COMMUNICATION DEVICE, COMMUNICATION METHOD, AND PROGRAM

Abstract

This communication device performs a connection establishment process with an other communication device that relays communication with a prescribed communication device, and when transmitting a connection request to the other communication device during the connection establishment process, transmits to the other communication device, along with the request, first data that is a part of the data to be transmitted to the prescribed communication device, and information indicating the conditions for the other communication device to discard the first data.

Description

[Technical field]

[0001] The present invention relates to a communication device, a communication method, and a program, and in particular to a data transmission control technique. [Background technology]

[0002] Vehicles can obtain various information or provide information to others by using V2X (Vehicle-to-Everything) communication, in which a vehicle wirelessly communicates with another vehicle or object. When a vehicle transmits data to a device such as a server on the Internet or a network built by a service provider, the vehicle needs to connect to a specific communication device such as a base station or an access point that can connect to such a network. However, a vehicle is not always in an environment in which it can connect to such a specific communication device. For this reason, it is assumed that a vehicle communicates with a specific communication device, for example, via another vehicle that can connect to such a specific communication device. Patent Document 1 describes a configuration in which vehicles are connected to each other and data is transferred to a specific node. In Patent Document 1, a vehicle close to a specific node is identified by communication between vehicles, and data is transferred to the vehicle close to the specific node. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-184051 A Summary of the Invention [Problem to be solved by the invention]

[0004] A communication device may be able to perform large-volume data communication by establishing a connection with another communication device that is the other party of the communication before data transfer. However, if the communication device or the other communication device is a vehicle, it is assumed that the communication environment is unstable due to the movement of the vehicle, and the connection cannot be established. In addition, since the communication environment from the other communication device to a specific communication device such as a base station or an access point is not necessarily stable, even if a connection between the communication device and the other communication device can be established, the communication environment between the other communication device and the specific communication device may not be stable. In this case, the other communication device may not be able to accept a connection request that is based on relaying. In this way, depending on the environment of the communication device or the other communication device that performs relay transmission, the communication device may not be able to establish a connection or transfer data due to changes in the communication environment, and the convenience of communication may be reduced.

[0005] The present invention provides a technique for improving the convenience of communications. [Means for solving the problem]

[0006] A communication device according to one aspect of the present invention has an execution means for executing a connection establishment process with another communication device that relays communication with a predetermined communication device, and when transmitting a connection request to the other communication device, the execution means transmits, together with the request, first data that is a part of data to be transmitted to the predetermined communication device, and information indicating a condition for the other communication device to discard the first data, to the other communication device. and when there is no second other communication device that is different from the other communication device and that can relay communication with the predetermined communication device, the execution means transmits the request, the first data, and information indicating the condition to the other communication device. do. In addition, a communication device according to another embodiment of the present invention has an execution means for executing a connection establishment process with another communication device that relays communication with a specified communication device, and when the execution means sends a connection request to the other communication device, it transmits to the other communication device, together with the request, first data that is part of the data to be sent to the specified communication device and information indicating conditions for the other communication device to discard the first data, and the information indicating the conditions includes information indicating a geographical range, and if the other communication device moves beyond the geographical range without transmitting the first data, the first data is discarded. Effect of the Invention

[0007] According to the present invention, it is possible to improve the convenience of communication.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same reference numerals are used to designate the same or similar components throughout the drawings. [Brief description of the drawings]

[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [Figure 1] FIG. 1 illustrates an example of a system configuration. [Diagram 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Diagram 3] FIG. 2 illustrates an example of a functional configuration of a communication device. [Figure 4] FIG. 2 is a diagram illustrating an example of a flow of processes executed in the system. [Diagram 5] FIG. 2 is a diagram illustrating an example of a flow of processes executed in the system. [Figure 6] FIG. 2 is a diagram illustrating an example of a flow of processes executed in the system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] (System Configuration) FIG. 1 shows an example of the configuration of the system of this embodiment. This system is a wireless communication system in which vehicles 111 to 114 capable of wireless communication connect to a predetermined network such as the Internet and communicate with each other. The vehicles 111 to 114 according to this embodiment connect to, for example, a base station 101 of a cellular communication system and communicate with a predetermined communication device. The vehicles 111 to 114 are configured to be able to connect to each other and communicate with each other using a communication method different from the cellular communication method with the base station 101. Here, the communication method different from the cellular communication method is, for example, any of the communication methods such as cellular V2X (Vehicle-to-Everything), wireless LAN, DSRC (Dedicated Short Range Communications), and Bluetooth (registered trademark). Note that although cellular V2X is one aspect of the cellular communication method, since it is not communication between a base station and a terminal (i.e., the vehicles 111 to 114) but communication between a device other than the base station and a terminal (the vehicles 111 to 114), these communication methods are treated as different communication methods throughout this embodiment and the claims. The combination of the cellular communication method and another communication method is just an example, and the vehicles 111 to 114 are configured to be connected to a first device such as the base station 101 by a first communication method, and to be mutually connectable by a second communication method different from the first communication method. Although only one base station 101 and four vehicles 111 to 114 are illustrated in Fig. 1, it goes without saying that a large number of these devices may exist.

[0012] The vehicles 111 to 114 can use the second communication method to perform, for example, inter-vehicle communication as well as communication with other devices such as wireless LAN access points. In one example, the vehicle 112 is assumed to be in a position where it can communicate with the other fixed device 121 using a communication method other than the cellular communication method. In addition, the vehicles 113 and 114 may also be able to connect to and communicate with surrounding devices depending on their positions. Note that, although FIG. 1 shows an example in which the vehicle 112 can directly connect to the other fixed device 121, this is not limiting, and for example, the vehicle 112 may be able to communicate with the other fixed device 121 via a wireless communication device of another vehicle or the like. The same applies to other vehicles.

[0013] By executing cellular communication with the base station 101, the vehicles 111 to 114 can transmit information acquired by sensors of the vehicles to a device such as a predetermined information processing server. The information processing server can execute various processes such as control of automatic driving by using this information. Furthermore, by executing cellular communication with the base station 101, the vehicles 111 to 114 can acquire various information such as driving control information and service information according to the vehicle's position from a server that holds predetermined information. On the other hand, in an environment in which many vehicles communicate in parallel, the communication capacity that the base station 101 can provide may be insufficient. For this reason, in this embodiment, for example, communication of a communication device (for example, the vehicle 112) that can be connected to a device 121 of a communication system different from the cellular communication system is offloaded by executing communication between the device 121 and the vehicle 111. Furthermore, the communication of the vehicle 111 is offloaded to another device via the other vehicles 112 to 114. Note that the communication of the vehicles 113 to 114 can also be offloaded via other vehicles or other devices.

[0014] Here, focusing on the vehicle 111, the vehicle 111 may establish a connection with a surrounding vehicle and communicate with a predetermined communication device such as a server on the Internet through the connection. For this purpose, the vehicle 111 transmits a connection request to other surrounding vehicles to request relay of the communication, and establishes a connection. At this time, the vehicle 111 may establish a connection with another vehicle that has good wireless quality of the communication with the vehicle 111 by the second communication method, for example. However, even if the vehicle 111 executes a connection establishment process with the vehicle 112, for example, when the vehicle 111 and the vehicle 112 are moving together, the communication environment may fluctuate significantly over time, and the connection may not be established. In this case, when the vehicle 111 is to transmit data, the vehicle 111 cannot establish a connection with the other vehicle (for example, the vehicle 112), and the data cannot be transmitted. In one example, when the vehicle is controlled based on the transmitted data, if such data cannot be transmitted at all, the control may not be possible. For this reason, it is important to avoid a situation in which data transmission cannot be performed at all as much as possible.

[0015] On the other hand, by transmitting data without establishing a connection, the vehicle 111 can leave open the possibility that a specific communication device can receive the data. However, in this case, if the vehicle 111 always transmits data without establishing a connection, the vehicle 111 will not establish a connection even if it is in a state where it can establish a connection, and therefore communication cannot be performed with sufficient frequency utilization efficiency when transmitting a large amount of data, for example. In contrast, if the vehicle 111 attempts to establish a connection and fails, it can transmit data without establishing a connection. However, in this case, the time until the data can be transmitted is extended.

[0016] In this embodiment, in consideration of such circumstances, when the vehicle 111 transmits a connection request to another vehicle (e.g., the vehicle 112) that relays communication with a predetermined communication device such as a server on the Internet, the vehicle 111 transmits first data, which is a part of data to be transmitted, together with the request in a process of establishing a connection with the other vehicle. Here, the first data includes at least information for identifying the destination predetermined communication device and user data to be delivered to the predetermined communication device. Then, when the vehicle 111 succeeds in the process of establishing a connection with the other vehicle, the vehicle 111 transmits second data, which is different from the first data, among the data to be transmitted, to the other vehicle with which the connection has been established, via the established connection. Note that, when the vehicle 111 fails in the process of establishing a connection with the other vehicle, the vehicle 111 does not transmit the second data. According to this, the vehicle 111 can send out, for example, a part of data that requires real-time characteristics among the data to be transmitted without establishing a connection, and can transmit other data that does not require real-time characteristics among the data to be transmitted through the established connection when the connection is successfully established. According to this, the vehicle 111 can use a combination of communication in a state where a connection is not established and communication in a state where a connection is established, and can transmit a small amount of data quickly when a connection cannot be established, and can transmit, for example, all data to be transmitted by high-speed, large-capacity communication when a connection can be established. Note that the other vehicle may reject a connection request from the vehicle 111, for example, when it is not in a state where it can communicate with a specific communication device (for example, when it is outside the communication range with the device 121), but at that time, it will receive the first data. In this case, the other vehicle that has received the first data may transmit the first data to the specific communication device in response to a state where it is possible to transmit data to the specific communication device.

[0017] In addition, when transmitting the connection request, the vehicle 111 may further transmit the first data and information indicating a condition for the other vehicle that received the request to discard the first data. That is, a long time may pass without the other vehicle that received the first data from the vehicle 111 being able to transmit the first data to a predetermined communication device. In such a case, the data that is held in the other vehicle without being able to transmit may waste storage capacity. In addition, it may be assumed that the data transmitted by the vehicle 111 becomes obsolete within a short period of time after transmission, and is not useful even if it reaches a predetermined communication device after a long time has passed. In consideration of such circumstances, the information indicating the condition includes, for example, information indicating an expiration date. Then, the other vehicle that received the first data discards the first data based on the fact that the expiration date has passed without being able to transmit the first data. In addition, the information indicating the expiration date may be indicated, for example, by the elapsed time from the timing when the first data was transmitted, or may be indicated by information of the time measured by an internal clock. In addition, the information indicating the condition may include, for example, information indicating a geographical range. In this case, if the other vehicle receives the first data and moves beyond the geographical range without being able to transmit the first data, the other vehicle may discard the first data. Note that the information indicating these conditions may be used in combination. Furthermore, the vehicle 111 may transmit information indicating still another condition. The information indicating such a condition can prevent the other vehicle from continuing to hold the first data.

[0018] In one example, the vehicle 111 may execute a connection establishment process for each of one or more other vehicles (other communication devices) capable of relaying communication with a predetermined communication device. At this time, the vehicle 111 may, for example, sequentially transmit a connection establishment request to each of the other vehicles present in the vicinity. At this time, when there are a plurality of other vehicles that are not attempting a connection, the vehicle 111 may not transmit the first data and information on the discard condition of the first data. That is, when there is only one other vehicle that is not attempting a connection, the vehicle 111 may transmit the first data and information on the discard condition together with the connection establishment request, and in other cases, may not transmit the first data and information on the condition. For example, when there is only one other vehicle present in the vicinity that is capable of relaying communication with a predetermined communication device, the vehicle 111 may transmit the connection request, the first data, and information on the discard condition to the other vehicles. On the other hand, when there are two other vehicles around that can relay communication with a predetermined communication device, the vehicle 111 transmits only a connection request to the first other vehicle, and when the first other vehicle rejects the connection request, the vehicle 111 transmits the first data and information on the discard condition to the second other vehicle when transmitting the connection request. In this way, when the vehicle 111 is in a state where it is highly likely that a connection cannot be established with any of the other vehicles, the vehicle 111 transmits a part of the data to be transmitted and information on the discard condition of the part of the data when transmitting the connection request. This allows the vehicle 111 to establish a connection and communicate as much as possible in a state where a connection can be established. Note that, for example, when the vehicle 111 transmits a connection request to a predetermined number of other vehicles and fails to connect, even if there are two or more other vehicles that can relay communication with the predetermined communication device, the vehicle 111 may transmit the first data and information on the discard condition when transmitting the connection request next. That is, the vehicle 111 may transmit the first data and the like together with the connection request before executing the connection establishment process with all the other vehicles. Furthermore, the vehicle 111 may transmit the first data and the like together with the connection request based on the fact that a predetermined period of time has elapsed since the vehicle 111 first started the connection establishment process.This makes it possible to prevent unnecessary execution of many connection establishment processes when there are many other vehicles.

[0019] When the vehicle 111 receives a rejection message from another vehicle in response to the connection request transmitted together with the first data, the vehicle 111 may consider that the other vehicle has received the first data. In other words, in a situation in which the other vehicle cannot interpret the connection request message, a rejection message is not transmitted, and therefore, in a situation in which a rejection message is transmitted, the vehicle 111 may consider that the first data has been received. The vehicle 111 may transmit the first data, etc., when transmitting a connection request, until it receives a rejection message in response to the connection request transmitted together with the first data.

[0020] It is assumed that the vehicle 111 periodically transmits data for a predetermined control, for example. In this case, the vehicle 111 may transmit the periodically transmitted data as the above-mentioned first data. At this time, the other vehicle that receives the first data may transfer the first data to the predetermined communication device in response to a situation in which data transmission to the predetermined communication device is possible. Therefore, for example, the first data transmitted earlier may reach the predetermined communication device later than another first data transmitted later. Therefore, when the predetermined communication device receives a plurality of first data, the vehicle 111 may also transmit information corresponding to the order of the first data (for example, a serial number) so that the data can be sorted in chronological order. This allows the predetermined communication device to appropriately rearrange and use the received plurality of first data when the first data has a meaning in chronological order.

[0021] In the above example, the vehicle 111 has been described as the focus, but the vehicles 112 to 114 can also execute the same process when they themselves request the transfer of data to another device. The configuration and operation of the vehicles 111 to 114 that execute such a process will be described below.

[0022] (Device configuration) FIG. 2 shows an example of the hardware configuration of the communication device provided in the vehicle 111 to vehicle 114 of this embodiment. Note that FIG. 2 shows an example of the hardware configuration of the communication device part according to this embodiment, and other configurations such as the configuration of the vehicle of the vehicle 111 to vehicle 114 are omitted from the illustration. In one example, the communication device is configured to include a general-purpose computer, and the computer has, for example, a CPU 201, a memory 202, a storage device 203, a communication circuit 204, and an input / output circuit 205. For example, the CPU 201 executes a program stored in the memory 202 to execute processes described below and control the entire device. Note that the CPU 201 can be replaced by any one or more processors such as an MPU or an ASIC. The memory 202 holds a program for causing the communication device to execute various processes, and also functions as a work memory when the program is executed. In one example, the memory 202 is a RAM (random access memory) or a ROM (read only memory). The storage device 203 is, for example, a removable external storage device or a built-in hard disk drive, and holds various information. The communication circuit 204 executes signal processing related to communication, acquires various information from an external device through a communication network, and transmits various information to the external device. The information acquired by the communication circuit 204 may be stored in, for example, the memory 202 or the storage device 203. The communication device may have a plurality of communication circuits 204. The input / output circuit 205 controls, for example, the output of screen information to be displayed on a display device (not shown) and audio information to be output from a speaker, and the reception of user input via a keyboard, a pointing device, or the like. The input / output circuit 205 may control a device that performs input and output in an integrated manner, such as a touch panel. The configuration of FIG. 2 is an example, and the communication device may have dedicated hardware that executes the above-mentioned processing, for example.

[0023] 3 shows an example of the functional configuration of a communication device provided in vehicles 111 to 114 of this embodiment. The communication device has, as its functions, for example, a connection establishment processing unit 301, a data setting unit 302, and a condition setting unit 303. Note that these functional units may be embodied by, for example, CPU 201 executing a program stored in memory 202 or storage device 203, or may be embodied by dedicated hardware.

[0024] The connection establishment processing unit 301 executes a process for establishing a connection with another communication device (another vehicle) that relays communication between the device itself and a predetermined communication device such as a server on the Internet. The connection establishment processing unit 301, for example, transmits a connection establishment request to the other device and establishes a connection based on receiving a response indicating that the connection establishment request has been accepted by the other device. Note that this connection establishment process is performed according to a procedure defined in a communication standard used between the device itself and the other device. However, in this embodiment, the connection process includes a procedure in which the connection establishment processing unit 301 transmits a connection establishment request message to the other device. Note that, in one example, the connection establishment process may include a procedure for transmitting a response message to a message such as a connection request from the other device. That is, the connection establishment process necessarily includes a procedure for transmitting some kind of message to the other device to which the connection is to be made. Note that some kind of message transmitted in the connection establishment process can be treated in the same way as the above-mentioned connection establishment request. That is, together with any of these messages, a part of the data to be transmitted and information regarding the conditions for discarding the data may be transmitted.

[0025] The data setting unit 302 sets data to be transmitted to another device. The data setting unit 302 selects and sets data to be actually transmitted to another device from among the data to be transmitted. In one example, the data setting unit 302 may select information to be transmitted to a specific communication device early, such as information for controlling a vehicle, as data to be transmitted together with a connection request. At this time, the data setting unit 302 selects data having a size not exceeding a predetermined size as data to be transmitted together with a connection request. That is, the data setting unit 302 selects partial data having a size not exceeding a predetermined size from among the data to be transmitted as data to be transmitted together with a connection request. The data setting unit 302 may divide the data to be transmitted to generate a plurality of pieces of data not exceeding a predetermined size, and transmit the partial data obtained by the division every time a connection request is made. For example, the data setting unit 302 may generate information (e.g., a serial number or time information) capable of identifying the order of the divided data or data whose order is significant, and set the information as auxiliary information of the data. Furthermore, the data setting unit 302 sets data to be transmitted, which is different from the partial data transmitted together with the connection request, to the other device when a connection with the other device is established by, for example, the connection establishment processing unit 301. In one example, the data setting unit 302 can set all data that has not been transmitted during the connection request processing as data to be transmitted after the connection is established.

[0026] When partial data is transmitted together with a connection request, the condition setting unit 303 sets information regarding a condition for another device that receives the partial data to discard the partial data. The information regarding the condition may include, for example, information regarding a validity period and information regarding a geographical range.

[0027] Various options and the like related to processing when a communication device makes a connection request have been described above, and will not be repeated here.

[0028] (Processing flow) Next, an example of the flow of processing executed in the wireless communication system will be described with reference to Figs. 4 to 6. Since the details of information transmitted and received in each process described below are as described above, the description here will only outline the flow of processing, and will not repeat detailed description. This processing is embodied, for example, by CPU 201 of a communication device provided in vehicle 111 executing a program stored in memory 202 or storage device 203. Here, the flow of processing when vehicle 111 executes connection establishment processing to request vehicle 112 to relay will be described. However, this is just an example, and similar processing can be performed when vehicles 112 to 114 execute connection establishment processing with other connection destination vehicles to request relay.

[0029] 4 to 6, vehicle 111 transmits a connection request to vehicle 112, and at that time transmits partial data that is a part of the data to be transmitted, and information on the conditions under which the partial data should be discarded (S401). In addition, in Fig. 4 and Fig. 5, vehicle 112 rejects the connection request for a reason such as a state in which a connection with device 121 cannot be established (S402). In this case, vehicle 112 holds the partial data that was received when receiving this connection request, and information on the conditions for discarding the partial data.

[0030] 4, it is assumed that the vehicle 112 then establishes a connection with the device 121, for example, in response to moving to a position where the vehicle 112 can connect to the device 121 (S403). When this connection is established, the vehicle 112 transmits the partial data held by the vehicle 112 to the device 121 (S404). This allows data that is generated in the vehicle 111 and should be transmitted to a specific communication device within a short period of time to the specific communication device (via the device 121) even if a connection cannot be established.

[0031] 5, it is assumed that the condition for discarding data is met when, for example, the validity period indicated as a condition has elapsed without being able to establish a connection with the device 121, or the vehicle 112 has moved beyond a geographical range indicated as a condition (S501). In this case, the vehicle 112 discards the data without transferring the data to a predetermined communication device (S502). This makes it possible to prevent the vehicle 112 from holding the data received from the vehicle 111 for an unnecessarily long period of time.

[0032] In FIG. 6, it is assumed that the vehicle 112 accepts the connection request received from the vehicle 111 and permits the connection (S601). After that, various processes for establishing a connection are executed between the vehicles 111 and 112, but in FIG. 6, the processes are omitted from the illustration in order to simplify the explanation. In this case, the vehicle 111 transfers the remaining data, which is different from the partial data transmitted in S401, of the data to be transmitted to the vehicle 112 through the established connection (S602). Then, the vehicle 112 transmits all of the received data to the device 121, with a specific communication device as the destination, through the connection established with the device 121 (S603). In this way, when the vehicle 111 can establish a connection with the vehicle 112 that can relay its own communication, it can transmit a relatively large amount of data in a stable communication environment.

[0033] In one example, the vehicle 111 may transmit data for an application that requires real-time performance in a state where a connection is not established when a connection request is transmitted, and transmit data for an application that does not require real-time performance in a state where a connection is established. For example, the vehicle 111 may transmit data collected by a sensor for autonomous driving together with a connection request, and transmit data that does not require immediacy, such as data for vehicle maintenance, after the connection is established. In this way, by determining whether to transmit data without waiting for the connection to be established or to transmit data after the connection is established depending on the use of the data, it is possible to provide a service that efficiently uses communication to the vehicle.

[0034] <Summary of the embodiment> 1. The communication device according to this embodiment is The communication device includes an execution unit that executes a process of establishing a connection with another communication device that relays communication with the predetermined communication device, When sending a connection request to the other communication device, the execution means transmits to the other communication device, together with the request, first data that is part of the data to be sent to the specified communication device, and information indicating the conditions for the other communication device to discard the first data.

[0035] According to this embodiment, even if a communication device fails to establish a connection with a counterpart device that relays communication with a specific communication device, it is possible to transmit a part of the data to be transmitted to the counterpart device. Then, when the counterpart device becomes able to transmit the part of the data to the specific communication device, the part of the data is transmitted, thereby completing communication from the communication device to the specific communication device. On the other hand, when the counterpart device is not able to transmit data to the specific communication device, it can discard the part of the data it received based on the discarding conditions. This makes it possible to prevent the counterpart device from holding data for a long period of time and wasting storage capacity even though it is not able to transmit data to the specific communication device.

[0036] 2. In the above embodiment 1, If the establishment of a connection with the other communication device based on the request is successful, second data, which is different from the first data among the data to be transmitted to the specified communication device, is transmitted to the other communication device.

[0037] According to this embodiment, in a situation where a connection with a partner device can be established, it is possible to transmit not only a part of the data to be transmitted, but all of the data.

[0038] 3. In the above embodiment 2, If the establishment of a connection with the other communication device based on the request is not successful, the second data of the data to be transmitted to the specified communication device is not transmitted to the other communication device.

[0039] According to this embodiment, in an environment where a connection with a partner device cannot be established, for example, only data that requires real-time transmission is transmitted, and data that does not require real-time transmission and can be deferred for transmission at a later opportunity.

[0040] 4. In any one of the above embodiments 1 to 3, When there is no second other communication device different from the other communication device that can relay communication with the specified communication device, the execution means transmits the request, the first data, and information indicating the condition to the other communication device.

[0041] According to this embodiment, when there is no other device capable of relaying communication with a specific communication device, additional data is transmitted together with the connection request. Therefore, when a connection can be established with another device capable of relaying, it is possible to prevent unnecessary transmission of additional data when transmitting the connection request. This makes it possible to suppress deterioration of frequency utilization efficiency.

[0042] 5. In the above embodiment 4, When the second other communication device exists and the request has not been sent to the second other communication device, the execution means sends the request to the other communication device and does not send the first data and information indicating the condition to the other communication device.

[0043] According to this embodiment, when there is a possibility of establishing a connection with another device capable of performing relay, the establishment of the connection with the device is prioritized, and it is possible to prevent unnecessary transmission of additional data when transmitting a connection request, thereby suppressing deterioration of frequency utilization efficiency.

[0044] 6. In the above embodiment 4 or 5, When there are one or more second other communication devices and the request has been sent to each of the one or more second other communication devices but a connection has not been established, the execution means transmits the request, the first data, and information indicating the condition to the other communication devices.

[0045] According to this embodiment, when a connection cannot be established with another device capable of performing relaying, data is transmitted along with a connection request, thereby reducing the frequency with which data is transmitted without a connection being established and suppressing deterioration in frequency utilization efficiency.

[0046] 7. In any of the above embodiments 1 to 6, The information indicating the condition includes information indicating an expiration date, and the first data is discarded if the expiration date has passed without the first data being transmitted from the other communication device.

[0047] According to this embodiment, the data received in addition to the connection request can be discarded in the other communication device after a certain period of time has elapsed, thereby preventing the data from being held without being able to be sent to a specific communication device.

[0048] 8. In any of the above embodiments 1 to 7, The information indicating the condition includes information indicating a geographical range, and if the other communication device leaves the geographical range without transmitting the first data, the first data is discarded.

[0049] According to this embodiment, in other communication devices, data received in addition to a connection request can be discarded when the data moves beyond a specified range, thereby preventing the data from being held without being able to be sent to a specified communication device.

[0050] 9. In any of the above embodiments 1 to 8, When the execution means transmits a plurality of the first data to one or more other communication devices, it generates information corresponding to an order of each of the plurality of the first data, and transmits the information corresponding to the order to the other communication devices together with the request.

[0051] According to this embodiment, when data having a significance in order is transmitted, the receiver can specify the order in which the data was transmitted. In other words, the timing at which the data will be transmitted to the specified communication device is unknown in the other communication device. Therefore, when multiple data are transmitted to the other communication device at multiple transmission timings and then transferred to the specified communication device, the specified communication device can sort the received data in chronological order.

[0052] 10. In any of the above embodiments 1 to 9, The communication device and the other communication device are vehicles.

[0053] According to this embodiment, the communication device can transmit certain data to other vehicles while driving, for example, and when the other vehicles are able to establish a connection with a specific communication device, the data can be transferred to them.

[0054] 11. The communication method according to this embodiment is 1. A communication method performed by a communication device, comprising: Executing a process of establishing a connection with another communication device that relays communication with the predetermined communication device; In the connection establishment process, when sending a connection request to the other communication device, first data that is part of the data to be sent to the specified communication device and information indicating the conditions for the other communication device to discard the first data are sent to the other communication device together with the request.

[0055] According to this embodiment, even if a communication device fails to establish a connection with a counterpart device that relays communication with a specific communication device, it is possible to transmit a part of the data to be transmitted to the counterpart device. Then, when the counterpart device becomes able to transmit the part of the data to the specific communication device, the part of the data is transmitted, thereby completing communication from the communication device to the specific communication device. On the other hand, when the counterpart device is not able to transmit data to the specific communication device, it can discard the part of the data it received based on the discarding conditions. This makes it possible to prevent the counterpart device from holding data for a long period of time and wasting storage capacity even though it is not able to transmit data to the specific communication device.

[0056] 12. The program according to this embodiment is A program for causing a computer included in a communication device to execute a process for establishing a connection with another communication device that relays communication with a predetermined communication device, In the connection establishment process, when a connection request is sent to the other communication device, first data that is part of the data to be sent to the specified communication device and information indicating the conditions for the other communication device to discard the first data are sent to the other communication device together with the request.

[0057] According to this embodiment, even if a communication device fails to establish a connection with a counterpart device that relays communication with a specific communication device, it is possible to transmit a part of the data to be transmitted to the counterpart device. Then, when the counterpart device becomes able to transmit the part of the data to the specific communication device, the part of the data is transmitted, thereby completing communication from the communication device to the specific communication device. On the other hand, when the counterpart device is not able to transmit data to the specific communication device, it can discard the part of the data it received based on the discarding conditions. This makes it possible to prevent the counterpart device from holding data for a long period of time and wasting storage capacity even though it is not able to transmit data to the specific communication device.

[0058] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. 1. A communication device, comprising: The communication device includes an execution unit that executes a process of establishing a connection with another communication device that relays communication with the predetermined communication device, when transmitting a connection request to the other communication device, the execution means transmits, together with the request, first data that is a part of data to be transmitted to the predetermined communication device, and information indicating a condition for the other communication device to discard the first data, to the other communication device; The execution means of the communication device transmits the request, the first data, and information indicating the condition to the other communication device when there is no second other communication device different from the other communication device that can relay communication with the specified communication device.

2. A communication device, The communication device includes an execution unit that executes a process of establishing a connection with another communication device that relays communication with the predetermined communication device, when transmitting a connection request to the other communication device, the execution means transmits, together with the request, first data that is a part of data to be transmitted to the predetermined communication device, and information indicating a condition for the other communication device to discard the first data, to the other communication device; The information indicating the condition includes information indicating a geographical range, and if the other communication device moves beyond the geographical range without transmitting the first data, the first data is discarded.

3. The communication device according to claim 1 or 2, wherein if a connection with the other communication device based on the request is successfully established, second data different from the first data among the data to be transmitted to the specified communication device is transmitted to the other communication device.

4. The communication device according to claim 3, wherein if a connection with the other communication device based on the request is not successfully established, the second data among the data to be transmitted to the specified communication device is not transmitted to the other communication device.

5. The communication device according to claim 1, wherein the execution means, when the second other communication device exists and the request has not been sent to the second other communication device, sends the request to the other communication device and does not send the first data and information indicating the condition to the other communication device.

6. The communication device according to claim 1 or 5, wherein, when there are one or more second other communication devices and the request has been sent to each of the one or more second other communication devices but a connection has not been established, the execution means transmits the request, the first data, and information indicating the condition to the other communication devices.

7. The communication device according to claim 1 , wherein the information indicating the condition includes information indicating an expiration date, and the first data is discarded if the expiration date has elapsed without the first data being transmitted from the other communication device.

8. 8. The communication device according to claim 1, wherein when the execution means transmits a plurality of the first data to one or more other communication devices, the execution means generates information corresponding to an order of each of the plurality of the first data, and transmits the information corresponding to the order to the other communication devices together with the request.

9. The communication device according to claim 1 , wherein the communication device and the other communication device are vehicles.

10. 1. A communication method performed by a communication device, comprising: Executing a process of establishing a connection with another communication device that relays communication with the predetermined communication device; In the connection establishment process, when transmitting a connection request to the other communication device, first data that is a part of data to be transmitted to the predetermined communication device and information indicating a condition for the other communication device to discard the first data are transmitted to the other communication device together with the request; A communication method, when there is no second other communication device different from the other communication device that can relay communication with the specified communication device, transmitting the request, the first data, and information indicating the condition to the other communication device.

11. A communication method performed by a communication device, comprising: Executing a process of establishing a connection with another communication device that relays communication with the predetermined communication device; In the connection establishment process, when transmitting a connection request to the other communication device, first data that is a part of data to be transmitted to the predetermined communication device and information indicating a condition for the other communication device to discard the first data are transmitted to the other communication device together with the request; A communication method, wherein the information indicating the condition includes information indicating a geographical range, and if the other communication device moves beyond the geographical range without transmitting the first data, the first data is discarded.

12. A program for causing a computer provided in a communication device to execute the communication method described in claim 10 or 11.

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