subscriber in advance, if the current state of the called terminal is unreachable;
If it is determined that the current state of the called terminal is an incoming call, the call control server transmits a first callable message to the calling terminal in response to the call connection request message on behalf of the called terminal So that a ring back tone is provided; And
Requesting connection of the incoming call after the call control server prevents shadowing of the incoming call
Wherein the shade redirect prevention method comprises:
3. The method of claim 2,
The call control server discards the second callable message received from the called terminal through the incoming CSCF
Further comprising the steps of:
3. The method of claim 2,
The status checking step includes:
Wherein the call control server confirms whether the current state of the called terminal is in an idle state, an awake state, or an unconnected state.
3. The method of claim 2,
The status checking step includes:
Wherein the call control server obtains whether the current state of the called terminal is in an awake state, an idle state, or an unconnected state in cooperation with a system in which the call control server knows the current state of the terminal.
In the method for providing ring back tone,
A state checking step of, when the call control server receives the call connection request message, acquiring the current state of the called terminal and confirming whether or not the call is available;
Performing, as a result of the checking of the status checking step, a 'shadow call forwarding service', which is a service of 'forwarding to another telephone number set by a subscriber in advance, if the current state of the called terminal is unreachable; And
If it is determined that the current state of the called terminal is an incoming call, the call control server transmits a first callable message to the calling terminal in response to the call connection request message on behalf of the called terminal So that a ring back tone is provided
The method comprising the steps of:
The method according to claim 6,
The call control server discards the second callable message received from the called terminal through the incoming CSCF
Further comprising the steps of:
The method according to claim 6,
The status checking step includes:
Wherein the call control server confirms whether the current state of the called terminal is currently idle, awake, or unconnected.
The method according to claim 6,
The status checking step includes:
Wherein the call control server obtains whether the current state of the called terminal is in an awake state, an idle state, or an unconnected state in cooperation with a system in which the call control server knows the current state of the terminal.
A method for preventing shadow call forwarding,
A state checking step of, when the call control server receives the call connection request message, acquiring and confirming the current state of the called terminal;
Processing the incoming call if the current state of the called terminal is ACTIVE as a result of the checking of the state;
If it is determined that the current state of the called terminal is not in service (NOT-IN-SERVICE) as a result of the checking of the status, it is determined that the incoming call is terminated or " a service for switching to another telephone number Performing a call forwarding service; And
If the current state of the called terminal is an IDLE state or an IN-SERVICE state as a result of the state checking step, the call control server adjusts a call connection request transaction timeout, Processing the incoming call after preventing the switching
Wherein the shade redirect prevention method comprises:
11. The method of claim 10,
If it is determined that the current state of the called terminal is idle, the call control server transmits a first callable message in response to the call connection request message on behalf of the called terminal, So that a ring back tone is provided
Further comprising the steps of:
12. The method of claim 11,
The call control server discards the second callable message received from the called terminal
Further comprising the steps of: 13. The method of claim 12,
If the current state of the called terminal is in the IN-SERVICE state as a result of the checking of the state, the call control server transmits, in response to the call connection request message, Message to the calling terminal so that a ring back tone is provided
Further comprising the steps of:
11. The method of claim 10,
The status checking step includes:
The call control server is operable with an authentication, authorization, and accounting (AAA) server that knows the current state of the terminal to determine whether the current state of the called terminal is ACTIVE, idle, (IN-SERVICE) state or not-in-service state.
15. The method of claim 14,
The status checking step includes:
Requesting, by the call control server, the current state of the called terminal to the home AAA server upon receiving a call connection request message; And
Wherein the call control server independently processes the received call connection request message without interworking with the home AAA server if the home AAA server does not have the terminal status reporting function and if the home AAA server has the terminal status reporting function, Obtaining whether the current state of the called terminal is ACTIVE, IDLE, IN-SERVICE, or NOT-IN-SERVICE,
Wherein the shade redirect prevention method comprises:
11. The method of claim 10,
The adjustment of the call connection request transaction time-
And adjusts the timer so as to secure a time at which paging for the called terminal can be completed.
17. The method of claim 16,
If the call control server does not receive any response message from the called terminal until the timer expires, sending a temporary call disabled message to the calling terminal informing the corresponding current state
Further comprising the steps of:
In the method for providing ring back tone,
A state checking step of, when the call control server receives the call connection request message, acquiring and confirming the current state of the called terminal;
Processing the incoming call if the current state of the called terminal is ACTIVE as a result of the checking of the state;
If it is determined that the current state of the called terminal is not in service (NOT-IN-SERVICE) as a result of the checking of the status, it is determined that the incoming call is terminated or " a service for switching to another telephone number Performing a call forwarding service; And
If it is determined that the current state of the called terminal is idle, the call control server transmits a first callable message in response to the call connection request message on behalf of the called terminal, So that a ring back tone is provided
The method comprising the steps of:
19. The method of claim 18,
The call control server discards the second callable message received from the called terminal
Further comprising the steps of:
20. The method of claim 19,
If the current state of the called terminal is in the IN-SERVICE state as a result of the checking of the state, the call control server transmits, in response to the call connection request message, Message to the calling terminal so that a ring back tone is provided
Further comprising the steps of:

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