Method and control device

Abstract

To provide a system that can confirm positional information of a searching object by causing the searching object to previously possess a portable communication terminal to search a location of a lost pet or child, an elderly person walking outside alone, or a person in distress in hill-climbing and the like and by using communication between the portable communication terminal and a cellular network, in order to solve the problem that appropriate countermeasure means for searching a terminal cannot be selected when the terminal and a control device become unable to communicate with each other in a related technique.SOLUTION: In a first aspect in disclosure of the present specification, a control device 3 estimates a position of a terminal 1, determines a communication probability at the estimated position, and outputs information indicating appropriate countermeasure means on the basis of the determined communication probability.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application relates to searching for a terminal, and particularly to the selection of countermeasures for searching for a terminal.

Background Art

[0002] In order to search for the whereabouts of a lost pet, child, elderly person walking alone outdoors, a person in distress during mountain climbing, etc., a mobile communication terminal is made to be carried by the search target in advance, and a system that can confirm the location information of the search target by using the communication between the mobile communication terminal and the cellular network has been studied.

[0003] Patent Document 1 discloses that by having a mobile communication terminal on a pet, when the pet gets lost, the owner can obtain location information from the terminal (hereinafter referred to as the lost terminal) carried by the lost pet via the Internet. In addition, it is disclosed that in order to search for a lost pet, a search request is made to members in the vicinity of the pet. Regarding the discovery of the pet, it is disclosed that the member who has received the request makes a visual or auditory confirmation and reports it.

[0004] On the one hand, 3GPP (registered trademark) has defined Proximity-based services (ProSe) since Release 12 specifications (see, for example, Non-Patent Documents 1 and 2). ProSe is sometimes expressed as Device-to-Device communication (D2D communication, direct communication between terminals). ProSe includes ProSe discovery and ProSe direct communication. ProSe discovery enables the detection of the fact that wireless terminals (ProSe-enabled UEs) capable of ProSe direct communication are in proximity. In one example, ProSe discovery can be performed by a procedure in which a certain ProSe-enabled UE discovers another ProSe-enabled UE using only the capabilities of the wireless communication technology (e.g., Evolved Universal Terrestrial Radio Access (E-UTRA) technology) possessed by the two ProSe-enabled UEs. In another example, ProSe discovery can be performed by a radio access network (E-UTRA Network (E-UTRAN)) or a core network (Evolved Packet Core (EPC)).

[0005] ProSe direct communication enables the establishment of a communication path between two or more ProSe-enabled UEs existing within the direct communication range after the ProSe discovery procedure. In other words, ProSe direct communication enables a ProSe-enabled UE to communicate directly with another ProSe-enabled UE without going through a base station (eNodeB). ProSe direct communication may be performed using the same wireless communication technology (E-UTRA technology) as when accessing a base station (eNodeB), or may be performed using the wireless technology of a wireless radio access network (WLAN) (that is, IEEE 802.11 radio technology).

[0006] Furthermore, 3GPP Release 12 defines a partial coverage scenario where one UE is outside network coverage and the other UE is inside network coverage (see, for example, Sections 4.4.3, 4.5.4, and 5.4.4 of Non-Patent Document 1). In the partial coverage scenario, the UE outside coverage is called the remote UE, and the UE inside coverage that relays the network between the remote UE and the network is called the ProSe UE-to-Network Relay. The ProSe UE-to-Network Relay relays traffic (downlink and uplink) between the remote UE and the network (E-UTRAN and EPC). More specifically, the ProSe UE-to-Network Relay attaches to the network as a UE, establishes a PDN connection for communicating with the ProSe function entity or other Packet Data Network (PDN), and communicates with the ProSe function entity to initiate ProSe direct communication. The ProSe UE-to-Network Relay further performs a discovery procedure with the remote UE, communicates with the remote UE on the UE-to-UE direct interface (e.g., sidelink or PC5 interface), and relays traffic (downlink and uplink) between the remote UE and the network. When Internet Protocol version 4 (IPv4) is used, the ProSe UE-to-Network Relay operates as a Dynamic Host Configuration Protocol Version 4 (DHCPv4) Server and Network Address Translation (NAT). When IPv6 is used, the ProSe UE-to-Network Relay operates as a stateless DHCPv6 Relay Agent.In this specification, a wireless terminal having ProSe functions and relay functions such as ProSe UE-to-Network Relay is referred to as a "relay wireless terminal" or "relay UE". Further, a wireless terminal that receives a relay service by a relay wireless terminal (relay UE) is referred to as a "remote wireless terminal" or "remote UE".

[0007] In 3GPP Release 12, the ProSe function communicates with ProSe-enabled UEs via a Public Land Mobile Network (PLMN) and assists ProSe discovery and ProSe direct communication. The ProSe function is a logical function used for operations related to the PLMN necessary for ProSe. The functionality provided by the ProSe function includes, for example, (a) communication with third-party applications (ProSe Application Server), (b) authentication of UEs for ProSe discovery and ProSe direct communication, (c) transmission of configuration information (e.g., specification of radio resources and transmission power) for ProSe discovery and ProSe direct communication to UEs, and (d) provision of EPC-level ProSe discovery. The ProSe function may be implemented in one or more network nodes or entities. In this specification, one or more network nodes or entities that execute the ProSe function are referred to as "ProSe function entities" or "ProSe function servers".

[0008] The ProSe direct communication in 3GPP Release 12 is one specific example of direct communication between terminals. The direct communication between terminals in a public land mobile network (PLMN) includes a discovery phase and a direct communication phase supported by functions or nodes (e.g., ProSe function) arranged in the network, similar to ProSe in 3GPP Release 12. The direct communication between terminals is communication that occurs between a plurality of adjacent wireless terminals without going through any network nodes (e.g., base stations). The direct communication between terminals is sometimes also called device-to-device (D2D) communication or peer-to-peer communication. The ProSe direct communication is an example of direct communication between terminals and is sometimes also called ProSe communication.

[0009] As used herein, the term "public land mobile communication network" refers to a wide-area wireless infrastructure network and means a mobile communication system with a multiple access scheme. A mobile communication system with a multiple access scheme enables multiple mobile terminals to perform wireless communication substantially simultaneously by sharing wireless resources including at least one of time, frequency, and transmission power among the multiple mobile terminals. Representative multiple access schemes are Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), or Orthogonal Frequency Division Multiple Access (OFDMA) or combinations thereof. The public land mobile communication network includes a radio access network and a core network. The public land mobile communication network is, for example, a 3GPP Universal Mobile Telecommunications System (UMTS), 3GPP Evolved Packet System (EPS), 3GPP2 CDMA2000 system, Global System for Mobile communications (GSM (registered trademark)) / General packet radio service (GPRS) system, 5G NR system, WiMAX system, or Mobile WiMAX system. EPS includes a Long Term Evolution (LTE) system and an LTE-Advanced system.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Non-Patent Documents

[0011]

Non-Patent Document 1

[0012] Patent Document 1 discloses that when a search target having a lost terminal goes missing, the lost terminal and the control device communicate by the operation of the requester to identify the position of the lost terminal and request a search from neighboring members.

[0013] However, Patent Document 1 does not disclose anything about the case where the lost terminal becomes unable to communicate with the control device, and the lost terminal cannot be searched.

[0014] One of the objects to be achieved by the disclosure in this specification is to provide a communication device, a communication terminal, a communication method, and a communication program for searching for a terminal that has become unable to communicate with a control device. [Means for Solving the Problems]

[0015] In the first aspect, the communication method performed by the control device is to receive, from the first terminal, the first position information and the first acceleration information of the first terminal at a first timing, and transmit, to the first terminal, a first search signal requesting a response. When it is determined that there is no response to the search signal, the second position information of the first terminal at a second timing is estimated using the first position information and the first acceleration information, and based on the position and the communication probability at the position, a first communication probability corresponding to the second position information is determined, and information indicating countermeasure means for searching for the first terminal corresponding to the first communication probability is output.

[0016] In the second aspect, the control device includes a receiving unit that receives, from the first terminal, the first position information and the first acceleration information of the first terminal at a first timing, and a transmitting unit that transmits, to the first terminal, a first search signal requesting a response. When it is determined that there is no response to the search signal, an estimating unit that estimates the second position information of the first terminal at a second timing using the first position information and the first acceleration information, a determining unit that determines a first communication probability corresponding to the second position information based on the position and the communication probability at the position, and an output unit that outputs information indicating countermeasure means for searching for the first terminal corresponding to the first communication probability.

[0017] In the third aspect, the program includes a set of instructions (software code) for causing a computer to perform the method according to the first aspect described above when loaded into the computer.

Advantages of the Invention

[0018] According to the above aspect, a communication device, a communication terminal, a communication method, and a communication program for searching for a terminal that has become unable to communicate with a control device can be provided.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2-A

Figure 2-B

Figure 3-A

Figure 3-B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10-A

Figure 10-B

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0020] Hereinafter, specific aspects in the disclosure of this specification will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and for the sake of clarity of explanation, duplicate explanations will be omitted as necessary.

[0021] <The First Aspect in the Disclosure of this Specification> In related technologies, when the terminal and the control device become unable to communicate, it is not possible to select an appropriate countermeasure means for searching for the terminal. In the first aspect, the control device 3 estimates the position of the terminal, determines the communication probability at the estimated position, and outputs information indicating an appropriate countermeasure means based on the determined communication probability.

[0022] FIG. 1 is a sequence diagram showing an example of the operations of the terminal 1 and the control device 3 in the first aspect. In step 1, the terminal 1 transmits the position information and acceleration information regarding the terminal 1 at the first timing to the control device 3.

[0023] Note that as step 0 before step 1, the control device 3 may request the terminal 1 to transmit the position information and acceleration information. The position information and acceleration information may be transmitted at different timings, or may be transmitted simultaneously. Also, each of the position information and acceleration information may be an average value over a predetermined period, or a value at a predetermined timing. Further, the acceleration information may be a maximum value over a predetermined period.

[0024] The transmission of the position information and acceleration information by the terminal 1 may be based on a preset period, the establishment of a connection between the terminal 1 and the network by the terminal 1, the detection of deterioration of the communication quality of the terminal 1, the battery remaining amount of the terminal 1 falling below a threshold value, a sudden change in the position information or acceleration information of the terminal 1, etc.

[0025] The location information is collected by a location sensor provided in the terminal 1. The location sensor may collect, as the location information, information measured by receiving a signal from a global positioning system (GPS) that utilizes artificial satellites, for example. The location sensor may collect, as the location information, information measured based on a signal from a base station of a mobile phone communication network, for example. The location sensor may collect, as the location information, information measured based on radio waves of a communication standard of the IEEE 802.11 series, for example. The location information collected by the location sensor may be recorded in the memory until it is transmitted to the control device 3.

[0026] The acceleration information is collected by an acceleration sensor provided in the terminal 1. The acceleration information collected by the acceleration sensor may be recorded in the memory until it is transmitted to the control device 3.

[0027] In step 2, the control device 3 transmits a search signal requesting a response signal to the terminal 1. This search signal may be, for example, an outgoing call, an email transmission, a notification to an application, or the like. Note that the transmission of the search signal may be triggered by, for example, a request regarding the search of the terminal 1 being input to the control device 3, or the inability to receive at least either the location information or the acceleration information for a predetermined period. Note that instead of transmitting the search signal to the terminal 1, the control device 3 may inquire about the connection status of the terminal 1 to the mobile phone communication network. The response signal may be, for example, a response to an outgoing call from the control device 3, a reply to an email received from the control device 3, some action with respect to the notified application, or the like.

[0028] In step 3, the control device 3 determines that no response signal has been received from the terminal 1. The control device 3 determines that no response signal has been received from the terminal 1 in response to not receiving a response signal for a predetermined period or receiving a response signal indicating an inability to respond.

[0029] In step 4, the control device 3 estimates the position of the terminal 1 at a second timing different from the first timing based on either or both of the position information and the acceleration information regarding the terminal 1 at the recorded first timing. As an example, the estimation of the position of the terminal 1 at the second timing may be performed by starting from the latest (e.g., the first timing) position information and using the moving distance and direction based on the latest (e.g., the first timing) acceleration information. As an example, the estimation of the position of the terminal 1 at the second timing may be performed by starting from the latest (e.g., the first timing) position information and using the moving distance and direction based on the previous position information, the elapsed time, the acceleration information, etc. The moving distance and direction estimated from the acceleration information may be estimated as a region by using fluctuating parameters such as the movement probability. The moving distance and direction estimated from the position information may be estimated as a region by taking the difference in the position information for a predetermined period and using fluctuating parameters such as the movement probability. Note that when the first timing is the latest information, the position information regarding the terminal 1 at this first timing may be directly used as the position of the terminal 1 at the second timing for estimation.

[0030] In step 5, from the position and the information indicating the communication probability at the position, the communication probability of the terminal 1 at the estimated position is determined. The information indicating the communication probability may be held by the control device 3 or may be acquired from the external network at any time. The information indicating the communication probability may be calculated from the communication performance at the position, may be the communication speed at the position, may be the signal-to-interference plus noise power ratio (SINR) at the position, or may be the packet loss rate at the position. Also, the information indicating the communication probability may be generated from the arrangement information of the base stations regarding the position, the frequency information of the base station cells, the arrangement information of the interfering stations, etc.

[0031] The communication probability may be determined by the attributes related to the location at the corresponding position. For example, in an area outside the coverage, such as a mountainous area or the vicinity of the sea where no base station cell is installed at the position or where radio waves cannot reach even if installed, the communication probability may be set as "low". Also, for example, when the position is an area where radio waves from base station cells scattered in the city such as a park cannot reach, the communication probability may be set from "medium" to "low". Also, for example, in the case of areas such as indoors of buildings such as buildings, gaps between buildings, along walls, and underground passages, areas where radio waves reach and areas where they do not reach are mixed, and the terminal 1 may temporarily enter an out-of-coverage area (dead zone), so the communication probability corresponding to the position may be set as "medium". Also, for example, in the case of outdoors such as on a road in an urban area, assuming that radio waves from base station cells basically reach, the communication probability corresponding to the position may be set as "high".

[0032] In step 6, the control device 3 selects countermeasures for searching for the terminal 1 based on the communication probability of the terminal 1. Then, the control device 3 outputs information indicating the selected countermeasures. The output may be to display information indicating one or more countermeasures on a user interface (UI), or may be to send a search request to a predetermined search agency.

[0033] When the control device 3 determines that it cannot receive a response signal, in order to facilitate the search, it may send at least one of an LED blinking request and a warning sound generation request to the terminal 1 at a predetermined interval. In particular, when the communication probability of the terminal is determined to be "high" or "medium", at least one of the LED blinking request and the warning sound generation request may be sent.

[0034] The countermeasures may be selected based on examples as shown below. FIG. 13 is a diagram showing an example of the correspondence between the following communication probabilities and countermeasures.

[0035] For example, when the communication probability is determined to be "high", the inability to receive a response signal can be construed as a situation where communication is impossible despite being within the cellular coverage area. Such situations may include, for example, the owner of terminal 1 being involved in some trouble or a malfunction occurring in terminal 1. In this case, it may not be appropriate to search using terminal 2 that can perform D2D communication. If the owner of terminal 1 is involved in an incident, it may also affect the person searching with terminal 2. Therefore, in this case, the control device 3 selects, as a countermeasure, "reporting to a group that conducts a predetermined search (e.g., police, fire department, security company, etc.) and requesting the search of terminal 1".

[0036] For example, when the communication probability is determined to be "medium", it is assumed that terminal 1 has temporarily entered an out-of-range area (dead zone). Therefore, the control device 3 selects, as a countermeasure, "transmitting a search signal to terminal 1 again after waiting for a predetermined period". If there is still no response signal, the control device 3 may determine that the determined communication probability is inappropriate. In this case, the control device 3 may assume the communication probability to be "low to medium", reselect the corresponding countermeasure, and output information indicating the countermeasure.

[0037] For example, when the communication probability is determined to be "low to medium", since it is assumed that terminal 1 has entered an out-of-range area, it may be selected as a countermeasure to "search using terminal 2 that can perform D2D communication". Depending on the attributes of the estimated position at this time, the control device 3 may also determine the type of terminal 2 that can be used as a countermeasure.

[0038] For example, if the estimated position is an area where a person carrying Terminal 2 can enter, the type of Terminal 2 may be a mobile terminal. Also, for example, if the estimated position is an area where it is difficult for people to enter, such as in the mountains, or if it is determined that there is no accessible path for people, the type of Terminal 2 may be the Terminal 2 equipped on a drone, or Terminal 2 may have the function of a drone. Also, for example, if the estimated position is on the sea, the type of Terminal 2 may be a ship. Also, for example, when the determined type of Terminal 2 is a mobile terminal, the control device 3 may select an appropriate holder. The holder may be, for example, a transporter, a local organization, a salesperson, etc.

[0039] Also, for example, as an attribute related to the estimated position, the estimated size of the out-of-range area (dead zone) near the estimated position may be used. For example, when it is estimated that the dead zone is an area such as indoors in a building like a building or an underground passage, since it is assumed that the dead zone is relatively small, the control device 3 may select, as a countermeasure means, to request a search for the Terminal 2 carried by a person. Also, in another example, when it is estimated that the dead zone is an area such as a mountainous area, since it is assumed that the dead zone is relatively large, the control device 3 may select, as a countermeasure means, to request a search for the Terminal 2 that can be operated even when a person is away, such as a drone. Also, in another example, when it is estimated that the dead zone is indoors in a building such as a building, the control device 3 may determine, as a search means, to send a search request to a predetermined search agency such as the police because it is estimated that it is difficult to enter for the search of Terminal 1. In this case, the control device 3 may also notify information such as the phone number of Terminal 1 that can be used by the predetermined search agency for the search.

[0040] Figure 2 is a flowchart showing an example of the operation of the control device 3 in the first aspect.

[0041] Figure 2-A is a flowchart showing an example of the operation of the control device 3 that collects the position information and acceleration information of Terminal 1.

[0042] In step 20, the control device 3 transmits a signal to the terminal 1, requesting the terminal 1 to transmit position information and acceleration information to the control device 3. Note that this step 20 may be omitted. The request may explicitly request either the position information or the acceleration information, or may request both the position information and the acceleration information. Each of the position information and the acceleration information may be the information at the timing measured by the sensor, or may be the information for a predetermined period measured by the sensor. When the acceleration information is the information for a predetermined period, it may be the information indicating the average value, or may be the information including the maximum value and the minimum value.

[0043] In step 21, the control device 3 receives the position information and the acceleration information regarding the terminal 1 at the first timing from the terminal 1. The reception may receive the position information and the acceleration information together, or may receive only one of them. Also, the reception period may or may not be constant.

[0044] In step 22, the control device 3 records the received position information and acceleration information, and ends the flow or repeats from step 20. The recording may be to record in the memory of the control device 3, or may be to record in an external database connected to the control device 3.

[0045] FIG. 2-B is a flowchart showing an example of the operation of the control device 3 for searching the terminal 1. In step 23, the control device 3 transmits a search signal to the terminal 1, requesting the terminal 1 to transmit a response signal to the control device 3.

[0046] The search signal may be, for example, a call, a mail transmission, a notification to an application, etc. Note that the transmission of the search signal may be triggered by, for example, a request regarding the search of the terminal 1 being input to the control device 3, or the inability to receive at least one of the position information and the acceleration information for a predetermined period. Note that instead of transmitting the search signal to the terminal 1, the control device 3 may inquire about the connection status of the terminal 1 to the mobile phone communication network.

[0047] In step 24, the control device 3 determines whether it has received a response signal for the search signal in step 23. If it is determined that the signal has been received, the control device 3 outputs information indicating that it has been received and ends the flow. The output may be, for example, displayed on a user interface. If it is determined that the signal could not be received, the process proceeds to step 25. The response signal may be, for example, a response to a call from the control device 3, a reply to an email received from the control device 3, or some operation on the notified application, etc.

[0048] In step 25, the control device 3 estimates the position of the terminal 1 at a second timing different from the first timing based on either or both of the position information and the acceleration information regarding the terminal 1 at the first timing recorded. As an example, the estimation of the position of the terminal 1 at the second timing may be to estimate by using the latest (for example, the first timing) position information as a starting point and the moving distance and direction based on the latest (for example, the first timing) acceleration information.

[0049] As an example, the estimation of the position of the terminal 1 at the second timing may be to estimate by using the latest (for example, the first timing) position information as a starting point and the moving distance and direction based on the previous position information, elapsed time, acceleration information, etc. The moving distance and direction estimated from the acceleration information may be an area estimated by using fluctuating parameters such as the moving probability. The moving distance and direction estimated from the position information may be an area estimated by taking the difference in the position information for a predetermined period and using fluctuating parameters such as the moving probability. When the first timing is the latest information, the position information regarding the terminal 1 at this first timing may be used as it is to estimate the position of the terminal 1 at the second timing.

[0050] In step 26, the control device 3 determines the communication probability of the terminal at the estimated position from the information indicating the position and the communication probability at that position.

[0051] The information indicating the communication probability may be held by the control device 3, or may be acquired from an external database or Internet service at any time. The information indicating the communication probability may be calculated from the communication performance at the position, may be the communication speed at the position, may be the received signal power to interference and noise power ratio SINR (Signal to Interference plus Noise power Ratio) at the position, or may be the packet loss rate at the position. Further, the information indicating the communication probability may be generated from the base station arrangement information, base station cell frequency information, interference station arrangement information, etc. related to the position.

[0052] The communication probability may be determined by the attributes related to the location corresponding to the position. For example, in an area where there is no base station cell installed at the position, or an out-of-range area such as a mountainous area or the vicinity of the sea where radio waves do not reach even if installed, the communication probability may be set as "low". Also, for example, when the position is an area where radio waves from base station cells scattered in the city such as a park do not reach, the communication probability may be set from "medium" to "low". Also, for example, in the case of areas such as indoors of buildings such as buildings, gaps between buildings, along walls, and underground passages, since there are mixed areas where radio waves reach and areas where they do not reach, and the terminal 1 may temporarily enter an out-of-range area (dead zone), the communication probability corresponding to the position may be set as "medium". Also, for example, in the case of outdoors such as on a road in an urban area, assuming that radio waves from base station cells basically reach, the communication probability corresponding to the position may be set as "high".

[0053] In step 27, the control device 3 selects countermeasure means for searching for the terminal 1 based on the determined communication probability. Then, the control device 3 outputs information indicating the selected countermeasure means. The output may be to display information indicating one or more countermeasure means on the user interface, or may be to send a search request to a predetermined search agency.

[0054] When the control device 3 determines that it cannot receive a response signal, it may transmit at least one of an LED blinking request and a warning sound generation request to the terminal 1 at a predetermined interval to facilitate the search. In particular, when the communication probability of the terminal is determined to be "high" or "medium", at least one of the LED blinking request and the warning sound generation request may be transmitted.

[0055] Figure 3 is a flowchart showing an example of the operation of the terminal 1 in the first aspect.

[0056] Figure 3-A is a flowchart showing an example of the operation of the terminal 1 regarding the reporting of position information and acceleration information. In step 31, the terminal 1 determines whether it meets a predetermined reporting condition. If it meets the condition, it proceeds to step 32. If it does not meet the condition, it repeats step 31 until it meets the condition or ends the flow.

[0057] The predetermined conditions may be, for example, receiving a reporting request from the control device 3, reaching a pre-set period, establishing a connection with the network by the terminal 1, detecting deterioration of the communication quality of the terminal 1, falling below the threshold of the remaining battery level of the terminal 1, sudden changes in the position information or acceleration information of the terminal 1, and so on.

[0058] In step 32, the terminal 1 transmits the position information and acceleration information regarding the terminal 1 at the first timing to the control device 3 and ends the flow.

[0059] The position information and acceleration information may be information collected by a position sensor and an acceleration sensor provided in the terminal 1 respectively. Each of the position information and acceleration information may be information on the timing measured by the sensor, or information on a predetermined period measured by the sensor. When the acceleration information is information on a predetermined period, it may be information indicating an average value, or information including a maximum value and a minimum value. Also, the collected information may be recorded in the memory of the terminal 1, and the terminal 1 may transmit the recorded information. Also, the position information and acceleration information may be transmitted simultaneously or separately.

[0060] Figure 3-B is a flowchart showing an example of the operation of the terminal 1 that receives a search signal from the control device 3. In step 33, the terminal 1 receives from the control device 3 a search signal that requests to transmit a response signal to the control device 3. The search signal may be, for example, an outgoing call, an email transmission, a notification to an application, or the like.

[0061] In step 34, the terminal 1 transmits a response signal to the control device 3 and ends the flow. The response signal may be, for example, a response to an outgoing call from the control device 3, a reply to an email received from the control device 3, some action on the notified application, or the like.

[0062] In related art, when the terminal and the control device become unable to communicate, it was not possible to select an appropriate countermeasure for searching for the terminal. According to the configuration of the first aspect in the disclosure of this specification, since the position of the terminal is estimated, the communication probability at the estimated position is determined, and information indicating the countermeasure corresponding to the determined communication probability is output, it becomes possible to select an appropriate countermeasure according to the situation.

[0063] <The second aspect in the disclosure of this specification> In the second aspect, a case where a countermeasure using D2D communication is selected based on the communication probability at the estimated position of the terminal 1 will be described.

[0064] In related art, for a terminal that has become unable to communicate due to being out of range or the like, the procedure for searching has not been considered. Also, searching based on human judgment based on vision and hearing has been performed, and there is a possibility of false detection.

[0065] According to the second aspect, it becomes possible to search for a terminal that has become unable to communicate due to being out of range, or being in a state where it cannot respond even though it is within range, etc., using D2D communication. Also, since D2D communication is used for searching, it becomes possible to accurately search for the terminal over a wide range.

[0066] FIG. 4 is a sequence diagram showing an example of the operation of a communication system having the terminal 1, terminals 2-2, 2-3, 2-4, and the control device 3 on the second side.

[0067] On the second side, after step 5 in FIG. 1 on the first side, an example of the operation when it is determined that the terminal 1 is incommunicable based on the communication probability at the estimated position and countermeasure means using D2D communication are selected will be described. Up to step 5, the description is omitted because the operation is the same as that in FIG. 1.

[0068] In step 108, the control device 3 transmits a search request to at least one or more D2D - communicable terminals 2 (as an example, terminals 2-2, 2-3, 2-4 are shown in the figure). The transmission of the search request may be to transmit a search request specified based on a step (not shown) of displaying information indicating a plurality of countermeasure means on a user interface (UI) and the operator selecting at least one countermeasure means. The search request may include the attributes of the terminal 1 and information regarding the estimated position. The search request may include the capability information of the terminal 2 (for example, D2D communication capability, mobility, flight capability, etc.) desired by the control device 3. Also, the search request may be transmitted by specifying the destination or transmitted to all registered destinations.

[0069] In step 109, the terminals 2 (in FIG. 4, as an example, terminals 2-2 and 2-3) transmit a response signal to the search request to the control device 3. When the terminal 2 can respond to the search request, it transmits a permission response indicating permission as the response signal. On the other hand, when the terminal 2 cannot respond to the search request, it may transmit a rejection response indicating rejection as the response signal or may ignore it without transmitting a response signal. In FIG. 4, an example where the terminal 2-4 does not respond to the search request is shown. When indicating permission, the terminal 2 may include information of the terminal 2 (for example, information regarding the holder, communication capability (radio wave transmission distance, corresponding frequency, corresponding mobile network operator, etc.), remaining battery level of the terminal 2, etc.) in the response signal.

[0070] In step 110, the control device 3 transmits search information to the terminal 2 that has transmitted a response signal (permission response) indicating permission. Here, the terminal 2 that has transmitted the response signal which is a permission response is also referred to as a D2D terminal. The control device 3 may select the destination for transmitting the search information based on the information of the terminal 2 included in the response signal. In FIG. 4, as an example, the case where the terminal 2-3 is not selected and the terminal 2-2 is selected is shown.

[0071] The search information may be generated based on the information of the terminal 2 included in the permission response. The search information may be, for example, the attribute information of the terminal 1 (information about the holder, type of the terminal, reason for the search, etc.), the estimated position of the terminal 1, the communication probability at the estimated position of the first terminal, the navigation information indicating the area where the D2D search signal should be transmitted, and the like. Here, the D2D search signal is a search signal that requests a response signal from the terminal 1 and is transmitted from the terminal 2 to the terminal 1 using D2D communication. The navigation information may be generated from the estimated position of the terminal 1. Also, the navigation information may be generated in consideration of the communication ability of the terminal 2, the information indicating the communication probability, and the like. Also, the navigation information may indicate the number of times, time, position, etc. at which the D2D search signal should be transmitted. If a response indicating permission is not received, the control device 3 may select new countermeasures based on the estimated position and the fact that no response has been received, and end the flow.

[0072] In step 111, the terminal 2 transmits a D2D search signal using D2D communication. As the D2D search signal, for example, a ProSe Direct Discovery signal may be used. The terminal 2 can search a range including the moving distance in addition to the reach distance of the D2D search signal by transmitting the D2D search signal, for example, while moving. The D2D search signal may include a request for blinking of the LED or a request for reproduction of a warning sound to the terminal 1.

[0073] In step 112, in response to receiving the D2D search signal from terminal 2, terminal 1 transmits a response signal to terminal 2 using D2D communication. As the response signal, for example, a ProSe Direct Discovery signal may be used. The response signal may include, for example, the identifier of terminal 1, the location information of terminal 1, the status of terminal 1 (such as whether it can operate, the status of the holder, the remaining battery level, etc.). Also, terminal 1 may blink the LED or play a warning sound in response to receiving the D2D search signal or a request from control device 3.

[0074] In step 113, terminal 2 transmits the search result to control device 3. The search result may indicate that a response signal has been received from terminal 1, or may indicate that a predetermined D2D search signal has been transmitted but no response signal has been received. The search result when a response signal is received may include, for example, the location information of terminal 1, the location information of terminal 2 when the response signal is received, the status of terminal 1 (such as whether it can operate, the status of the holder, the remaining battery level, etc.). The search result when no response signal is received may include, for example, the movement history of terminal 2, the number of transmissions from terminal 2, etc.

[0075] Figure 5 is a flowchart showing an example of the operation of control device 3 in the second aspect.

[0076] In the second aspect, after step 26 in FIG. 2 of the first aspect, it is the operation of control device 3 when countermeasure means using D2D communication is selected based on the communication probability at the estimated position. Steps 20 to 26 are omitted because they are the same as the operations in FIG. 2 of the first aspect.

[0077] In step 208, the control device 3 transmits a search request to at least one D2D communication-capable terminal 2. It may also be to display information indicating a plurality of countermeasures on a user interface (UI) and transmit a search request specified based on a step (not shown) in which an operator selects at least one countermeasure. The search request may include information about the attributes of terminal 1 and the estimated position. The search request may include the ability information of terminal 2 that the control device 3 desires (for example, D2D communication ability, mobility ability, flight ability, etc.). Also, the search request may be transmitted by specifying the destination, or may be transmitted to all registered destination candidates.

[0078] In step 209, the control device 3 receives a response signal from terminal 2 for the search request. The response signal may be a permission response indicating permission if it can respond to the search request. The response signal may be a rejection response indicating rejection for the search request. Also, if the response signal cannot be received even after a predetermined period has elapsed, the control device 3 may determine that there is no terminal 2 capable of responding to the search request. The response signal indicating permission (permission response) may include, for example, information about terminal 2 (for example, information about the owner, communication ability (radio wave transmission distance, corresponding frequency, corresponding mobile network operator, etc.), remaining battery level of terminal 2, etc.). If the response signal indicating permission (permission response) is not received, the control device 3 may select new countermeasures based on the estimated position and the fact that no response has been received, output the corresponding information, and end the flow.

[0079] In step 210, the control device 3 transmits search information to at least one terminal 2 that received the permission response in step 209. Here, the terminal 2 that has transmitted the response signal, which is the permission response, is also called a D2D terminal. The control device 3 may select the destination for transmitting the search information based on the information of the terminal 2 included in the response signal. The search information may be generated based on the information of the terminal 2 included in the permission response. The search information may be, for example, the attribute information of terminal 1 (information about the holder, type of terminal, reason for search, etc.), the estimated position of terminal 1, the communication probability of the estimated position, navigation information indicating the area where the D2D search signal should be transmitted, and so on. The navigation information may be generated from the estimated position of terminal 1. Also, the navigation information may be generated in consideration of information indicating the communication ability and communication probability of terminal 2. Also, the navigation information may indicate the number of times, time, position, etc. at which the D2D search signal should be transmitted.

[0080] In step 211, the control device 3 receives a search result from the terminal 2 to which the search information was transmitted in step 210. The search result may indicate that the terminal 2 has received a response signal from the terminal 1, or may indicate that the terminal 2 has transmitted a predetermined D2D search signal but has not received a response signal. The search result in the case of receiving a response signal may include, for example, the position information of terminal 1, the position information of terminal 2 when the response signal was received, the status of terminal 1 (action availability, status of the holder, remaining battery power, etc.), and so on. The search result in the case of not receiving a response signal may include, for example, the movement history of terminal 2, the number of transmissions from terminal 2, and so on.

[0081] In step 212, the control device 3 outputs the search result by the terminal 2 and ends the flow. The output may be displayed on a user interface.

[0082] Figure 6 is a flowchart showing an example of the operation of terminal 1 in the second aspect. The operations in steps 31 to 34 are omitted because they are the same as those in Figure 3.

[0083] In step 35, terminal 1 receives a D2D search signal using D2D communication from terminal 2.

[0084] In step 36, based on the D2D search signal received in step 35, a response signal is transmitted to terminal 2, which is the source, using D2D communication, and the flow ends. The response signal may include, for example, the identifier of terminal 1, the location information of terminal 1, the status of terminal 1 (such as whether it can move, the status of the holder, the remaining battery level, etc.). Note that terminal 1 may blink an LED or play a warning sound in response to the reception of the D2D search signal or a request from control device 3.

[0085] Figure 7 is a flowchart showing an example of the operation of terminal 2 in a second aspect. In step 301, terminal 2 receives a search request from control device 3. The search request may include information about the attributes of terminal 1 and the estimated location. The search request may also include the capability information desired by control device 3 (such as D2D communication capability, mobility capability, flight capability, etc.).

[0086] In step 302, terminal 2 transmits a response signal to control device 3 for the search request. The response signal may be a permission response indicating permission for the search request. The response signal may also be a rejection response indicating rejection. Also, when rejecting the search request, it is not necessary to transmit a response signal. When rejecting, the flow ends. When indicating permission, the response signal indicating permission (permission response) may include information about terminal 2 (such as information about the holder, communication capabilities (such as radio wave transmission distance, corresponding frequency, corresponding mobile network operator, etc.), the remaining battery level of terminal 2, etc.). Here, terminal 2 that has transmitted a response signal that is a permission response is also called a D2D terminal.

[0087] In step 303, the terminal 2 receives search information from the control device 3. The search information may be, for example, the attribute information of the terminal 1 (information about the holder, the type of the terminal, the reason for the search, etc.), the estimated position of the terminal 1, the communication probability of the estimated position, the navigation information indicating the area to be searched, and the like. The navigation information may be generated from the estimated position of the terminal 1. Further, the navigation information may be generated in consideration of the communication ability of the terminal 2, information indicating the communication probability, and the like. Further, the navigation information may indicate the number of times, the time, the position, etc. at which the D2D search signal should be transmitted.

[0088] In step 304, the terminal 2 transmits a D2D search signal using D2D communication based on the search information. For example, a ProSe Direct Discovery signal may be used as the D2D search signal. The terminal 2 can search a range corresponding to the moving distance in addition to the reach distance of the D2D search signal by transmitting the D2D search signal while moving, for example. The D2D search signal may include a request for blinking of the LED or a request for reproduction of a warning sound to the terminal 1.

[0089] In step 305, the terminal 2 determines whether it has satisfied either of the conditions: receiving a response signal to the D2D search signal or completing the transmission of a predetermined D2D search signal. If the condition is satisfied, the process proceeds to step 306. If not satisfied, step 304 is repeated. The predetermined conditions may be, for example, transmitting the D2D search signal for a period set by the search information or the like, transmitting the D2D search signal a set number of times, transmitting the D2D search signal in a specified area, and the like. The received response signal may include, for example, the identifier of the terminal 1, the position information of the terminal 1, the status of the terminal 1 (whether it can move, the status of the holder, the remaining battery level, etc.), and the like.

[0090] In step 306, the terminal 2 transmits the search result using the D2D search signal to the control device 3 and ends the flow. The search result in the case of receiving a response signal may include, for example, the position information of the terminal 1, the position information of the terminal 2 when receiving the response signal, the status of the terminal 1 (such as whether it can move, the status of the holder, the remaining battery level, etc.), and so on. The search result in the case of not receiving a response signal may include, for example, the movement history of the terminal 2, the number of outgoing calls from the terminal 2, and so on.

[0091] In the related art, procedures for searching for a terminal that has become incommunicable due to being out of range or the like have not been considered. Also, searches have been conducted based on human judgment based on vision and hearing, and there has been a possibility of false detection.

[0092] According to the second aspect in the disclosure of this specification, it becomes possible to search for a terminal that has become incommunicable due to being out of range or being in a state where it cannot respond even though it is within range, using D2D communication. Also, because D2D communication is used for searching, it becomes possible to accurately search for terminals over a wide range.

[0093] <The third aspect in the disclosure of this specification> In the configuration of the second aspect in the disclosure of this specification, the case where the terminal 2 is a single unit has been described. In the third aspect in the disclosure of this specification, countermeasures for more efficiently searching for the terminal 1 by using a plurality of terminals 2 will be described.

[0094] FIG. 8 is a sequence diagram showing an example of the operation of a communication system including the terminal 1, terminals 2-1, 2-2, 2-3, 2-4, and the control device 3 in the third aspect. The operations up to step 6 are omitted because they are the same as those in FIGS. 1 and 4.

[0095] In step 108, the control device 3 sends a search request to a plurality of D2D communication-capable terminals 2 (e.g., terminal 2-1, terminal 2-2, terminal 2-3, terminal 2-4). The transmission of the search request may be based on a step (not shown) of displaying information indicating a plurality of countermeasures on a user interface (UI) and having the operator make a selection. The search request may include information about the attributes of terminal 1 and the estimated position. The search request may also include the capability information desired by the control device 3 (for example, D2D communication capability, mobility capability, flight capability, etc.). Further, the search request may be sent by specifying the destination or may be sent to all registered destinations.

[0096] In step 409, at least a plurality of terminals 2 (e.g., terminal 2-1, terminal 2-2, terminal 2-3) send a response signal to the search request to the control device 3. When terminal 2 can respond to the search request, it sends a permission response indicating permission as the response signal. On the other hand, when terminal 2 cannot respond to the search request, it may send a rejection response indicating rejection as the response signal or may ignore it without sending a response signal. In FIG. 8, an example where terminal 2-4 does not respond to the search request is shown. When indicating permission, terminal 2 may include terminal information (for example, position information, information about the owner, communication capability (radio wave transmission distance, corresponding frequency, corresponding mobile network operator, setting information related to D2D communication, etc.), remaining battery level of the terminal, mobility capability, flight capability, etc.) in the response signal.

[0097] In step 410, the control device 3 transmits search information to a plurality of terminals 2 (e.g., terminals 2-1 and 2-2) that have transmitted a response signal (permission response) indicating permission. Here, the terminal 2 that has transmitted the response signal which is a permission response is also referred to as a D2D terminal. The control device 3 may select the destination to which the search information is to be transmitted based on the information of the terminals included in the response signal. In FIG. 8, as an example, the case where the terminal 2-3 is not selected and the terminals 2-1 and 2-2 are selected is shown. If a response indicating permission is not received, the control device 3 may select new countermeasures based on the estimated position and the fact that no response has been received, and end the flow. The selection of the plurality of terminals 2 by the control device 3 may be based on whether D2D communication is possible between the plurality of terminals 2 (for example, between the terminals 2-1 and 2-2).

[0098] The search information may be generated based on the information of the terminal 2 included in the permission response. The search information may be, for example, the attribute information of the terminal 1 (information about the holder, type of the terminal, reason for search, etc.), the estimated position of the terminal 1, the communication probability of the estimated position, the navigation information indicating the area where the D2D search signal should be transmitted, the information of other terminals 2 that transmit the D2D search signal (as an example, including the information of the terminal 2-2 in the search information and transmitting it to the terminal 2-1), and so on.

[0099] The navigation information is generated from the estimated position of the terminal 1, the information of the terminal 2-1, and the information of the terminal 2-2. The information of the terminal 2-1 and the terminal 2-2 used for generating the navigation information may be, for example, the communication capabilities of the terminal 2-1 and the terminal 2-2, or the position information of the terminal 2-1 and the position information of the terminal 2-2, or both the communication capabilities and the position information. Also, the information of the terminal 2-1 and the terminal 2-2 used for generating the navigation information may be an appropriate combination of the elements included in the information of the terminal 2 included in the response signal. Further, the navigation information may be generated by further considering the information indicating the communication probability at the estimated position of the terminal 1.

[0100] The navigation information may indicate the number of times, time, location, etc. at which the D2D search signal should be transmitted. At this time, the number of times, time, location, etc. at which the D2D search signal should be transmitted may be determined according to the remaining battery level of terminal 2. For example, when the remaining battery level is sufficient, short-time transmissions may be repeated many times, or for example, when the remaining battery level is low, long-time transmissions may be performed a small number of times.

[0101] Also, the navigation information may indicate areas that prohibit or restrict the intrusion of terminal 2-1 or terminal 2-2. At this time, the navigation information may indicate areas based on geographical and topographical information such as cliffs and steep slopes.

[0102] The navigation information may include map information indicating the D2D radio wave reach range of other terminals. As an example, the navigation information may be generated to indicate an area where terminal 2-2 does not transmit a D2D search signal in the same area as terminal 2-1. Also, the navigation information may be generated to indicate an appropriate area where, for example, terminal 2-2 transmits a D2D search signal within an area where it can be connected to the mobile communication network via terminal 2-1.

[0103] In step 411, a plurality of terminals 2 (e.g., terminal 2-1 and terminal 2-2) establish a D2D communication path among the plurality of terminals 2 based on the search information. The D2D communication path may be, for example, a path of ProSeDirect Communication. The path may be used as a relay path that connects terminal 2 (e.g., terminal 2-2, remote terminal) to the mobile communication network via another terminal 2 (e.g., terminal 2-1, relay terminal). Regarding the relay, it may be, for example, ProSe UE-to-NW Relay communication. Also, the D2D communication path may be used for the exchange of information indicating an area where a D2D search signal has already been transmitted. Also, the D2D communication path may be used for sharing with other terminals that have discovered terminal 1.

[0104] In step 412, terminal 2 (e.g., terminal 2-2) transmits a D2D search signal while maintaining a direct communication path with another terminal 2 (e.g., terminal 2-1). For the D2D search signal, for example, a ProSe Direct Discovery signal may be used. Further, the D2D search signal may include a request for blinking the LED to terminal 1 or a request for playing a warning sound. Terminal 2 can perform the transmission of the D2D search signal while moving, for example, to search a range corresponding to the moving distance in addition to the reach distance of the D2D search signal. Further, in the configuration of the third aspect, since terminal 2-1 can establish a D2D path while communicating with the base station, terminal 2-2 can transmit a D2D search signal after entering an area where communication with the base station is not possible. According to this, compared with the configuration of the second aspect, terminal 1 can be searched over a wider range corresponding to the D2D communication distance of terminal 2-2 in addition to the D2D communication distance of terminal 2-1.

[0105] In step 413, when terminal 1 receives the D2D search signal, it transmits a response signal to terminal 2-2, which is the transmission source of the D2D search signal, using D2D communication. For the response signal, for example, a ProSe Direct Discovery signal may be used. The response signal may include, for example, the identifier of terminal 1, the location information of terminal 1, the status of terminal 1 (such as mobility, the status of the holder, remaining battery level, etc.). Note that terminal 1 may blink the LED or play a warning sound in response to receiving the D2D search signal or a request from control device 3.

[0106] In step 414, terminal 2 (e.g., terminal 2-2) transmits the search result to another terminal 2 (e.g., terminal 2-1) via the established path. The search result may indicate that a response signal has been received from terminal 1, or may indicate that a predetermined D2D search signal has been transmitted but no response signal has been received. The search result in the case of receiving a response signal may include, for example, the location information of terminal 1, the location information of terminal 2-2 when the response signal was received, the status of terminal 1 (such as mobility, the status of the holder, remaining battery level, etc.). The search result in the case of not receiving a response signal may include, for example, the movement history of terminal 2-2, the number of transmissions from terminal 2-2, etc.

[0107] In step 415, another terminal 2 (e.g., terminal 2-1) reports to the control device 3 the search result of terminal 1 using D2D communication by a plurality of terminals 2 (e.g., terminal 2-1 and terminal 2-2). The search result may be the same as the content transmitted from terminal 2 (e.g., terminal 2-2). Further, the search result may include, in addition to the content transmitted from terminal 2 (e.g., terminal 2-2), the location information of another terminal 2 (e.g., terminal 2-1), the movement history of another terminal 2 (e.g., terminal 2-1), etc. The control device 3 may output the received search result.

[0108] FIG. 9 is a flowchart showing an example of the operation of the control device 3 in the third aspect.

[0109] In the third aspect, after step 26 in FIG. 2 of the first aspect, when it is determined that terminal 1 is incommunicable based on the communication probability at the estimated position and countermeasure means using D2D communication by a plurality of terminals are selected, the operation of the control device 3 will be described. The operations up to step 26 are omitted because they are the same as those in FIGS. 2 and 5.

[0110] In step 208, the control device 3 transmits a search request to a plurality of D2D communication-capable terminals 2 (e.g., terminal 2-1, terminal 2-2, terminal 2-3, terminal 2-4). The transmission of the search request may be based on a step (not shown) of displaying information indicating a plurality of countermeasure means on a user interface (UI) and the operator selecting it. The search request may include the attributes of terminal 1 and information regarding the estimated position. The search request may include the capability information of terminal 2 desired by the control device 3 (for example, D2D communication capability, movement capability, flight capability, etc.). Further, the search request may be transmitted by designating the destination or transmitted to all registered destinations.

[0111] In step 509, the control device 3 receives response signals to the search request from at least a plurality of terminals 2 (e.g., terminals 2-1, 2-2, 2-3). When the response signal indicates permission (permission response), the control device 3 may determine that the terminal is capable of handling the search request. When the response signal indicates rejection (rejection response), the control device 3 may determine that the terminal is incapable of handling the search request. Also, when the control device 3 does not receive a response signal, it may determine that the terminal has indicated rejection. The response signal indicating permission may include information of the terminal 2 (for example, information about the holder, communication capabilities (radio wave transmission distance, corresponding frequency, corresponding mobile network operator, etc.), remaining battery level of the terminal 2, etc.). When the control device 3 does not receive a response signal indicating permission (permission response), it may select new countermeasures based on the estimated position and the fact that no response has been received, output the corresponding information, and end the flow.

[0112] In step 510, the control device 3 transmits search information to the plurality of terminals 2 (e.g., terminals 2-1, 2-2) that received the permission response in step 509. Here, the terminal 2 that has transmitted a response signal indicating permission is also called a D2D terminal. The control device 3 may select the destination for transmitting the search information based on the information of the terminal included in the response signal. FIG. 9 shows an example where the terminal 2-3 that indicated permission in step 509 is not selected and the terminals 2-1 and 2-2 are selected. The selection of the plurality of terminals 2 by the control device 3 may be based on whether D2D communication is possible between the plurality of terminals 2 (for example, between terminals 2-1 and 2-2).

[0113] The search information may be generated based on the information of the terminal 2 included in the permission response. The search information may include, for example, attribute information of the terminal 1 (information about the holder, type of the terminal, reason for the search, etc.), the estimated position of the terminal 1, the communication probability of the estimated position, navigation information indicating the area where the D2D search signal should be transmitted, information of other terminals that transmit the D2D search signal (as an example, including the information of the terminal 2-2 in the search information and transmitting it to the terminal 2-1), etc.

[0114] The navigation information is generated from the estimated position of terminal 1 and the information of a plurality of terminals 2 (e.g., the information of terminal 2-1 and the information of terminal 2-2). The information of terminal 2-1 and terminal 2-2 used for generating the navigation information may be, for example, the communication capabilities of terminal 2-1 and terminal 2-2, or the position information of terminal 2-1 and terminal 2-2, or both the communication capabilities and the position information. Also, the information of terminal 2-1 and terminal 2-2 used for generating the navigation information may be an appropriate combination of the elements included in the information of the terminals included in the response signal. Further, the navigation information may be generated by further considering information indicating the communication probability at the estimated position of terminal 1.

[0115] The navigation information may indicate the number of times, time, position, etc. at which the D2D search signal should be transmitted. At this time, the number of times, time, position, etc. at which the D2D search signal should be transmitted may be determined according to the remaining battery level of terminal 2. For example, navigation information may be generated to control terminal 2 to repeat short-time transmissions frequently when the remaining battery level is sufficient, or navigation information may be generated to control terminal 2 to perform long-time transmissions a small number of times when the remaining battery level is low.

[0116] Also, the navigation information may indicate areas where the intrusion of a plurality of terminals 2 (e.g., terminal 2-1 or terminal 2-2) is prohibited or restricted. At this time, the navigation information may determine the areas based on geographical and topographical information such as cliffs and steep slopes.

[0117] The navigation information may include map information indicating the D2D radio wave reach range of other terminals. The navigation information may be generated, for example, to indicate an area where a terminal 2 (e.g., terminal 2-2) does not transmit a D2D search signal in the same area as another terminal 2 (e.g., terminal 2-1). Also, the navigation information may be generated to indicate an appropriate area where a terminal 2 (e.g., terminal 2-2, remote terminal) transmits a D2D search signal within an area where it can be connected to a base station via another terminal 2 (e.g., terminal 2-1, relay terminal).

[0118] In step 511, the control device 3 receives, from a terminal 2 (e.g., terminal 2-2) via another terminal 2 (e.g., terminal 2-1), a search result of terminal 1 using D2D communication by a plurality of terminals 2 (e.g., terminal 2-1 and terminal 2-2). The search result received by the control device 3 may be the same as the content transmitted from the terminal 2 (e.g., terminal 2-2). Also, the search result may include, in addition to the content transmitted from the terminal 2 (e.g., terminal 2-2), the position information of another terminal 2 (e.g., terminal 2-1), the movement history of another terminal 2 (e.g., terminal 2-1), and the like.

[0119] In step 512, the control device 3 outputs the search result and ends the flow. The output may be displayed on a user interface.

[0120] Regarding the operation of terminal 1 in the third aspect, since it is the same as in FIGS. 3 and 6, it is omitted.

[0121] FIG. 10 is a flowchart showing an example of the operation of a plurality of terminals 2 in the third aspect.

[0122] FIG. 10-A is a flowchart showing an example of the operation of a terminal 2 (e.g., terminal 2-2) in the third aspect. The operations up to step 302 are omitted since they are the same as in FIG. 7 of the second aspect.

[0123] In step 603, the terminal 2 (e.g., terminal 2-2) receives, from the control device 3, search information requesting to search for the terminal 1 in cooperation with another terminal 2 (e.g., terminal 2-1).

[0124] The search information may be generated based on the information of the terminal 2 included in the permission response. The search information may include, for example, the attribute information of the terminal 1 (information about the holder, type of the terminal, reason for search, etc.), the estimated position of the terminal 1, the communication probability of the estimated position, navigation information indicating the area where the D2D search signal should be transmitted, information of other terminals transmitting the D2D search signal (e.g., information of terminal 2-1), and the like.

[0125] The navigation information is generated from the estimated position of the terminal 1 and the information of a plurality of terminals 2 (e.g., information of terminal 2-1 and terminal 2-2). The information of the plurality of terminals 2 (e.g., information of terminal 2-1 and terminal 2-2) used for generating the navigation information may be, for example, the communication capabilities of the plurality of terminals 2 (e.g., communication capabilities of terminal 2-1 and terminal 2-2), the position information of the plurality of terminals 2 (e.g., position information of terminal 2-1 and terminal 2-2), or both the communication capabilities and the position information. Also, the information of the plurality of terminals 2 (e.g., terminal 2-1 and terminal 2-2) used for generating the navigation information may be an appropriate combination of elements included in the information of the terminals included in the response signal. Further, the navigation information may be generated by further considering information indicating the communication probability at the estimated position of the terminal 1.

[0126] The navigation information may indicate the number of times, time, position, etc. at which the D2D search signal should be transmitted. At this time, according to the remaining battery level of the terminal 2 (e.g., terminal 2-2), the number of times, time, position, etc. at which the D2D search signal should be transmitted may be determined. For example, when the remaining battery level is sufficient, navigation information may be generated to control the terminal 2 to repeat a large number of transmissions in a short time, or when the remaining battery level is low, navigation information may be generated to control the terminal 2 to perform a small number of transmissions over a long time.

[0127] The navigation information may also indicate areas where entry is prohibited or restricted. At this time, the navigation information may determine the area based on geographical and topographical information such as cliffs and steep slopes.

[0128] The navigation information may include map information indicating the D2D radio wave reach range of other terminals (e.g., terminal 2-1). At this time, the navigation information may be generated to indicate, for example, an area where D2D search signals are not transmitted in the same area as terminal 2-1. Also, the navigation information may be generated to indicate an appropriate area where D2D search signals are transmitted within an area where connection to the base station is possible via terminal 2-1.

[0129] In step 604, a plurality of terminals 2 establish a D2D communication path with other terminals 2 (e.g., terminal 2-2 and terminal 2-1) based on the search information. The D2D communication path may be, for example, a ProSe Direct Communication path. The path may also be used as a relay path connecting to the mobile communication network via terminal 2-1 (e.g., a relay terminal). For the relay, it may be, for example, ProSe UE-to-NW Relay communication. Also, the D2D communication path may be used for the exchange of information indicating areas where D2D search signals have already been transmitted. Also, the D2D communication path may be used for sharing with other terminals (e.g., terminal 2-1) that have discovered terminal 1.

[0130] In step 605, terminal 2 (e.g., terminal 2-2) transmits a D2D search signal while maintaining a direct communication path with another terminal 2 (e.g., terminal 2-1). As the D2D search signal, for example, a ProSe Direct Discovery signal may be used. Further, the D2D search signal may include a request for blinking of the LED to terminal 1 or a request for playback of a warning sound. Terminal 2-2 can search a range corresponding to the movement distance in addition to the reach distance of the D2D search signal by transmitting the D2D search signal, for example, while moving. Further, in the configuration of the third aspect, since terminal 2-1 (e.g., relay terminal) can establish a D2D path while communicating with the base station, terminal 2-2 can transmit a D2D search signal after entering an area where it cannot communicate with the base station. According to this, compared to the configuration of the second aspect, terminal 1 can be searched over a wider range than the D2D communication distance of terminal 2-1 plus the D2D communication distance of terminal 2-2.

[0131] In step 606, terminal 2 (e.g., terminal 2-2) determines whether it has satisfied either the condition of receiving a response signal to the D2D search signal or the condition of completing transmission of a predetermined D2D search signal. If the condition is satisfied, the process proceeds to step 607. If the condition is not satisfied, step 605 is repeated.

[0132] As the response signal, for example, a ProSe Direct Discovery signal may be used. The response signal may include, for example, an identifier of terminal 1, location information of terminal 1, the status of terminal 1 (such as mobility, the status of the holder, remaining battery level, etc.).

[0133] The predetermined condition may be, for example, transmitting the D2D search signal for a period set by search information or the like, transmitting the D2D search signal a set number of times, or completing transmission of the D2D search signal in a specified area.

[0134] In step 607, terminal 2 (e.g., terminal 2-2) transmits the search result to another terminal 2 (e.g., terminal 2-1) via the established path and ends the flow.

[0135] The search result may indicate that a response signal has been received from terminal 1, or may indicate that a predetermined D2D search signal has been transmitted but no response signal has been received. The search result in the case of receiving a response signal may include, for example, the location information of terminal 1, the location information of terminal 2-2 when the response signal is received, the status of terminal 1 (operability, status of the holder, remaining battery level, etc.), and so on. The search result in the case of not receiving a response signal may include, for example, the movement history of terminal 2-2, the number of outgoing calls from terminal 2-2, and so on.

[0136] Figure 10-B is a flowchart showing an example of the operation of another terminal 2 (e.g., terminal 2-1) in the third aspect. The operations up to step 604 are the same as those in Figure 10-A and are therefore omitted.

[0137] In step 608, another terminal 2 (e.g., terminal 2-1) receives the search result from terminal 2 (e.g., terminal 2-2) via the D2D communication path.

[0138] The search result may indicate that a response signal has been received from terminal 1, or may indicate that a predetermined D2D search signal has been transmitted but no response signal has been received. The search result in the case where terminal 2 (e.g., terminal 2-2) receives a response signal may include, for example, the location information of terminal 1, the location information of terminal 2-2 when the response signal is received, the status of terminal 1 (operability, status of the holder, remaining battery level, etc.), and so on. The search result in the case where terminal 2 (e.g., terminal 2-2) does not receive a response signal may include, for example, the movement history of terminal 2-2, the number of outgoing calls from terminal 2-2, and so on.

[0139] In step 609, another terminal 2 (e.g., terminal 2-1) transmits the search result of terminal 1 using D2D communication by a plurality of terminals 2 (e.g., terminal 2-1 and terminal 2-2) to the control device 3 and ends the flow.

[0140] The search results transmitted to the control device 3 may be the same as the content transmitted from the terminal 2 (e.g., terminal 2-2). Further, the search results may include, in addition to the content transmitted from the terminal 2 (e.g., terminal 2-2), the location information of other terminals 2 (e.g., terminal 2-1), the movement history of other terminals 2 (e.g., terminal 2-1), and the like.

[0141] According to the configuration of the third aspect of searching for the terminal 1 using a plurality of terminals 2, it becomes possible to perform the search more efficiently than when the terminal 2 searches for the terminal 1 alone. Further, by using D2D relay communication, it becomes possible to search areas that cannot be searched by the terminal 2 alone.

[0142] <Other aspects in the disclosure of this specification> Regarding the improvement in the accuracy of position estimation and the improvement in the search accuracy of each countermeasure means in the above-mentioned disclosure, an explanation will be given.

[0143] FIG. 14 is an example in the above-mentioned disclosure when the control device 3 analyzes the tendency of the acceleration information of the terminal 1. For example, during time periods such as going to work or school, the movement of the owner who owns the terminal 1 and the terminal 1 itself also becomes large, so the acceleration values shown on the horizontal axis also tend to be relatively large and have a large variation. Also, at night, since the user is at home and sleeping, the acceleration values tend to be very small and have little variation. The tendency also changes depending on age, gender, occupation, weather, and season. For children, during school hours during the day, there is inevitably a cycle of movement according to class and break times, and at night, there is no movement because they go to bed. Also, for the elderly, the movement as a whole becomes small. The movement is mainly walking during the day, and the user is at home at other times, so the movement is small. Also, when the owner of the terminal 1 changes due to theft or the like, the tendency changes greatly.

[0144] By retaining the tendency for each attribute as pattern data in advance and performing a comparative analysis with the acceleration information of the collected terminal 1, the accuracy of the estimated position can be improved. When the difference component between the acceleration information of terminal 1 and the pattern data is greater than a certain threshold value and the number of times is greater than the threshold number of times, it may be determined that there is an abnormality. Also, it may be reported to the administrator of terminal 1 that an abnormality has been determined. Further, this pattern data can also be the past information of this terminal itself. Thereby, when it becomes information on movements different from the past, it is also possible to determine that there is an abnormality.

[0145] FIG. 15 is an example in which the above-described trend analysis is performed on position information in the same manner as acceleration information. The position information is converted to an absolute value by replacing the moving distance from the information before and after it. This moving distance information, similar to the acceleration information, has tendencies that change depending on age, gender, occupation, weather, and season. For example, if it is a child, on weekdays, it takes positions near school, cram school, and home. When using means of transportation such as buses or trains during commuting, the reflected tendency appears. In the case of position information, information on movements by vehicles that cannot be measured by an acceleration sensor can also be obtained due to changes in the position information.

[0146] By retaining the tendency for each attribute as pattern data in advance and performing a comparative analysis with the position information of the collected terminal 1, the accuracy of the estimated position can be improved. When the difference component between the position information of terminal 1 and the pattern data is greater than a certain threshold value and the number of times is greater than the threshold number of times, it may be determined that there is an abnormality. Also, it may be reported to the administrator of terminal 1 that an abnormality has been determined. Further, this pattern data can also be the past information of this terminal itself. Thereby, when it becomes information on movements different from the past, it is also possible to determine that there is an abnormality.

[0147] Also, although examples of analyzing each of the acceleration information and the position information have been described, they may be analyzed in combination. When an abnormality is determined simultaneously in the analysis using both, since the probability of theft further increases, applications such as prohibiting the use of services on the corresponding terminal are also possible.

[0148] Finally, a configuration example of the terminal 1, the terminals 2 (terminals 2-1, 2-2, 2-3, 2-4), and the control device 3 according to the disclosure of this specification will be described.

[0149] FIG. 11 is a block diagram showing the configuration of the terminal 1 according to the disclosure of this specification. The terminals 2 (terminals 2-1, 2-2, 2-3, 2-4) may also have the same configuration.

[0150] The wireless transceiver 1101 may be composed of a Radio Frequency (RF) transceiver and an antenna. The RF transceiver performs analog RF signal processing for communicating with a base station device in a PLMN. The RF transceiver may further be used for ProSe direct discovery and direct communication between terminals. The RF transceiver may include a first transceiver used for communication with a base station device in a PLMN and a second transceiver used for D2D communication with other terminals (e.g., terminal 2, etc.). The analog RF signal processing performed by the RF transceiver includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver is coupled to an antenna and a baseband processor. That is, the RF transceiver receives modulation symbol data (or OFDM symbol data) from the baseband processor, generates a transmission RF signal, and supplies the transmission RF signal to the antenna. Also, the RF transceiver generates a baseband reception signal based on the received RF signal received by the antenna and supplies this to the baseband processor 1102.

[0151] The baseband processor 1102 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of a transmission format (transmission frame), (d) channel encoding / decoding, (e) modulation (symbol mapping) / demodulation, (f) spreading / inverse spreading, and (g) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT), etc. On the other hand, the control plane processing includes communication management of layer 1 (e.g., transmission power control), layer 2 (e.g., radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0152] The baseband processor 1102 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU), or Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1103 described later.

[0153] The application processor 1103 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 1103 may include a plurality of processors (a plurality of processor cores). The application processor 1103 realizes various functions of the terminal 1 by executing a system software program (Operating System (OS)) read from the memory 1105 or a memory not shown and various application programs (for example, a call application, a WEB browser, a mailer, a camera operation application, a music playback application).

[0154] In some implementations, as shown by the dashed line in the figure, the baseband processor 1102 and the application processor 1103 may be integrated on one chip. In other words, the baseband processor 1102 and the application processor 1103 may be implemented as one System on Chip (SoC) device 1104. The SoC device may also be referred to as a system Large Scale Integration (LSI) or a chipset.

[0155] The memory 1105 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 1105 may physically include a plurality of independent memory devices. The volatile memory is, for example, SRAM, DRAM, or a combination thereof. The non-volatile memory is, for example, MROM, PROM, flash memory, or a hard disk drive, or a combination thereof. For example, the memory 1105 may include an external memory device accessible from the baseband processor 1102, the application processor 1103, and the SoC. The memory 1105 may include an embedded memory device integrated within the baseband processor 1102, within the application processor 1103, or within the SoC 1104. Further, the memory 1105 may include a memory within the UICC.

[0156] Memory 1105 stores the communication module. As already described, the memory may physically include a plurality of independent memory devices, and software and data may be stored in the same memory device or in different memory devices.

[0157] The communication module includes software modules executed by baseband processor 1102 or application processor 1103. Thereby, baseband processor 1102 or application processor 1103 communicates with control device 3 and base station devices.

[0158] Furthermore, the communication module includes instruction groups and data for performing the processing of terminals 1 and 2 described using sequence diagrams and flowcharts in the disclosure of this specification. Thereby, baseband processor 1102 or application processor 1103 can perform the processing described in the disclosure of this specification by reading out and executing a group of software modules including the communication module from the memory.

[0159] The terminal, user equipment (UE) (including, for example, mobile station, mobile terminal, mobile device, or wireless device) in this specification is an entity connected to a network via a wireless interface.

[0160] The UE in this specification is not limited to a dedicated communication device, and may be any device having the communication function as the UE described in this specification.

[0161] As terms, each of "User Equipment (UE) (as a word used in 3GPP)", "mobile station", "mobile terminal", "mobile device", and "wireless terminal" is generally intended to be synonymous with each other, and may be a stand-alone mobile station such as a terminal, mobile phone, smartphone, tablet, cellular IoT terminal, IoT device, etc.

[0162] Note that the terms "UE" and "wireless terminal" also include devices that have been stationary for a long period of time. This should be understood.

[0163] Also, the UE may be, for example, production equipment, manufacturing equipment, and / or energy-related machinery (as an example, including boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal power generators, nuclear power generators, storage batteries, nuclear systems, nuclear-related equipment, heavy electrical equipment, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machines, manipulators, robots, robot application systems, tools, dies, rolls, conveying devices, lifting devices, cargo handling devices, textile machines, sewing machines, printing machines, printing-related machines, paper-making machines, chemical machines, mining machines, mining-related machines, construction machines, construction-related machines, agricultural machines and / or implements, forestry machines and / or implements, fishery machines and / or implements, safety and / or environmental protection appliances, tractors, bearings, precision bearings, chains, gears, power transmission devices, lubrication devices, valves, pipe joints, and / or application systems of any of the devices or machines described above).

[0164] Also, the UE may be, for example, a transportation device (as an example, vehicles, automobiles, motorcycles, bicycles, trains, buses, limousines, rickshaws, ships (ship and other watercraft), airplanes, rockets, satellites, drones, balloons, etc.).

[0165] Also, the UE may be, for example, an information and communication device (as an example, electronic computers and related devices, communication devices and related devices, electronic components, etc.).

[0166] The UE may also be, for example, a refrigerator, a refrigeration application product or device, a commercial and service equipment, a vending machine, an automatic service machine, an office machine and device, a consumer electric and electronic appliance (such as a voice device, a speaker, a radio, a video device, a TV, a range hood, a rice cooker, a coffee maker, a dishwasher, a washing machine, a dryer, a fan, a ventilation fan and related products, a vacuum cleaner, etc.).

[0167] The UE may also be, for example, an electronic application system or device (such as an X-ray device, a particle accelerator device, a radioactive substance application device, a sound wave application device, an electromagnetic application device, an electric power application device, etc.).

[0168] The UE may also be, for example, a light bulb, lighting, a measuring instrument, an analytical instrument, a testing machine and a measuring machine (such as a smoke detector, a human alarm sensor, a motion sensor, a wireless tag, etc.), a watch (watch or clock), a physicochemical machine, an optical machine, a medical device and / or a medical system, a weapon, a sharp tool, or a hand tool, etc.

[0169] The UE may also be, for example, a personal digital assistant or device with a wireless communication function (such as an electronic device (such as a personal computer or an electronic measuring instrument) configured to be attached with or inserted with a wireless card or a wireless module, etc.).

[0170] The UE may also be, for example, a device or a part thereof that provides the following applications, services, and solutions in the "Internet of Things (IoT)" using wired or wireless communication technologies.

[0171] An IoT device (or thing) is equipped with appropriate electronic devices, software, sensors, network connections, etc. that enable the device to collect and exchange data with each other and with other communication devices.

[0172] An IoT device may also be an automated device that follows software instructions stored in its internal memory.

[0173] An IoT device may also operate without the need for human supervision or intervention. Also, an IoT device may be a permanently installed device and / or may remain in an inactive state for an extended period of time.

[0174] An IoT device may also be implemented as part of a stationary device. An IoT device may be embedded in a non-stationary device (such as a vehicle), or attached to an animal or person being monitored / tracked.

[0175] It will be understood that IoT technology can be implemented on any communication device that can connect to a communication network to send and receive data, regardless of whether it is controlled by human input or software instructions stored in memory.

[0176] It will be understood that an IoT device may also be referred to as a Machine Type Communication (MTC) device, or a Machine to Machine (M2M) communication device, or an NB-IoT (Narrow Band-IoT) UE.

[0177] It will also be understood that a UE can support one or more IoT or MTC applications.

[0178] Some examples of MTC applications are listed in the following table (source: 3GPP TS22.368 V13.2.0 (2017-01-13) Annex B, the content of which is incorporated herein by reference). This list is not exhaustive and shows MTC applications as an example.

[0179]

Table 1

[0180] Applications, services, and solutions include, by way of example, MVNO (Mobile Virtual Network Operator) services / systems, disaster prevention radio services / systems, in-building wireless telephone (PBX (Private Branch eXchange)) services / systems, PHS / digital cordless telephone services / systems, POS (Point of Sale) systems, advertising transmission services / systems, multicast (MBMS (Multimedia Broadcast and Multicast Service)) services / systems, V2X (Vehicle to Everything: vehicle-to-vehicle communication and road-vehicle / pedestrian-vehicle communication) services / systems, in-train mobile radio services / systems, location information-related services / systems, disaster / emergency wireless communication services / systems, IoT (Internet of Things) services / systems, community services / systems, video distribution services / systems, Femto cell application services / systems, VoLTE (Voice over LTE) services / systems, wireless TAG services / systems, charging services / systems, radio on-demand services / systems, roaming services / systems, user behavior monitoring services / systems, communication carrier / communication NW selection services / systems, function-limited services / systems, PoC (Proof of Concept) services / systems, personal information management services / systems for terminals, display / video services / systems for terminals, non-communication services / systems for terminals, ad hoc NW / DTN (Delay Tolerant Networking) services / systems, etc.

[0181] Note that the above categories of UEs are merely application examples of the technical ideas and aspects described in this specification. They are not limited to these examples, and it goes without saying that those skilled in the art can make various changes.

[0182] FIG. 12 is a block diagram showing the configuration of the control device 3 according to the disclosure of this specification. The control device 3 includes a network interface 1201, a processor 1202, and a memory 1203.

[0183] The network interface 1201 is used to communicate with the terminals 1 and 2. The network interface 1201 may include, for example, a network interface card (NIC) compliant with the IEEE802.3 series.

[0184] The processor 1202 reads and executes software (computer program) from the memory 1203, thereby performing the processing of the control device 3 described with reference to the sequence diagram and the flowchart in the above aspects. The processor 1202 may be, for example, a microprocessor, an MPU, or a CPU. The processor 1202 may include a plurality of processors.

[0185] The memory 1203 is composed of a combination of a volatile memory and a non-volatile memory. The memory 1203 may include storage arranged separately from the processor. In this case, the processor 1202 may access the memory 1203 via an I / O interface (not shown).

[0186] In the example of the figure, the memory 1203 is used to store a group of software modules for operating the control device 3. The software module includes a group of instructions and data for executing the processing of the control device 3 described in the disclosure of this specification (for example, the processing of receiving position information and acceleration information from the terminal 1, the processing of transmitting a search signal to the terminal 1, the processing of transmitting a search request to the terminal 2, etc.). The processor 1202 can perform the processing of the control device 3 described in the disclosure of this specification by reading and executing the group of software modules including the software module from the memory 1203.

[0187] As described with reference to the drawings, each of the processors of the terminals 1 and 2 (2-1, 2-2, 2-3, 2-4) and the control device 3 according to the above disclosure executes one or more programs including a set of instructions for causing a computer to execute the algorithms described with reference to the drawings. These programs are stored using various types of non-transitory computer readable media and can be supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), Compact Disc Read Only Memory (CD-ROM), CD-R, CD-R / W, semiconductor memories (e.g., mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)). Also, the programs may be supplied to a computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. Transitory computer readable media can supply the programs to a computer via wired communication paths such as electric wires and optical fibers, or wireless communication paths.

[0188] Each of the above aspects may be implemented independently or in appropriate combination.

[0189] The above aspects have been shown by an example in which the control device 3 is arranged on the Internet. However, the control device 3 may be arranged in a node within a PLMN (e.g., a base station, a mobility management device, or a subscriber management device, etc.).

[0190] Furthermore, the above-mentioned aspects are merely examples of application of the technical idea obtained by the inventor of the present invention, and the technical idea is not limited to the above-mentioned aspects, and various modifications are possible.

[0191] For example, some or all of the above aspects may be described as, but are not limited to, the following notes.

[0192] (Appendix 1.) A communication method performed in a control device, First position information and acceleration information of the first terminal at a first timing are received from the first terminal. Receive, Transmitting a first search signal to the first terminal requesting a response signal; If it is determined that there is no response signal to the search signal, The first position information and the acceleration information are used to calculate the first position at a second timing. Estimating a second location of the terminal; determining a second communication probability corresponding to the second location information based on the location and the first communication probability at the location; outputting information indicating a countermeasure for searching for the first terminal, the countermeasure corresponding to the second communication probability; Communication methods.

[0193] (Appendix 2.) The countermeasure means includes transmitting a search request to at least one or more second terminals that transmit a second search signal to the first terminal using Device to Device (D2D) communication, the search request requesting the first terminal to be searched for. 2. A communication method as described in claim 1.

[0194] (Appendix 3.) receiving an acceptance response, which is a response signal indicating acceptance in response to the search request, from at least one D2D terminal that is the second terminal; Transmitting search information indicating an area in which the second search signal is transmitted to the D2D terminal; The communication method described in Supplementary Note 2.

[0195] (Supplementary Note 4.) Receive search result information including the reception result of the response to the second search signal transmitted in the area from the D2D terminal, Output the received search result information, The communication method described in Supplementary Note 3.

[0196] (Supplementary Note 5.) The area is generated based on the second communication probability, The communication method described in Supplementary Note 3 or 4.

[0197] (Supplementary Note 6.) When receiving the permission response from a plurality of the second terminals, Generate the search information so that the areas indicated by each of the search information do not overlap based on the attributes of the plurality of the second terminals respectively included in the plurality of the permission responses, The communication method described in any one of Supplementary Notes 3 to 5.

[0198] (Supplementary Note 7.) When receiving, from at least one second terminal among the D2D terminals, a search result indicating the response content from the first terminal to the second search signal, Transmit the search result to at least one other second terminal among the D2D terminals different from the second terminal, The communication method described in any one of Supplementary Notes 4 to 6.

[0199] (Supplementary Note 8.) When it is determined that the second communication probability is high, Transmit a search request of the first terminal to a group that performs a search, The communication method described in any one of Supplementary Notes 1 to 7.

[0200] (Supplementary Note 9.) When it is determined that the second communication probability is neither low nor high, Resend the first search signal to the first terminal, The communication method according to any one of Supplementary Notes 1 to 8.

[0201] (Supplementary Note 10.) When it is determined that the second communication probability is low and it is further determined that there is no accessible path for a human on the position indicated by the second position information, Specify a terminal using a drone as the second terminal. The communication method according to any one of Supplementary Notes 2 to 9.

[0202] (Supplementary Note 11.) A control device, A receiving unit that receives, from a first terminal, first position information and acceleration information of the first terminal at a first timing, A transmitting unit that transmits a first search signal requesting a response to the first terminal, Here, when it is determined that there is no response to the search signal, An estimating unit that estimates second position information of the first terminal at a second timing using the first position information and the acceleration information, A determining unit that determines a second communication probability corresponding to the second position information based on the position and the first communication probability at the position, An output unit that outputs information indicating countermeasure means corresponding to the second communication probability, A control device comprising the above.

[0203] (Supplementary Note 12.) The countermeasure means includes transmitting a search request to at least one or more second terminals that search for the first terminal, requesting them to transmit a second search signal using Device to Device (D2D) communication to the first terminal. The control device according to Supplementary Note 11.

[0204] (Supplementary Note 13.) The receiving unit is further configured to receive a permission response, which is a response signal indicating permission for the search request, from a D2D terminal that is at least one or more of the second terminals. The transmitting unit is further configured to transmit search information indicating an area for transmitting the second search signal to the D2D terminal. The control device according to Supplementary Note 12.

[0205] (Supplementary Note 14.) The receiving unit is further configured to receive search result information including a reception result of a response to the second search signal transmitted in the area from the D2D terminal. The output unit is further configured to output the received search result information. The control device according to Supplementary Note 13.

[0206] (Supplementary Note 15.) The area is generated based on the second communication probability. The control device according to Supplementary Note 13 or 14.

[0207] (Supplementary Note 16.) When permission responses are received from a plurality of the second terminals, The search information is generated so that the areas indicated by the respective pieces of search information do not overlap based on the attributes of the plurality of second terminals each included in the plurality of permission responses. The control device according to any one of Supplementary Notes 13 to 15.

[0208] (Supplementary Note 17.) When a search result indicating the response content from the first terminal to the second search signal is received from at least one second terminal among the D2D terminals, The transmitting unit is further configured to transmit the search result to at least one other second terminal among the D2D terminals different from the second terminal. The control device according to any one of Supplementary Notes 14 to 16.

[0209] (Supplementary Note 18.) When it is determined that the second communication probability is high, The transmitting unit is further configured to transmit a search request of the first terminal to a group that performs a search. The control device according to any one of Supplementary Notes 11 to 17.

[0210] (Supplementary Note 19.) When the second communication probability is not determined to be low and not determined to be high, the transmission unit is further configured to retransmit the first search signal to the first terminal, The control device according to any one of Supplementary Notes 11 to 18.

[0211] (Supplementary Note 20.) When it is determined that the second communication probability is low and it is further determined that there is no accessible path for a human on the position indicated by the second position information, specify a terminal using a drone as the second terminal, The control device according to any one of Supplementary Notes 12 to 19.

Explanation of Signs

[0212] 1 Terminal 2 Terminal 3 Control Device

Claims

1. A communication method for searching for a first terminal, comprising: receiving a first signal from a second terminal, the first signal including information regarding the capabilities of the second terminal; Transmitting first information regarding information stored in the first terminal to the second terminal; receiving second information transmitted from the second terminal after the response information is received by the second terminal; The response information is transmitted from the first terminal to the second terminal based on the first information. method.

2. The method of claim 1 , wherein the response information is transmitted using Device to Device (D2D) communication.

3. The method according to claim 1 , wherein the second terminal is a terminal that performs Device to Device (D2D) communication.

4. The method of claim 3 , wherein the second terminal is a drone terminal.

5. The method according to any one of claims 1 to 4, wherein the first information is information requesting searching for the first terminal.

6. The method of claim 5 , wherein the first signal is information regarding granting the request.

7. A control device capable of communication for searching with respect to a first terminal, receiving means for receiving a first signal from a second terminal, the first signal including information about the capabilities of said second terminal; A transmitting means for transmitting, to the second terminal, first information relating to information stored in the first terminal; receiving means for receiving second information transmitted from the second terminal after the response information is received by the second terminal; The response information is transmitted from the first terminal to the second terminal based on the first information.

8. The control device according to claim 7 , wherein the response information is transmitted using Device to Device (D2D) communication.

9. The control device according to claim 7 , wherein the second terminal is a terminal that performs Device to Device (D2D) communication.

10. The control device according to claim 9 , wherein the second terminal is a drone terminal.

11. The control device according to any one of claims 7 to 10, wherein the first information is information requesting a search for the first terminal.

12. The control device according to claim 11 , wherein the first signal is information regarding grant of the request.

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