JP2011049673A - Circuit switching call processing node, packet switching call processing node, mobile communication system, and mobile communication method - Google Patents

Abstract

An object of the present invention is to enable the reception of a circuit-switched call to a mobile station even when the packet-switched call and the circuit-switched call are in conflict or when an SGSN failure occurs during the circuit-switched call. To do.
An VLR / MSC 101 transmits an incoming request signal to an SGSN 102 to an SGSN 102, and an incoming request signal is transmitted to the SGSN 102 when a call response is not received from the MS 106 after a predetermined period of time elapses. In response to reception of the incoming request signal, the SGSN 102 adds a flag to the incoming request signal to urge the response to be returned, and then the incoming request retransmission unit 203 that transmits the incoming request signal to the SGSN 102 again, and the incoming request with the flag added An incoming call processing unit 205 that transmits a paging signal for calling the MS 106 to the RNC / BTS 107 when a signal is transmitted and no response is received from the SGSN 102 after a predetermined period has elapsed.
[Selection] Figure 1

Description

  The present invention relates to a circuit-switched call processing node, a packet-switched call processing node, a mobile communication system, and a mobile communication method.

  Conventionally, when a mobile station MS performs location registration in a packet-switched network, the mobile station MS performs linked network location registration control (hereinafter referred to as “Combined location registration control”) that also performs location registration in the circuit-switched network. A communication system is known (for example, Patent Document 1).

JP 2009-105939 A

  As shown in FIG. 9, such a mobile communication system 100 includes a VLR / MSC 101 that is a circuit-switched call processing node, an SGSN 102 that is a packet-switched call processing node, a GMSC 103 that is a gateway node that routes a circuit-switched call, and positional information. GMLC 104 that is a gateway that controls the packet, GGSN 105 that is the gateway that controls the packet call, MS 106 that is the mobile station used by the user, RNC / BTS 107 that is the radio controller existing between the VLR / MSC 101 and SGSN 102 and the MS 106, And a Gs interface 108 that is an interface between the VLR / MSC 101 and the SGSN 102. The MS 106 includes a terminal and a UIM for identifying a user (user A in FIG. 9) who uses the terminal. In FIG. 9, the service area of the circuit-switched call covered by each VLR / MSC 101 is shown as LocationArea 109, and the service area of the packet-switched call covered by each SGSN 102 is shown as RoutingArea110.

  In this mobile communication system 100, when the MS 106 enters the Location Area 109 and the Routing Area 110, the MS 106 performs the above-mentioned Combined location registration for the network to be managed in order to allow use of the service in the service area. Specifically, first, the MS 106 transmits a location registration request signal to the SGSN 102. The SGSN 102 that has received the location registration request signal from the MS 106 holds the user profile (“subscriber information of the user A” in FIG. 9) of the user who uses the MS 106 if the packet call service is permitted, and the Gs interface. A location switching request signal on the circuit switching side is transmitted to the VLR / MSC 101 via 108. The VLR / MSC 101 performs a location registration request on the circuit switching side via the Gs interface 108, and if the circuit switching call service is permitted, the user profile of the user who uses the MS 106 ("subscriber of user A in FIG. 9"). Information "). When the combined location registration is completed, a Gs association that enables cooperation between the VLR / MSC 101 and the SGSN 102 is established.

  When the GMSC 103 receives a call request signal for a circuit-switched call to the MS 106 in a state where the MS 106 is registered in the Combined position as described above, and the circuit-switched service is activated and receives an incoming call to the MS 106, first the user of the circuit-switched service It is connected to the VLR / MSC 101 that manages the profile (S1 in FIG. 9). The VLR / MSC 101 transmits an incoming call request signal to the SGSN 102 with which the Gs association has been established, and makes an incoming call request (S2).

  The SGSN 102 confirms the communication state of the MS 106 (user A) corresponding to the incoming call request, and transmits a signal for making an incoming call to the MS 106 to the subordinate RNC / BTS 107 (S3). The RNC / BTS 107 calls the corresponding MS 106 (S4). The procedure for informing the MS 106 that there is an incoming circuit-switched call (or packet-switched call) and calling the MS 106 is called paging, and is a signal transmitted from the SGSN 102 to the RNC / BTS 107 in step S3. Is called a paging signal.

  Here, information called Non Searching Indication is set in the paging signal transmitted from the SGSN 102 (or VLR / MSC 101) to the RNC / BTS 107. The setting value of Non Searching Indication is one of “searching”, “Non-searching”, or “Non-setting” of Non Searching Indication (details are defined in 3GPP TS 25.413). When Non-searching Indication = non-searching, the RNC / BTS 107 performs paging (calling to the mobile device (MS 106)) for all the areas accommodated.

  When Non-searching Indication = searching, it means that there is a call that is already in communication with the MS 106 (this determination is made in the core network (SGSN 102 or VLR / MSC 101)), so the RNC / BTS 107 performs IMSI search processing for the connected call. And execute a call based on the result of this search process. Here, IMSI is an abbreviation for International Mobile Subscriber Identity, which is a subscriber identifier and is used as a key for identifying a user.

  Also, the call signal from the RNC / BTS 107 to the MS 106 uses two types of signals depending on whether the MS 106 is communicating. That is, when Non-searching Indication = non-searching, a call signal called PAGING TYPE1 is sent to the MS 106, while when Non-searching Indication = searching, a call signal called PAGING TYPE2 is sent to the user equipment. To do.

  Note that if it is not possible to determine whether there is a communication call in the core network, non-searching indication is not set. When the Non Searching Indication is not set, the RNC / BTS 107 performs IMSI search, determines whether the corresponding MS 106 is communicating, and makes an appropriate terminal call. More specifically, the RNC / BTS 107 manages the IMSI in communication, and when the IMSI of the corresponding MS 106 is detected by IMSI search, the RNC / BTS 107 determines that the MS 106 is in communication. When the RNC / BTS 107 determines that the MS 106 is not communicating, the RNC / BTS 107 transmits a PAGING TYPE 1 call signal to the MS 106. If it is determined that the MS 106 is communicating, a PAGING TYPE 2 call signal is sent to the MS 106.

  In the example of FIG. 9, since the MS 106 is not in a communication state and the SGSN 102 recognizes that the state of the user A (MS 106) is not communicating, the SGSN 102 sends a non-searching indication to the RNC / BTS 107 in step S3. = Send a paging signal set as non-searching. Similarly, in step S4, the RNC / BTS 107 transmits a paging type 1 call signal to the MS 106.

  Then, the MS 106 that is called upon receiving an appropriate call signal from the RNC / BTS 107 returns an incoming call response to the VLR / MSC 101 (S5). In the conventional mobile communication system 100, the incoming process of the circuit switching system is performed in this way.

  In the conventional mobile communication system 100 as described above, when any failure occurs in the SGSN 102 during the incoming processing of the circuit switching service, a call from the RNC / BTS 107 to the MS 106 is executed via the SGSN 102. The call cannot be received and the incoming call cannot be made. In this case, when the VLR / MSC 101 receives no incoming response from the MS 106, the VLR / MSC 101 can directly send a paging signal to the RNC / BTS 107 without going through the SGSN 102.

  However, even if such a measure is taken, there may be a situation where the incoming of the circuit switching service fails. Specifically, the mobile station originated a packet-switched service while the circuit-switched call was being processed to the MS 106 via the SGSN 102, and the packet-switched call and the circuit-switched call were in conflict. There are cases.

  As shown in FIG. 10, after the above-described steps S1 to S4, while the call signal reaches the MS 106, the MS 106 performs packet-based switching service transmission (S6). Since the calling signal from the RNC / BTS 107 is PAGING TYPE1 (not communicating), the user equipment (MS 106) that is transmitting the packet cannot respond to the calling signal, and the incoming call fails (S7).

  The VLR / MSC 101 has not received the incoming call response from the MS 106, and therefore determines that some failure has occurred in the SGSN 102, and transmits a paging signal to the RNC / BTS 107 in order to carry out the incoming call to the RNC / BTS 107 itself. (S8).

  At this time, the VLR / MSC 101 recognizes that the MS 106 is not communicating, and it is considered that the packet communication of the MS 106 is not performed due to the failure of the SGSN 102. Further, since IMSI search has a large calculation load and affects the processing capability of the RNC / BTS 107, it is not preferable to set “Non Searching indication” of the paging signal transmitted to the RNC / BTS 107 to “unset” (Combined location registration control in the first place). Is a configuration for suppressing paging with non-searching indication “not set”). For this reason, the VLR / MSC 101 transmits a paging signal set as Non-searching Indication = non-searching to the RNC / BTS 107 on the premise that there is no previous call (packet communication is not performed).

  In response to receiving the paging signal set as Non-searching Indication = non-searching from the VLR / MSC 101, the RNC / BTS 107 calls the MS 106 with a PAGING TYPE1 call signal, assuming that the MS 106 is in a non-communication state.

  During this time, a packet outgoing call from the MS 106 reaches the SGSN 102 and enters a packet communication state (S9).

  The MS 106 that has received the PAGING TYPE1 paging signal from the RNC / BTS 107 cannot respond to the paging signal that is paging as non-communication because it is in packet communication, and the incoming call fails (S10). The VLR / MSC 101 performs post-processing (response to the caller side, etc.) as an incoming call failure because no incoming call response has been received.

  As described above, in the conventional mobile communication system, there is a problem that it is not possible to perform incoming call control when the packet-switched call transmission and the circuit-switched call call conflict. Then, it is desirable to perform incoming control of a circuit-switched call in consideration of the contention problem and a case where the incoming of a circuit-switched call and the occurrence of a failure of an SGSN (packet-switched call processing node) compete.

  The present invention has been made in order to solve the above-described problem. When a packet-switched call originates from a circuit-switched call, or the circuit-switched call arrives, a failure of the packet-switched call processing node occurs. An object of the present invention is to provide a circuit-switched call processing node, a packet-switched call processing node, a mobile communication system, and a mobile communication method capable of receiving a circuit-switched call to a mobile station even when a mobile station occurs.

  In order to solve the above problems, a circuit-switched call processing node according to the present invention receives an incoming call request signal from a gateway node to a mobile station via a packet-switched call processing node and a radio network controller. A circuit-switched call processing node that performs an incoming call request transmission means for transmitting an incoming request signal to the packet-switched call processing node; and the incoming call request transmission means transmits the incoming call request signal after the elapse of a predetermined period of time. An incoming request retransmitting means for retransmitting the incoming request signal to the packet-switched call processing node when a call response is not received from the mobile station related to the request signal. The transmission means prompts the packet-switched call processing node to send a response back to the circuit-switched call processing node in response to receiving the incoming request signal After sending the information to the incoming request signal by the incoming request transmission means or the incoming request retransmission means, the response is received from the packet-switched call processing node after a predetermined period. If not, an incoming call processing means for transmitting a paging signal for calling a mobile station to the radio network controller is provided.

  Similarly, in order to solve the above-described problem, the packet-switched call processing node according to the present invention receives an incoming request signal from the gateway node to the mobile station from the circuit-switched call processing node via the radio controller. In the packet-switched call processing node that performs incoming call processing, information that prompts the packet-switched call processing node to send a response back to the circuit-switched call processing node is added to the incoming request signal received from the circuit-switched call processing node. A response transmission means for transmitting a response to the circuit-switched call processing node.

  Similarly, in order to solve the above-described problem, it is preferable that the mobile communication system according to the present invention includes the circuit-switched call processing node and the packet-switched call processing node described above.

  Similarly, in order to solve the above problems, a mobile communication method according to the present invention is a mobile communication method executed by a mobile communication system including a circuit-switched call processing node and a packet-switched call processing node. An incoming request transmission means for transmitting an incoming request signal to the packet-switched call processing node in response to receiving an incoming request signal from the gateway node to the mobile station, When the incoming request retransmitting means of the processing node has not received a call response from the mobile station related to the incoming request signal after the elapse of a predetermined period after the incoming request signal is transmitted in the incoming request transmission step, An incoming request retransmission step for retransmitting the signal to the packet-switched call processing node, and an incoming request transmission step or an incoming request retransmission In the step, the incoming call request transmission means or the incoming call request retransmission means assigns and transmits information that prompts the packet-switched call processing node to return a response to the circuit-switched call processing node in response to reception of the incoming call request signal. And a response transmission step of transmitting a response to the circuit-switched call processing node when the response transmission means of the packet-switched call processing node is given information to the incoming request signal received from the circuit-switched call processing node. And the incoming call processing means of the circuit-switched call processing node adds information to the incoming call request signal in the incoming call request transmission step or the incoming call request retransmission step, and then transmits the information from the packet-switched call processing node after a lapse of a predetermined period. When the response is not received, a paging signal for calling the mobile station is transmitted to a radio network controller that performs incoming processing to the mobile station Characterized in that it comprises a paging signal transmitting step.

  According to such a circuit-switched call processing node, a packet-switched call processing node, a mobile communication system, and a mobile communication method, a packet-switched call and a circuit-switched call are in conflict with each other, and the mobile station fails to receive the call. In such a case, the incoming call request signal is transmitted again to the packet-switched call processing node when the circuit-switched call processing node does not receive a call response from the mobile station related to the incoming call request signal. When the retransmitted incoming request signal is received by the packet-switched call processing node, the packet-switched call transmitted from the mobile station has also reached the packet-switched call processing node, and the mobile station communicates with the packet-switched call processing node. If the mobile station is in the middle, it is possible to transmit an appropriate paging signal to the radio controller after recognizing the communication state of the mobile station. Then, the radio control apparatus can call the mobile station that is performing packet communication. As a result, even when the packet-switched call and the circuit-switched call are in conflict, the circuit-switched call is received by the mobile station. Is possible.

  In addition, the circuit-switched call processing node sends information that prompts the packet-switched call processing node to return a response in response to reception of the incoming request signal, and does not receive this response from the packet-switched call processing node Then, a paging signal for calling the mobile station is transmitted to the radio network controller. As a result, the circuit-switched call processing node can recognize whether or not a failure has occurred in the packet-switched call processing node based on the presence / absence of a response from the packet-switched call processing node. When a failure occurs in the packet-switched call processing node, the incoming-call processing to the mobile station via the packet-switched call-processing node can be stopped, and the incoming-call processing can be changed to only the wireless control device. As a result, it is possible to receive a circuit-switched call to a mobile station even when a failure occurs in a packet-switched call processing node when a circuit-switched call is received.

  The circuit-switched call processing node includes a first timer means that is activated when an incoming request signal is transmitted by the incoming request transmission means, and an incoming request to which information has been assigned by the incoming request transmission means or the incoming request retransmission means. Second timer means that is activated when a signal is transmitted, and the incoming request retransmitting means receives an incoming call when no call response is received from the mobile station when the first timer expires. The request signal is retransmitted, and the incoming call processing means may transmit the paging signal to the radio network controller when a response from the packet-switched call processing node is not received when the second timer expires. Is preferred.

  With this configuration, the timing at which the incoming request signal is retransmitted to the packet-switched call processing node, and the timing at which the incoming-call processing via the packet-switched call processing node is stopped and the paging signal is transmitted to the radio controller are set to the first timer and The second timer can be set individually, and the system status can be accurately identified and appropriate incoming processing can be performed.

  In addition, the set time of the second timer is preferably shorter than that of the first timer. With this configuration, it is possible to quickly determine that a failure has occurred in the packet-switched call processing node, and it is possible to quickly realize the arrival of a circuit-switched call to the mobile station.

  According to the circuit-switched call processing node, the packet-switched call processing node, the mobile communication system, and the mobile communication method according to the present invention, when the packet-switched call originates from the circuit-switched call, or the circuit-switched call arrives. Even when a failure occurs in the packet-switched call processing node at this time, it is possible to receive a circuit-switched call to the mobile station.

It is a functional block diagram of VLR / MSC and SGSN of the mobile communication system which concerns on one Embodiment of this invention. It is a hardware block diagram of VLR / MSC and SGSN. FIG. 4 is a sequence diagram showing processing executed when a packet-switched call transmission and a circuit-switched call arrival compete in the mobile communication system according to the present embodiment. FIG. 4 is a sequence diagram showing processing executed when a packet-switched call transmission and a circuit-switched call arrival compete in the mobile communication system according to the present embodiment. It is a figure which shows the operation | movement of the incoming call process shown to FIG. In the mobile communication system which concerns on this embodiment, it is a sequence diagram which shows the process performed when the incoming call of a circuit switching call and the failure generation of SGSN compete. In the mobile communication system which concerns on this embodiment, it is a sequence diagram which shows the process performed when the incoming call of a circuit switching call and the failure generation of SGSN compete. It is a figure which shows the operation | movement of the incoming call process shown to FIG. It is a figure which shows the structure of the conventional mobile communication system, and the operation | movement of the incoming process of the circuit switching call in this mobile communication system. It is a figure which shows the state which becomes an incoming call impossible in the incoming process of the circuit switching call in the conventional mobile communication system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a functional block diagram of the VLR / MSC 101 and the SGSN 102 in the mobile communication system 100 according to the present embodiment. The overall configuration of the mobile communication system 100 according to the present embodiment is the same as the overall configuration of the conventional mobile communication system 100 shown in FIG. 9, and new functions are added to the VLR / MSC 101 and the SGSN 102 as shown in FIG. It is a thing. Hereinafter, the difference between the configuration of the mobile communication system according to the present embodiment and the configuration of the conventional mobile communication system will be mainly described.

  The VLR / MSC 101 according to the present embodiment instructs to return an incoming request response indicating that the SGSN 102 has received an incoming request when a call response corresponding to the incoming request transmitted to the SGSN 102 is not received from the MS 106. In addition, an incoming request is retransmitted to the SGSN 102 after a flag for adding is added. With regard to such a function, as shown in FIG. 1, the VLR / MSC 101 includes an incoming request transmission unit (incoming request transmission unit) 201, a first timer 202, an incoming request retransmission unit (incoming request retransmission unit) 203, a second A timer 204 and an incoming call processor (incoming call processing means) 205 are included.

  The incoming request transmission unit 201 transmits an incoming request signal to the SGSN 102 in response to receiving a circuit switching call paging request from the GMSC 103. Also, the incoming request transmission unit 201 activates the first timer 202 simultaneously with the incoming request transmission, and if no incoming call response is received from the MS 106 before the first timer 202 expires, the incoming request request retransmission unit 203 Send to.

  The incoming request transmission unit 201 confirms whether or not the Gs association is being established in response to the reception of the call request for the circuit-switched call. When the Gs association is established, the incoming request signal is transmitted to the SGSN 102 as described above. On the other hand, when the Gs association is not established, a circuit switching call (paging) is performed to the RNC / BTS 107. To the incoming call processing unit 205.

  The first timer 202 is a timer function that is activated simultaneously with the incoming request transmission in response to an instruction from the incoming request transmission unit 201 as described above. Specifically, it is a response waiting timer from the MS 106 and counts the time required from the time when the incoming request signal is transmitted to the SGSN 102 until the reception of the call response signal from the MS 106. As the first timer 202, a conventional T3313 timer can be applied.

  The incoming call request retransmission unit 203 retransmits the incoming call request to the SGSN 102 when no call response is received from the MS 106 even when the first timer 202 expires. The incoming request retransmission unit 203 adds a flag indicating that the SGSN 102 returns an incoming request response in response to reception of the incoming request, and then transmits the incoming request to the SGSN 102.

  The incoming request retransmitting unit 203 activates the second timer 204 simultaneously with the incoming request transmission, and if the incoming request is not received from the SGSN 102 until the second timer 204 expires, the incoming processing unit 205 Send to.

  The incoming request retransmission unit 203 also activates the first timer 204 simultaneously with the incoming request transmission, receives the incoming request response from the SGSN 102 before the second timer expires, and calls from the MS 106 until the first timer 202 expires. When the response is not received, the incoming call request may be transmitted to the SGSN 102 again.

  The second timer 204 is a timer function that is activated simultaneously with the incoming request transmission in response to an instruction from the incoming request retransmission unit 203 as described above. Specifically, it is a response waiting timer from the SGSN 102 and counts the time required from the time when the incoming request signal is transmitted to the SGSN 102 until the time when the incoming request response signal is received from the SGSN 102. The set time of the second timer 204 is preferably set to be shorter than that of the first timer 202 so that the failure of the SGSN 102 can be quickly grasped.

  The incoming call processing unit 205 performs an incoming call to the RNC / BTS 107 when the incoming call request response is not returned from the SGSN 102 even when the second timer 204 expires. The incoming call processing unit 205 transmits to the RNC / BTS 107 a paging signal whose non-searching indication is not set.

  The SGSN 102 according to the present embodiment is configured to send back an incoming request response when the incoming request received from the VLR / MSC 101 is flagged. With regard to such a function, as shown in FIG. 1, the SGSN 102 includes an incoming request receiving unit 301, an incoming request response transmitting unit (response transmitting unit) 302, and an incoming processing unit 303.

  When receiving an incoming request from the VLR / MSC 101, the incoming request receiving unit 301 transmits a message to that effect to the incoming processing unit 303. In addition, the incoming request receiving unit 301 checks whether or not the received incoming request has a flag, and if a flag is added, transmits this fact to the incoming request response transmitting unit 302.

  The incoming request response transmission unit 302 transmits an incoming request response to the VLR / MSC 101 when a flag is added to the incoming response received from the VLR / MSC 101.

  In response to the incoming call request, the incoming call processing unit 303 checks the current communication status such as the presence / absence of packet communication for the user (MS 106) related to this incoming call request, sets a non-searching indication according to the communication status, and sets a paging signal Is transmitted to the RNC / BTS 107.

  FIG. 2 is a hardware configuration diagram of the VLR / MSC 101 and the SGSN 102. The VLR / MSC 101 and the SGSN 102 physically include a CPU (Central Processing Unit) 111, a RAM (Random Access Memory) 112 and a ROM (Read Only Memory) 113, which are main storage devices, an auxiliary storage device 114 such as a hard disk device, The computer includes an input device 115 such as an input key that is an input device, an output device 116 such as a display, and a communication module 117 that is a data transmission / reception device such as a network card. The functions of the VLR / MSC 101 and the SGSN 102 described with reference to FIG. 1 are performed by reading predetermined computer software on the hardware such as the CPU 111 and the RAM 112 shown in FIG. This is realized by operating the device 116 and the communication module 117 and reading and writing data in the RAM 112 and the auxiliary storage device 114.

  Next, with reference to FIGS. 3 to 8, processing executed in the mobile communication system 100 of the present embodiment will be described, and a mobile communication method according to the present embodiment will be described. In the present embodiment, the mobile communication system 100 has a case where a packet-switched call originates from a circuit-switched call, or a SGSN 102 (packet-switched call processing node) failure occurs when a circuit-switched call arrives. Then, the incoming call processing is performed so that a circuit-switched call to the MS 106 can be established. As a premise of these processes, the MS 106 is registered in the Combined location in the Location Area 109 managed by the VLR / MSC 101 and the Routing Area 110 managed by the SGSN 102.

  First, with reference to FIGS. 3 to 5, processing executed in the mobile communication system 100 when a packet-switched call transmission and a circuit-switched call arrival conflict will be described. 3 and 4 are sequence diagrams showing this process, and FIG. 5 is a diagram showing the operation of the incoming call process shown in FIGS.

  As shown in FIG. 3, first, when the GMSC 103 receives a circuit switching call calling request signal for the MS 106, the GMSC 103 transmits the circuit switching call calling request to the VLR / MSC 101 (S101). In the VLR / MSC 101, in response to the reception of the call request signal, the incoming request transmission unit 201 confirms the contract state of the user of the MS 106 regarding the call request, the service provision status, etc., and the MS 106 can use the circuit switching service. It is determined whether or not (S102). When it is determined that the MS 106 can use the circuit switching service, the process proceeds to step S103. If it is determined that the circuit-switched service cannot be used, the MS 106 returns an error response to the call request for the circuit-switched call to the call request transmission source and ends the process (S104).

  Subsequently, the incoming request transmission unit 201 determines whether or not the MS 106 has already been registered for the Combined location and the Gs association is being established (S103). If the Gs association is being established, the process proceeds to step S105. If the Gs association has not been established, the VLR / MSC 101 (incoming call processing unit 205) makes a circuit switching call (paging) to the RNC / BTS 107 (S106). Note that step S106 is a conventional circuit-switching incoming process, and thus the description thereof is omitted.

  Then, the incoming request transmission unit 201 transmits an incoming request signal to the SGSN 102 with which the Gs association has been established (S105: incoming request transmission step). At the same time as this transmission processing, the incoming request signal is transmitted to the SGSN 102. The first timer (T3313 timer) 202 for counting the time required from the start to reception of the call response signal from the MS 106 is started (S107).

  Next, in SGSN 102, when an incoming request signal is received from VLR / MSC 101 by incoming request receiver 301, this incoming request signal is transmitted to incoming processor 303. In response to the reception of the incoming request signal, the incoming processing unit 303 checks whether or not the MS 106 corresponding to the incoming request is in packet communication (S108). When packet communication is not in progress (no communication), the incoming call processing unit 303 calls the mobile device (paging), that is, a paging signal set as Non-searching Indication = non-searching is sent to the RNC / BTS 107. It is transmitted (S109).

  When the packet communication is in progress, the MS 106 is called (paging) while the packet communication is in progress, that is, a paging signal set as Non-searching Indication = searching is transmitted to the RNC / BTS 107 (S110). At this time, the MS 106 is in packet communication, and when the process proceeds to step S110, the recognition of the SGSN 102 matches the actual state of the MS 106. This sequence diagram relates to the incoming call processing when the SGSN 102 recognizes the communication state of the MS 106 as “not communicating” as described above, and actually the MS 106 is “in communication”. Description of is omitted.

  Next, in response to the reception of the paging signal in step S109, the RNC / BTS 107 sends a PAGING TYPE1 call signal corresponding to the non-searching indication setting value (non-searching) of this paging signal to the MS 106. (S112). At this time, the MS 106 is transmitting a packet switching service (S111) and is transmitting a packet. On the other hand, the call signal from the RNC / BTS 107 is PAGING TYPE1 (not communicating). For this reason, since the type of the call signal is different from the actual communication state of the own device and the MS 106 cannot react to the call signal, the incoming call fails (S113).

  Since the call response is not transmitted from the MS 106 to the VLR / MSC 101 due to the incoming failure in step S113, the first timer 202 started in step S107 expires in the VLR / MSC 101 and times out (S114). Even if a predetermined time (first timer setting time) has elapsed since the incoming request transmission unit 201 transmitted the incoming request to the SGSN 102, a call response indicating completion of incoming processing cannot be received from the MS 106 for some reason. Thus, it is determined that the incoming call has failed, and that fact is transmitted to the incoming call request retransmission unit 203. Then, a flag indicating that the SGSN 102 returns an incoming request response in response to reception of this incoming request is added to the incoming request signal by the incoming request request retransmission unit 203 (S115). It is transmitted to the SGSN 102 (S116: incoming request re-transmission step).

  As shown in FIG. 4, simultaneously with the transmission processing in step S116, the first timer 202 is started (S117), and at the time of reception of the incoming request response signal from the SGSN 102 from the time of transmission of the incoming request signal to the SGSN 102 The second timer 204 for counting the time required until the time is started (S118).

  In addition, the packet outgoing call of the packet switching service originated by the MS 106 in step S111 reaches the SGSN 102 (S119), the subscriber information of the user A of the MS 106 held in the user profile of the SGSN 102 is updated, and the state of the MS 106 is changed. “Non-communication” is changed to “packet communication” (S120).

  Next, in the SGSN 102, when the incoming request receiving unit 301 receives the incoming request signal transmitted from the VLR / MSC 101 in step S116, it is confirmed whether or not a flag is added to this incoming request signal ( S121). If the flag is added, the fact is transmitted to the incoming request response transmission unit 302, and the incoming request response transmission unit 302 generates an incoming request response signal indicating that the SGSN 102 has received the incoming request. (S122: response transmission step). When the VLR / MSC 101 receives an incoming request response signal, the incoming request retransmission unit 203 stops the second timer (S123). If no flag is added, the process proceeds to step S124. It should be noted that the processing in steps S121 to S123 is also performed when an incoming request is received in step S105. When the incoming request in step S105 is received, since no flag is added to this incoming request, no processing is performed and the process proceeds to step S108.

  Subsequently, in the SGSN 102, the incoming call processor 303 confirms whether the MS 106 corresponding to the incoming call request received in step S116 is in packet communication (S124). Here, since the SGSN 102 recognizes that the MS 106 is in packet communication in step S120, the mobile device call (paging) of the MS 106 is performed during packet communication, that is, Non-searching Indication = searching is set. A paging signal is transmitted to the RNC / BTS 107 (S125). If it is determined that the packet communication is not in progress (no communication), the mobile device is called as a packet non-communication (S126).

  Next, in response to the reception of the paging signal in step S125, the RNC / BTS 107 performs an IMSI search according to the setting value of the non-searching indication of this paging signal being “searching” (S127). MS 106 (user A) is identified. Here, IMSI (International Mobile Subscriber Identity) is a subscriber identifier and is used as a key for identifying a user. Then, a calling signal of PAGING TYPE 2 corresponding to the non-searching indication setting value (searching) of the paging signal is sent to the MS 106 (S128).

  Since the MS 106 is in packet communication and can respond to the PAGING TYPE2 call signal, the call response signal is transmitted to the VLR / MSC 101 (S129), and the incoming call process is continued (S130).

  In the VLR / MSC 101, in response to receiving the call response signal from the MS 106, the incoming request re-sending unit 203 stops the first timer (S131), and the incoming call processing is continued (S132).

  If the VLR / MSC 101 receives the incoming request response in step S122 within the set time of the second timer and the call response in step S129 is not received within the set time of the first timer, the VLR The incoming request transmission unit 201 of the / MSC 101 may transmit the incoming request again to the SGSN 102, or the incoming request retransmission unit 203 may retransmit the incoming request with a flag to the SGSN 102.

  Here, the incoming call processing of this embodiment shown in FIG. 5 is compared with the conventional incoming call failure situation described above with reference to FIG. In the conventional method of FIG. 10, when the VLR / MSC 101 does not receive a call response from the MS 106 even after a predetermined time has elapsed since the time when the VLR / MSC 101 transmitted an incoming request to the SGSN 102 (S2), the VLR / MSC 101 directly receives the RNC / BTS 107. The MSC 106 is called by transmitting a paging signal. On the other hand, in this embodiment, in the above-described case, the VLR / MSC 101 retransmits the incoming request signal to the SGSN again (S116 in FIGS. 3 and 5). As a result, the SGSN 102 can transmit a paging signal reflecting the latest communication state of the MS 106 (S125 in FIGS. 3 and 5), and the incoming process to the MS 106 can be executed.

  Next, processing executed in the mobile communication system 100 when a failure of the SGSN 102 (packet switching call processing node) occurs when a circuit-switched call is received will be described with reference to FIGS. 6 and 7 are sequence diagrams showing this process, and FIG. 8 is a diagram showing the operation of the incoming call process shown in FIGS.

  The processing steps of steps S201 to S207 are the same as steps S101 to S107 of FIG.

  When the incoming call request signal in step S205 is transmitted from the VLR / MSC 101 to the SGSN 102, in this sequence, since the SGSN 102 has failed as described above, the SGSN 102 cannot normally receive the incoming call request signal (S208). ). As a result, the mobile device call is not executed from the SGSN 102 and the call response signal from the MS 106 cannot be received by the VLR / MSC 101. Therefore, the first timer 202 started in step S207 expires and times out (S209).

  Subsequently, in the VLR / MSC 101, the incoming call request transmission unit 201 sends a call response indicating that the incoming call processing has been completed even after a predetermined time (first timer set time) has elapsed since the incoming call request was transmitted to the SGSN 102. It cannot be received from the MS 106, and it is determined that the incoming call has failed for some reason, and that fact is transmitted to the incoming call request retransmission unit 203. Then, a flag indicating that the SGSN 102 returns an incoming request response in response to reception of this incoming request is added to the incoming request signal by the incoming request request retransmission unit 203 (S210). It is transmitted to the SGSN 102 (S211: incoming request re-transmission step). Simultaneously with the transmission processing in step S211, the first timer 202 is started (S212), and the time required from the time when the incoming request signal is transmitted to the SGSN 102 until the time when the incoming request response signal is received from the SGSN 102 is counted. Therefore, the second timer 204 is started (S213).

  When the incoming call request signal in step S211 is transmitted from the VLR / MSC 101 to the SGSN 102, the SGSN 102 cannot normally receive the incoming call request signal as in step S208 (S214). As a result, the SGSN 102 does not execute the process of confirming the presence or absence of the flag of the incoming request signal, and the incoming request response signal is not returned from the SGSN 102 to the VLR / MSC 101. Therefore, the second timer 204 started in step S213 expires and times out. (S215). If the second timer times out, the first timer is also stopped as shown in FIG. 7 (S216).

  An incoming request request response signal indicating that the SGSN 102 has received an incoming request signal even after a predetermined time (second timer set time) has elapsed since the incoming request retransmission unit 203 transmitted the incoming request with the flag added to the SGSN 102. Cannot be received from the SGSN 102, it is determined that some failure has occurred in the SGSN 102, and that fact is transmitted to the incoming call processing unit 205. Then, the incoming call processing unit 205 calls the mobile station (paging) of the MS 106 (S217: paging signal transmission step), and the paging signal is transmitted to the RNC / BTS 107. Here, since a failure has occurred in the SGSN 102 and the conventional Combined location registration process cannot be executed, the VLR / MSC 101 cannot grasp the communication status of the MS 106 and cannot determine whether there is a call in communication. Therefore, the non-searching indication setting value is “not set” in the paging signal in step S217. Further, the first timer 202 is started at the same time as the transmission process in step S217 (S218).

  Next, in response to reception of the paging signal in step S217, the RNC / BTS 107 performs IMSI search in response to the setting value of the non-searching indication of this paging signal being “not set” (S219). The MS 106 (user A) to be called is specified, and it is determined whether or not the MS 106 is communicating. Then, a terminal call is performed using an appropriate call signal according to the determination result (S220). More specifically, when it is determined by the IMSI search that the MS 106 is not communicating, a PAGING TYPE 1 call signal is sent to the MS 106. If it is determined that the MS 106 is communicating, a PAGING TYPE 2 call signal is sent to the MS 106.

  Since the MS 106 can respond to the call signal received from the RNC / BTS 107, the call response signal is transmitted to the VLR / MSC 101 (S221), and the incoming call processing is continued (S222).

  In the VLR / MSC 101, in response to receiving the call response signal from the MS 106, the incoming call processing unit 205 stops the first timer (S223), and the incoming call process is continued (S224).

  If the call response in step S221 is not received by the VLR / MSC 101 within the set time of the first timer, the incoming call processing unit 205 of the VLR / MSC 101 determines that the incoming call has failed, and this An error response to the circuit-switched call call request may be returned to the call request source.

  Here, the incoming call processing of the present embodiment shown in FIG. 8 is compared with the conventional incoming call failure situation described above with reference to FIG. In the conventional method of FIG. 10, when the VLR / MSC 101 transmits an incoming call request to the GSN 102 (S2), if a call response is not received from the MS 106 even after a predetermined time has elapsed, a problem has occurred in the incoming call processing. The VLR / MSC 101 transmits a paging signal directly to the RNC / BTS 107 to call the MSC 106 without determining the cause of the problem. On the other hand, in the present embodiment, in the above-described case, the VLR / MSC 101 adds a flag for causing the SGSN 102 to perform a process of returning an incoming request response indicating that the incoming request has been received, and then re-adds the SGSN to the SGSN. The incoming call request signal is retransmitted (S211 in FIGS. 6 and 8). As a result, if the incoming call request response signal is not received from the SGSN 102 within the predetermined time (second timer set time), it is determined that a failure has occurred in the SGSN 102, and the mobile station by the incoming call processing unit 205 promptly It is possible to switch to calling (S217 in FIGS. 6 and 8), and it is possible to quickly realize incoming call processing to the MS.

  As described above, according to the mobile communication system 100, the VLR / MSC 101, the SGSN 102, and the mobile communication method according to the present embodiment, the packet-switched call and the circuit-switched call are competing for the incoming call to the MS 106. In the case of failure, the incoming request request retransmission unit 203 of the VLR / MSC 101 transmits the incoming request signal to the SGSN 102 again when the VLR / MSC 101 does not receive a call response from the MS 106 related to the incoming request signal. When this retransmitted incoming request signal is received by the SGSN 102, a packet exchange call originated from the MS 106 has also reached the SGSN 102, and the incoming call processing unit 303 of the SGSN 102 indicates that the MS 106 is in communication Can be transmitted to the RNC / BTS 107 with an appropriate paging signal (that is, a paging signal set to Non-searching Indication = searching). The RNC / BTS 107 can call the MS 106 during packet communication. As a result, even if the packet-switched call and the circuit-switched call are in conflict, the circuit-switched call can be received by the MS 106. It becomes.

  In addition, the incoming request re-transmission unit 203 of the VLR / MSC 101 adds and transmits a flag including information that prompts the SGSN 102 to send back a response in response to reception of the incoming request signal. When this response (incoming request response signal) is not received from the SGSN 102, the incoming call processor 205 of the VLR / MSC 101 transmits a paging signal for calling the MS 106 to the RNC / BTS 107. As a result, the VLR / MSC 101 can recognize whether or not a failure has occurred in the SGSN 102 based on whether or not an incoming request response signal has been received from the SGSN 102. When a failure has occurred in the SGSN 102, the incoming call processing to the MS 106 via the SGSN 102 can be stopped and changed to incoming call processing via only the RNC / BTS 107. As a result, even when a failure of the SGSN 102 occurs when a circuit-switched call is received, it is possible to receive a circuit-switched call to the MS 106.

  Further, the VLR / MSC 101 transmits to the SGSN 102 the first timer 202 that is started when the incoming request transmission unit 201 transmits the incoming request signal to the SGSN 102, and the incoming request signal that has been flagged by the incoming request retransmission unit 203. A second timer 204 that is activated when the first timer 202 expires, the incoming request retransmitting unit 203 sends an incoming request signal to the SGSN 102 when no call response has been received from the MS 106. When the second timer 204 expires, the incoming call processing unit 205 transmits a paging signal to the RNC / BTS 107 when a response from the SGSN 102 is not received. Therefore, the timing at which the incoming request signal is retransmitted to the SGSN 102 and the timing at which the incoming call processing via the SGSN 102 is stopped and the paging signal is transmitted to the RNC / BTS 107 are individually set by the first timer 202 and the second timer 204. Therefore, it is possible to accurately identify the state of the system and perform appropriate incoming call processing.

  Further, since the set time of the second timer 204 is shorter than that of the first timer 202, it is possible to quickly determine that a failure has occurred in the SGSN 102, and to promptly receive a circuit-switched call to the MS 106. realizable.

  As described above, the mobile communication system 100, the VLR / MSC 101, the SGSN 102, and the mobile communication method according to the present invention have been described with the preferred embodiments, but the present invention is not limited to the above embodiments. For example, the incoming request transmission unit 201 may add a flag indicating that an incoming request response is returned to the incoming request and then transmit the incoming request signal to the SGSN 102. In this case, the incoming request transmission unit 201 activates the second timer 204 in addition to the first timer 202 when the incoming request is transmitted. If the incoming request is not received from the SGSN 102 even when the second timer 204 expires, the incoming request processor 205 does not retransmit the incoming request, and the incoming processor 205 receives the paging signal to the RNC / BTS 107. The transmission process may be implemented.

  DESCRIPTION OF SYMBOLS 100 ... Mobile communication system, 101 ... VLR / MSC (circuit switching call processing node), 102 ... SGSN (packet switching call processing node), 103 ... GMSC (gateway node), 107 ... RNC / BTS (radio controller), 201 ... incoming call request transmission part (incoming call request transmission means), 202 ... first timer, 203 ... incoming call request retransmission part (incoming call request retransmission means), 204 ... second timer, 205 ... incoming call processing part (incoming call processing means), 302 ... an incoming request response transmission unit (response transmission means).

Claims (6)

In the circuit-switched call processing node that performs the incoming call processing via the packet-switched call processing node and the radio controller in response to receiving the incoming request signal from the gateway node to the mobile station,
An incoming request transmission means for transmitting the incoming request signal to the packet-switched call processing node;
When the incoming request signal is transmitted from the mobile station related to the incoming request signal after a lapse of a predetermined period after the incoming request signal is transmitted by the incoming request request transmission means, the incoming call request signal is processed by the packet exchange call processing. An incoming request retransmission means for retransmitting to the node;
With
The incoming request transmission unit or the incoming request re-transmission unit provides information that prompts the packet-switched call processing node to return a response to the circuit-switched call processing node in response to reception of the incoming request signal. Send
further,
When the response is not received from the packet-switched call processing node after a lapse of a predetermined period after being transmitted with the information added to the incoming request signal by the incoming request transmitting means or the incoming request retransmitting means, A circuit-switched call processing node comprising an incoming call processing means for transmitting a paging signal for calling the mobile station to a radio network controller. A first timer that is started when the incoming request signal is transmitted by the incoming request transmission means;
A second timer that is started when an incoming request signal to which the information is given is transmitted by the incoming request transmission unit or the incoming request retransmission unit;
With
The incoming request re-transmission means re-transmits the incoming request signal when the first timer has expired and a call response has not been received from the mobile station,
The incoming call processing means transmits the paging signal to the radio network controller when a response from the packet-switched call processing node is not received when the second timer expires. The circuit-switched call processing node according to claim 1.   3. The circuit-switched call processing node according to claim 2, wherein a setting time of the second timer is shorter than that of the first timer. In a packet-switched call processing node that performs incoming processing through a radio controller in response to receiving an incoming request signal from a gateway node to a mobile station from a circuit-switched call processing node,
The circuit-switched call processing node, when the incoming request signal received from the circuit-switched call processing node is given information prompting the packet-switched call processing node to send a response back to the circuit-switched call processing node A packet-switched call processing node, comprising response transmission means for transmitting the response to the message.   A mobile communication system comprising the circuit-switched call processing node according to any one of claims 1 to 3 and the packet-switched call processing node according to claim 4. A mobile communication method executed by a mobile communication system comprising a circuit-switched call processing node and a packet-switched call processing node,
An incoming request transmission step for transmitting an incoming request signal to the packet-switched call processing node in response to the incoming request transmission means of the circuit-switched call processing node receiving an incoming request signal from the gateway node to the mobile station; ,
An incoming request re-transmission means of the circuit-switched call processing node receives a call response from the mobile station related to the incoming request signal after the elapse of a predetermined period after the incoming request signal is transmitted in the incoming request transmission step. If not, an incoming request retransmission step for retransmitting the incoming request signal to the packet-switched call processing node;
Including
In the incoming call request transmission step or the incoming call request retransmission step, the incoming call request transmission means or the incoming call request retransmission means is configured such that, in response to reception of the incoming call request signal, the packet-switched call processing node is the circuit-switched call processing node. With information prompting them to send back a response,
A response that the response transmission means of the packet-switched call processing node transmits a response to the circuit-switched call processing node when the information is added to the incoming request signal received from the circuit-switched call processing node Sending step;
The packet switching call processing node of the circuit-switched call processing node adds the information to the incoming request signal in the incoming request transmission step or the incoming request re-transmission step. A paging signal transmission step of transmitting a paging signal for calling the mobile station to a radio network controller that performs incoming processing to the mobile station when the response is not received from a processing node;
A mobile communication method comprising:

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