JP2012217084A - Mobile device and communication connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile device and a communication connection method, capable of preventing restriction of a conventional circuit-switched communication service, when the mobile device is located in a cell which is formed by a mobile communication system constituted only by a packet switch domain and to which packet communication is restricted.SOLUTION: A mobile device 300 includes: a notification information receiver 301 for receiving, from an in-zone mobile communication system, notification information including packet communication restriction in an in-zone cell formed by the in-zone mobile communication system in which the mobile device is located; a restriction detector 303 for detecting the presence or absence of packet communication restriction in the mobile communication system based on the received notification information; a RAT selector 305 for selecting a wireless access technique to be used when executing the circuit-switched communication service, based on the detected packet communication restriction; and a connection request transmitter 307 for determining a mobile communication system to be connected to, and for transmitting a connection request for the circuit-switched communication service, based on the selected wireless access technique.

Description

  The present invention relates to a mobile device and a communication connection method that can be connected to a plurality of mobile communication systems having different radio access technologies (RAT).

  In the 3rd Generation Partnership Project (3GPP), specifications relating to a plurality of mobile communication systems having different radio access technologies (RAT) such as 3G (W-CDMA) and Long Term Evolution (LTE) are defined. LTE does not use a circuit switching domain (CS domain), and is configured only by a packet switching domain (PS domain).

  However, for a while after the introduction of LTE, it is planned to provide a service combining 3G and LTE for reasons such as the area of LTE deployment and facility planning.

  Specifically, services that have been provided using CS domain functions, such as voice communications, are now being considered to utilize 3G CS domains. Therefore, CS fallback for switching to a 3G CS domain is defined even when a mobile device is waiting in the LTE network (for example, Non-Patent Document 1).

  In addition, when access restriction, specifically packet communication restriction that restricts packet communication, is performed in LTE, a mobile device cannot be located in a cell formed by LTE (hereinafter, LTE cell). 3GPP also stipulates that the cell (LTE cell in which packet communication regulation is not performed, or a mobile communication system (eg, 3G) cell using another RAT) is searched. Such access restriction types include restriction during construction associated with construction of facilities, access restriction that does not permit access at all, and access class restriction that restricts a specific access class.

3GPP TS 23.272, Circuit Switched (CS) fallback in Evolved Packet System (EPS); Stage 2

  However, when access restrictions as described above, specifically, packet communication restrictions that restrict packet communication are performed, if a mobile station is located in an LTE cell where the packet communication restrictions are performed, voice communication Conventional circuit-switched communication services such as incoming / outgoing calls are also restricted, and serviceability is significantly reduced.

  Therefore, the present invention has been made in view of such a situation, and in the case where the cell is formed in a cell formed by a mobile communication system composed only of a packet switching domain, packet communication regulation is performed in the cell. Therefore, it is an object of the present invention to provide a mobile device and a communication connection method that can prevent a conventional circuit-switched communication service from being restricted.

  In order to solve the problems described above, the present invention has the following features. First, the first feature of the present invention is a mobile device (mobile device 300) connectable to a plurality of mobile communication systems (LTE system 10, 3G system 20) having different radio access technologies. Broadcast information including packet communication regulation indicating that packet communication via a serving cell formed by a serving mobile communication system (LTE system 10) is restricted is received from the visited mobile communication system. A broadcast information receiving unit (broadcast information receiving unit 301) and a restriction detection unit (regulation detection unit) for detecting presence / absence of packet communication restriction in a cell of the mobile communication system based on the broadcast information received by the broadcast information receiving unit 303) and a selection for selecting a radio access technology to be used when a circuit-switched communication service is executed based on the packet communication restriction detected by the restriction detection unit (RAT selection unit 305) and a mobile communication system to be connected based on the radio access technology selected by the selection unit, and connection of the circuit-switched communication service to the determined mobile communication system The gist is to include a connection request transmission unit (connection request transmission unit 307) that transmits a request.

  In the first aspect of the present invention, the restriction detection unit is connected to a cell of a mobile communication system (3G system 20) using a radio access technology that is connectable to the mobile device and different from the mobile communication system in the area. Further detecting whether or not the circuit-switched communication service is restricted, and the selecting unit detects whether or not there is packet communication restriction in the cell of the visited mobile communication system detected by the restriction detecting unit, and the visited mobile communication A radio access technology to be used when executing the circuit switched communication service may be selected based on whether or not the circuit switched communication service is restricted in a cell of a mobile communication system using a radio access technology different from the system. .

  In the first feature of the present invention, the broadcast information is transmitted via a peripheral cell (3G cell) formed around the serving cell by a mobile communication system using a radio access technology different from the serving mobile communication system. Information indicating whether or not there is a restriction on the circuit-switched communication service, and the selection unit detects packet communication restriction in the cell of the mobile communication system in the area detected by the restriction detection unit, and the line in the neighboring cell. A radio access technology used when executing the circuit-switched communication service may be selected based on the presence or absence of restrictions on the switched communication service.

  In the first aspect of the present invention, the connection request transmission unit determines whether voice communication based on Voice over IP can be performed using the radio access technology selected by the selection unit, and the Voice over IP When voice communication by voice over IP can be executed, a voice communication connection request by voice over IP is transmitted to the determined mobile communication system, and when voice communication by voice over IP cannot be executed, the determined mobile communication system Alternatively, a connection request for voice communication by a circuit-switched call may be transmitted.

  According to a second aspect of the present invention, there is provided a communication connection method in a mobile device connectable to a plurality of mobile communication systems having different radio access technologies, which is formed by a visited mobile communication system in which the mobile device is located. Detecting the presence or absence of packet communication restriction in a cell of the mobile communication system based on broadcast information including packet communication restriction indicating that packet communication via a serving cell is restricted; and detecting the detected packet communication A step of selecting a radio access technology to be used when performing a circuit-switched communication service based on the regulation; a mobile communication system to be connected is determined based on the selected radio access technology; and the determined mobile Sending a connection request for the circuit-switched communication service to the communication system. .

  According to the characteristics of the present invention, even when a packet communication restriction is performed in a cell formed in a cell formed by a mobile communication system including only a packet switching domain, the conventional circuit switching type It is possible to provide a mobile device and a communication connection method that can prevent the communication service from being restricted.

1 is an overall schematic configuration diagram of a mobile communication system according to an embodiment of the present invention. FIG. 3 is a functional block diagram of a mobile device 300 according to an embodiment of the present invention. 2 is a functional block diagram of an eNodeB 150 according to the embodiment of the present invention. FIG. It is the flow which concerns on the connection operation example 1 to the mobile communication system of the mobile device 300 which concerns on embodiment of this invention. It is the flow which concerns on the connection operation example 2 to the mobile communication system of the mobile device 300 which concerns on embodiment of this invention. It is the flow which concerns on the connection operation example 3 to the mobile communication system of the mobile device 300 which concerns on embodiment of this invention.

  Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Overall Schematic Configuration of Mobile Communication System FIG. 1 is an overall schematic configuration diagram of a mobile communication system according to the present embodiment. As shown in FIG. 1, the mobile communication system according to the present embodiment includes an LTE system 10 and a 3G system 20. The LTE system 10 is configured only by a packet switching (PS) domain. On the other hand, the 3G system 20 includes a PS domain and a circuit switched (CS) domain.

  The LTE system 10 is a mobile communication system according to the Long Term Evolution (LTE) scheme. The 3G system 20 is a mobile communication system according to the 3G system (W-CDMA). That is, the LTE system 10 and the 3G system 20 use different radio communication technologies (RAT).

  In this embodiment, Voice over IP (VoIP) is used for voice communication and videophone in the LTE system 10, and circuit switching (CS) is used for voice communication in the 3G system 20. To do.

  The LTE system 10 includes a network device 100 and an eNodeB 150. The 3G system 20 includes a network device 200, an RNC 210, and a NodeB 250. The mobile device 300 can be connected to a plurality of mobile communication systems (LTE system 10, 3G system 20).

  The network device 100 is connected to the eNodeB 150. The network device 200 is connected to the NodeB 250. The network device 100 and the network device 200 are connected to each other and provided on a core network (not shown). The network device 100 and the network device 200 transmit and receive communication signals such as voice communication and control signals between the LTE system 10 and the 3G system 20.

  The eNodeB 150 is a radio base station that sets a radio access bearer (RAB) according to the LTE scheme as the mobile device 300 and performs radio communication. Specifically, eNodeB 150 sets a PS bearer, which is a RAB for packet communication, as mobile device 300.

  The RNC 210 controls the mobile device 300 via the NodeB 250. The NodeB 250 is a radio base station that performs radio communication by setting a radio access bearer (RAB) according to the 3G scheme as the mobile device 300. Specifically, NodeB 250 sets, as mobile device 300, a PS bearer that is an RAB for packet communication or a CS bearer that is an RAB for circuit switching.

(2) Functional Block Configuration of Mobile Device FIG. 2 is a functional block diagram of the mobile device 300. As shown in FIG. 2, the mobile device 300 includes a notification information receiving unit 301, a restriction detecting unit 303, a RAT selecting unit 305, and a connection request transmitting unit 307.

  The broadcast information receiving unit 301 receives various types of broadcast information transmitted from the LTE system 10 and the 3G system 20. In particular, the broadcast information receiving unit 301 regulates packet communication via a serving cell (LTE cell, see FIG. 1) formed by a serving mobile communication system (eg, LTE system 10) in which the mobile device 300 is located. The broadcast information including the packet communication restriction indicating that the communication is performed is received from the in-zone mobile communication system.

  The packet communication restriction is a kind of access restriction and means a state in which communication (including VoIP) using IP packets is restricted in the entire LTE system 10 or a specific LTE cell. Reasons for packet communication regulation include regulation during construction associated with construction of facilities, etc., access prohibition regulation that does not permit any access, and access class regulation that regulates a specific access class.

  In addition, broadcast information including such packet communication regulations is transmitted by a mobile communication system (3G system 20) using a radio access technology (RAT) different from the mobile communication system (LTE system 10). ) May include information indicating that the packet communication regulation via the peripheral cell (3G cell) formed in the vicinity of (3) is not performed, and information indicating whether or not the circuit-switched communication service is regulated.

  Note that information such as packet communication restrictions can be transmitted using, for example, SIB2 (System Information Block Type 2) of broadcast information in the LTE system 10 and SIB3 (System Information Block Type 3) of the 3G system 20.

  The restriction detection unit 303 detects access restrictions performed in the LTE system 10 and the 3G system 20. In particular, in the present embodiment, the restriction detection unit 303 detects presence / absence of packet communication restriction in the cell of the mobile communication system (LTE system 10 or 3G system 20) based on the broadcast information received by the broadcast information reception unit 301. .

  Specifically, the restriction detection unit 303 detects SIB3 or SIB2 of the broadcast information received by the broadcast information reception unit 301, and detects whether there is a packet communication restriction in the cell of the mobile communication system (or the entire mobile communication system). To do.

  In addition, the restriction detection unit 303 is a cell of a mobile communication system (for example, 3G system 20) that uses a RAT that is different from the mobile communication system in which the mobile device 300 is connected, and to which the mobile device 300 is located. It is also possible to further detect the presence / absence of restrictions on the circuit-switched communication service via. The circuit-switched communication service is, for example, voice communication, ISDN videophone, and Short Message Service (SMS). In order to transmit such a circuit-switched communication service via the PS domain, it is necessary to convert information to be transmitted into IP packets using VoIP.

  Specifically, the restriction detection unit 303 performs a cell search, receives broadcast information from a 3G cell formed around a serving cell (for example, an LTE cell), and receives a line through the 3G cell. Detects the presence or absence of restrictions on switched communication services.

  The RAT selection unit 305 selects an RAT to be used when performing packet communication based on the packet communication restriction detected by the restriction detection unit 303. For example, when the packet communication restriction is performed in the LTE system 10, the RAT selection unit 305 determines to execute the packet communication via the 3G system 20 using the RAT different from the LTE system 10, and performs the packet communication. The 3G method is selected as the RAT used for execution. On the contrary, when the packet communication restriction is performed in the 3G system 20, the RAT selection unit 305 determines to execute the packet communication via the LTE system 10 using the RAT different from the 3G system 20, and the packet communication The LTE method is selected as the RAT used when executing.

  In addition to the packet communication restriction in the cell of the visited mobile communication system detected by the restriction detection unit 303, the RAT selection unit 305 includes a mobile communication system (3G system 20) that uses a different RAT from the visited mobile communication system. Based on the regulation of the circuit-switched communication service in the cell, it is possible to select the RAT used when performing packet communication.

  Specifically, the RAT selection unit 305, when packet communication restriction is performed in the cell of the visited mobile communication system, the cell of the mobile communication system using the RAT different from the visited mobile communication system (or the mobile communication) It is determined, based on information indicating whether or not there is a restriction on the circuit-switched communication service included in the broadcast information transmitted from the visited mobile communication system, that the circuit-switched communication service is not regulated in the entire system) To do. Note that information indicating the presence / absence of restrictions on circuit-switched communication services can be transmitted using SIB2 of broadcast information in LTE system 10 and SIB3 in 3G system 20, similar to information such as packet communication restrictions. .

  When determining that the circuit-switched communication service is not regulated in the mobile communication system, the RAT selection unit 305 selects the RAT used by the mobile communication system as the RAT used when performing packet communication. .

  Further, the RAT selection unit 305 is based on the regulation of the circuit-switched communication service in the neighboring cell located around the serving cell in addition to the packet communications regulation in the cell of the serving mobile communication system detected by the regulation detecting unit 303. Thus, it is possible to select the RAT used when executing packet communication.

  Specifically, the RAT selection unit 305 performs the cell search as described above when the packet communication restriction is performed in the cell of the mobile communication system in the area, and the circuit-switched communication service via the peripheral cell. The presence / absence of restriction is detected, and it is determined that the restriction of the circuit-switched communication service is not performed in the peripheral cell. When the RAT selection unit 305 determines that the circuit-switched communication service is not regulated in the neighboring cell, the RAT used by the mobile communication system forming the neighboring cell is used as the RAT used when performing packet communication. select.

  The connection request transmission unit 307 determines a mobile communication system to be connected based on the RAT selected by the RAT selection unit 305. Furthermore, when a request for packet communication occurs, the connection request transmission unit 307 transmits a connection request for a circuit-switched communication service to the determined mobile communication system.

  The connection request transmission unit 307 can also determine whether voice communication (and SMS, etc.) by VoIP can be performed using the RAT selected by the RAT selection unit 305. When the voice communication by VoIP can be performed, the connection request transmission unit 307 transmits a voice communication connection request by VoIP to the determined mobile communication system. On the other hand, when voice communication by VoIP cannot be performed, the connection request transmission unit 307 transmits a connection request for voice communication by a circuit switching (CS) call to the determined mobile communication system.

(3) Functional Block Configuration of Radio Base Station FIG. 3 is a functional block diagram of eNodeB 150. As illustrated in FIG. 3, the eNodeB 150 includes a restriction information acquisition unit 151 and a broadcast information transmission unit 153.

  The restriction information obtaining unit 151 obtains access restriction information in the LTE system 10 (or a specific cell) from the network device 100 positioned above the eNodeB 150. Further, the restriction information acquisition unit 151 acquires access restriction information in the 3G system 20 (or a specific cell). Note that the access restriction information includes packet communication restriction as described above.

  Broadcast information transmitting section 153 transmits broadcast information including the access restriction information to the LTE cell based on the access restriction information acquired by restriction information acquiring section 151. As described above, broadcast information including packet communication restriction can be transmitted using SIB2 of broadcast information in the LTE system 10 and SIB3 in the 3G system 20.

(4) Operation of Mobile Device Next, operation examples 1 to 3 of the mobile device 300 described above will be described with reference to FIGS. 4 to 6.

(4.1) Operation example 1
FIG. 4 is a flowchart according to connection operation example 1 of the mobile device 300 to the mobile communication system. Connection operation example 1 is a case where voice transmission is performed from a mobile communication system (labeled RAT A) in which packet communication is restricted.

  As shown in FIG. 4, the mobile device 300 receives access restriction information (packet communication restriction) in a serving cell from a radio base station of RAT A (for example, LTE) (S10). Based on the received access restriction information, the mobile device 300 recognizes that the packet communication restriction is performed in RAT A and executes a search for neighboring cells formed around the serving cell (S20). . In addition, the peripheral cell may overlap a part cell or a whole area with the serving cell. The mobile device 300 determines whether or not there is a restriction (voice service restriction) of a circuit-switched communication service in RAT B (for example, 3G) different from RAT A by cell search.

  When the circuit-switched communication service is restricted, the mobile device 300 does not make a voice communication call and continues to reach RAT A (S30). On the other hand, when the circuit-switched communication service is not regulated, the mobile device 300 determines the provision status of the circuit-switched communication service (voice service) in RAT B (S40). Specifically, mobile device 300 determines whether or not VoIP is supported in RAT B.

  When VoIP is supported in RAT B, mobile device 300 starts voice communication using VoIP using RAT B (S50).

  On the other hand, when VoIP is not supported in RAT B, mobile station 300 performs CS fallback (CSFB) to RAT B, and requests connection of voice communication to RAT B, that is, 3G system 20 by a circuit-switched call. Is transmitted (S60). Thereafter, the mobile device 300 starts voice communication using a circuit-switched call using RAT B (S70).

(4.2) Operation example 2
FIG. 5 is a flowchart according to connection operation example 2 of the mobile device 300 to the mobile communication system. Hereinafter, differences from the connection operation example 1 described above will be mainly described. In this connection operation example, the mobile device 300 acquires information on access restriction of RAT B in addition to RAT A from the RAT A radio base station in the area (S110). Specifically, the mobile device 300 receives broadcast information including access restriction information in RAT A and RAT B from a RAT A radio base station (for example, eNodeB 150).

  Based on the received notification information, the mobile device 300 determines whether or not there is a neighboring cell that is not subject to circuit-switched communication service restriction (voice service restriction) (S120).

  Since the processes of steps S130 to S170 are the same as steps S30 to S70 of the connection operation example 1 described above, the description thereof is omitted.

  According to connection operation example 2, as compared with connection operation example 1 in which mobile device 300 performs a cell search, mobile device 300 can be quickly transferred to a neighboring cell.

(4.3) Operation example 3
FIG. 6 is a flowchart according to connection operation example 3 of the mobile device 300 to the mobile communication system. Hereinafter, differences from the connection operation example 1 described above will be mainly described. In this connection operation example, the mobile device 300 shows an incoming operation of voice communication.

  As shown in FIG. 6, the mobile device 300 receives access restriction information (packet communication restriction) in a serving cell from a radio base station of RAT A (for example, LTE) (S210). This operation is the same as step S10 in connection operation example 1. The mobile device 300 accepts an incoming voice communication in a state where it is located in the RAT A (LTE system 10) (S220).

  Since mobile communication 300 cannot perform voice communication due to packet communication restrictions in RAT A, mobile device 300 executes a search for neighboring cells formed around the serving cell (S230). Furthermore, the mobile device 300 determines whether or not there is a restriction (voice service restriction) of a circuit-switched communication service in RAT B (for example, 3G) different from RAT A by cell search. This operation is the same as step S20 in the connection operation example 1.

  Thereafter, the mobile device 300 executes the processes of steps S240 to S280 in the same manner as the transmission in the connection operation example 1 described above.

(5) Action / Effect According to the mobile device 300 according to the present embodiment, based on the broadcast information received by the broadcast information receiving unit 301, the presence / absence of packet communication restriction in the cell of the mobile communication system is detected. Further, based on the detected packet communication regulation, a RAT used when a circuit-switched communication service such as voice communication is executed is selected, and a mobile communication system to be connected is determined.

  For this reason, when the mobile device 300 is located in a cell (LTE cell) in which packet communication is restricted, conventional circuit-switched communication services such as voice communication are also restricted, and serviceability Can be solved.

  In this embodiment, the mobile communication system (3G system 20) using a RAT different from the mobile communication system in the broadcast information broadcast from the mobile communication system (for example, LTE system 10), The information indicating that the circuit-switched communication service is not regulated via the peripheral cell (3G cell) formed in FIG. For this reason, compared with the case where the mobile device 300 performs a cell search, the mobile device 300 can be quickly transitioned to a neighboring cell by CS fallback.

  In the present embodiment, when the mobile device 300 can execute voice communication by VoIP, the mobile device 300 transmits a connection request for voice communication by VoIP to the mobile communication system determined as the connection destination. On the other hand, when voice communication by VoIP cannot be performed, the mobile device 300 transmits a connection request for voice communication using a circuit-switched call to the mobile communication system determined as the connection destination. For this reason, when VoIP can be used, a PS domain that transmits IP packets can be preferentially utilized.

  That is, according to the mobile device 300, even when packet communication or VoIP is regulated in the LTE system 10, the mobile device 300 can be transitioned to the 3G system 20 by CS fallback, and the existing CS fallback While using the function, it is possible to easily and reliably suppress the deterioration of serviceability.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through one embodiment of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the mobile device 300 is configured to transmit a connection request for voice communication by VoIP to the mobile communication system determined as a connection destination when voice communication by VoIP can be performed. Such functions may not necessarily be implemented.

  Further, in the above-described embodiment, the state of the neighboring cell is acquired by broadcast information or cell search. However, when such operation is not performed and the packet communication restriction is performed in the serving cell, it is immediately performed. Alternatively, the mobile device 300 may transition to the corresponding RAT, that is, the 3G system 20 by CS fallback.

  In the above-described embodiment, 3G and LTE have been described as examples. However, the present invention can also be applied to wireless access technologies (for example, GSM and wireless LAN) other than 3G and LTE.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

10 ... LTE system
20… 3G system
100 ... Network equipment
150 ... eNodeB
151… Regulatory Information Acquisition Department
153 ... Broadcast information transmission unit
200 ... Network equipment
210 ... RNC
250… NodeB
300 ... mobile equipment
301 ... Broadcast information receiver
303… Regulation detector
305 ... RAT selector
307: Connection request transmitter

Claims (5)

A mobile device connectable to a plurality of mobile communication systems having different radio access technologies,
Receiving notification information including packet communication restriction indicating that packet communication via a visited cell formed by a visited mobile communication system in which the mobile station is located is restricted from the visited mobile communication system A broadcast information receiving unit;
Based on the broadcast information received by the broadcast information reception unit, a restriction detection unit that detects presence or absence of packet communication restriction in a cell of the mobile communication system,
A selection unit that selects a radio access technology to be used when a circuit-switched communication service is executed based on the packet communication restriction detected by the restriction detection unit;
A connection request transmission unit that determines a mobile communication system to be connected based on the radio access technology selected by the selection unit, and transmits a connection request for the circuit-switched communication service to the determined mobile communication system And a mobile device. The restriction detection unit further detects presence or absence of restriction of the circuit-switched communication service via a cell of a mobile communication system using a radio access technology that is connectable to the mobile device and different from the mobile communication system in the area. And
The selection unit includes presence / absence of packet communication restriction in the cell of the visited mobile communication system detected by the restriction detection unit, and the cell in the mobile communication system using a radio access technology different from the visited mobile communication system. The mobile device according to claim 1, wherein a radio access technology to be used when executing the circuit-switched communication service is selected based on whether or not the circuit-switched communication service is regulated. The broadcast information indicates whether or not the circuit-switched communication service is restricted via a peripheral cell formed around the cell by a mobile communication system using a radio access technology different from the mobile communication system in the area. Including information,
The selection unit is configured to switch the circuit based on the presence / absence of packet communication restriction in the cell of the visited mobile communication system detected by the restriction detection unit and the restriction on the circuit-switched communication service in the peripheral cell. The mobile device according to claim 1, wherein a radio access technology to be used when executing a mobile communication service is selected. The connection request transmission unit
Determining whether voice over IP voice communication can be performed using the radio access technology selected by the selection unit;
When voice communication by Voice over IP can be executed, a connection request for voice communication by Voice over IP is transmitted to the determined mobile communication system,
2. The mobile device according to claim 1, wherein when voice communication based on the Voice over IP cannot be executed, a connection request for voice communication based on a circuit-switched call is transmitted to the determined mobile communication system. A communication connection method in a mobile device connectable to a plurality of mobile communication systems having different radio access technologies,
Based on notification information including packet communication regulation indicating that packet communication via a serving cell formed by a serving mobile communication system in which the mobile station is located is regulated, in the cell of the mobile communication system Detecting the presence or absence of packet communication restriction;
Selecting a radio access technology to be used when executing a circuit-switched communication service based on the detected packet communication restriction;
Determining a mobile communication system to be connected based on the selected radio access technology, and transmitting a connection request for the circuit-switched communication service to the determined mobile communication system.

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