JP2016158093A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system in which a plurality of terminals can perform terminal-to-terminal communication, without being controlled from a base station, upon occurrence of disaster.SOLUTION: In a communication system including a base station, and a plurality of terminals capable of terminal-to-terminal communication, each of the plurality of terminals has, as the operation mode when performing terminal-to-terminal communication, a first mode for using a wireless resource allocated by the base station, and a second mode for using a wireless resource allocated by the own terminal or the opposite terminal. The first and second terminals, out of the plurality of terminals, are visiting a cell constituted by the base station, respectively. Upon accepting an input on the occurrence of a disaster, the first terminal sets the operation mode to the second mode.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a communication system including a plurality of terminal devices and a base station.

  Conventionally, inter-terminal (D2D: device to device) communication in which terminals (UE: User Equipment) communicate with each other without using a base station apparatus (eNB: evolved NodeB) is known. D2D communication is also referred to as D2D Proximity Services (ProSe). Proximity Services is standardized in Release 12 of 3GPP (3rd Generation Partnership Project) as shown in Non-Patent Documents 1 to 3. In particular, Non-Patent Document 2 discloses “Proximity discovery” (hereinafter referred to as “D2D discovery service”), which is a proximity detection service in D2D Proximity Services.

  The D2D discovery service can be executed by an LTE (Long Term Evolution) terminal having a D2D discovery function and an application program using D2D Proximity Services. In addition, a service that enables proximity detection between UEs located in a range where the eNB supports D2D discovery is being studied.

  In the D2D discovery service, a UE can be arbitrarily selected from a radio resource pool dedicated to discovery assigned by an eNB or a radio resource pool set in advance by a SIM (Subscriber Identity Module) or the like by executing an application program that uses D2D Proximity Services. One or more resources (blocks) are selected and a discovery signal is transmitted. As a result, the UE notifies its own existence to other UEs. In addition, the UE receives all or part of the radio resources for discovery in order to discover the presence of other UEs.

  The discovery signal includes a ProSe (Proximity Service) UE ID and a ProSe Application ID. The ProSe Application ID is a dedicated ID assigned for each application program. Therefore, each of the plurality of application programs using D2D makes a transmission request for a discovery signal including ProSe Application ID to the control unit of the own terminal. In addition, each application program can identify the presence of another UE executing the same application program based on the discovery signal of the other UE received at the UE. In that case, UE notifies the user of the said UE by displaying an identification result on a display.

  According to D2D communication, since it does not go through a radio base station or a network device, it is expected to increase the possibility that a radio communication terminal can make a call even during congestion. Therefore, even when a transmission request is not accepted due to congestion on the network side, etc., it has been studied to increase the possibility of providing a communication application using D2D communication.

  For example, JP2013-223194A (Patent Document 1) discloses a wireless communication terminal capable of executing D2D communication. The wireless communication terminal receives a transmission restriction including communication environment setting information necessary for direct communication. The wireless communication terminal executes direct communication with another wireless communication terminal based on the setting information when the communication application determines that the communication application can be executed by direct communication in a case where transmission to the wireless access network is restricted. .

JP 2013-223194 A

3GPP TR 36.843 V12.0.1 (2014-03): 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on LTE Device to Device Proximity Services; Radio Aspects (Release 12) 3GPP TR 23.703 V12.0.0 (2014-02): 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on architecture enhancements to support Proximity-based Services (ProSe) (Release 12) 3GPP TS 23.303 V12.1.0 (2014-06): 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Proximity-based services (ProSe); Stage 2 (Release 12)

  In the configuration of Patent Document 1, the wireless communication terminal can start D2D communication that does not pass through the base station by receiving from the base station a transmission restriction that includes communication environment setting information necessary for D2D communication. is there. However, there is a possibility that the base station becomes congested when a disaster occurs, and the wireless communication terminal may not be able to receive information necessary for D2D communication from the base station. Therefore, in such a case, with the configuration of Patent Document 1, there is a problem that the wireless communication terminal cannot start D2D communication.

  The present disclosure has been made to solve the above-described problems, and an object in one aspect is to enable a plurality of terminal devices to perform inter-terminal communication when a disaster occurs. An object is to provide a communication system.

  According to an embodiment, a communication system including a base station and a plurality of terminal devices capable of inter-terminal communication is provided. Each of the plurality of terminal devices has a first mode using radio resources allocated by the base station as an operation mode when performing communication between terminals, and radio resources allocated by the own terminal device or the counterpart terminal device. A second mode to be used. Each of the first terminal device and the second terminal device among the plurality of terminal devices is located in a cell formed by the base station. The first terminal device sets the operation mode to the second mode when receiving an input regarding the occurrence of the disaster.

  According to the present disclosure, when a disaster occurs, a plurality of terminal apparatuses can execute inter-terminal communication without receiving control related to inter-terminal communication from the base station.

1 is a diagram showing an overall configuration of a communication system according to a first embodiment. It is a figure for demonstrating allocation mode. 6 is a sequence diagram for explaining an example of communication processing performed between a plurality of terminals and a base station in Embodiment 1. FIG. FIG. 3 is a block diagram showing a hardware configuration of a terminal according to the first embodiment. 3 is a block diagram showing a hardware configuration of a base station according to Embodiment 1. FIG. 3 is a functional block diagram for illustrating a functional configuration of a terminal according to the first embodiment. FIG. 3 is a functional block diagram showing a functional configuration of a base station according to Embodiment 1. FIG. It is a flowchart which shows the process which the terminal according to Embodiment 1 performs. It is a flowchart which shows the process which the other terminal according to Embodiment 1 performs. FIG. 11 is a sequence diagram for explaining an example of communication processing performed between a plurality of terminals and a base station in the second embodiment. It is a flowchart which shows the process which the terminal according to Embodiment 2 performs. It is a flowchart which shows the process which the other terminal according to Embodiment 2 performs. It is a figure which shows the whole structure of the communication system according to Embodiment 3. FIG. FIG. 10 is a sequence diagram for explaining an example of communication processing performed between a plurality of terminals and a base station in the third embodiment. It is a flowchart which shows the process which the terminal according to Embodiment 3 performs. It is a flowchart which shows the process which the other terminal according to Embodiment 3 performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. Hereinafter, the application program is referred to as “application” for short.

[Embodiment 1]
<Overall system configuration>
(Device configuration)
FIG. 1 shows an overall configuration of a communication system according to the first embodiment. Referring to FIG. 1, the communication system according to the first embodiment is a communication system corresponding to LTE, for example. The communication system includes radio terminal apparatuses (hereinafter simply referred to as “terminals”) 10 and 20 and radio base stations (hereinafter simply referred to as “base stations”) 50. Base station 50 constitutes cell 500. Terminals 10 and 20 are located in cell 500.

  Terminals 10 and 20 are UEs that perform wireless communication according to a radio access technology such as LTE. Specifically, the terminals 10 and 20 can perform D2D communication (inter-terminal communication) with other nearby terminals without going through the base station, and are LTE terminals having a D2D discovery function ( Mobile terminal device conforming to the LTE standard). Typically, the terminals 10 and 20 are smartphones.

  In the terminals 10 and 20, an application program (hereinafter also referred to as “D2D compatible application”) that uses the D2D discovery service is installed in advance. The D2D-compatible application is an application that can use the D2D Proximity Service as described above. Examples of D2D compatible applications include applications such as SNS, games, advertisements, and communication applications. In addition, for example, “ProSe UE ID” is assigned to the terminals 10 and 20 as an identifier of a terminal capable of executing D2D Proximity Services.

  The terminals 10 and 20 arbitrarily select a radio resource for transmitting a D2D discovery signal based on the radio resource pool information from the base station 50. Further, the terminal 10 and the terminal 20 can transmit / receive a discovery signal to / from each other without using the base station 50. Each of the terminals 10 and 20 transmits a discovery signal for notifying the surrounding terminals of the presence of the own terminal using arbitrarily selected radio resources for transmitting the discovery signal. The discovery signal typically includes a ProSe Application ID for identifying an application and a ProSe UE ID for identifying a terminal.

(Assignment mode)
FIG. 2 is a diagram for explaining the allocation mode. Specifically, FIG. 2A is a diagram for explaining the first allocation mode (hereinafter, illustrated as “Made 1”). FIG. 2B is a diagram for explaining the second allocation mode (hereinafter, illustrated as Mode 2). In FIG. 2, the terminal 10 is an example of a transmission side terminal, and the terminal 20 is an example of a reception side terminal.

  As shown in FIG. 2A, in the first allocation mode, the base station 50 allocates radio resources used for user data communication in D2D communication (communication between terminals) that communicate with each other without going through the base station. Specifically, the base station 50 allocates to the terminals 10 and 20 radio resources used for user data communication in D2D communication from among radio resources (D2D radio resources) used for D2D communication. The base station 50 notifies the allocated radio resources to the terminals 10 and 20 (resource allocation). The terminal 10 transmits user data to the terminal 20 using the allocated radio resource. The terminal 20 receives user data from the terminal 10 using the allocated radio resource. In the first allocation mode, the base station 50 uses radio resources other than the D2D radio resources broadcast in the cell managed by the base station 50 among the radio resources used in the cellular communication performed between the terminals 10 and 20 and the base station 50. Resources may be assigned to the terminals 10 and 20.

  On the other hand, as shown in FIG. 2B, in the second allocation mode, the terminal 10 or the terminal 20 allocates radio resources used for user data communication in the D2D communication. Specifically, the terminal 10 or the terminal 20 autonomously allocates a radio resource used for user data communication in D2D communication from D2D radio resources broadcast from a cell managed by the base station 50. However, the terminal 10 or the terminal 20 may be configured to autonomously allocate radio resources used for user data communication in D2D communication from predetermined D2D radio resources. The terminal 10 or the terminal 20 notifies the allocated radio resources to other terminals (resource allocation). The terminal 10 and the terminal 20 transmit / receive user data to / from each other using the assigned radio resource.

  As described above, in the communication system according to the first embodiment, as an allocation mode for allocating radio resources used for user data communication in D2D communication, the first allocation mode in which base station 50 allocates radio resources, and terminal 10 or terminal 20 A second allocation mode for allocating radio resources. In other words, the terminal 10 and the terminal 20 use the radio resource allocated from the base station 50 (that is, the radio resource allocated in the first allocation mode) as the operation mode when executing D2D communication. Mode (hereinafter, simply referred to as “mode 1”) and a second operation mode (hereinafter, referred to as “radio resource allocated in the second allocation mode”) allocated by the own terminal or the partner terminal. Simply referred to as “mode 2”).

<Overview of system operation>
Here, a procedure will be described in which the terminal 10 and the terminal 20 start D2D communication in mode 2 (D2D communication using radio resources allocated by the own terminal or the partner terminal) when a disaster occurs.

  FIG. 3 is a sequence diagram for explaining an example of communication processing performed between the plurality of terminals 10 and 20 and the base station 50 in the first embodiment. In the following description, terminal 10 and terminal 20 will be described as an example of a plurality of terminals that perform D2D communication, but three or more terminals may perform D2D communication. In the initial state of the sequence, it is assumed that the terminal 10 and the terminal 20 are not performing D2D communication.

  Referring to FIG. 3, base station 50 broadcasts D2D radio resources (pools) to terminal 10 and terminal 20 (sequences SQ2, SQ4). Terminal 10 and terminal 20 receive the earthquake early warning as an example of emergency information from base station 50 (sequences SQ6 and SQ8). As an emergency information delivery method, ETWS (Earthquake and Tsunami Warning System), CBS (Cell Broadcast Service), and the like are assumed. The emergency information may be information on various disasters such as information on tsunami prediction, typhoon warning, and information on fire.

  Terminal 10 and terminal 20 accept an instruction from the user via a touch panel or the like, and activate the disaster information application (sequences SQ10 and SQ12). The user of each terminal, for example, confirms the display on which the earthquake early warning is displayed, determines that a disaster has occurred (or will soon occur), and presses a button for starting the disaster information app . Note that the terminal 10 and the terminal 20 may be configured to automatically activate the disaster information application based on the reception of emergency information.

  The disaster information application is a D2D-compatible application and can distribute and receive information related to disasters (disaster related information). Specifically, the terminal 10 and the terminal 20 can set the operation mode to mode 2 and start D2D communication in mode 2 by activating the disaster information application.

  The terminal 10 or the terminal 20 autonomously allocates radio resources used for user data communication in the D2D communication from the D2D radio resources broadcast from the base station 50, and the radio allocated to other terminals. The resource is notified (sequence SQ14).

  Terminal 10 transmits the disaster related information to terminal 20 using the assigned radio resource, and terminal 20 receives the disaster related information transmitted using the radio resource (sequence SQ16). Specifically, the terminal 20 detects the assigned radio resource, and if there is disaster related information in the radio resource, the terminal 20 receives the disaster related information. The terminal 20 displays disaster-related information on a display or outputs from a speaker.

  The disaster-related information is various information related to the disaster, and includes, for example, evacuation place, evacuation route, distribution, and water supply facility information when a disaster occurs in an area where D2D communication is possible. As a specific example, a staff of a local government, a police, a fire engine, or the like is assumed as a user of the terminal 10 on the side of distributing disaster-related information, and a nearby resident is assumed as a user of the terminal 20.

  In the above sequence, the base station 50 has described the configuration in which the D2D radio resource is broadcast to the terminal 10 and the terminal 20 (sequence SQ2, SQ4). However, the terminal 10 and the terminal 20 store the predetermined D2D radio resource in the memory. You may remember. In this case, in sequence SQ14, terminal 10 or terminal 20 autonomously allocates radio resources used for user data communication in D2D communication from predetermined D2D radio resources stored in the memory. The assigned radio resource is notified to the terminal.

  In the above sequence, the terminal 10 and 20 has received the emergency information from the base station 50, so that the user of each terminal determines the occurrence of a disaster and activates the disaster information application. I can't. For example, when the user of each terminal confirms emergency information through TV, disaster prevention radio broadcasting, etc., or when he / she experiences a disaster such as an earthquake or fire, he / she determines that a disaster has occurred and uses the disaster information app. It may be activated.

  Further, the D2D wireless resource may be stored in the disaster information application. In this case, the D2D radio resource can be used when the disaster information application is activated. Specifically, the terminal that has activated the disaster information app autonomously allocates radio resources used for user data communication in D2D communication from the D2D radio resources stored in the disaster information app. As a result, the terminal can communicate with another terminal that has activated the disaster information application.

  In the above sequence, the configuration in which the terminal 10 and the terminal 20 are not executing the D2D communication before the emergency information is received (before the disaster occurs) has been described, but the D2D communication in the mode 1 (from the base station 50) The configuration may be such that (D2D communication using assigned radio resources) is executed.

  Specifically, base station 50 allocates radio resources used for communication of user data in D2D communication from among D2D radio resources broadcasted in sequences SQ2 and SQ4 to terminal 10 and terminal 20. The wireless resource is notified to the terminal 10 and the terminal 20. The terminal 10 transmits user data to the terminal 20 using the allocated radio resource, and the terminal 20 receives user data from the terminal 20 using the allocated radio resource. Then, after receiving emergency information from base station 50 (sequences SQ6 and SQ8), terminal 10 and terminal 20 activate the disaster information application (sequences SQ10 and SQ12). In this case, the terminal 10 and the terminal 20 operating in the mode 1 can start the D2D communication in the mode 2 by switching the operation mode from the mode 1 to the mode 2 by starting the disaster information application. It becomes.

  Thus, when a disaster occurs, each terminal starts D2D communication in mode 2 in which radio resources used for user data communication in D2D communication are autonomously allocated from D2D radio resources. As a result, each terminal does not need to receive control related to D2D communication from the base station when a disaster occurs, and thus can quickly start D2D communication even when the base station is congested.

<Hardware configuration>
(Terminal)
FIG. 4 is a block diagram representing a hardware configuration of terminal 10 according to the first embodiment. Referring to FIG. 4, terminal 10 includes, as main components, CPU (Central Processing Unit) 152, memory 154, touch panel 156, display 158, wireless communication interface (I / F) 160, and memory interface. (I / F) 164, speaker 166, GPS (Global Positioning System) controller 168, and battery 170 are included. Note that the hardware configuration of the terminal 20 is the same as the hardware configuration of the terminal 10.

  The CPU 152 functions as a control unit that controls the operation of each unit of the terminal 10 by reading and executing the program stored in the memory 154. The CPU 152 implements each process (step) of the terminal 10 to be described later by executing the program.

  The memory 154 is realized by a RAM (Random Access Memory), a ROM (Read-Only Memory), a flash memory, or the like. The memory 154 stores a program executed by the CPU 152, data used by the CPU 152, and the like.

  The touch panel 156 is provided on a display 158 having a function as a display unit, and is, for example, a capacitance type. The touch panel 156 detects a touch operation on the touch panel 156 by an external object every predetermined time, and inputs touch coordinates to the CPU 152.

  The wireless communication interface 160 is connected to the communication antenna 162. The communication antenna 162 and the radio communication interface 160 are used for cellular communication via the base station 50 and D2D communication with other terminals, for example.

  The memory interface 164 reads data from the external storage medium 165. The CPU 152 reads data from the memory 154 and stores the data in the external storage medium 165 via the memory interface 164. The storage medium 165 includes a CD (Compact Disc), a DVD (Digital Versatile Disk), a BD (Blu-ray (registered trademark) Disc), a USB (Universal Serial Bus) memory, an SD (Secure Digital) memory card, and the like. A medium for storing the program in a nonvolatile manner can be mentioned.

  The speaker 166 outputs sound in accordance with an instruction from the CPU 152. For example, the speaker 166 outputs an alarm for notifying the user of a disaster.

  The GPS controller 168 acquires the position information of the terminal 10 by receiving a GPS signal or a position signal (positioning signal) from the base station. The GPS controller 168 inputs the acquired position information of the terminal 10 to the CPU 152.

  The battery 170 is a chargeable / dischargeable power storage element, and typically includes a secondary battery such as a lithium ion battery or a nickel metal hydride battery.

  Note that the terminal 10 may include a button for receiving an instruction from the user and a microphone for receiving an utterance to the terminal 10.

(Base station 50)
FIG. 5 is a block diagram showing a hardware configuration of base station 50 according to the first embodiment. Referring to FIG. 5, base station 50 includes, as main components, CPU 202 for executing various processes, memory 204 for storing programs executed by CPU 202, data, and the like, and a wireless communication network. Wireless communication (I / F) 206 and communication antenna 208 for transmitting / receiving various data to / from a device located in cell 500, and wired communication interface (I / F) 210 for wired communication with other devices. Including. The CPU 202 implements each process of the base station 50 by executing a program stored in the memory 204.

<Functional configuration>
(Terminal)
FIG. 6 is a functional block diagram showing a functional configuration of terminal 10 according to the first embodiment. Referring to FIG. 6, terminal 10 includes an application execution unit 102, a D2D communication management unit 104, a storage unit 106, an emergency information management unit 108, and a wireless communication unit 110 as main functional configurations. These functions are mainly realized by the CPU 152 of the terminal 10 executing a program stored in the memory 154 and giving a command to the components of the terminal 10. Some or all of these functional configurations may be realized by hardware. The terminal 10 includes a storage unit 106 corresponding to the memory 154. The functional configuration of the terminal 20 is the same as the functional configuration of the terminal 10 described below.

  The application execution unit 102 reads a D2D-compatible application (for example, a disaster information application) stored in advance in the storage unit 106 from the storage unit 106 and executes the application. The application execution unit 102 receives a user operation and activates the application. The application execution unit 102 may automatically activate an application when emergency information is received by the emergency information management unit 108.

  The D2D communication management unit 104 manages various processes related to D2D communication. Specifically, the D2D communication management unit 104 sets the operation mode for executing the D2D communication to mode 2 when receiving an input regarding the occurrence of the disaster. The input relating to the occurrence of a disaster includes an input for starting an app (for example, a disaster information app) used when a disaster occurs. That is, the D2D communication management unit 104 sets the operation mode to mode 2 when the disaster information application is activated by the application execution unit 102.

  Note that the D2D communication management unit 104 may not be configured to set the operation mode based on the activation of the disaster information application. For example, the D2D communication management unit 104 accepts input of emergency information (reception) from an external device (for example, the base station 50) or input of information indicating that a disaster has been detected from a user as input related to the occurrence of a disaster. In this case, the operation mode may be set to mode 2.

  In another aspect, the D2D communication management unit 104 has received an input regarding a disaster when the terminal 10 is operating in mode 1 (while the terminal 10 is performing D2D communication in mode 1 with another terminal). In this case, the operation mode is switched from mode 1 to mode 2.

  The storage unit 106 stores an OS, various application software, and various data. For example, the storage unit 106 stores radio resource information that can be used in D2D communication. The emergency information management unit 108 receives emergency information via the wireless communication unit 110.

  The wireless communication unit 110 performs various processes for transmitting data from the antenna and various processes for receiving a signal received by the antenna.

(base station)
FIG. 7 is a functional block diagram for illustrating a functional configuration of base station 50 according to the first embodiment. Referring to FIG. 7, base station 50 includes a communication control unit 502, an emergency information control unit 506, and a wireless communication unit 508 as main functional configurations. These functions are mainly realized by the CPU 202 of the base station 50 executing a program stored in the memory 204 and giving a command to the components of the base station 50. Some or all of these functional configurations may be realized by hardware. The base station 50 includes a storage unit 504 corresponding to the memory 204.

  The communication control unit 502 controls communication between the terminal 10 and the terminal 20. The wireless communication unit 508 performs various processes for transmitting data from the antenna and various processes for receiving a signal received by the antenna.

  The storage unit 504 stores an OS, various application software, and various data. For example, the storage unit 504 stores position information, identification information, and the like of each terminal located in the cell 500.

  When the emergency information control unit 506 receives emergency information distributed from the Japan Meteorological Agency or the like, the emergency information control unit 506 stores the emergency information in the storage unit 504. The emergency information control unit 506 transmits emergency information to each terminal located in the cell 500.

<Processing procedure>
Processing performed in each device of the terminal 10 and the terminal 20 will be specifically described.

(Terminal 10)
FIG. 8 is a flowchart showing an example of processing executed by terminal 10 according to the first embodiment. The following steps are realized by the CPU 152 of the terminal 10 executing a program stored in the memory 154.

  Referring to FIG. 8, terminal 10 notifies base station 50 of the position of the terminal, and starts communication with base station 50 (step S2). The terminal 10 receives control information necessary for D2D communication from the base station 50 (step S4). The control information may include permission information for permitting D2D communication using the wireless communication network and communication environment setting information necessary for D2D communication. In the setting information, in addition to radio resources such as a frequency band allowed in D2D communication, radio signal strength of a radio signal, transmission timing of a terminal (execution timing of D2D communication), an identifier (telephone number) of a partner (incoming side) , Terminal identifiers and subscriber identifiers, etc.).

  The terminal 10 determines whether or not an emergency earthquake bulletin distributed from the Japan Meteorological Agency or the like has been received via the base station 50 (step S6). If terminal 10 has not received the earthquake early warning (NO in step S6), terminal 10 repeats the process of step S6. If terminal 10 has not received the earthquake early warning (NO in step S6), terminal 10 repeats the process of step S6.

  The terminal 10 receives an instruction from the user and activates the disaster information application (step S8). Specifically, the terminal 10 sets the operation mode to mode 2 by starting the disaster information application. As a result, the terminal 10 is in a state in which D2D communication in mode 2 can be executed.

  The terminal 10 determines whether an input of disaster related information for distribution to another terminal is accepted via the touch panel 156 (step S10). If terminal 10 has not received the input of disaster related information (NO in step S10), terminal 10 repeats the process of step S10. When the terminal 10 receives the input of the disaster related information (YES in step S10), the terminal 10 transmits the disaster related information by D2D communication in mode 2 (step S12). Specifically, the terminal 10 autonomously allocates radio resources used for user data communication in D2D communication from the D2D radio resources received from the base station 50 and notifies the counterpart terminal (for example, the terminal 20). . The terminal 10 transmits disaster related information using the allocated radio resource.

(Terminal 20)
FIG. 9 is a flowchart showing an example of processing executed by terminal 20 according to the first embodiment. The following steps are realized by the CPU 152 of the terminal 20 executing a program stored in the memory 154.

  Referring to FIG. 9, terminal 20 notifies base station 50 of the position of the terminal, and starts communication with base station 50 (step S22). The terminal 20 receives control information necessary for D2D communication from the base station 50 (step S24).

  The terminal 20 determines whether or not the earthquake early warning has been received via the base station 50 (step S26). If terminal 20 has not received the earthquake early warning (NO in step S26), terminal 20 repeats the process in step S26. If the terminal 20 has received the earthquake early warning (YES in step S26), it accepts an instruction from the user and starts the disaster information application (step S28). Specifically, the terminal 20 sets the operation mode to mode 2 by starting the disaster information application. As a result, the terminal 20 is in a state in which D2D communication in mode 2 can be executed.

  The terminal 20 determines whether disaster-related information has been received using the radio resource allocated from the terminal 10 (whether there is distribution of disaster-related information) (step S30). If the terminal 20 has not received the disaster related information (NO in step S30), the terminal 20 repeats the process of step S30. When the terminal 20 receives the disaster related information (YES in step S30), the terminal 20 displays the disaster related information on the display 158. The terminal 20 may output the disaster-related information from the speaker 166 by voice.

<Advantages>
According to Embodiment 1, when a disaster occurs, each terminal performs D2D communication in a mode that uses radio resources that are autonomously allocated by the terminal itself or the partner terminal. Therefore, each terminal can start D2D communication when a disaster occurs without receiving information necessary for D2D communication from the base station (without receiving control related to inter-terminal communication from the base station). As a result, each terminal can stably perform D2D communication between its own terminal and the partner terminal in the event of a disaster. Therefore, it is possible to transmit disaster-related information to the partner terminal or to send disaster-related information to the partner terminal. The possibility that it can be received from is increased.

[Embodiment 2]
In Embodiment 1, the terminal 20 demonstrated the structure which detects a disaster by reception of emergency information etc. In the second embodiment, a configuration will be described in which the terminal 10 notifies the terminal 20 of the occurrence of a disaster using a D2D discovery signal.

<Overall system configuration>
The apparatus configuration and allocation mode of the communication system according to the second embodiment are the same as the apparatus configuration and allocation mode of the communication system according to the first embodiment, respectively. However, in order to distinguish from terminals 10 and 20 according to the first embodiment, terminals 10 and 20 according to the second embodiment are referred to as “terminal 10A” and “terminal 20A”, respectively.

<Overview of system operation>
Here, a procedure in which the terminal 10A and the terminal 20A start D2D communication in mode 2 when a disaster occurs will be described. FIG. 10 is a sequence diagram for explaining an example of communication processing performed between the plurality of terminals 10A and 20A and the base station 50 in the second embodiment.

  Referring to FIG. 10, the processes of sequences SQ2 to SQ6 are the same as the processes of FIG. 2, and therefore description thereof will not be repeated here. Terminal 10A receives an instruction from the user via a touch panel or the like, and activates the disaster information application (sequence SQ24). As a result, the terminal 10A is in a state where D2D communication in mode 2 can be executed.

  Terminal 10A transmits disaster notification information for notifying the occurrence of a disaster in a discovery signal for notifying the partner terminal of the presence of the terminal itself (sequence SQ26). That is, the discovery signal transmitted from the terminal 10A includes the above-described ProSe Application ID, the ProSe UE ID for identifying the terminal, and disaster notification information for notifying a disaster.

  When receiving the discovery signal including the disaster notification information, terminal 20A automatically activates the disaster information application (sequence SQ28). When the terminal 20A receives a discovery signal including disaster notification information, the terminal 20A displays the disaster notification information on the display 158 and confirms that a disaster has occurred to the user (or that a disaster will occur soon). You may let them. In this case, the terminal 20A receives an instruction from the user via a touch panel or the like, and activates the disaster information application. As a result, the terminal 20A is in a state where D2D communication in mode 2 can be executed.

  Then, the processes of sequences SQ14 and SQ16 are executed. Since the processes of sequences SQ14 and SQ16 are the same as the processes of FIG. 2, the description thereof will not be repeated here.

<Processing procedure>
Processing performed in each device of terminal 10A and terminal 20A will be specifically described.

(Terminal 10A)
FIG. 11 is a flowchart showing an example of processing executed by terminal 10A according to the second embodiment. The following steps are realized by the CPU 152 of the terminal 10A executing a program stored in the memory 154.

  Referring to FIG. 11, the processes in steps S2 to S8 are the same as the processes in FIG. The terminal 10A activates the disaster information application (step S8), and transmits a discovery signal (disaster information expression) including disaster notification information for notifying the occurrence of a disaster (step S102). Since the processing of steps S10 and S12 is the same as the processing of FIG. 8, detailed description thereof will not be repeated.

(Terminal 20A)
FIG. 12 is a flowchart showing an example of processing executed by terminal 20A according to the second embodiment. The following steps are realized by the CPU 152 of the terminal 20A executing a program stored in the memory 154.

  Referring to FIG. 12, the processes in steps S22 and S24 are the same as the processes in FIG. 9, and therefore detailed description thereof will not be repeated. The terminal 20A activates the disaster information application (step S28), and determines whether a disaster information expression has been received (step S202). When terminal 20A has not received the disaster information expression (NO in step S202), terminal 20A repeats the process of step S202. When terminal 20A receives the disaster information expression (YES in step S202), terminal 20A executes the processes of steps S28 to S32. Since the processing of steps S28 to S32 is the same as the processing of FIG. 8, detailed description thereof will not be repeated.

<Advantages>
According to the second embodiment, the terminal can detect the occurrence of the disaster by receiving the disaster information expression from the other peripheral terminals. Therefore, even when the terminal cannot receive emergency information when a disaster occurs, D2D communication in mode 2 can be started.

[Embodiment 3]
Embodiment 3 demonstrates the structure which performs D2D communication between the terminal which is located in the cell 500 of the base station 50, and the terminal which is no longer located in the cell 500. FIG.

<Overall system configuration>
FIG. 13 shows an overall configuration of a communication system according to the third embodiment. Referring to FIG. 13, the device configuration and the allocation mode of the communication system according to the third embodiment are the same as the device configuration and the allocation mode of the communication system according to the first embodiment, respectively. However, in order to distinguish from terminals 10 and 20 according to Embodiment 1, terminals 10 and 20 according to Embodiment 3 are referred to as “terminal 10B” and “terminal 20B”, respectively. In Embodiment 3, terminal 30B is included as a terminal different from terminals 10B and 20B. The terminal 30B is a terminal having the same function as the terminals 10B and 20B.

<Overview of system operation>
Here, a procedure will be described in which a terminal 10B located in the cell 500 and a terminal 30B not located in the cell 500 start D2D communication in mode 2 when a disaster occurs.

  FIG. 14 is a sequence diagram for explaining an example of communication processing performed between the plurality of terminals 10B and 30B and the base station 50 in the third embodiment.

  Referring to FIG. 14, base station 50 broadcasts D2D radio resources to terminal 10B and terminal 30B (sequences SQ2, SQ40). At this time, it is assumed that the terminal 30B is in the cell 500 that the base station 50 configures.

  Terminal 10B receives the earthquake early warning from base station 50 (sequence SQ6). At this time, since the terminal 30B is not located in the cell 500 formed by the base station 50, the terminal 30B cannot receive the earthquake early warning.

  Terminal 10B and terminal 30B accept an instruction from the user via a touch panel or the like, and activate the disaster information application (sequences SQ10 and SQ42). For example, when the user of the terminal 30 </ b> B confirms emergency information via a television, a disaster prevention radio broadcast, or the like, or when he / she feels an earthquake, he / she determines that a disaster has occurred and activates the disaster information application. Thereby, the terminal 10B is in a state where the D2D communication in the mode 2 can be executed (the operation mode is set to the mode 2). Terminal 30B is in a state where it can search for a synchronization signal transmitted from another terminal in order to execute D2D communication in mode 2.

  Terminal 10B transmits a synchronization signal in order to perform D2D communication in mode 2 with other terminals not located in cell 500 (sequence SQ44). Specifically, since the terminal 10 </ b> B is located in the cell 500, the terminal 10 </ b> B can receive the synchronization signal from the base station 50, but other terminals not located in the cell 500 cannot receive the synchronization signal from the base station 50. Therefore, the terminal 10B tries to start D2D communication by synchronizing the transmission / reception timing with the other terminal by transmitting a synchronization signal to the other terminal not in the cell 500. Note that the terminal 10B periodically transmits a synchronization signal after the disaster information application is activated.

  The terminal 10B autonomously allocates radio resources used for user data communication in D2D communication from among the D2D radio resources broadcast from the base station 50, and for other terminals (here, the terminal 30B), The allocated radio resource is notified (sequence SQ46). Terminal 10B transmits the disaster related information to terminal 30B using the allocated radio resource, and terminal 30B receives the disaster related information transmitted using the radio resource (sequence SQ48).

  In the above sequence, the terminal 30 </ b> B has been described with respect to the configuration in which the disaster information application is activated by receiving an instruction from the user, but the configuration is not limited thereto. For example, as described in the second embodiment, the terminal 30B may be configured to activate the disaster information application when receiving the disaster information expression transmitted from the terminal 10B.

<Processing procedure>
Processing performed in each device of terminal 10B and terminal 30B will be specifically described.

(Terminal 10B)
FIG. 15 is a flowchart showing an example of processing executed by terminal 10B according to the third embodiment. The following steps are realized by the CPU 152 of the terminal 10B executing a program stored in the memory 154.

  Referring to FIG. 15, the processes in steps S2 to S8 are the same as the processes in FIG. 8, and therefore detailed description thereof will not be repeated. When the terminal 10B activates the disaster information application (step S8), the terminal 10B transmits a synchronization signal for performing D2D communication with other terminals not located in the cell 500 (step S112). The terminal 10B periodically transmits a synchronization signal after the disaster information application is activated. Since the processing of steps S10 and S12 is the same as the processing of FIG. 8, detailed description thereof will not be repeated.

(Terminal 30B)
FIG. 16 is a flowchart showing an example of processing executed by terminal 30B according to the third embodiment. The following steps are realized by the CPU 152 of the terminal 30B executing a program stored in the memory 154. Note that the terminal 30B is not located in the cell 500. For this reason, the user of the terminal 30B determines that a disaster has occurred when emergency information is confirmed via a television, a disaster prevention radio broadcast, or when the user himself / herself experiences an earthquake.

  Referring to FIG. 16, terminal 30B accepts an instruction from the user and activates the disaster information application (step S42). Thereby, terminal 30B sets the operation mode to mode 2, and searches for a synchronization signal transmitted from the other terminal in order to perform D2D communication in mode 2 with another terminal (here, terminal 10B). be able to.

  The terminal 30B determines whether a synchronization signal has been received (has been searched for a synchronization signal) (step S44). If terminal 30B has not received the synchronization signal (NO in step S44), terminal 30B repeats the process of step S44. When the terminal 30B receives the synchronization signal (YES in step S44), the terminal 30B shifts to a state in which D2D communication in mode 2 can be started (step S46). That is, when the synchronization signal is received when the terminal 30B is operating in the mode 2, the terminal 10B and the terminal 30B execute the D2D communication in the mode 2.

  The terminal 30B determines whether disaster-related information has been distributed (received) using the radio resource allocated from the terminal 10B (step S48). If terminal 30B has not received the disaster-related information (NO in step S48), terminal 30B repeats the process of step S48. If the terminal 30B has received the disaster related information (YES in step S48), the terminal 30B displays the disaster related information on the display 158 (step S50). The terminal 30B may output the disaster related information from a speaker.

<Advantages>
According to the third embodiment, when a disaster occurs, a terminal that is in the cell transmits a synchronization signal to a terminal that is not in the cell. Therefore, if a terminal that is not in the cell can receive the synchronization signal, a terminal that is in the cell and a terminal that is not in the cell can perform D2D communication in mode 2.

[Other embodiments]
It is also possible to provide a program that causes a computer to function and execute control as described in the above flowchart. Such a program is recorded on a non-temporary computer-readable recording medium such as a flexible disk attached to the computer, a CD-ROM (Compact Disk Read Only Memory), a ROM, a RAM, and a memory card as a program product. It can also be provided. Alternatively, the program can be provided by being recorded on a recording medium such as a hard disk built in the computer. A program can also be provided by downloading via a network.

  The program may be a program module that is provided as a part of an operating system (OS) of a computer and that calls necessary modules in a predetermined arrangement at a predetermined timing to execute processing. In that case, the program itself does not include the module, and the process is executed in cooperation with the OS. A program that does not include such a module can also be included in the program according to the present embodiment.

  Further, the program according to the present embodiment may be provided by being incorporated in a part of another program. Even in this case, the program itself does not include the module included in the other program, and the process is executed in cooperation with the other program. A program incorporated in such another program can also be included in the program according to the present embodiment.

  The configuration illustrated as the above-described embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part of the configuration is omitted without departing from the gist of the present invention. It is also possible to change the configuration.

  In the above-described embodiment, the processing and configuration described in the other embodiments may be adopted as appropriate.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 10A, 10B, 20, 20A, 20B, 30B terminal, 50 base station, 102 application execution unit, 104 communication management unit, 106, 504 storage unit, 108 emergency information management unit, 110, 508 wireless communication unit, 152, 202 CPU, 154, 204 memory, 156 touch panel, 158 display, 160 wireless communication interface, 162, 208 communication antenna, 164 memory interface, 165 storage medium, 166 speaker, 168 GPS controller, 170 battery, 500 cell, 502 communication control unit 506 Emergency information control unit.

Claims (5)

A communication system comprising a base station and a plurality of terminal devices capable of inter-terminal communication,
Each of the plurality of terminal devices is assigned by a first mode using radio resources assigned by the base station and an own terminal device or a counterpart terminal device as an operation mode when the inter-terminal communication is executed. A second mode using radio resources,
Each of the first terminal device and the second terminal device among the plurality of terminal devices is located in a cell configured by the base station,
When the first terminal apparatus receives an input regarding the occurrence of a disaster, the first terminal apparatus sets the operation mode to the second mode.   The communication system according to claim 1, wherein the second terminal device sets the operation mode to the second mode when receiving an input related to the occurrence of the disaster.   When each of the first terminal device and the second terminal device receives an input relating to the disaster while operating in the first mode, the second terminal device starts the second mode from the first mode. The communication system according to claim 1, wherein the communication system is switched to a mode.   The communication system according to claim 1 or 2, wherein the first terminal device transmits disaster notification information for notifying the occurrence of the disaster in a discovery signal for notifying the presence of the terminal device. . The first terminal device transmits a synchronization signal for performing inter-terminal communication with a third terminal device not located in the cell among the plurality of terminal devices,
When the third terminal apparatus receives the synchronization signal when operating in the second mode, the first terminal apparatus and the third terminal apparatus are in the second mode. The communication system according to claim 1 or 2, wherein the inter-terminal communication is executed.

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