CN114866983A

CN114866983A - Information processing apparatus, information processing method, and non-volatile storage medium storing program

Info

Publication number: CN114866983A
Application number: CN202111619503.3A
Authority: CN
Inventors: 林一成
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2021-01-18
Filing date: 2021-12-28
Publication date: 2022-08-05
Also published as: TW202231084A; TWI804150B; JP2022110462A

Abstract

The present disclosure relates to an information processing apparatus, an information processing method, and a nonvolatile storage medium storing a program. An information processing device mounted on a vehicle and performing wireless communication according to the LTE standard, the information processing device comprising a processor configured to: transmitting a request for requesting updating of a tracking area in which the vehicle is located to a first base station of the tracking area in which the vehicle is located; determining whether or not a predetermined condition is satisfied when a signal for rejecting the request because the information processing apparatus cannot be identified is received from the first base station; when a predetermined condition is satisfied, the first base station is determined to be a pseudo base station, and communication with the first base station is prohibited.

Description

Information processing apparatus, information processing method, and non-volatile storage medium storing program

Technical Field

The present disclosure relates to an information processing apparatus, an information processing method, and a nonvolatile storage medium storing a program.

Background

There is known a technique of extracting a base station located within a predetermined distance from a host vehicle based on position information of the base station and position information of the host vehicle, and attempting communication with a base station having a highest radio wave reception level among the extracted base stations (for example, refer to japanese patent application laid-open No. 2010-288153).

Disclosure of Invention

An object of the present disclosure is to provide a technique effective in suppressing communication with a device disguised as a base station.

An information processing device according to an aspect of the present disclosure is mounted on a vehicle, and performs wireless communication according to the LTE (Long-Term Evolution) standard, and includes a processor configured to:

transmitting a request for requesting updating of a tracking area in which the vehicle is located to a first base station of the tracking area in which the vehicle is located;

determining whether or not a predetermined condition is satisfied when a signal for rejecting the request is received from the first base station for the reason that the information processing apparatus cannot be identified; and

and prohibiting communication with the first base station when it is determined that the predetermined condition is satisfied.

An information processing method according to an aspect of the present disclosure controls a computer that is mounted in a vehicle and performs wireless communication according to an LTE (Long-Term Evolution) standard, and includes the following operations executed by the computer:

determining whether or not a predetermined condition is satisfied when a signal for rejecting the request is received from the first base station for the reason that the computer cannot be identified; and

A storage medium according to an aspect of the present disclosure stores a program for causing a computer mounted on a vehicle and performing wireless communication according to an LTE (Long-Term Evolution) standard to execute, wherein the program causes the computer to execute: transmitting a request for requesting updating of a tracking area in which the vehicle is located to a first base station of the tracking area in which the vehicle is located; determining whether or not a predetermined condition is satisfied when a signal for rejecting the request is received from the first base station for the reason that the computer cannot be identified; and prohibiting communication with the first base station when it is determined that the predetermined condition is satisfied.

The present disclosure can also be understood as an information processing program for causing a computer mounted in a vehicle and connected to a core network via a base station by wireless communication of the LTE (Long-Term Evolution) standard to execute the information processing method, or a nonvolatile storage medium storing the information processing program.

According to the present disclosure, it is possible to provide a technique effective in suppressing communication with a device disguised as a base station.

Drawings

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals indicate like elements, and wherein:

fig. 1 is a diagram showing an outline of a mobile communication system.

Fig. 2 is a diagram showing an example of a hardware configuration of the mobile terminal.

Fig. 3 is a block diagram showing an example of a functional configuration of the mobile terminal.

Fig. 4 is a diagram showing an example of the prohibited list.

Fig. 5 is a sequence diagram schematically showing a flow of data transmitted and received by the mobile terminal and a flow of processing performed by the mobile terminal when the first base station is a legitimate base station.

Fig. 6 is a sequence diagram schematically showing the flow of data transmitted and received by the mobile terminal and the flow of processing performed by the mobile terminal when the first base station is a pseudo base station.

Fig. 7 is a flowchart showing a process flow executed by the mobile terminal triggered by the reception of the signal notifying the TAI.

Detailed Description

A mobile communication system based on the LTE (Long-Term Evolution) standard includes a Radio Access Network (RAN) and a Core Network (EPC) that comply with the specifications of 3GPP (3rd Generation Partnership Project).

A Radio Access Network (RAN) includes a mobile terminal (UE) and a base station (eNodeB: evolved NodeB). The core network (EPC) includes a Control-plane (C-plane) function set and a User-plane (U-plane) function set. An MME (Mobile Management Entity) as a control Entity that manages the movement and communication paths of the user terminal is included in the control plane function group. The user plane function group includes an SGW (Serving Gateway) that relays user Data and a PGW (Packet Data Network Gateway) that is a relay point with an external Network.

In the mobile communication system as described above, the position of the mobile terminal is managed in units of Tracking Areas (TAs). The Tracking Area (TA) is formed of 1 or more cells, and a base station (eNodeB) is arranged in each cell. A cell is the communication range of a base station. This may be a communication range in which the base station is designed, or a range in which the radio wave actually reaches. The base station (eNodeB) of each cell has a function of periodically notifying a mobile terminal in a cell under its own management of an identifier (TAI: Tracking Area Identity) of a Tracking Area (TA) to which each cell belongs. The terminal that has received the identification of the tracking area (hereinafter, sometimes referred to as "TAI") compares the TAI received last time with the TAI received this time. Here, when the Tracking Area (TA) in which the mobile terminal is located changes due to the movement of the mobile terminal, the TAI received last time is different from the TAI received this time. In such a case, the mobile terminal transmits a request (TAU request) for requesting Update (TAU) of a Tracking Area (TA) in which the mobile terminal is located to the MME via the base station (eNodeB). Thus, information on a Tracking Area (TA) where the mobile terminal is located is updated on the core network (EPC) side including the MME. For example, on the core network (EPC) side, authentication processing of a mobile terminal, bearer reconfiguration processing (logical communication path from a base station (eNodeB) of a Tracking Area (TA) where the mobile terminal is located to an external network) and the like are performed. As a result, the mobile terminal can be connected to the external network even when the mobile terminal moves to a different Tracking Area (TA).

In addition, a device (hereinafter, also referred to as a "pseudo base station") which is pseudo-installed as a base station (eNodeB) may be installed in the tracking area by a malicious third person. When a mobile terminal located in such a Tracking Area (TA) transmits a TAU request to a pseudo base station, a signal (for example, a signal including a cause value #9 defined in 3GPP, which may be hereinafter referred to as a "TAU reject signal") may be received to reject the TAU request because the mobile terminal cannot be identified.

In order to suppress the leakage of the illegal information from the pseudo base station, a method is conceivable in which, when the mobile terminal receives the TAU reject signal, communication between the mobile terminal and a Tracking Area (TA) in which the pseudo base station is located is prohibited. For example, a method is conceivable in which the TAI of the Tracking Area (TA) in which the pseudo base station is located is registered in a prohibited list (list in which the TAI of the Tracking Area (TA) to be prohibited is registered) set for each mobile terminal.

However, even if a TAU request is transmitted from the mobile terminal to the MME via a legitimate base station (eNodeB) when the mobile terminal moves from the service area of the Radio Access Network (RAN) to the outside of the service area and then returns to the service area of the Radio Access Network (RAN), the TAU request may be rejected for the same reason as described above. This is because, if the time period in which the mobile terminal is located outside the service area of the Radio Access Network (RAN) is equal to or longer than a certain time period (for example, about 70 minutes), so-called "implicit detach processing" is performed to delete information (for example, GUTI: global Unique Temporary Identity) of the mobile terminal registered on the core network (EPC) side when the previous attach processing is performed. In such a case, if the mobile terminal is capable of switching between the wireless communication method of the LTE standard and the wireless communication method of the 3G (3rd Generation: 3rd Generation) standard, the external network can be accessed by performing the attach process using the wireless communication method of the 3G standard, but in the mobile terminal capable of only the wireless communication of the LTE standard, there is a possibility that a state in which the mobile terminal cannot access the external network continues for a long period of time. As a result, a state in which the user of the mobile terminal cannot use the internet or the like may continue for a long period of time. For example, when the mobile terminal is a communication terminal mounted on a vehicle, there is a possibility that a communication service such as an emergency notification cannot be used. Therefore, it is desirable to accurately determine whether or not the source of the TAU reject signal is the pseudo base station, and effectively prohibit communication with the pseudo base station.

In contrast, in the information processing device (corresponding to a mobile terminal mounted in a vehicle) of the present disclosure, when a Tracking Area (TA) in which the vehicle (information processing device) is located changes (including a case where the Tracking Area (TA) when returning from outside the service area of the Radio Access Network (RAN) to inside the service area is different from the last Tracking Area (TA), the control unit transmits a TAU request to a base station (first base station) of the Tracking Area (TA) in which the vehicle is located. On the other hand, when the TAU reject signal is transmitted from the first base station to the information processing apparatus, the control unit determines whether or not a predetermined condition is satisfied. The "predetermined condition" is a condition specific to the pseudo base station, and is, for example, a condition for transmitting a signal for requesting Subscriber Identity information (IMSI) allocated to the information processing apparatus. In addition, the predetermined condition may include, in addition to the above condition, that the first base station does not start encrypted communication accompanied by the authentication process (that is, communication based on plaintext data is continued between the mobile terminal and the first base station). Thus, the control unit may determine that the predetermined condition is satisfied when a signal requesting the subscriber identification information (IMSI) is received from the first base station and/or when a signal requesting the subscriber identification information (IMSI) is received from the first base station in plain text data. This makes it possible to accurately determine whether the TAU reject signal is transmitted from the pseudo base station or the legitimate base station. When it is determined that the predetermined condition is satisfied, the control unit determines that the first base station is a pseudo base station and can prohibit communication with the first base station.

According to the present disclosure, since the pseudo base station can be determined with high accuracy, communication with the pseudo base station can be appropriately suppressed.

Here, in the information processing apparatus of the present disclosure, when communication with the first base station is prohibited, the control unit may prohibit communication only with a cell in which the first base station is located in a Tracking Area (TA) in which the vehicle is located. Thereby, the information processing apparatus can access the external network via a base station (second base station) of a cell other than the cell in which the first base station is arranged in a Tracking Area (TA) in which the vehicle is located.

The control unit may transmit an attach request to the second base station when the information processing apparatus accesses the external network via the second base station. The attach request is a request to register the information processing apparatus in the network. Thus, when the first base station is a pseudo base station, unnecessary continuation of communication with the first base station can be suppressed, and the information processing apparatus can be prevented from falling into a state in which it cannot be connected to an external network. The "attach request" is a signal requesting a process (attach process) for newly setting a bearer from a base station of a Tracking Area (TA) in which the information processing apparatus is located to an external network and assigning temporary identification information such as GUTI to the information processing apparatus.

In addition, it can be assumed that there is no cell that the information processing apparatus can access in the Tracking Area (TA) where the vehicle is located, except for the cell where the first base station is located. In such a case, if the communication with the cell is continuously prohibited for a long time, the information processing apparatus may be in a state in which it cannot access the external network for a long time. Therefore, when communication with the first base station is prohibited, the control unit may prohibit communication with the cell in which the first base station is located for a predetermined time of 5 minutes or less. Thus, the information processing apparatus can access the external network via the base station other than the first base station in the cell when the predetermined time has elapsed. In this case, the control unit may transmit a TAU request or an attach request to a base station other than the first base station.

Further, when the TAU reject signal is received, if the predetermined condition is not satisfied, it can be estimated that the first base station is a legitimate base station that is not a fake base station. That is, by performing the implicit detach process of the information processing apparatus on the core network (EPC) side, it can be estimated that the TAU reject signal is transmitted from the first base station to the information processing apparatus. Therefore, when the TAU reject signal is received, the control unit may transmit an attach request to the first base station if a predetermined condition is not satisfied. Thus, in the case where the first base station is a legitimate base station, it is possible to suppress the communication between the information processing apparatus and the first base station from being unnecessarily prohibited. As a result, the information processing apparatus can be connected to the external network via the legitimate first base station.

< embodiment >

Hereinafter, specific embodiments of the present disclosure will be described based on the drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

(Overall System Structure)

Fig. 1 is a diagram showing a schematic configuration of a mobile communication system to which an information processing device according to the present disclosure is applied. The mobile communication system of the present embodiment includes a Radio Access Network (RAN) and a core network (EPC).

The Radio Access Network (RAN) includes a mobile terminal 100 mounted on the vehicle 10 and a plurality of base stations (enodebs) 201 and 202. The mobile terminal 100 is a communication terminal for connecting various devices mounted on the vehicle 10 to an external network (PDN), and has a wireless communication function of the LTE (Long-Term Evolution) standard, but does not have a wireless communication function of the 3G (3rd Generation) standard. Such a mobile terminal 100 corresponds to the "information processing apparatus" of the present disclosure. In the Radio Access Network (RAN) shown in fig. 1, only 1 vehicle 10 having the mobile terminal 100 is shown, but a plurality of vehicles may be used.

The base station (eNodeB)201-202 is connected to the MME300 of the core network (EPC) by using an S1 interface, and performs transmission and reception of various control signals with the MME (mobile Management entity) 300. The base station (eNodeB)201 and 202 have a radio interface function for performing radio communication with the mobile terminal 100 in a radio communication system conforming to the specification of 3GPP (3rd Generation Partnership Project). For example, the base station (eNodeB)201-202 has a function of performing Radio Resource Control (RRC) with the mobile terminal 100, a function of periodically notifying the mobile terminal 100 in the cell of the identification tai (tracking Area identity) of the Tracking Area (TA), and the like. The base station (eNodeB)201 and 202 may be configured to have a function of encrypting signals and compressing IP headers to be processed in wireless communication with the mobile terminal 100.

In the example shown in fig. 1, one Tracking Area (TA), two cells (a first cell and a second cell) included in the Tracking Area (TA), a first base station (eNodeB)201 arranged in the first cell, and a second base station (eNodeB)202 arranged in the second cell are shown, but the number of Tracking Areas (TA), the number of cells in the Tracking Area (TA), and the number of base stations (eNodeB) arranged in the cell are not limited to the example shown in fig. 1.

The core Network (EPC) includes an MME300, an sgw (serving gateway)400, and a pgw (packet Data Network gateway) 500. Only one MME300, SGW400, and PGW500 are illustrated in the core network (EPC) shown in fig. 1, respectively, but a plurality of MME's, SGW400, and PGW500 may be provided.

MME300 forms a control plane function group of the core network (EPC), and performs mobility control such as location management, paging (simultaneous call), and handover of mobile terminal 100. For example, in the location management of the mobile terminal 100, the MME300 adds or deletes the mobile terminal 100 located in each Tracking Area (TA) to or from the tracking area list generated for each Tracking Area (TA). MME300 also has a function of performing security processing such as mutual authentication and encryption with mobile terminal 100. The MME300 also has a function of performing addition of the mobile terminal 100 to the tracking area list and new setting of a bearer, which is a logical path between the base station (eNodeB)201 and 202 of the Tracking Area (TA) in which the mobile terminal 100 is located and an external Network (PDN: Packet Data Network), based on an attach request from the mobile terminal 100. MME300 also has a function of updating the tracking Area list and resetting the bearer in response to a tau (tracking Area update) request from mobile terminal 100. MME300 processes only the control signal and does not process the user data.

SGW400 is a gateway that relays packets transmitted as user data. The SGW400 is configured to be able to communicate with a plurality of base stations (enodebs) 201 and 202 and to be able to track the mobile terminal 100 performing handover. In addition, SGW400 has a function of performing new setting or re-setting of bearers in cooperation with MME 300.

PGW500 is a gateway that becomes a connection point for an external network (PDN). Specifically, the PGW500 has a function of assigning an IP address to the mobile terminal 100, authenticating a user, performing packet control at an application level, and the like.

The external network (PDN) is a network connected to a core network, typically the internet. Various servers (web server, mail server, content server, etc.) that communicate with the mobile terminal 100 are provided in the external network (PDN).

Fig. 2 is a diagram showing an example of the hardware configuration of the mobile terminal 100. The mobile terminal 100 according to the present embodiment is a communication terminal mounted on the vehicle 10, and performs various processes for connecting various devices (for example, a car navigation system, an antitheft system, an emergency notification system, and the like) mounted on the vehicle 10 to an external network (PDN). As shown in fig. 2, the mobile terminal 100 includes a processor 101, a main storage unit 102, an auxiliary storage unit 103, a communication unit 104, and the like. The portable terminal 100 is configured to realize a function suitable for a predetermined purpose by loading and executing a program stored in a recording medium to a work area of the main storage unit 102 by the processor 101.

The Processor 101 is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The processor 101 controls the mobile terminal 100 to perform various calculations for information processing.

The main storage unit 102 includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). As described above, the main storage unit 102 sets a work area for the processor 101 to execute a program.

The auxiliary storage unit 103 includes, for example, an EPROM (Erasable Programmable ROM) or a Hard Disk Drive (Hard Disk Drive). The auxiliary storage part 103 can include a removable medium, i.e., a removable recording medium. The removable medium is, for example, a disk recording medium such as a USB (Universal Serial Bus) memory, a CD (Compact Disc) or a DVD (Digital Versatile Disc). The auxiliary storage unit 103 stores various programs, various data, and various tables in a readable and writable manner on a recording medium. In addition, the programs stored in the auxiliary storage unit 103 include programs for realizing various functions for prohibiting the communication between the mobile terminal 100 and the pseudo base station, in addition to an Operating System (OS) and the like. A part or all of the information may be stored in the main storage unit 102. In addition, the information stored in the main storage unit 102 may be stored in the auxiliary storage unit 103.

The communication unit 104 is a radio communication circuit that performs radio communication conforming to the LTE standard specified by 3GPP (3rd Generation Partnership Project). The wireless communication circuit performs communication with a base station (eNodeB)201 and 202 using mobile communication of the LTE standard.

The series of processes executed by the mobile terminal 100 configured as described above can be executed by hardware or software.

(functional Structure of Mobile terminal)

Here, an example of a functional configuration of the mobile terminal 100 in the present embodiment will be described with reference to fig. 3. As shown in fig. 3, the mobile terminal 100 according to the present embodiment includes a TAU processing unit F110, a determination unit F120, an attachment processing unit F130, a TAI storage unit M110, and a forbidden list storage unit M120 as functional components. The TAU processing section F110, the determination section F120, and the attachment processing section F130 are realized by the processor 101 executing a program loaded from the auxiliary storage section 103 to the main storage section 102. The combination of the TAU processing unit F110, the determination unit F120, and the attachment processing unit F130 corresponds to a "control unit" of the present disclosure. Note that any one or a part of the TAU processing unit F110, the determination unit F120, and the attachment processing unit F130 may be implemented by a hardware circuit. The TAI storage unit M110 and the forbidden list storage unit M120 are storage areas set in the auxiliary storage unit 103.

The TAI storage unit M110 stores a TAI of a Tracking Area (TA) where the mobile terminal 100 (vehicle 10) is located. The data stored in the TAI storage unit M110 is updated when the attach process is completed, when the TAU process is completed, and the like.

The prohibition list storage unit M120 stores a list (hereinafter, also referred to as "prohibition list") for registering an object for which communication with the mobile terminal 100 is prohibited. In the present embodiment, the target to which communication with the mobile terminal 100 is prohibited is managed not in units of Tracking Areas (TAs), but in units of cells. The cell to be inhibited from communication is a cell in which a pseudo base station is arranged, and is determined by a determination unit F120 described later. In this example, the "pseudo base station" is a device that is a pseudo base station (eNodeB) and is installed in the Tracking Area (TA) by a malicious third party.

Fig. 4 shows an example of the prohibited list stored in the prohibited list storage unit M120. As shown in fig. 4, the barred list has fields for cell ID and barred time. The configuration of the prohibited list is not limited to the example shown in fig. 4, and the fields can be added, changed, or deleted as appropriate. Information (cell ID) for identifying each cell to be prohibited from communication is registered in the cell ID field. The prohibited time field is registered with a time for prohibiting communication with a cell that is a target of communication prohibition. In the prohibited time field, 5 minutes is registered as an initial value, and thereafter, the remaining time counted down in seconds is registered. For a cell whose remaining time becomes "0 min 00 sec", information on the cell is deleted from the forbidden list.

When the Tracking Area (TA) in which the vehicle 10 (mobile terminal 100) is located changes, the TAU processing unit F110 executes processing related to updating (TAU) of the Tracking Area (TA) in which the vehicle 10 is located. Specifically, when receiving a notification signal of the TAI from the base station (eNodeB)201 or 202 of the Tracking Area (TA) in which the vehicle 10 is located, the TAU processing unit F110 compares the received TAI with the TAI stored in the TAI storage unit M110. When the received TAI is different from the TAI stored in the TAI storage unit M110, the TAU processing unit F110 performs a process for establishing a control link (e.g., rrc (radio Resource control) connection) between the mobile terminal 100 and the base station (eNodeB)201 or 202. At this time, the TAU processing unit F110 selects, as the connection destination of the control link, a base station having the strongest radio wave intensity, which is a cell of the forbidden list not registered in the forbidden list storage unit M120, among the base stations (eNodeB)201 or 202 in the Tracking Area (TA) in which the vehicle 10 is located. When a control link is established between the base station (eNodeB)201 or 202 and the mobile terminal 100, the TAU processing unit F110 transmits a TAU request using the control link. The TAU request includes Temporary identification information (GUTI) assigned from MME300 to mobile terminal 100, and the like.

The TAU request is transmitted to the MME300 of the core network (EPC) via the base station (eNodeB)201 or 202 that establishes a control link with the mobile terminal 100. The MME300 that has received the TAU request acquires information related to the IMSI and bearer of the mobile terminal 100, and the like, based on the GUTI included in the TAU request. The MME300 updates the tracking area list based on the acquired information. That is, the MME300 deletes the mobile terminal 100 from the tracking area list of the Tracking Area (TA) in which the mobile terminal 100 was located immediately before, and adds the mobile terminal 100 to the tracking area list of the Tracking Area (TA) in which the mobile terminal 100 is currently located. Further, the MME300 performs bearer reconfiguration based on the information acquired as described above. That is, the MME300 releases the bearer from the base station of the Tracking Area (TA) where the mobile terminal 100 was located immediately before to the external network (PDN), and newly sets the bearer from the base station (eNodeB)201 and 202 of the Tracking Area (TA) where the mobile terminal 100 is currently located to the external network (PDN). In this way, when the update of the tracking area list and the reconfiguration of the bearer are completed, a signal (TAU Accept) indicating that the TAU processing on the core network (EPC) side is completed is transmitted from the MME300 to the mobile terminal 100 via the base station (eNodeB)201 or 202. The signal (TAU Accept) at this time includes information on the GUTI newly allocated from the MME300 and the like.

When the communication unit 104 of the mobile terminal receives a signal (TAU Accept) indicating that the TAU processing on the core network (EPC) side is completed, the TAU processing unit F110 changes (updates) the TAI stored in the TAI storage unit M110 to the TAI of the Tracking Area (TA) where the mobile terminal 100 is currently located. The TAU processor F110 also performs a process of releasing the RRC connection established with the base station (eNodeB)201 or 202. When such a process is completed, the TAU processing unit F110 transmits a signal (TAU Complete) indicating that the TAU processing on the mobile terminal 100 side is completed, to the MME300 via the base station (eNodeB)201 or 202.

Note that, in some cases, MME300 may not be able to acquire information related to the IMSI and bearer of mobile terminal 100 based on the GUTI included in the TAU request. For example, when the mobile terminal 100 having completed the attach process moves from inside the service area of the Radio Access Network (RAN) to outside the service area and then returns to inside the service area, if the time during which the mobile terminal 100 is outside the service area is equal to or longer than a certain time (for example, about 70 minutes), there is a possibility that the implicit detach process is performed on the core network (EPC) side. The "separation processing" is processing for releasing a bearer, deallocating an IP address, deallocating a GUTI, and the like. When the implicit detach process is performed, the MME300 cannot acquire information related to the IMSI and the bearer of the mobile terminal 100 based on the GUTI included in the TAU request. In such a case, a signal for rejecting the TAU request (a signal (TAU reject signal) including the cause value #9 defined in 3 GPP) is transmitted from MME300 to mobile terminal 100 via base station (eNodeB)201 or 202 for the reason that mobile terminal 100 cannot be identified.

Here, it is assumed that a pseudo base station having a stronger radio wave intensity than a legitimate base station is provided in the Tracking Area (TA). In such a case, the TAU processing unit F110 may select the pseudo base station as the connection destination of the control link. As a result, the TAU request may be transmitted not to the legitimate base station but to the fake base station. For example, in the case where either one of the first base station (eNodeB)201 and the second base station (eNodeB)202 provided in the Tracking Area (TA) shown in fig. 1 is a pseudo base station, it is possible to transmit a TAU request to the pseudo base station among these base stations (eNodeB)201 and 202. When the TAU request is transmitted to the pseudo base station, a TAU reject signal is transmitted from the pseudo base station to the mobile terminal 100 for the same reason as in the case where the implicit detach process is performed. In this case, it is effective to prohibit communication with the pseudo base station in order to suppress illegal information leakage by the pseudo base station, but communication with the base station is also prohibited when the base station that is the source of the TAU reject signal is a legitimate base station (when the mobile terminal 100 receives the TAU reject signal due to the implicit detach processing). As a result, the mobile terminal 100 may fall into a state in which it cannot be connected to an external network (PDN), and the occupant of the vehicle 10 may not be able to use the internet or the like. In particular, in the mobile terminal 100 having only the radio communication function of the LTE standard and not having the radio communication function of the 3G standard, the state in which the connection to the external network (PDN) is not possible is likely to be prolonged. Therefore, it is necessary to accurately determine whether the TAU reject signal is transmitted from the legitimate base station or the pseudo base station. Therefore, in the present example, when the communication unit 104 receives the TAU reject signal, the TAU processing unit F110 transmits the TAU to the determination unit F120.

The determination unit F120 performs processing for determining whether the base station (eNodeB)201 or 202 that is the transmission source of the TAU reject signal is a legitimate base station or a fake base station. In this example, the determination unit F120 determines whether or not a predetermined condition including the following two conditions is satisfied. The predetermined condition may include only one of the following two conditions. (Condition 1) receiving a signal requesting IMSI from a base station (Condition 2) the base station does not attempt to start encrypted communication (transmitting and receiving a signal requesting IMSI in plaintext data, etc.) with authentication processing

The above-mentioned predetermined condition is a condition specific to the pseudo base station. Thus, when the predetermined condition is satisfied (when the conditions 1 and 2 are satisfied), the determination unit F120 determines that the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a pseudo base station. When determining that the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a pseudo base station, the determination unit F120 registers the cell ID of the cell in which the base station (eNodeB)201 or 202 is located and the initial value (5 minutes) of the prohibition time in the prohibition list storage unit M120. The determination unit F120 also has a function of updating the time registered in the prohibited time field of the prohibited list in units of seconds. At the same time, the determination unit F120 also has a function of deleting information on a cell registered in the barred time field of the barred list, the cell having a time of "0 minutes 00 seconds", from the barred list. When the predetermined condition is not satisfied, the determination unit F120 determines that the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a legitimate base station. The determination result of the determination unit F120 is transmitted from the determination unit F120 to the attachment processing unit F130.

The attachment processing unit F130 performs attachment processing based on the determination result of the determination unit F120. First, when determining that the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a legitimate base station, the attachment processing unit F130 transmits an attachment request to the MME300 via the base station (eNodeB)201 or 202 that is the source of the TAU reject signal. The attach request is a signal requesting a process of newly setting up a bearer from a base station (eNodeB)201 or 202 of a Tracking Area (TA) in which the mobile terminal 100 is located to an external network (PDN), including IMSI. It should be noted that information specifying the address of the external network (PDN) may also be included in the attach request.

In the MME300 that has received the attach request, security processing such as mutual authentication and encryption with the mobile terminal 100 is performed based on the IMSI. Further, in MME300, a bearer setup request to SGW400 is made based on the address of the external network (PDN). When the address of the external network (PDN) is not included in the attach request, the bearer setup request to the SGW400 is made based on the default address. SGW400 makes a request for PGW500 to set a communication path (packet transmission path) between SGW400 and PGW 500. Upon receiving such a setting request, PGW500 assigns an IP address to mobile terminal 100 and sets a communication path between SGW400 and PGW 500. In addition, MME300 transmits a bearer setup request including the address of SGW400 to base station (eNodeB)201 or 202. At this time, the MME300 also transmits a signal indicating that the Attach Accept process is completed (Attach Accept), the IP address assigned by the PGW500, the GUTI assigned by the MME300, and the like to the base station (eNodeB)201 or 202. The base station (eNodeB)201 or 202 transmits a signal (Attach Accept) indicating that the attachment process is completed, an IP address, GUTI, and the like to the mobile terminal 100. In addition, the base station (eNodeB)201 or 202 sets a communication path between the base station (eNodeB)201 or 202 and the SGW 400. Thereby, a bearer from the base station (eNodeB)201 or 202 of the Tracking Area (TA) in which the mobile terminal 100 is located to the external network (PDN) is newly set.

When the communication unit 104 of the mobile terminal 100 receives a signal (Attach Accept), an IP address, a GUTI, and the like indicating that the Attach process is completed, the Attach processing unit F130 registers the TAI of the Tracking Area (TA) in which the mobile terminal 100 is located in the TAI storage unit M110.

According to the above procedure, when the mobile terminal 100 is implicitly detached, it is possible to suppress the mobile terminal 100 from falling into a state in which it is not possible to connect to an external network (PDN).

Next, when determining that the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a pseudo base station, the attachment processing unit F130 transmits an attachment request to the MME300 via the base station (eNodeB)201 or 202 that is not determined as a pseudo base station (eNodeB)201 or 202 that is not registered in a cell of the prohibited list) among the base stations (eNodeB)201 or 202 in the Tracking Area (TA) in which the mobile terminal 100 is located. In this case, on the core network (EPC) side, bearer new setting and new assignment of an IP address and a GUTI are performed by the same procedure as in the case where the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a legitimate base station. Thus, when the base station (eNodeB)201 or 202 that is the source of the TAU reject signal is a pseudo base station, unnecessary continuation of communication with the pseudo base station can be suppressed, and the mobile terminal 100 can be prevented from falling into a state in which it cannot be connected to an external network (PDN).

The series of processes executed by the mobile terminal 100 configured as described above can be executed by hardware or software. The functional configuration of the mobile terminal 100 is not limited to the example shown in fig. 3, and the omission, replacement, and addition of the components may be performed as appropriate.

(flow of treatment)

Next, an outline of the flow of data transmitted and received by the mobile terminal 100 and the flow of processing performed by the mobile terminal 100 in the present embodiment will be described with reference to fig. 5 and 6. Fig. 5 is a sequence diagram schematically showing the flow of data transmitted and received by the mobile terminal 100 and the flow of processing performed by the mobile terminal 100 when the transmission destination of the TAU request is a legitimate base station (in the example shown in fig. 5, the first base station (eNodeB) 201). Fig. 6 is a sequence diagram schematically showing the flow of data transmitted and received by the mobile terminal 100 and the flow of processing performed by the mobile terminal 100 when the transmission destination of the TAU request is a pseudo base station (in the example shown in fig. 6, the first base station (eNodeB) 201).

In fig. 5, when the TAI is notified from the first base station (eNodeB)201 to the mobile terminal 100 (S10), the TAU processing unit F110 of the mobile terminal 100 compares the received TAI with the TAI stored in the TAI storage unit M110. If the received TAI is different from the TAI stored in the TAI storage unit M110, the TAU processing unit F110 determines that the Tracking Area (TA) in which the mobile terminal 100 is located has changed (S11).

When determining that the Tracking Area (TA) in which the mobile terminal 100 is located has changed, the TAU processing unit F110 establishes a control link with the first base station (eNodeB)201, and transmits a TAU request using the established control link (S12). Note that, if the radio wave intensity of the second base station (eNodeB)202 is stronger than the radio wave intensity of the first base station (eNodeB)201, the TAU processing unit F110 may establish a control link with the second base station (eNodeB)202 and transmit a TAU request to the second base station (eNodeB) 202.

Here, if the first base station (eNodeB)201 is a legitimate base station, the TAU request received from the mobile terminal 100 is transmitted to the MME 300. In the example shown in fig. 5, since the implicit detach process of the mobile terminal 100 has already been performed, the MME300 transmits a TAU reject signal including the reason value #9 to the first base station (eNodeB) 201. In this case, the first base station (eNodeB)201 transfers the TAU reject signal from the MME300 to the mobile terminal 100 using the control link (S13).

In the mobile terminal 100 that has received the TAU reject signal, the reception of the TAU reject signal is passed from the TAU processing unit F110 to the determination unit F120. The determination unit F120 determines whether or not the above-described predetermined condition is satisfied. In the example shown in fig. 5, since the IMSI request is not made using plaintext data, the determination unit F120 determines that the first base station (eNodeB)201 is a legitimate base station (S14). The determination result is transmitted from the determination unit F120 to the attachment processing unit F130.

The attach processing unit F130 transmits an attach request using a control link established with the first base station (eNodeB)201 (S15). Thus, an attach process is performed on the core network (EPC) side, a bearer from the first base station (eNodeB)201 to the external network (PDN) is newly set, and an IP address and GUTI are newly allocated to the mobile terminal 100. Thus, even when the mobile terminal 100 performs the implicit detach process by staying for a certain time or more outside the service area of the Radio Access Network (RAN), the mobile terminal 100 can be connected to the external network (PDN).

Next, in fig. 6, when the TAI is notified to the mobile terminal 100 from the second base station (eNodeB)202, which is a legitimate base station (S20), the TAU processing unit F110 compares the received TAI with the TAI stored in the TAI storage unit M110, and determines that the Tracking Area (TA) in which the mobile terminal 100 is located has changed (S21).

When determining that the Tracking Area (TA) in which the mobile terminal 100 is located has changed, the TAU processing unit F110 establishes a control link with one of the first base station (eNodeB)201 and the second base station (eNodeB) 202. In the example of fig. 6, since the radio wave intensity of the first base station (eNodeB)201 as a pseudo base station is stronger than the radio wave intensity of the second base station (eNodeB)202 as a legitimate base station, the TAU processing unit F110 establishes a control link with the first base station (eNodeB)201 and transmits a TAU request using the established control link. In this case, the TAU request from the mobile terminal 100 is transmitted not to the second base station (eNodeB)202, which is a legitimate base station, but to the first base station (eNodeB)201, which is a pseudo base station (S22).

When the first base station (eNodeB)201, which is a pseudo base station, receives the TAU request, the IMSI request signal is transmitted from the first base station (eNodeB)201 to the mobile terminal 100 (S23). The IMSI request signal is a signal requesting transmission of the IMSI of the mobile terminal 100 to the first base station (eNodeB) 201. On the other hand, when the mobile terminal 100 transmits a response signal including the IMSI (S24), the first base station (eNodeB)201 transmits a TAU reject signal to the mobile terminal 100 (S25).

Here, since the first base station (eNodeB)201 as a pseudo base station is not connected to the core network (EPC), it is not possible to start the encrypted communication accompanied by the mutual authentication with the mobile terminal 100. Therefore, the signals transmitted and received at S23 to S25 in fig. 6 become signals based on plaintext data. As a result, the determination unit F120 of the mobile terminal 100 determines that the first base station (eNodeB)201 is a pseudo base station (S26).

When it is determined that the first base station (eNodeB)201 is a pseudo base station, the cell ID of the cell (first cell) in which the first base station (eNodeB)201 is located and the initial value of the prohibited time are registered in the prohibited list storage unit M120 (S27), and the countdown of the prohibited time is started (S28). Thereby, communication with the cell in which the first base station (eNodeB)201 is located is prohibited for 5 minutes.

When communication with the cell in which the first base station (eNodeB)201 is located is prohibited, the attachment processing unit F130 transmits an attachment request to a base station located in another cell. In the example shown in fig. 6, an attach request is sent to a second base station (eNodeB)202 located in a second cell (S29). Thereby, a bearer from the second base station (eNodeB)202 to the external network (PDN) is newly set, and the mobile terminal 100 is newly allocated GUTI and IP address. As a result, it is possible to suppress the mobile terminal 100 from unnecessarily continuing communication with the first base station (eNodeB)201 as a pseudo base station and to suppress the mobile terminal 100 from falling into a state in which it is not possible to connect to the external network (PDN).

After that, when the prohibition time of the first cell registered in the prohibition list becomes "0 min 00 sec", the determination unit F120 deletes the information on the first cell from the prohibition list (S30).

Next, a flow of processing executed by the mobile terminal 100 in the present embodiment will be described based on fig. 7. Fig. 7 is a flowchart showing a process flow executed by the mobile terminal 100 triggered by the reception of a signal notifying TAI. In the example shown in fig. 7, the mobile terminal 100 (the vehicle 10) is assumed to be located in the Tracking Area (TA) in fig. 1 (the Tracking Area (TA) including the first cell and the second cell). In this case, the radio wave intensity of the first base station (eNodeB)201 is set to be stronger than the radio wave intensity of the second base station (eNodeB) 202.

In the processing flow of fig. 7, when the communication unit 104 receives a signal notifying the TAI of the Tracking Area (TA) in which the mobile terminal 100 is located (step S101), the communication unit 104 transmits the signal to the TAU processing unit F110.

The TAU processing unit F110 compares the TAI included in the signal with the TAI stored in the TAI storage unit M110 (hereinafter, sometimes referred to as "TAIold"). That is, the TAU processing unit F110 determines whether the TAI matches the TAIold (step S102). If the TAI matches the TAIold (affirmative determination is made in step S102), the execution of the present processing flow is ended. On the other hand, if the TAI does not match the TAIold (negative determination is made in step S102), the process of step S103 is executed.

In step S103, the TAU processing unit F110 establishes a control link with the first base station (eNodeB)201 having the stronger radio wave intensity among the first base station (eNodeB)201 and the second base station (eNodeB)202, and transmits a TAU request using the established control link. As described above, the GUTI assigned to the mobile terminal 100 is included in the TAU request.

After the process of step S103 is executed, the TAU processing unit F110 determines whether or not the communication unit 104 has received a TAU reject signal including the cause value #9 as a response signal to the TAU request (step S104). At this time, when the communication unit 104 receives a signal (TAU Accept) indicating that TAU processing on the core network (EPC) side is completed, a negative determination is made in step S104. When a negative determination is made in step S104, execution of the present processing flow is ended. Thereafter, as described above, the TAU processing unit F110 returns a signal (TAU Complete) indicating that the TAU processing on the mobile terminal 100 side is completed. On the other hand, when the communication unit 104 receives the TAU reject signal, it makes an affirmative determination in step S104. When an affirmative determination is made in step S104, the process of step S105 is executed.

In step S105, the determination unit F120 determines whether or not a predetermined condition is satisfied. The "predetermined condition" in this example is that both of the aforementioned (condition 1) and (condition 2) are satisfied. Here, as shown in fig. 6 described above, when the communication unit 104 receives the IMSI request signal (condition 1) and transmits and receives a signal including the IMSI request signal as plaintext data (transmission and reception performed at S23 to S25 in fig. 6) (condition 2), the determination unit F120 determines that the predetermined condition is satisfied (affirmative determination is performed at step S105).

When an affirmative determination is made in step S105, the determination unit F120 determines that the first base station (eNodeB)201 is a pseudo base station (step S106). In this case, the determination unit F120 registers the cell ID of the cell (first cell) in which the first base station (eNodeB)201 is located and the initial value of the prohibited time in the prohibited list of the prohibited list storage unit M120 (step S107). Next, the determination unit F120 starts counting down the barred time associated with the first cell in the barred list (step S108).

When the process of step S108 ends, the attachment processing unit F130 establishes a control link with the second base station (eNodeB)202, and transmits an attachment request using the established control link (step S109). Thereby, an attach request is sent to MME300 via second base station (eNodeB) 202. As a result, on the core network (EPC) side, a bearer from the second base station (eNodeB)202 to the external network (PDN) is newly set, and the mobile terminal 100 is newly assigned a GUTI and an IP address. This can suppress unnecessary continuation of communication with the first base station (eNodeB)201 as a pseudo base station, and can suppress the mobile terminal 100 from falling into a state in which it cannot be connected to an external network (PDN).

When the process of step S109 ends, the determination unit F120 determines whether or not the barring time for the first cell registered in the barring list is reduced to "0 minutes 00 seconds" (step S110). When a negative determination is made in step S110, the process of step S110 is repeatedly executed. On the other hand, when an affirmative determination is made in step S110, the determination unit F120 deletes the information on the first cell from the prohibited list (step S111). When the process of step S111 ends, execution of the present process flow ends. Here, it is also possible to assume a situation in which a legitimate base station is disposed in the same first cell as the first base station (eNodeB)201 and there are no cells accessible to the mobile terminal 100 other than the first cell. If the prohibition of communication with the first cell is continued for a long time in such a situation, there is a possibility that the state in which the mobile terminal 100 cannot connect to the external network (PDN) will be prolonged. In contrast, when the prohibition time of the first cell is set to a short time of about 5 minutes, it is also possible to transmit a TAU request or an attach request to a legitimate base station of the first cell after the prohibition time has elapsed. As a result, it is possible to suppress the mobile terminal 100 from falling into a state in which it cannot connect to an external network (PDN) for a long period of time.

When it is determined in step S105 that the predetermined condition is not satisfied (negative determination is made in step S105), the determination unit F120 determines that the first base station (eNodeB)201 is a valid base station because it can be assumed that the implicit detach process is performed on the core network (EPC) side (step S112).

When determining that the first base station (eNodeB)201 is a legitimate base station, the attachment processing unit F130 transmits an attachment request using a control link established with the first base station (eNodeB)201 (step S113). When the process of step S113 is completed, execution of the present process flow is ended. This can prevent unnecessary prohibition of communication with the first base station (eNodeB)201 as a legitimate base station when the TAU reject signal is issued for legitimate reasons, as in the case where the implicit detach process is performed. This can suppress the mobile terminal 100 from falling into a state in which it cannot connect to an external network (PDN).

According to the process flow of fig. 7, it is possible to accurately determine whether or not the TAU reject signal including the cause value #9 is transmitted from the pseudo base station. Accordingly, when the source of the TAU reject signal is the pseudo base station, the mobile terminal 100 can be prohibited from communicating with the pseudo base station. As a result, unnecessary continuation of communication between the mobile terminal 100 and the pseudo base station can be suppressed. Further, when communication between the mobile terminal 100 and the pseudo base station is prohibited, the mobile terminal 100 transmits an attach request to the MME300 via a legitimate base station different from the pseudo base station, and therefore, it is also possible to suppress the mobile terminal 100 from falling into a state in which it cannot connect to an external network (PDN). On the other hand, when the TAU reject signal including the cause value #9 is transmitted from a legitimate base station, it is possible to suppress unnecessary prohibition of communication between the mobile terminal 100 and the legitimate base station. Thereby, the mobile terminal 100 can transmit an attach request to the MME300 via a legitimate base station. As a result, when the TAU reject signal including the cause value #9 is a signal transmitted from a legitimate base station, it is possible to suppress the mobile terminal 100 from falling into a state in which it cannot connect to the external network (PDN).

Therefore, according to the present embodiment, it is possible to suppress the mobile terminal 100 from falling into a state in which it cannot be connected to an external network (PDN), regardless of whether the source of the TAU reject signal is a pseudo base station or a legitimate base station. This effectively suppresses communication between the mobile terminal 100 and the pseudo base station. As a result, it is possible to suppress the occupant of the vehicle 10 from falling into a state where the internet or the like is unavailable.

< others >

The above embodiment is merely an example, and the present disclosure can be implemented with appropriate modifications within a scope not departing from the gist thereof. The processes and structures described in the present disclosure can be freely combined and implemented without causing any technical contradiction. The processing described as being performed by 1 device may be shared and executed by a plurality of devices. The processing described as being performed by a different device may be executed by 1 device. In a computer system, how each function is realized by a hardware configuration can be flexibly changed.

In addition, the present disclosure can also be implemented by: the computer program having the functions described in the above embodiments is supplied to a computer, and 1 or more processors included in the computer read and execute the program. Such a computer program may be provided to a computer by using a nonvolatile computer-readable storage medium that can be connected to a system bus of the computer, or may be provided to the computer via a network. A nonvolatile computer-readable storage medium is a recording medium capable of storing information such as data and programs by an electrical, magnetic, optical, mechanical, or chemical action and reading from a computer or the like. Such a nonvolatile computer-readable storage medium is, for example, any type of disk such as a magnetic disk (a flexible disk (registered trademark) or a Hard Disk Drive (HDD)) or an optical disk (a CD-ROM, a DVD disk, a blu-ray disk, or the like). The nonvolatile computer-readable storage medium may be a medium such as a Read Only Memory (ROM), a Random Access Memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, or an SSD (Solid State Drive).

Claims

1. An information processing device mounted on a vehicle and performing wireless communication according to the LTE standard,

the information processing apparatus includes a processor configured to:

2. The information processing apparatus according to claim 1,

the predetermined condition includes receiving a signal requesting subscriber identification information assigned to the information processing apparatus from the first base station.

3. The information processing apparatus according to claim 2,

the predetermined condition further includes that the first base station does not start encrypted communication accompanying an authentication process.

4. The information processing apparatus according to any one of claims 1 to 3,

in the case where communication with the first base station is prohibited, the processor is configured to prohibit communication with a cell in which the first base station is located in a tracking area in which the vehicle is located.

5. The information processing apparatus according to claim 4,

while inhibiting communication with the cell in which the first base station is located, the processor is configured to send an attach request to a second base station located in a different cell than the first base station.

6. The information processing apparatus according to claim 4 or 5,

in the case where communication with the first base station is prohibited, the processor is configured to prohibit communication with the cell for a predetermined time.

7. The information processing apparatus according to any one of claims 1 to 6,

in a case where it is determined that the predetermined condition is not satisfied, the processor is configured to transmit an attachment request to the first base station.

8. An information processing method for controlling a computer mounted on a vehicle and performing wireless communication according to the LTE standard,

the information processing method includes executing, with the computer, the following actions:

9. The information processing method according to claim 8,

the predetermined condition includes receiving a signal requesting subscriber identification information assigned to the computer from the first base station.

10. The information processing method according to claim 9,

11. The information processing method according to any one of claims 8 to 10,

in the case where communication with the first base station is prohibited, the computer prohibits communication with a cell in which the first base station is located in a tracking area in which the vehicle is located.

12. The information processing method according to claim 11,

the information processing method further includes: the computer transmits an attachment request to a second base station located in a cell different from the first base station while communication with the cell in which the first base station is located is prohibited.

13. The information processing method according to claim 11 or 12,

the computer prohibits communication with the cell for a predetermined time in a case where communication with the first base station is prohibited.

14. The information processing method according to any one of claims 8 to 13,

the information processing method further includes: when it is determined that the predetermined condition is not satisfied, the computer transmits an attachment request to the first base station.

15. A non-volatile storage medium storing a program for causing a computer mounted on a vehicle to execute wireless communication according to the LTE standard,

the program causes the computer to perform the following actions:

16. The non-volatile storage medium of claim 15,

17. The non-volatile storage medium of claim 16,

18. The non-volatile storage medium according to any one of claims 15 to 17,

the program causes the computer to prohibit communication with a cell in which the first base station is located in a tracking area in which the vehicle is located, in a case where communication with the first base station is prohibited.

19. The non-volatile storage medium of claim 18,

the program further causes the computer to transmit an attach request to a second base station located in a cell different from the first base station while communication with the cell in which the first base station is located is prohibited.

20. The non-volatile storage medium according to any one of claims 15 to 19,

the program further causes the computer to transmit an attach request to the first base station when it is determined that the predetermined condition is not satisfied.