JP2009267997A - Mobile communication method, mobile station, and core network device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable circuit switching communication (both of transmission and reception) even if a mobile station UE waits in an LTE-form system. <P>SOLUTION: A mobile communication method includes: a step of allowing an exchanger MME having received a service request for first protocols to transmit a service response for first protocols indicating relationship to the start of the circuit switching communication to a radio base station eNB; a step of allowing the radio base station eNB that has received setting information indicating relationship to the start of the circuit switching communication to transfer the service response for first protocols to a function EMM and to simultaneously transmit instruction information to a function AS; a step of allowing the function EMM that has received the service response for first protocols to instruct the function MM to start the circuit switching communication; a step of allowing the function MM that has received the instruction information to select a cell of a second communication system; and a step of allowing the function MM to establish a link for circuit switching communication via the cell of the second communication system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication system in which a system of a first communication method that is not compatible with circuit-switched communication and a system of a second communication method that is compatible with circuit-switched communication coexist. The present invention relates to a mobile communication method, a mobile station, and a core network device in which a mobile station that is performing starts circuit-switched communication.

  A communication start operation in a conventional LTE (Long Term Evolution) system will be described with reference to FIG.

  As shown in FIG. 5, in step S3000, the mobile station UE performs a location registration process (Attach / TAU (Tracking Area Update)) on the LTE switching system MME.

  In step S3001A, the application function AP of the mobile station UE transmits “Primitive” to the function EMM that performs processing corresponding to the EMM protocol in response to a transmission operation by the user.

  Alternatively, the LTE exchange MME transmits “S1 Paging” to the LTE radio base station eNB in step S3001B, and transmits “Paging” to the function EMM in step S3001C.

  As a result, in step S3002, the function EMM transmits “Primitive” to the function AS that performs the AS protocol processing.

  In step S3003, the function AS transmits “RRC Connection Request” to the radio base station eNB.

  In step S3004, the radio base station eNB transmits “RRC Connection Setup” to the function AS.

  In steps S3005 to S3007, the function EMM transmits “NAS Service Request” to the function AS, and the function AS includes the received “NAS Service Request” in the “RRC Connection Setup Complete”, and the radio base station eNB The radio base station eNB extracts “S-TMSI” from the received “RRC Connection Request”, and also extracts “NAS Service Request” from the received “RRC Connection Setup Complete”. The “S-TMSI” and “NAS Service Request” are included in the “S1 Initial UE Message” and transmitted to the exchange MME.

  In step S3008, the exchange MME transmits "S1 Initial UE Context Setup" including "UE capability (mobile station capability information)" to the radio base station eNB.

  In step S3009, the radio base station eNB transmits “RRC Security Mode Command” to the function AS, and in step S3010, the function AS transmits “Primitive” to the function EMM.

  In step S3011, the radio base station eNB transmits “RRC Connection Reconfiguration” to the function AS, and in step S3012, the function AS transmits “Primitive” to the function EMM.

  In step S3013, the function AS transmits “RRC Security Mode Complete” to the radio base station eNB, and transmits “RRC Connection Reconfiguration Complete” to the radio base station eNB in step S3014.

  In step S3015, the radio base station eNB transmits “S1 Setup Complete” to the exchange MME.

In step S3016, “U-Plane” is conducted between the mobile station UE and the network.
3GPP TS36.300 V8.4.0, March 2008 3GPP TS 23.272 V1.0, March 2008

  However, since the conventional LTE system does not support circuit switched (CS) communication, when the mobile station UE is waiting in the LTE system, the circuit switched communication (transmission) There was a problem that it was not possible to carry out incoming calls).

  Therefore, the present invention has been made in view of the above-described problems, and performs circuit-switched communication (both outgoing and incoming calls) even when the mobile station UE is waiting in an LTE system. It is an object of the present invention to provide a mobile communication method, a mobile station, and a core network device that can be used.

  According to a first aspect of the present invention, there is provided a mobile communication system in which a system of a first communication method that is not compatible with circuit-switched communication and a system of a second communication method that is compatible with circuit-switched communication are mixed. A mobile communication method in which a mobile station waiting in the system starts circuit-switched communication, wherein the mobile station terminates between the mobile station and the core network device of the first communication method. A first protocol processing unit that performs protocol compatible processing; a second protocol processing unit that performs second protocol compatible processing that terminates between the mobile station and the core network device of the second communication method; and A third protocol processing unit that performs processing corresponding to the third protocol that terminates with the access network device, and the core network device of the first communication method When a first protocol service request requesting to start circuit-switched communication is received from the first protocol processing unit via the first communication method wireless access network device, the first communication method wireless A process A for transmitting a service response for the first protocol indicating that it is related to the start of circuit-switched communication to the access network device, and the radio access network device of the first communication method is a core of the first communication method. When setting information indicating that it is related to the start of circuit-switched communication is received from the network device, the third protocol processing is performed simultaneously with the transfer of the first protocol service response to the first protocol processing unit. Transmitting instruction information for instructing a unit to perform cell selection of the second communication method; and the first When the protocol processor receives the service response for the first protocol, the process C instructing the second protocol processor to start the circuit-switched communication; and the third protocol processor When the instruction information is received, the step D of selecting the cell of the second communication method, and the second protocol processing unit receiving the instruction is selected by the third protocol processing unit. And a step E of establishing a link for circuit-switched communication through a communication system cell.

  In the first aspect of the present invention, in the step A, when the core network device of the first communication method receives the first protocol service request indicating that it is related to the start of circuit-switched communication, The service response for the first protocol and the setting information may be transmitted to the radio access network device of the first communication method.

  In the first feature of the present invention, the core network device of the first communication system transmits a paging signal including identification information of the mobile station, and the core network device of the first communication system includes the first communication system. Receiving initial information including identification information of the mobile station from a radio access network apparatus of communication system, and in step A, the core network apparatus of the first communication system is included in the paging signal When the identification information of the mobile station matches the identification information of the mobile station included in the initial information, the service response for the first protocol and the setting are sent to the radio access network device of the first communication method. Information may be transmitted.

  In the first feature of the present invention, in the step A, the first protocol processing unit sends the first protocol service request to the radio station between the mobile station and the radio access network device of the first communication method. It may be included in the link establishment response and transmitted to the core network device of the first communication method.

  In the first feature of the present invention, in the step B, the radio access network device of the first communication method includes the service response for the first protocol in the instruction information to the third protocol processing unit. May be transmitted.

  According to a second aspect of the present invention, there is provided a mobile communication system in which a system of a first communication method that is not compatible with circuit-switched communication and a system of a second communication method that is compatible with circuit-switched communication are mixed. A mobile station capable of starting circuit-switched communication even when waiting in the system, the first protocol terminating between the mobile station and the core network device of the first communication system A first protocol processing unit that performs a corresponding process, a second protocol processing unit that performs a second protocol corresponding process that terminates between the mobile station and the core network device of the second communication method, and wireless access to the mobile station A third protocol processing unit that performs processing corresponding to a third protocol that terminates with the network device, wherein the first protocol processing unit is configured to transmit the first communication method. The first protocol service unit is configured to transmit a service request for the first protocol indicating that it is related to the start of circuit-switched communication via a radio access network device, and the first protocol processing unit When receiving a service response for the first protocol indicating that it is related to the start of circuit-switched communication from the access network device, the second protocol processing unit is instructed to start the circuit-switched communication And the third protocol processing unit receives the instruction information instructing to perform cell selection of the second communication method from the radio access network device of the first communication method. The second protocol is configured to select a two-communication cell and receives an instruction from the first protocol processing unit. Processing unit, a gist that it is configured to establish a link for circuit switched communications via the cell of the second communication scheme selected by the third protocol processor unit.

  A third feature of the present invention is that the first communication method used in a mobile communication system in which a system of the first communication method that cannot cope with circuit-switched communication and a system of the second communication method that can cope with circuit-switched communication are mixed. A core network device, wherein a first protocol processing unit of the mobile station that performs processing corresponding to a first protocol that terminates between the mobile station and the core network device of the first communication method, When a service request for the first protocol is received via the radio access network device, the circuit switching communication is started to the first protocol processing unit via the radio access network device of the first communication method. At the same time as transmitting a service response for the first protocol indicating the relationship, a line exchange is made to the radio access network device of the first communication method. It is summarized as that is configured to transmit the setting information indicating that relate to the beginning of the communication.

  In the third aspect of the present invention, when the service request for the first protocol indicating that it is related to the start of circuit-switched communication is received, the first access to the radio access network apparatus of the first communication method is performed. The protocol service response and the setting information may be transmitted.

  In the third aspect of the present invention, a paging signal including the identification information of the mobile station is transmitted, and initial information including the identification information of the mobile station is received from a radio access network device of the first communication method. When the mobile station identification information included in the paging signal matches the mobile station identification information included in the initial information, the radio access network apparatus of the first communication method is configured. The service response for the first protocol and the setting information may be transmitted.

  In the third aspect of the present invention, the setting information may be transmitted including the first protocol service response.

  As described above, according to the present invention, a mobile communication method capable of performing circuit-switched communication (both outgoing and incoming) even when the mobile station UE is standing by in an LTE system. A mobile station and a core network device can be provided.

(Configuration of mobile communication system according to the first embodiment of the present invention)
With reference to FIG.1 and FIG.2, the structure of the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 1, in the mobile communication system according to the present embodiment, an LTE system (first communication system) system that is incompatible with circuit-switched communication and a WCDMA / GSM (second communication system) that is compatible with circuit-switched communication. ) System is mixed.

  Specifically, an LTE (first communication) system includes an exchange MME (first communication core network device) and a radio base station eNB (first communication wireless access network device). ing.

  The WCDMA / GSM (second communication system) system includes a circuit-switched communication switch MSC (second communication system core network device), a packet communication switch SGSN (second communication system core network device), A radio network controller RNC / BSC (second communication system radio access network apparatus) and a radio base station NodeB / BTS (second communication system radio access network apparatus) are provided.

  Further, as shown in FIG. 2, the mobile station UE performs a function EMM (first protocol) compatible processing that terminates between the mobile station UE and the exchange MME (core network device of the first communication method). Function MM (second protocol processing) for performing processing corresponding to the MM protocol (second protocol) terminated between the first protocol processing unit) and the mobile station UE and the exchange MSC / SGSN (core network device of the second communication method) AS) (third protocol processing unit) that performs AS protocol (third protocol) compatible processing that terminates between the mobile station UE and the radio base station eNB / radio control device RNC / BSC (radio access network device) ).

  Note that the AS protocol is originally a first AS protocol that terminates between the mobile station UE and the radio base station eNB, a second AS protocol that terminates between the mobile station UE and the radio network controller RNC (a radio network controller in WCDMA), It is divided into third AS protocols that are terminated between the mobile station UE and the radio network controller BSC (radio network controller in GSM), which are independent protocols.

  In this specification, for convenience, these three types of AS protocols are collectively referred to as “AS protocol”, but in detail, the function of performing “cell selection of the second communication scheme” in the following embodiment is the second This is a function of the second AS protocol or the third AS protocol according to the communication method (WCDMA method or GSM method).

  All other functions in the following embodiments are functions performed by the first AS protocol.

(Operation of the mobile communication system according to the first embodiment of the present invention)
With reference to FIG.3 and FIG.4, operation | movement of the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  First, with reference to FIG. 3, transmission processing from the mobile station UE will be described.

  As shown in FIG. 3, in step S1000, the mobile station UE performs location registration processing (Attach / TAU) for the LTE exchange MME and the WCDMA / GSM exchange MSC. In step S1000, after performing such location registration processing, the mobile station UE is waiting in the LTE system.

  In step S <b> 1001, the application function AP of the mobile station UE transmits “Primitive” to the function EMM that performs processing corresponding to the EMM protocol in response to a transmission operation by the user.

  In step S <b> 1002, the function EMM transmits “Primitive” to the function AS that performs AS protocol compatible processing.

  In step S1003, the function AS transmits “RRC Connection Request” to the radio base station eNB.

  In step S1004, the radio base station eNB transmits “RRC Connection Setup” to the function AS.

  In steps S1005 to S1007, the function EMM transmits “NAS Service Request” to the function AS, and the function AS includes the received “NAS Service Request” in the “RRC Connection Setup Complete”, and the radio base station eNB The radio base station eNB extracts “S-TMSI” from the received “RRC Connection Request”, and also extracts “NAS Service Request” from the received “RRC Connection Setup Complete”. The “S-TMSI” and “NAS Service Request” are included in the “S1 Initial UE Message” and transmitted to the exchange MME.

  Here, it is assumed that the “NAS Service Request (first protocol service request)” includes information “CSFB” indicating that it is related to the start of circuit-switched communication.

  In steps S1008 to S1010, when the exchange MME receives the “NAS Service Request (service request for the first protocol)” including the information “CSFB”, the “UE capability (of the mobile station) is transmitted to the radio base station eNB. “NAS Service Accept” is transmitted in “S1 Initial UE Context Setup” including “capability information)”.

  Here, in “S1 Initial UE Context Setup (setting information)” and “NAS Service Accept (service response for first protocol)”, information “CSFB (Circuit Switch FallBack)” indicating that it is related to the start of circuit-switched communication. "Is included.

  After that, the radio base station eNB extracts “NAS Service Accept” from the received “S1 Initial UE Context Setup”, and extracts the extracted “NAS Service Accept” in “RRC HO from EUTRA” or “RRC Connection Re” And to the exchange MME.

  In other words, the radio base station eNB transmits “NAS Service Accept” to the function EMM and simultaneously transmits “RRC HO from EUTRA” or “RRC Connection Release” to the function AS.

  Here, “RRC HO from EUTRA” or “RRC Connection Release” includes “Redirection Information”.

  “Redirection Information” is instruction information for instructing cell selection of the second communication method of WCDMA / GSM (second communication method).

  Further, “Redirection Information” may include the frequency of the second communication method, the cell ID, the system information of the cell, and the like.

  Further, the “Redirection Information” may include information “CSFB” indicating that it is related to the start of circuit-switched communication.

  Further, the function AS extracts “NAS Service Accept” from the received “RRC HO from EUTRA” or “RRC Connection Release”, and transmits the extracted “NAS Service Accept” to the function EMM.

  In step S1011, when the function EMM receives “NAS Service Accept”, the function EMM transmits “Primitive” for instructing the function MM to start circuit switching communication.

  In step S1012, when the function AS receives “Redirection Information”, the function AS selects a cell of the WCDMA / GSM system.

  In step S1013, the radio base station eNB transmits “S1 Setup Complete” to the exchange MME. In step S1014, the exchange MME transmits “S1 Release” to the radio base station eNB, and step S1015. Then, the radio base station eNB transmits “S1 Release Complete” to the exchange MME.

  In step S1016, the function MM establishes a link for circuit switching (CS) communication via the WCDMA / GSM cell selected by the function AS, and “U-Plane” is established between the mobile station UE and the exchange MME. Is conducted.

  Secondly, with reference to FIG. 4, an incoming call process for the mobile station UE will be described.

  As shown in FIG. 4, in step S2000, the mobile station UE performs location registration processing (Attach / TAU) for the LTE exchange MME and the WCDMA / GSM exchange MSC. In step S1000, after performing such location registration processing, the mobile station UE is waiting in the LTE system.

  In step S2001, the WCDMA / GSM exchange MSC transmits “Paging (paging signal)” addressed to the mobile station UE to the LTE exchange MME. In step S2002, the WCDMA / GSM exchange radio control is performed. “Paging (paging signal)” addressed to the mobile station UE is transmitted to the device RNC / BSC.

  In step S2003, the LTE exchange MME transmits “S1 Paging (paging signal)” addressed to the mobile station UE to the LTE radio base station eNB, and in step S2004, the mobile station UE Then, “Paging (paging signal)” addressed to the mobile station UE is transmitted.

  “Paging (paging signal)” in step S2004 is included in “S1 Paging (paging signal)” in step S2003 and transmitted.

  Here, it is assumed that “Paging (paging signal)” transmitted in step S2004 includes “S-TMSI (SAE-Temporary Mobile Subscriber Identity)” that is identification information of the mobile station UE.

  On the other hand, the radio control apparatus RNC / BSC of the WCDMA / GSM scheme transmits “Paging (paging signal)” addressed to the mobile station UE to the subordinate radio base station Node B / BTS.

  In step S2005, the function EMM transmits “Primitive” to the function AS that performs AS protocol processing.

  In step S2006, the function AS transmits “RRC Connection Request” to the radio base station eNB.

  In step S2007, the radio base station eNB transmits “RRC Connection Setup” to the function AS.

  In steps S2008 to S2010, the function EMM transmits “NAS Service Request” to the function AS, and the function AS includes the received “NAS Service Request” in the “RRC Connection Setup Complete”, and the radio base station eNB The radio base station eNB extracts “S-TMSI (identification information of the mobile station UE)” from the received “RRC Connection Request”, and also receives the “NAS from the received“ RRC Connection Setup Complete ”. “Service Request” is extracted, and “S-TMSI” and “NAS Service Request” are extracted as “S1 Initial UE Message” (initial information). It is sent to the exchange MME, including within.

  Also, it is assumed that “S1 Initial UE Message (initial information)” includes “S-TMSI (identification information of mobile station UE)”.

  As a result, the exchange MME receives “S-TMSI (identification information of mobile station UE)” and “S1 Initial UE Message (initial information)” included in “Paging (paging signal)” in step S2004. When the TMSI (identification information of the mobile station UE) matches, in steps S2011 to S2013, the exchange MME transmits “S1 capability including the UE capability (capability information of the mobile station)” to the radio base station eNB. “NAS Service Accept” is transmitted in “Initial UE Context Setup”.

  Here, “S1 Initial UE Context Setup (setting information)” and “NAS Service Accept (service response for first protocol)” include information “CSFB” indicating that it is related to the start of circuit-switched communication. It shall be.

  After that, the radio base station eNB extracts “NAS Service Accept” from the received “S1 Initial UE Context Setup”, and extracts the extracted “NAS Service Accept” in “RRC HO from EUTRA” or “RRC Connection Re” And to the exchange MME.

  Further, the function AS extracts “NAS Service Accept” from the received “RRC HO from EUTRA” or “RRC Connection Release”, and transmits the extracted “NAS Service Accept” to the function EMM.

  The operations in steps S2014 to S2020 are the same as the operations in steps S1011 to S1017 in FIG.

(Operations and effects of the mobile communication system according to the first embodiment of the present invention)
According to the mobile communication system according to the first embodiment of the present invention, when a paging signal for circuit-switched communication is transmitted to a mobile station UE that is waiting in an LTE system, and the mobile station When the UE transmits the circuit switching communication, the mobile station UE can be forcibly instructed to start the circuit switching communication in the WCDMA / GSM system. Even when waiting on the line, line-switched communication (both outgoing and incoming) can be performed.

  Further, according to the mobile communication system according to the first embodiment of the present invention, the radio base station eNB transmits “NAS Service Accept” to the function EMM, and at the same time, “RRC HO” to the function AS. Since “from EUTRA” or “RRC Connection Release” is transmitted, the problem that “RRC HO from EUTRA” or “RRC Connection Release” arrives at the mobile station UE before “NAS Service Accept” is avoided. be able to.

  Although the present embodiment has been described focusing on the procedure for making and receiving calls when the mobile station UE is in the idle state, the present invention describes a case where the mobile station is already in the connected state in the first communication method. May be applied.

  In such a case, “RRC Connection Request” and “RRC Connection Setup” may be omitted, and “RRC Connection Setup Complete” may be replaced with another message.

(Example of change)
The operations of the mobile station UE, the radio base station eNB, and the exchange MME described above may be performed by hardware, may be performed by a software module executed by a processor, or may be performed by a combination of both. May be.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile station UE, the radio base station eNB, or the exchange MME. Further, the storage medium and the processor may be provided as a discrete component in the mobile station UE, the radio base station eNB, or the exchange MME.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. It is a figure which shows the protocol structure of the mobile station which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows the operation | movement at the time of transmission in the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 3 is a sequence diagram showing an operation at the time of an incoming call in the mobile communication system according to the first embodiment of the present invention. It is a sequence diagram which shows the operation | movement at the time of the outgoing / incoming call in the conventional mobile communication system.

Explanation of symbols

UE ... Mobile station eNB, NodeB, BTS ... Radio base station RNC, BSC ... Radio controller MME, MSC, SGSN ... Exchange

Claims (10)

In a mobile communication system in which a system of a first communication method that is not compatible with circuit-switched communication and a system of a second communication method that is compatible with circuit-switched communication are mixed, the mobile that is waiting in the system of the first communication method A mobile communication method in which a station starts circuit switched communication,
The mobile station includes a first protocol processing unit that performs processing corresponding to a first protocol that terminates between the mobile station and the core network device of the first communication method, and a core network of the mobile station and the second communication method. A second protocol processing unit that performs processing corresponding to the second protocol that terminates with the device, and a third protocol processing unit that performs processing corresponding to the third protocol that terminates between the mobile station and the radio access network device And
A service request for a first protocol requesting that the core network device of the first communication system starts a circuit-switched communication from the first protocol processing unit via the radio access network device of the first communication system. A process A for transmitting a first protocol service response indicating that it is related to the start of circuit-switched communication to the radio access network device of the first communication method when received,
When the wireless communication network device of the first communication method receives setting information indicating that it is related to the start of circuit-switched communication from the core network device of the first communication method, the first protocol processing unit, Transmitting the instruction information for instructing the third protocol processing unit to perform cell selection of the second communication method simultaneously with transferring the service response for the first protocol;
A step C for instructing the second protocol processing unit to start the circuit-switched communication when the first protocol processing unit receives the first protocol service response;
When the third protocol processing unit receives the instruction information, the step D selects a cell of the second communication method;
The second protocol processing unit that has received the instruction includes a step E of establishing a link for circuit-switched communication via the cell of the second communication method selected by the third protocol processing unit. Mobile communication method.   In the step A, when the core network device of the first communication method receives the first protocol service request indicating that it is related to the start of circuit-switched communication, the radio access network device of the first communication method The mobile communication method according to claim 1, wherein the first protocol service response and the setting information are transmitted. The core network device of the first communication method transmits a paging signal including identification information of the mobile station;
The core network device of the first communication method receives initial information including identification information of the mobile station from the radio access network device of the first communication method;
In the step A, when the core network device of the first communication method matches the identification information of the mobile station included in the paging signal and the identification information of the mobile station included in the initial information, 2. The mobile communication method according to claim 1, wherein the first protocol service response and the setting information are transmitted to a radio access network device of one communication system.   In the step A, the first protocol processing unit includes the first protocol service request in a response for establishing a radio link between the mobile station and the radio access network device of the first communication method, The mobile communication method according to claim 1, wherein the mobile communication method transmits to the core network device of the first communication method.   In the step B, the radio access network device of the first communication method includes the first protocol service response in the instruction information and transmits the response to the third protocol processing unit. Item 2. The mobile communication method according to Item 1. In a mobile communication system in which a system of the first communication method that is not compatible with circuit-switched communication and a system of the second communication method that is compatible with circuit-switched communication are mixed, the system of the first communication method is waiting Even a mobile station that can start circuit-switched communication,
A first protocol processing unit that performs processing corresponding to a first protocol that terminates between the mobile station and the core network device of the first communication method;
A second protocol processing unit that performs a second protocol compatible process that terminates between the mobile station and the core network device of the second communication method;
A third protocol processing unit that performs third protocol compatible processing that terminates between the mobile station and the radio access network device;
The first protocol processing unit is configured to transmit a service request for the first protocol indicating that it is related to the start of circuit-switched communication via the radio access network device of the first communication method,
When the first protocol processing unit receives a first protocol service response indicating that it is related to the start of circuit-switched communication from the radio access network device of the first communication method, the first protocol processing unit And is configured to instruct to start the circuit-switched communication,
When the third protocol processing unit receives instruction information instructing to perform cell selection of the second communication method from the radio access network device of the first communication method, the third protocol processing unit changes the cell of the second communication method. Configured to choose,
Upon receiving an instruction from the first protocol processing unit, the second protocol processing unit establishes a link for circuit-switched communication via the cell of the second communication method selected by the third protocol processing unit. A mobile station that is configured as described above. A core network device of a first communication method used in a mobile communication system in which a system of a first communication method that is not compatible with circuit-switched communication and a system of a second communication method that is compatible with circuit-switched communication are mixed,
From the first protocol processing unit of the mobile station that performs processing corresponding to the first protocol that terminates between the mobile station and the core network device of the first communication method, via the radio access network device of the first communication method When a service request for the first protocol is received, the first protocol processing unit indicates that the first protocol processing unit is related to the start of circuit-switched communication via the radio access network device of the first communication method. Simultaneously with transmitting the protocol service response, the wireless communication network device of the first communication method is configured to transmit setting information indicating that it is related to the start of circuit-switched communication. A core network device.   When the service request for the first protocol indicating that it is related to the start of circuit-switched communication is received, the service response for the first protocol and the setting information are sent to the radio access network device of the first communication method. 8. The core network device according to claim 7, wherein the core network device is configured to transmit. Transmitting a paging signal including identification information of the mobile station, and receiving initial information including identification information of the mobile station from the radio access network device of the first communication method;
When the identification information of the mobile station included in the paging signal matches the identification information of the mobile station included in the initial information, the first protocol is transmitted to the radio access network apparatus of the first communication method. The core network device according to claim 7, wherein the core network device is configured to transmit a service response for use and the setting information.   8. The core network device according to claim 7, wherein the core network device is configured to transmit the setting protocol including the first protocol service response.

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