JP5352610B2 - Mobile device and roaming method - Google Patents

Description

  The present invention generally relates to mobile communication systems, and more particularly to a mobile device having a roaming function in a mobile communication system.

  In the current mobile communication system, even when a user travels from his home country to a foreign country, a mobile device (UE: User Equipment) such as a mobile phone used in his home country can be used overseas. Such a service is known as a roaming service. In this roaming, when a user uses a mobile device in a foreign country, the mobile device is operated by an operator with whom the user has a contract in his country, that is, an operator in the country with which HPLMN (Home Public Land Mobile Network) is affiliated. , Can connect to VPLMN (Visited Public Land Mobile Network) and communicate. If HPLMN is affiliated with several VPLMNs in the country, the mobile will communicate with one of them by roaming.

  Also, RAT (Radio Access Technology) that provides a service is usually different for each operator, that is, for each PLMN (Public Land Mobile Network). RAT indicates a communication method for mobile communication. The RAT specified in the 3GPP (3rd Generation Partnership Project) standard specification includes the 3rd generation communication system UMTS (Universal Mobile Telecommunications System), 2nd generation GSM (Global System for Mobile Communications), LTE (Long Term) Evolution).

  GSM is the most widespread RAT in the world and generally provides a wider area. However, because of the old communication method, there is a characteristic that the transmission speed of packet communication is relatively low. In addition to packet communication, voice services using circuit switching are generally provided.

  UMTS is a communication method that is spreading all over the world, but there are some countries such as developing countries that have not yet spread. UMTS is characterized in that the transmission speed of packet communication is higher than that of GSM by using technologies such as HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access). In addition, a voice service using circuit switching is generally provided in the same manner as GSM.

  LTE is a next-generation communication system, and the number of countries where it is introduced is very small among developed countries. LTE is a RAT that supports only the packet switching method, and enables high-speed packet communication that surpasses HSDPA and HSUPA. However, since LTE supports only packet switching and not circuit switching, packet communication using IMS (IP Multimedia Subsystem) called VoLTE (Voice over LTE) is used to provide voice services. When using a voice service called CSFB (Circuit Switching Fall Back), make sure to switch to the RAT that provides voice services by circuit switching such as UMTS and GSM and receive the voice service. One of the technologies that need to be introduced. VoLTE is currently being negotiated for standardization in 3GPP and is difficult to implement immediately. On the other hand, for CSFB, standardization in 3GPP has been completed, but since it involves the operation of switching RAT every time voice service is performed, it is smooth to receive voice service like UMTS and GSM. There will be a need to incorporate a mechanism that enables switching.

  As described above, each RAT has a characteristic, and there is a RAT that is more convenient for the user if it is not used depending on the service provision status of the network. Therefore, it is desirable to be able to limit the RAT that can be used for each PLMN in which the mobile device is located, or to limit the use of a PLMN that uses a specific RAT.

  In order to realize this, conventionally, it was supported by a network. In this case, when it is desired to limit the RAT that can be used by a mobile device in a specific PLMN, when the location registration by the mobile device is performed in the RAT of the PLMN, the operator of the PLMN rejects the location registration. However, this method expects the operation that the mobile device searches for another RAT as a result of the location registration being rejected. For example, in a situation where a desired RAT cell is not easily found, The state where the location registration is not successful continues for a while. For this reason, the time during which various services such as voice incoming and outgoing calls cannot be received lasts for a long time, and the convenience for the user may be reduced. In addition, useless signal exchange occurs such that the mobile device requests location registration and the network rejects it, which is not desirable from the viewpoint of NW load.

  On the other hand, a mobile device is generally equipped with a function capable of changing RAT Capability indicating whether or not RAT can be used by a user operation. Since it is assumed that the RAT Capability is changed by a user operation, the operation of changing the RAT Capability for each located PLMN is left to the user. In this case, by turning off RAT Capability, the mobile device will not search the RAT and will not be able to find the cell, so it will not be located in that RAT, and limiting the use of RAT itself It becomes possible. However, in this case, the user needs to change the RAT Capability.

  The above situation will be described in more detail using a specific example. As shown in FIG. 1, it is assumed that two operators PLMN A and PLMN B both provide UMTS and LTE as RATs. Here, it is assumed that a USIM (Universal Subscriber Identity Module card) of PLMN A is inserted in the mobile device, and PLMN A is the HPLMN of this mobile device. Here, in PLMN A, it is assumed that the connectivity of this mobile device to UMTS and LTE is ensured. The expression “connectivity is guaranteed” means that the connection test of the mobile device in UMTS or LTE of PLMN A has been completed, and it has been confirmed that there is no problem even if connected. On the other hand, in the roaming destination PLMN B, it is assumed that the connection test of the mobile device has been completed only in UMTS, and connectivity to LTE cannot be ensured. If the mobile device is located in a network where connectivity is not secured, there is a possibility that the mobile device may be reset or an out-of-service event occurs, and it is preferable not to connect in consideration of user convenience.

  Therefore, in the above example, PLMN A allows the mobile station to use both UMTS and LTE RATs, and PLMN B allows only the UMTS to be used so that the mobile station can use PLMN B. It is desirable to be able to avoid a situation that may be disadvantageous to the user that may occur due to being in LTE. Further, by making it possible to set the mobile device so as not to connect to the LTE of PLMN B, it becomes unnecessary for the operator to ensure connectivity, and the connection test to the LTE network of PLMN B can be omitted. As a result, it can be expected to significantly reduce the mobile device development period.

  In addition, if a problem with NW with a specific RAT or a disadvantage to the user has been found at a specific roaming destination, the NW problem will cause a problem for the user until network file exchange is waited for. An event that may be profitable may occur. Therefore, it is desirable to limit the use of only the RAT other than the RAT in which an event has occurred at a specific roaming destination to suppress a decrease in convenience for roaming users. For example, a particular VPLMN may not support UMTS and GSM handovers. Here, when the UMTS area is extremely small, it is possible that when receiving a voice service with UMTS, the call is frequently disconnected every time the user moves. In this case, if the voice service is provided by GSM from the beginning, it does not fall into the situation where the voice is disconnected. Therefore, the user's convenience is improved by connecting to GSM. That is, when the mobile device is located in this VPLMN, it is possible to suppress a decrease in convenience for roaming users by restricting the use of UMTS.

  Also, there may be differences in RAT communication charges at specific roaming destinations. In such a case, it is desirable to be able to avoid billing that is not assumed by the user in advance by limiting the RAT that can be used so that only the RAT with the lowest communication charge is used.

  In view of the above problems, an object of the present invention is to provide a technique for autonomously setting RAT capability in a mobile device in accordance with the use restriction of each RAT for an operator as a roaming destination.

  In order to solve the above-described problems, one feature of the present invention is a mobile device having a roaming function, which includes a communication hardware unit having a multi-RAT function for wireless communication using a plurality of RATs, and each operator serving as a roaming destination An association information storage unit that stores association information describing RAT that can be used by the mobile device, and based on the association information, the mobile device can use any RAT of the plurality of RATs in a roaming destination operator A RAT determination unit that determines whether or not to change RAT Capability for the plurality of RATs currently set in the mobile device based on the determination result; and to change the currently set RAT Capability The present invention relates to a mobile device having a communication control unit that changes the RAT capability of the RAT to be changed when the RAT is notified from the RAT determination unit.

  Another feature of the present invention is a roaming method for a mobile device having a roaming function, in which association information describing a RAT that can be used by the mobile device for each operator that is a roaming destination stored in the mobile device. Based on the step of determining which RAT of the plurality of RATs can be used by the mobile device at the roaming destination operator, and changing the RAT Capability currently set for the mobile device based on the result of the determination A step of determining whether to change the currently set RAT Capability, a step of changing the RAT Capability of the RAT to be changed, and a RAT in which the RAT Capability is set to ON. And a step of detecting a network of a roaming destination operator in operation.

  According to the present invention, RAT Capability can be set autonomously in a mobile device in accordance with usage restrictions of each RAT for an operator as a roaming destination.

FIG. 1 is a schematic diagram showing roaming processing of a conventional mobile device. FIG. 2 is a block diagram illustrating a configuration of a mobile device according to an embodiment of the present invention. FIG. 3 shows a PLMN-RAT association table according to an embodiment of the present invention. FIG. 4 is a sequence diagram showing roaming processing in a mobile device according to an embodiment of the present invention. FIG. 5A is a sequence diagram illustrating roaming processing in a mobile device according to another embodiment of the present invention. FIG. 5B is a sequence diagram illustrating roaming processing in a mobile device according to another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a mobile device according to an embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a configuration of a mobile device (UE) according to an embodiment of the present invention. The UE 10 includes an application (APL: APpLication) unit 100 that controls a user interface (UI), a protocol stack (PS: Protocol Stack) unit 200 that performs control related to communication, GSM, UMTS, LTE, and the like. The communication hardware unit 300 communicates signals with the network using various RAT radio waves, and the USIM interface unit 400 that provides an interface between the removable USIM and the UE 10.

  The UE 10 is typically a user apparatus (UE) such as a mobile phone terminal, a smartphone, or a personal computer. The UE 10 is typically composed of one or more of various hardware resources such as an auxiliary storage device, a memory device, a CPU, a communication device, a display device, and an input device. The auxiliary storage device is composed of a hard disk, a flash memory, and the like, and stores programs and data for realizing various processes described later. The memory device is composed of a RAM (Random Access Memory) or the like, and reads and stores the program from the auxiliary storage device when an instruction to start the program is given. The CPU functions as a processor for processing information, and realizes various functions described later in accordance with programs stored in the memory device. The communication device includes various communication circuits for wireless connection with a wireless device such as a base station. In the present embodiment, the communication hardware unit 300 composed of the communication device has a multi-RAT function that supports a plurality of radio access technologies (RAT). In this embodiment, three RATs, LTE, UMTS, and GSM, are exemplified as RATs supported by the communication hardware unit 300, but the mobile device according to the present invention is not limited to this. The UE 10 may not support LTE, UMTS, or GSM RAT, or may support another RAT.

  The APL unit 100 includes a user interface (UI) unit 110, a PLMN-RAT association table storage unit 120, a RAT determination unit 130, and an APL-PS message transmission / reception unit 140.

  The UI unit 110 provides a user interface between the UE 10 and the user, such as displaying various information on a display device such as a display of the UE 10 or receiving a user operation via the input device.

  The PLMN-RAT association table storage unit 120 stores a PLMN-RAT association table indicating the RAT that the UE 10 can use for each PLMN. The PLMN-RAT association table can be rewritten by the user via the UI unit 110, and can also be rewritten by a change notification from the RAT determination unit 130. The PLMN-RAT association table may be initially set so that the RAT of each PLMN can be used.

  The PLMN-RAT association table may be realized by a table format in which each PLMN and each RAT are associated as shown in FIG. In the illustrated embodiment, when the UE 10 can use RAT X in PLMN X, “◯” is input to the elements related to PLMN X and RAT X in the PLMN-RAT association table. On the other hand, when the use of RAT X is restricted in PLMN X, “x” is input to the elements related to PLMN X and RAT X in the PLMN-RAT association table.

  The RAT determination unit 130 refers to the PLMN-RAT association table stored in the PLMN-RAT association table storage unit 120 to determine the RAT that can be used by the UE 10 or the RAT that is restricted in use in the PLMN to be determined. To do.

  When a RAT whose use is restricted for a PLMN to be determined is detected, the RAT determination unit 130 needs to change the RAT capability for the detected RAT (that is, changes the RAT capability from ON to OFF). If necessary, a RAT Capability change request for setting the RAT to OFF is transmitted to the PS unit 200 via the APL-PS message transmission / reception unit 140. At this time, the RAT determination unit 130 may notify the user via the UI unit 110 that the RAT capability of the detected RAT has been changed to OFF.

  On the other hand, when the RAT that can be used for the PLMN to be determined is detected, the RAT determination unit 130 needs to change the RAT capability for the detected RAT (that is, changes the RAT capability from OFF to ON). If necessary, a RAT Capability change request for setting the RAT to ON is transmitted to the PS unit 200 via the APL-PS message transmission / reception unit 140. At this time, the RAT determination unit 130 may notify the user via the UI unit 110 that the detected RAT is set to ON.

  The APL-PS message transmission / reception unit 140 transmits the message received from the RAT determination unit 130 to the PS unit 200, and transmits the message received from the PS unit 200 to the RAT determination unit 130.

  The PS unit 200 includes an APL-PS message transmission / reception unit 210, a PLMN selection unit 220, and a radio unit 230.

  The APL-PS message transmission / reception unit 210 transmits the message received from the PLMN selection unit 220 to the APL unit 100, and transmits the message received from the APL unit 100 to the PLMN selection unit 220.

  The PLMN selection unit 220 determines a roaming destination PLMN and executes location registration in the selected network. The PLMN selection unit 220 determines a roaming destination PLMN based on a cell search result by the communication hardware unit 300. When a plurality of PLMNs are detected as roaming destinations as a result of the cell search by the communication hardware unit 300, the PLMN selection unit 220 selects between PLMNs recorded in the USIM inserted via the USIM interface unit 400. A PLMN having a higher priority is selected based on the connection priority. The PLMN selection unit 220 transmits PLMN information related to the PLMN to the APL unit 100 via the APL-PS message transmission / reception unit 210 in order to confirm the RAT that can be used in the PLMN selected in this way. When receiving the RAT Capability change request from the APL unit 100, the PLMN selecting unit 220 sets the RAT Capability according to the received RAT Capability change request, and selects the PLMN selected via the communication hardware unit 300 based on the set RAT Capability. Execute location registration.

  In response to an instruction from PLMN selection section 220, radio section 230 transmits a search and a location instruction to communication hardware section 300, and transmits a search result from communication hardware section 300 to PLMN selection section 220. .

  The communication hardware unit 300 implements various communication processes such as a cell search and a communication process with a connection destination network under the control of the PS unit 200. As described above, the communication hardware unit 300 has a multi-RAT function that supports communication using a plurality of RATs, and performs communication using a RAT in which RAT Capability is set to ON. The communication hardware unit 300 transmits cell information including the PLMN information of the cell detected as a result of the cell search to the PS unit 200.

  The USIM interface unit 400 accommodates a USIM that is typically detachable, and serves as an interface between the UE 10 and the USIM. The USIM stores an ID code used for caller identification, a telephone number, data preset by an operator, a program, and the like. As data preset by the operator, information on the operator VPLMN contracted as a roaming destination by the HPLMN as described above and information such as the connection priority between the VPLMNs are stored.

  Next, a roaming process in a mobile device according to an embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sequence diagram showing roaming processing in a mobile device according to an embodiment of the present invention. In this embodiment, the UE 10 supports three RATs, LTE, UMTS, and GSM. Initially, the RAT Capability of the UE 10 is set to ON for three RATs of LTE, UMTS, and GSM.

  As shown in FIG. 4, in step S <b> 401, UE 10 is in the PLMN B LTE network. When UE 10 is in the PLMN B LTE network, in step S402, communication hardware unit 300 receives broadcast information including PLMN information related to PLMN B in the broadcast broadcast from the PLMN B LTE network. The communication hardware unit 300 transmits the received notification information to the radio unit 230 of the PS unit 200, and the radio unit 230 notifies the PLMN selection unit 220 of the notification information. Here, when location registration is necessary due to the presence of PLMN B in the LTE network, the PLMN selection unit 220 instructs the communication hardware unit 300 via the radio unit 230 to perform location registration.

  In step S403, the PLMN selection unit 220 uses the APL-PS message transmission / reception unit 210 of the PS unit 200 in order to confirm which RAT is currently available for the UE 10 in the PLMN B that has been in the service area. The PLMN information regarding the acquired PLMN B is transmitted to the APL unit 100.

  In step S404, when the APL unit 100 receives the PLMN information, the RAT determination unit 130 refers to the PLMN-RAT association table stored in the PLMN-RAT association table storage unit 120 and can use the RAT that can be used in the PLMN B. To decide. For example, when the referenced PLMN-RAT association table is set as shown in FIG. 3, it can be confirmed that in PLMN B, the UE 10 can be used for UMTS and GSM, and the use of LTE is restricted. . That is, it can be seen that the use of the LTE network of PLMN B where UE 10 is located is restricted by UE 10.

  In step S405, the RAT determination unit 130 transmits a RAT Capability change request to the PS unit 200 when it is necessary to change the RAT capability based on the determined use restriction of each RAT in the PLMN B. As described above, for the RAT Capability initially set in the UE 10, all three RATs are turned on. However, since the use of LTE is restricted for PLMN B in this example, it is necessary to change the RAT capability for LTE from ON to OFF. For this reason, the RAT determination unit 130 transmits a RAT Capability change request for turning off LTE to the PS unit 200 via the APL-PS message transmission / reception unit 140. At this time, the RAT determination unit 130 may notify the UI unit 110 that LTE has been set to OFF, and display the fact to the user via a display or the like. When the APL-PS message transmission / reception unit 210 of the PS unit 200 receives the RAT Capability change request for turning off LTE, the APL-PS message transmission / reception unit 210 transmits the received RAT Capability change request to the PLMN selection unit 220. . Upon receiving this RAT Capability change request, the PLMN selection unit 220 stores that the RAT Capability for LTE is turned off, and the RAT Capability for LTE is set to OFF in the communication hardware unit 300 via the radio unit 230. And instructing the communication hardware unit 300 to execute cell search for the RAT excluding LTE.

  In step S406, the communication hardware unit 300 performs a cell search on the RAT excluding LTE, and notifies the radio unit 230 of cell information including the PLMN information of the detected cell. In this embodiment, it is assumed that the communication hardware unit 300 detects the UMTS network of the PLMN B in the service area. The radio unit 230 transmits the received cell information related to the UMTS network of PLMN B to the PLMN selection unit 220, and the PLMN selection unit 220 selects a PLMN to be connected based on the detected cell information and notifies the radio unit 230. In addition, since it is already confirmed that UMTS and GSM are currently available for PLMN B, the PLMN selection unit 220 detects the communication hardware unit 300 without requesting the RAT determination again from the APL unit 100. Select the UMTS of PLMN B that has been selected as the roaming destination.

  Here, when a plurality of cells are detected, the PLMN selection unit 220 selects the PLMN having the highest priority according to the priority of the PLMN described in the USIM inserted in the USIM interface unit 400. In addition, when the priority of RAT is also described in the priority of PLMN described in USIM, the RAT having the highest priority is selected from the RATs whose RAT Capability is set to ON for the selected PLMN. The selected PLMN and RAT may be notified to the radio unit 230.

  In step S407, when the radio unit 230 instructs to prevail in the MNTS network of the PLMN B, the communication hardware unit 300 detects the radio wave of the MNTS network of the PLMN B, and detects the detected UMTS of the PLMN B. Located in the network.

  In step S408, the communication hardware unit 300 receives the broadcast information including the PLMN information related to the PLMN B in the area that is broadcast by the UMTS network of the PLMN B that is in the area, and transmits the received broadcast information to the radio of the PS section 200. To the unit 230. Radio section 230 notifies PLMN selection section 220 of this notification information.

  In step S409, the PLMN selection unit 220 notifies the location registration to the UMTS network of PLMN B together with the RAT Capability for which LTE is set to OFF. Thereafter, the UE 10 operates as a terminal having RAT Capability in which LTE is set to OFF until the UE 10 is located in another PLMN cell, the power is turned OFF / ON, or the RAT Capability is changed by a user operation. To do. In this way, it is possible to limit the presence of the PLMN B in the LTE network by the UE 10 according to the setting of the PLMN-RAT association table.

  Next, a roaming process in a mobile device according to another embodiment of the present invention will be described with reference to FIG. In the above-described embodiment, the UE 10 originally located in the PLMN B LTE network has the same PLMN B as a new roaming destination based on the PLMN B LTE usage restrictions set in the PLMN-RAT association table. Connected to a different RAT, UMTS. On the other hand, in this embodiment, the UE 10 originally located in the PLMN B LTE is a different operator as a new roaming destination based on the PLMN B LTE usage restrictions set in the PLMN-RAT association table. A case of connecting to A will be described. 5A and 5B are sequence diagrams illustrating roaming processing in a mobile device according to another embodiment of the present invention. As is clear from FIG. 5, steps S501 to S505 in FIG. 5 are the same as steps S401 to S405 in FIG. For this reason, below, the process after step S506 is demonstrated.

  In step S506, the communication hardware unit 300 performs a cell search for the RAT excluding LTE. In this embodiment, it is assumed that the communication hardware unit 300 detects the UMTS of PLMN A, which is an operator different from the PLMN B in the service area. The communication hardware unit 300 notifies the radio unit 230 of cell information including the detected PLMN information of the cell. The radio unit 230 transmits the received cell information related to the UMTS network of PLMN A to the PLMN selection unit 220, and the PLMN selection unit 220 selects PLMN A as the PLMN to be connected based on the detected cell information, and the radio unit 230 Notice.

  In step S507, the UE 10 is in the detected MNTS network of PLMN A. In step S508, the communication hardware unit 300 receives the broadcast information including the PLMN information regarding the PLMN A in the area broadcast from the detected UMTS network of the PLMN A. The communication hardware unit 300 transmits the received notification information to the radio unit 230 of the PS unit 200, and the radio unit 230 notifies the PLMN selection unit 220 of the notification information. Here, when location registration is necessary due to the presence of PLMN A in the UMTS network, the PLMN selection unit 220 instructs the communication hardware unit 300 via the radio unit 230 to perform location registration.

  In step S509, it is unconfirmed which RAT can be used for the detected PLMN A. Therefore, the PLMN selection unit 220 needs to confirm which RAT is usable in the PLMN A. For this reason, the PLMN selection unit 220 confirms which RAT can be used by the UE 10 in the PLMN A that has been in the service area in order to check the APL unit via the APL-PS message transmission / reception unit 210 of the PS unit 200. The PLMN information regarding the acquired PLMN A is transmitted to 100.

  In step S510, when the APL unit 100 receives the PLMN information, the RAT determination unit 130 refers to the PLMN-RAT association table stored in the PLMN-RAT association table storage unit 120 and can use the RAT that can be used in the PLMN A. To decide. With reference to the PLMN-RAT association table shown in FIG. 3, the RAT determination unit 130 confirms that the UE 10 can use all RATs of LTS, UMTS, and GSM in PLMN A.

  In step S511, the RAT determination unit 130 transmits a RAT Capability change request to the PS unit 200 when it is necessary to change the RAT Capability based on the determined use restriction of each RAT in the PLMN A. In step S505, the RAT Capability of the UE 10 is set to OFF for LTE. However, as described above, since LTE can be used for PLMN A, it is necessary to change the RAT capability for LTE from OFF to ON. For this reason, the RAT determination unit 130 transmits a RAT Capability change request for turning on LTE to the PS unit 200 via the APL-PS message transmission / reception unit 140. At this time, the RAT determination unit 130 may notify the UI unit 110 that LTE has been set to ON, and display the fact to the user via a display or the like.

  In step S512, when the APL-PS message transmission / reception unit 210 of the PS unit 200 receives the RAT Capability change request for turning on LTE, the APL-PS message transmission / reception unit 210 transmits the received RAT Capability change request to the PLMN selection unit. 220. Upon receiving this RAT Capability change request, the PLMN selecting unit 220 stores that the RAT Capability for LTE is turned on, and the RAT Capability for LTE is set to ON in the communication hardware unit 300 via the radio unit 230. And instructing the communication hardware unit 300 to execute cell search for all RATs including LTE. The communication hardware unit 300 performs cell search for all RATs including LTE, and notifies the radio unit 230 of cell information including PLMN information of the detected cell. In this embodiment, it is assumed that the communication hardware unit 300 detects the LTE network of PLMN A that is in the service area. The radio unit 230 transmits the received cell information regarding the LTE network of PLMN A to the PLMN selection unit 220, and the PLMN selection unit 220 selects a PLMN to be connected based on the detected cell information and notifies the radio unit 230. Note that since it is already confirmed that LTE, UMTS, and GSM are currently available for PLMN A, the PLMN selection unit 220 does not request the APL unit 100 for RAT determination again, and the communication hardware unit 300 The LTE of PLMN A detected by the above is selected.

  Here, when a plurality of cells in PLMN A are detected, the PLMN selection unit 220 refers to the priority of the RAT described in the USIM inserted in the USIM interface unit 400, and has the highest priority over the PLMN A. It is also possible to select a RAT having a high degree and notify the radio unit 230 of the selected RAT.

  In step S513, when the wireless unit 230 gives an instruction to prevail in the LTE of PLMN A, the communication hardware unit 300 detects the radio wave of the LTE network of PLMN A, and detects the detected LTE network of PLMN A. Located in the area.

  In step S514, the communication hardware unit 300 receives the broadcast information including the PLMN information related to the PLMN A in the area that is broadcast by the LTE network of the PLMN A that is in the area, and transmits the received broadcast information to the radio of the PS section 200. To the unit 230. Radio section 230 notifies PLMN selection section 220 of this notification information.

  In step S515, the PLMN selection unit 220 notifies the location registration to the LTE network of PLMN A together with the RAT Capability for which LTE is set to ON. Thereafter, the UE 10 operates as a terminal having RAT Capability with LTE set to ON until it is located in another PLMN cell, power is turned off / on, or RAT Capability is changed by user operation. To do. In this way, according to the setting of the PLMN-RAT association table, the UE 10 can be located in the LTE network of PLMN A.

  In the embodiment described above, the PLMN-RAT association table indicating whether or not each RAT is available for each PLMN as shown in FIG. 3 is used, but the present invention is not limited to this. In another embodiment, the PLMN-RAT association table is a white list method in which a specific RAT is allowed only in a specific PLMN (in FIG. 3, LTE is “other than PLMN A” cannot be used “×”). Etc.), and a specific RAT can be expressed in various formats such as a black list method in which only a specific PLMN is not allowed. In addition, MCC (Mobile Country Code) sets restrictions on the use of each RAT on a country-by-country basis, allowing specific RATs to be allowed or not allowed when the operator is in the network. There are various setting methods (“×” of “MCC = DDD” in FIG. 3), and various setting methods are conceivable.

  Further, the PLMN-RAT association table may be held as a non-volatile value unique to the mobile device, or may be rewritable by a user operation. When the PLMN-RAT association table is held as a non-volatile value, it may be rewritten from the outside using ADL (Air Down Load), and the table may be updated as necessary.

  In addition, although the current mobile device can generally switch the RAT Capability manually by a user operation, the present invention changes the RAT Capability at a timing that does not depend on the user operation. . For this reason, there is a concern that the mobile device may use a RAT that is not assumed by the user. However, this problem can be solved by, for example, displaying on the display that the RAT Capability has been changed and notifying the user what RAT is currently supported by the mobile device. it can.

  Further, even when the RAT Capability is not displayed on the display, the RAT determination unit 130 stores the RAT set to OFF by the user operation, and the RAT Capability change request for the notification of the PLMN in the service area from the PS unit 200 The shape should be reflected in For example, in the sequence shown in FIG. 4, it is assumed that the RAT Capability has been set in advance as GSM = OFF by a user operation. At this time, if the mobile device is located in the LTE network of PLMN B, the RAT determination unit 130 receives a notification of the PLMN in the range from the PS unit 200, performs RAT determination for each PLMN, and transmits RAT Capability The change request is set to OFF for LTE and OFF for GSM. By setting to such RAT Capability, cell search is executed only by UMTS, and it is possible to prevent the case where GSM is excluded from the cell search target and located in a GSM cell that the user does not want. Become.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the specific embodiment mentioned above, In the range of the summary of this invention described in the claim, various deformation | transformation・ Change is possible.

10 Mobile equipment (UE)
100 Application (APL) part 200 Protocol stack (PS) part 300 Communication hardware part 400 USIM interface part

Claims (5)

A mobile device having a roaming function,
A communication hardware unit having a multi-RAT function for wireless communication using a plurality of RATs;
An association information storage unit that stores association information that describes RATs for which the mobile device can be used for each roaming destination;
Based on the association information, a roaming destination operator determines which RAT of the plurality of RATs can be used by the mobile device, and the plurality of currently set mobile devices based on the determination result A RAT determination unit that determines whether or not to change the RAT capability for the RAT;
When the RAT that should change the currently set RAT Capability is notified from the RAT determination unit, a communication control unit that changes the RAT Capability of the RAT to be changed;
Mobile machine with.   The communication control unit instructs the communication hardware unit to detect a network of a roaming operator operated by a RAT in which RAT Capability is set to ON among the plurality of RATs. Mobile machine.   The communication control unit determines whether the operator of the network detected by the communication hardware unit matches the operator in the area, and if it matches, roams to the detected network, and if not, The mobile device according to claim 2, wherein the mobile network operator notifies the RAT determination unit of the detected network operator to determine whether or not to change RAT Capability for the plurality of RATs currently set in the mobile device.   The RAT determination unit according to claim 1, wherein when determining that the currently set RAT capability should be changed, the RAT determination unit notifies the user via the user interface that the currently set RAT capability is to be changed. Mobile machine. A roaming method for a mobile device having a roaming function,
Based on the association information describing the RAT in which the connectivity that can be used by the mobile device is guaranteed for each operator that is the roaming destination stored in the mobile device, the mobile device is the roaming destination operator. Determining which RAT of the RAT is available;
Determining whether to change the RAT Capability currently set for the mobile device based on the result of the determination;
If it is determined that the currently set RAT Capability should be changed, changing the RAT Capability of the RAT to be changed;
Detecting a network of a roaming operator operated by RAT in which the RAT Capability is set to ON;
A roaming method.

Images