Communication device, communication method, and communication program

Abstract

A communication device (100) is capable of performing communication with a partner device using a single or a plurality of communication lines in order to transmit a packet received from a transmission source device to a transmission destination device, and comprises: a reception unit (101) that receives a packet from the transmission source device; a required characteristic determination unit (103) that determines a required characteristic required for communication on the basis of transmission source device information and transmission destination device information specified from the packet; a policy determination unit (105) that determines a policy which is a combination of communication lines to be used on the basis of the required characteristic; and a plurality of transmission units (107) that distribute and transmit the packet to each communication line on the basis of the policy. The policy determination unit determines the policy from among simple transmission that uses a single communication line, band synthesis transmission that transmits the packet to the plurality of communication lines by distribution, and redundant transmission that transmits the same packet by the plurality of communication lines.

Description

Communication device, communication method, and communication program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-105267, filed on June 28, 2024, the contents of which are incorporated herein by reference.

[0002] The present application relates to a communication device or the like that transmits data using one or more communication lines, and relates to a communication device or the like that transmits application data to a server using one or more communication lines from a communication device mounted on a mobile object such as an automobile.

[0003] When transmitting data from a communication device, if a multi-link communication device that simultaneously uses multiple lines is used, the data transmission time can be shortened.

[0004] With the aim of improving this speed, for example, Patent Document 1 describes a multi-link communication device that allocates communications according to the effective transmission speed of each line, thereby realizing efficient multi-link communication with low latency overall without causing excessive delays or placing excessive loads on each line.

[0005] Japanese Patent Application Laid-Open No. 2000-216815

[0006] Here, the inventors have found the following problem as a result of detailed investigation. According to Patent Document 1, since the characteristics of the communication path other than the effective transmission speed of each line are not taken into consideration, it is not possible to deal with cases where other characteristics take priority over the priority of the data transmission time. For example, when transmitting data that is sensitive to packet loss, it is more desirable to use a line with a low packet loss rate than a line with a high communication speed.

[0007] The present disclosure aims to realize a method for allocating packets to communication lines suitable for transmission, taking into consideration required characteristics, which are communication characteristics required by the packets to be transmitted.

[0008] A communication device according to one aspect of the present disclosure is a communication device capable of communicating with a counterpart device connected to a destination device using one or more communication lines in order to transmit a packet containing data received from the source device to the destination device, and includes: a receiving unit that receives the packet from the source device; a required characteristics determination unit that determines the required characteristics for the communication based on source device information indicating the source device identified from the packet and destination device information indicating the destination device identified from the packet; a strategy determination unit that determines a strategy, which is a combination of one or more of the communication lines to be used for the communication, based on the required characteristics; a transmission control unit that allocates the packet to each communication line based on the strategy; and multiple transmission units connected to each communication line and that transmit the packets, wherein the strategy determination unit determines the strategy from among simple transmission, which transmits the packet using a single communication line; bandwidth synthesis transmission, which allocates the packet to multiple communication lines and transmits it; and redundant transmission, which transmits the same packet over multiple communication lines.

[0009] It should be noted that the numbers in parentheses in the claims indicate the correspondence between the present invention and the embodiments described below, and are not intended to limit the present invention.

[0010] With the above-described configuration, the communication device etc. disclosed herein determines required characteristics for communication based on source device information and destination device information, and distributes packets to each communication line based on these required characteristics, thereby enabling multi-link communication suitable for the type of packet, the type of data contained in the packet, etc. Furthermore, since the communication device etc. disclosed herein determines a strategy from simple transmission, bandwidth synthesis transmission, and redundant transmission, it is possible to determine the optimal strategy for each control method of multiple communication lines.

[0011] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an explanatory diagram illustrating an overall configuration including a communication device 100 according to each embodiment, Fig. 2 is an explanatory diagram illustrating the layout of the communication device 100 according to each embodiment, Fig. 3 is a block diagram illustrating an example configuration of the communication device 100 according to a first embodiment, Fig. 4 is an explanatory diagram illustrating a method for determining required characteristic information according to the first embodiment and its contents, Fig. 5 is an explanatory diagram illustrating an example of required characteristic information according to the first embodiment, Fig. 6 is an explanatory diagram illustrating an example of line characteristic information according to the first embodiment, Fig. 7 is an explanatory diagram illustrating an example of information relating to a method for calculating an index of line characteristics for each control method according to the first embodiment, and Fig. 8 is an explanatory diagram illustrating the order of search for a control method according to the first embodiment. 9 is an explanatory diagram for explaining an example of the configuration of the counterpart device 200 of embodiment 1, FIG. 10 is a flow diagram for explaining the operation of the communication device 100 of embodiment 1, FIG. 11 is a flow diagram for explaining a method for determining required characteristics of the communication device 100 of embodiment 1, FIG. 12 is a flow diagram for explaining a method for determining a strategy for the communication device 100 of embodiment 1, FIG. 13 is a flow diagram for explaining a method for determining a strategy when the control method is bandwidth synthesis transmission in the communication device 100 of embodiment 1, and FIG. 14 is a flow diagram for explaining a method for determining a strategy when the control method is bandwidth synthesis transmission in the communication device 100 of embodiment 1.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] The present invention described below refers to the invention described in the claims and is not limited to the following embodiments. Furthermore, at least the words in double quotation marks refer to the words described in the claims and are not limited to the following embodiments.

[0014] The configurations and methods recited in the dependent claims are optional configurations and methods in the inventions recited in the independent claims. The configurations and methods of the embodiments corresponding to the configurations and methods recited in the dependent claims, as well as the configurations and methods recited only in the embodiments without being recited in the claims, are optional configurations and methods in the present invention. The configurations and methods recited in the embodiments when the recitation of the claims is broader than the recitation of the embodiments are also optional configurations and methods in the present invention, in the sense that they are examples of the configurations and methods of the present invention. In either case, by being recited in the independent claims, they become essential configurations and methods of the present invention.

[0015] The effects described in the embodiments are effects obtained when the configurations of the embodiments are provided as examples of the present invention, and are not necessarily effects that the present invention has.

[0016] When there are multiple embodiments (including examples and modifications, the same applies in this paragraph), the configurations disclosed in each embodiment are not limited to each embodiment, but can be combined across the embodiments. For example, a configuration disclosed in one embodiment may be combined with another embodiment. Also, configurations disclosed in multiple embodiments may be collected and combined.

[0017] The problems described in this disclosure are not publicly known problems, but have been independently discovered by the inventors, and together with the configuration and method of this disclosure, these facts affirm the inventive step of the invention.

[0018] 1. Configuration Prerequisite for the Embodiments (Overall Configuration and Arrangement of Communication Devices) The arrangement of the communication device 100 of each embodiment will be described using FIGS. 1 and 2. First, an example of the overall configuration including the communication device 100 of each embodiment will be described using FIG. 1. This example illustrates a case where data is transmitted from a first terminal device 10(N) (N: an integer assigned to each first terminal device) to a second terminal device 20(M) (M: an integer assigned to each second destination device). The first terminal device 10(N) (corresponding to the "source device") divides data generated or acquired by the first terminal device 10(N) into multiple packets and outputs them to a client device. The client device (corresponding to the "communication device") distributes the multiple packets received from the first terminal device 10(N) to one or more communication lines (1 to L) (L: the total number of communication lines) and transmits them to a server device (corresponding to the "counterparty device"). The server device rearranges multiple packets received from one or more communication lines to restore the original data, and transmits them to a second terminal device 20 (M) (corresponding to the "destination device"), which is the destination specified by the first terminal device 10 (N).

[0019] Packets transmitted from a client device are assigned a first sequence number, which is a number incremented in the order of packets transmitted for each communication line, and a second sequence number, which is a number incremented in the order of packets constituting the data for each data flow. The data flow is identified based on, for example, the IP address and port number of the first terminal device 10(N) as the source (together referred to as "source device information") and the IP address and port number of the second terminal device 20(M) as the destination (together referred to as "destination device information"). In addition, a line number identifying the line and a flow identification number identifying the flow may be included. This allows the server device to restore the data order of packets received from the client device based on the second sequence number, etc., and transmit them to the second terminal device 20(M).

[0020] The multiple communication lines may be communication lines using the same communication method or communication lines using different communication methods. For example, examples of wireless communication lines include IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), W-CDMA (Wideband Code Division Multiple Access), HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution), LTE-A (Long Term Evolution Advanced), 4G, 5G, etc., or DSRC (Dedicated Short Range Communication). In each embodiment, it is assumed that all of the multiple communication lines are wireless communication lines, but some or all of them may be wired communication lines. Examples of wired communication lines include LANs (Local Area Networks) such as Ethernet (registered trademark), the Internet, optical fiber lines, and fixed telephone lines.

[0021] Specific examples of the first terminal device 10(N) and the second terminal device 20(M) will be described later in the embodiments using FIG. 4. The term "terminal" for the first terminal device 10(N) and the second terminal device 20(M) refers to the starting point and ending point for data generation and usage, and does not limit the form of the device. For example, even a large-scale server device can be called a terminal device for data generation or usage. The client device distributes and transmits multiple packets to one or more communication lines, and the method of distribution will be described in each embodiment.

[0022] The first terminal device 10(N) and the client device may be integrated. Also, in this example, the first terminal device 10(N) divides data into multiple packets and outputs them to the client device, but the client device may receive data from the first terminal device 10(N) and divide it into multiple packets. Also, the second terminal device 20(M) and the server device may be integrated.

[0023] In this example, when data is transmitted from a client device to a server device using an uplink, the client device corresponds to the communication device 100 in each embodiment, and the server device corresponds to the counterpart device 200. In this case, the first terminal device 10(N) corresponds to the source device in each embodiment, and the second terminal device 20(M) corresponds to the destination device in each embodiment. Conversely, when data is transmitted from a server device to a client device using a downlink, the server device corresponds to the communication device 100 in each embodiment, and the client device corresponds to the counterpart device 200. In this case, the second terminal device 20(M) corresponds to the source device in each embodiment, and the first terminal device 10(N) corresponds to the destination device in each embodiment. In either case, the communication device 100 and the counterpart device 200 together constitute the communication system 1 in each embodiment. In the following description, an example will be described in which an uplink is used. In the embodiments described below, the first terminal device 10(N) is referred to as the source device, and the second terminal device 20(M) is referred to as the destination device.

[0024] Next, a case where the communication device 100 is mounted on a vehicle will be described using FIG. 2 . The communication device 100 is included in an electronic control system S consisting of multiple electronic control units (ECUs) mounted on a vehicle, which is a "mobile body," and is responsible for communication inside and outside the vehicle. The communication device 100 stores data generated by an application running on the ECU or data acquired by a sensor in multiple packets and transmits the packets to a counterpart device 200 outside the vehicle. In this case, the ECU or sensor corresponds to the "transmitting device." Note that the communication device 100 itself may also be in the form of an ECU, such as a communication ECU or a TCU (Telematics Control Unit) with a communication module. Here, a "mobile body" refers to a movable object, and may move at any speed. This also naturally includes a stationary moving body. Examples include, but are not limited to, automobiles, motorcycles, bicycles, pedestrians, ships, aircraft, and objects mounted on these. "Mounted" includes not only cases where the device is directly fixed to the moving body, but also cases where the device is not fixed to the moving body but moves along with the moving body. For example, it may be carried by a person riding on a moving object, or may be carried on cargo placed on a moving object.

[0025] The counterpart device 200 transmits the received data to, for example, an application server (corresponding to a "destination device"), and the application server then executes various applications using the received data.

[0026] In each embodiment, the communication device 100 can perform communication in parallel using, for example, multiple 5G lines operated by different communication carriers, or can perform communication in parallel using communication lines of wireless communication methods including 5G, 4G, and Wi-Fi. Of course, the types and number of communication lines are arbitrary.

[0027] The data transmitted from the communication device 100 to the counterpart device 200 may include, but is not limited to, image information acquired by an in-vehicle camera or location information acquired by a GPS sensor. In addition to data, the object to be transmitted may also be software or a program itself.

[0028] 2 illustrates a case in which the communication device 100 is mounted on a vehicle and the counterpart device 200 is installed outside the vehicle, but the locations where the communication device 100 and the counterpart device 200 are installed are not limited to this. That is, the communication device 100 may not be mounted on a vehicle, but may be installed, for example, inside a building or outdoors. The counterpart device 200 may also be mounted on a vehicle. Of course, the communication device 100 and the counterpart device 200 do not have to be mounted on both vehicles, and may be mounted on different vehicles, or both may be mounted on the same vehicle. When mounted on different vehicles, the communication device 100 and the counterpart device 200 may communicate with each other using, for example, vehicle-to-vehicle communication.

[0029] 3 is a block diagram showing the configuration of the communication device 100 according to this embodiment. The communication device 100 includes a first receiving unit 101, a required characteristic information storage unit 102, a required characteristic determination unit 103, a line characteristic information storage unit 104, a strategy determination unit 105, a transmission control unit 106, second transmitting units 107-1 to 107-L, second receiving units 108-1 to 108-L, a reception control unit 109, a first transmitting unit 110, a line characteristic information update unit 111, and a line characteristic information change unit 112.

[0030] Communication device 100 is a device capable of communicating with counterpart device 200 "connected" to a destination device using one or more communication lines in order to transmit packets containing data received from a source device to the destination device. With regard to packets that communication device 100 transmits to counterpart device 200, data received from the source device may be stored in multiple packets by communication device 100 or another device, or data may be stored in multiple packets by the source device. Here, "connected" includes not only direct connection but also indirect connection via several devices.

[0031] The communication device 100 can be configured with a general-purpose CPU (Central Processing Unit), volatile memory such as RAM, non-volatile memory such as ROM, flash memory, or hard disk, various interfaces, and an internal bus connecting these. The communication device 100 can be configured to perform the functions of each functional block shown in Figure 3 by executing software on this hardware.

[0032] The first receiving unit 101 (corresponding to the "receiving unit") receives a packet from the source device. When packets are generated within the communication device 100 rather than in the source device, data received from the source device is stored in a packet in a packet storage unit (not shown) provided in front of the first receiving unit 101, and the packet output from the packet storage unit is received by the first receiving unit 101. Even in this case, from the perspective of the first receiving unit 101, it can be said that a packet has been received from the first terminal device 10(N).

[0033] The required characteristic information storage unit 102 stores required characteristic information that links source device candidates and destination device candidates with required characteristic candidates. The required characteristic information storage unit 102 may be a volatile memory such as a RAM, or a non-volatile memory such as a flash memory or a hard disk.

[0034] The method for defining the required characteristic information and its contents will be explained using Figure 4. Generally, there may be multiple types of data used by a destination device. In such cases, the type of data can be identified by the combination of the source device and the destination device. For example, if a remote driving application that controls a vehicle in real time while viewing camera footage from a remote location is running on a server device, video data and location information are transmitted from the vehicle to the server device. In this case, the destination device for the video data and location information is the server device, while the source device for the video data is the camera or an ECU that manages the camera footage, and the source device for the location information is the GPS or an ECU that manages the location information.

[0035] For example, in a remote driving application, control is primarily performed using camera footage, and location information is used as supplementary information to complement the camera footage. In this case, since video data is large and requires real-time performance, wide bandwidth and low latency are desirable, but packet loss is acceptable as long as it does not distort the screen. Therefore, the candidate required characteristics are determined as follows: speed 15 Mbps, latency 120 ms, and success rate 90%. The success rate is the probability of successful transmission and reception, and is calculated by subtracting the packet loss rate from 100%. In contrast, since location information is small in size, a low communication speed is not a problem, but since it complements the camera footage, real-time performance similar to that of video data is required. Since small-sized data is generally more susceptible to data loss, packet loss should be kept as low as possible. Therefore, the candidate required characteristics are determined as follows: speed 2 Mbps, latency 120 ms, and success rate 95%.

[0036] Using yet another example, the method and content of the required characteristic information will be described. For example, in the case of a remote conference system, video data and audio data are transmitted from the terminal device of a participant participating in a conference to a server device, and the server device executing the remote conference system receives the data and forwards it to the terminal devices of other participants. In this case, the destination device for the video data and audio data is the server device or the terminal device of the other participant, such as a personal computer or smartphone, while the source device for the video data is a camera or the personal computer or smartphone of the participant who manages the video data, and the source device for the audio data is a microphone or the personal computer or smartphone of the participant who manages the audio data.

[0037] The remote conference system shares the same commonality as the remote driving application in the previous example in that it uses camera footage, but the video data in the remote conference system can be less real-time than that of the remote driving application, and some degree of screen disturbance is acceptable. Therefore, the candidate required characteristics are set to a speed of 10 Mbps, a delay of 200 ms, and a success rate of 85%. In contrast, audio data is smaller in size than video data, so a lower communication speed is not a problem. However, due to the nature of conferences, real-time performance is required to ensure smooth conversation, and audio interruptions are unacceptable. However, a lack of synchronization with the video does not pose a major problem. Therefore, the candidate required characteristics are set to a speed of 4 Mbps, a delay of 100 ms, and a success rate of 95%.

[0038] Another example is a big data analysis application that collects various sensor data and logs from a vehicle and performs statistical processing. In this case, the destination device for the logs is a server device, and the source device for the logs is a security sensor or an ECU that manages the logs. Since logs are data used for statistical processing, the requirements for speed and latency can be relaxed, but packet loss should be small because it affects the results of the statistical processing. Furthermore, since a huge amount of data needs to be transmitted, communication costs should be as low as possible. Therefore, the candidate required characteristics are set as follows: a speed of 7 Mbps, a latency of 300 ms, a success rate of 95%, and a communication cost of 2 yen / GB or less.

[0039] FIG. 5 is a diagram showing a specific example of the content of required characteristic information. As shown in FIG. 4, FIG. 5 associates and stores required characteristic candidates with predetermined source device candidates and destination device candidates. In FIG. 5, the source device candidate is recorded with the address and port of the source device, the destination device candidate is recorded with the address and port of the destination device, and protocol candidates, which are protocols used for communication. Then, the source device candidate and the destination device candidate are associated with required characteristic candidates, which indicate required characteristics required for communication between the source device candidate and the destination device candidate. In FIG. 5, speed (Mbps), delay (ms), success rate (%), and other indices are recorded as indicators of the required characteristic candidates. Of course, this is merely an example, and other indices may be recorded as required characteristic candidates. Instead of the success rate (%), a packet loss rate (%) may be recorded.

[0040] 5 , in accordance with the example described at the beginning of FIG. 4 , the address (x.x.x.x) and port number (100) of the ECU that manages the camera video (the source device), the address (a.a.a.a) and port number (100) of the server device that is the destination device, and the required characteristics required by the protocol (TCP) are recorded, including speed (15 Mbps), delay (120 ms), and success rate (90%). Also, the address (y.y.y.y) and port number (100) of the ECU that manages the location information (the source device), the address (a.a.a.a) and port number (200) of the server device that is the destination device, and the required characteristics required by the protocol (TCP) are recorded, including speed (2 Mbps), delay (120 ms), and success rate (95%).

[0041] Note that Figure 5 shows an example in which both source device candidates and destination device candidates are recorded, but if the required characteristics can be determined using only the source device candidates or only the destination device candidates, it is also possible to record only either the source device candidates or the destination device candidates.

[0042] In Fig. 5, the source device candidates, destination device candidates, protocol candidates, and required characteristic candidates defined as in Fig. 4 are recorded, but in addition, rows recording only protocol candidates and required characteristic candidates, and rows recording only required characteristic candidates, such as the bottom three rows in Fig. 5, are also included. How to use this will be described later in the section on required characteristic determination unit 103.

[0043] 5 indicates limit values, and therefore, in addition to a predetermined value, information such as "above" or "below" is added.

[0044] The required characteristics determination unit 103 determines required characteristics for communication to transmit a packet to the other device 200 based on the packet received by the first receiving unit 101. More specifically, the required characteristics for communication are determined based on source device information indicating a source device "identified" from the packet received by the first receiving unit 101 and destination device information indicating a destination device "identified" from the packet. Furthermore, the required characteristics may be determined based on a protocol "identified" from the packet. Methods for obtaining source device information and destination device information from a packet include, for example, using information indicating a source device or a destination device included in the received packet. Furthermore, the protocol may be obtained using information indicating a protocol included in the received packet. Alternatively, the source device information and destination device information may be estimated from the type of data included in the packet, the protocol used, the packet frame structure, and the packet transmission and reception time. Here, "identified" includes not only cases where the information included in the packet is directly or indirectly used to identify the device, but also cases where the information other than the information included in the packet, such as the packet structure or the packet transmission and reception time, is used to identify the device.

[0045] According to this embodiment, the required characteristics determination unit 103 determines required characteristics using required characteristics information stored in the required characteristics information storage unit 102 as shown in Fig. 5. For example, if the source device information included in the packet is an address (x.x.x.x) and a port number (100), the destination device information is an address (a.a.a.a) and a port number (100), and the protocol is TCP, these match the source device candidate, destination device candidate, and protocol candidate of ID (1) in Fig. 5, so the required characteristics determination unit 103 determines the corresponding required characteristics candidates to be a speed (15 Mbps), a delay (120 ms), and a success rate (90%).

[0046] If the required characteristic information does not contain a combination of source device candidate and destination device candidate that matches the combination of source device information and destination device information, one of the required characteristic candidates ID(101) to ID(103) is used. For example, if the protocol can be identified from the packet, the required characteristic candidate ID(101) or ID(102) is determined as the required characteristic. If the protocol cannot be identified either, the required characteristic candidate ID(103) is determined as the required characteristic.

[0047] The line characteristic information storage unit 104 stores line characteristic information indicating the line characteristics of each of the multiple communication lines. Like the required characteristic information storage unit 102, the line characteristic information storage unit 104 may be either a volatile memory such as a RAM or a non-volatile memory such as a flash memory or a hard disk.

[0048] Fig. 6 is a diagram showing a specific example of the contents of the line characteristic information. Fig. 6 shows a case where there are three communication lines. In Fig. 6, speed (Mbps), delay (ms), success rate (%), and communication cost are shown as line characteristic indicators for each communication line. Updating and changing these line characteristics will be described later. Note that a packet loss rate (%) may be recorded instead of the success rate (%).

[0049] The line characteristic information storage unit 104 may further store information regarding a calculation method of an index of line characteristics for each control method. When one or more communication lines are used in this embodiment, three control methods are possible for combinations: simple transmission, bandwidth synthesis transmission, and redundant transmission. Simple transmission is a control method in which a packet is transmitted using one of multiple communication lines. Bandwidth synthesis transmission is a control method in which a packet is distributed and transmitted to two or more of multiple communication lines. Redundant transmission is a control method in which the same packet is transmitted over two or more communication lines.

[0050] Figure 7 shows an example of information related to a method for calculating line characteristic indices for each control method. In the case of simple transmission, the line characteristics of each communication line in Figure 6 can be used as is. In the case of bandwidth synthesis transmission, the speed is calculated as the sum of the speeds of the multiple communication lines used, the delay is calculated as the maximum delay of the multiple communication lines used, the success rate is calculated as the weighted average of the success rates of the multiple communication lines used, and the communication cost is calculated as the weighted average of the costs of the multiple communication lines used. The speed is calculated as the sum of the speeds of the multiple communication lines because bandwidth synthesis transmission is a transmission mode that allows the sum of the previously selected transmission side paths to be treated as the transmission characteristic speed. The delay is calculated as the maximum delay of the multiple communication lines because, when communication is performed at the maximum speed across all communication lines used, the delay time is determined by the communication line with the longest delay. For example, in Figure 6, if packets are sent using communication line 1 at 25%, communication line 2 at 50%, and communication line 3 at 25%, then: Speed ​​(Mbps) = 15 + 10 + 20 = 45 Mbps Delay (ms) = max (200, 100, 50) = 200 ms Success rate (%) = 80 x 0.25 + 95 x 0.5 + 90 x 0.25 = 90% Communication cost (yen / GB) = 0 x 0.25 + 4 x 0.5 + 6 x 0.25 = 3.5 yen / GB.

[0051] In the case of redundant transmission, the speed is the minimum of the speeds of the multiple communication lines used, the delay is the minimum of the delays of the multiple communication lines used, the success rate is the product of the packet loss rates of the multiple communication lines used minus 100, and the communication cost is the total of the costs of the multiple communication lines used. For example, in Figure 6, when packets are sent using communication lines 1, 2, and 3, the following are obtained: Speed ​​(Mbps) = min (15, 10, 20) = 10 Mbps Delay (ms) = min (200, 100, 50) = 50 ms Success rate (%) = 100 - 100 x (1 - 0.8) (1 - 0.95) (1 - 0.9) = 99.9% Communication cost (yen / GB) = 0 + 4 + 6 = 10 yen / GB.

[0052] In this embodiment, the line characteristic information storage unit 104 stores line characteristic information and information on a calculation method for an index of line characteristics for each control method, but these may be collectively referred to as policy characteristic information. The line characteristic information storage unit 104 may also be referred to as a policy characteristic information storage unit.

[0053] The policy determination unit 105 determines a policy, which is a "combination" of one or more communication lines to be used for communication, based on the required characteristics determined by the required characteristics determination unit 103. Alternatively, the policy determination unit 105 may determine a policy, which is a "combination" of one or more communication lines to be used for communication and a "proportion" of packet allocation, based on the required characteristics determined by the required characteristics determination unit 103. The policy determination unit 105 determines a policy from among simple transmission, which transmits packets using a single communication line, bandwidth synthesis transmission, which distributes packets to multiple communication lines, and redundant transmission, which transmits the same packets over multiple communication lines. According to this embodiment, the policy determination unit 105 determines a policy from among candidate policies that satisfy the required characteristics as limit values, using line characteristic information stored in the line characteristic information storage unit 104 as shown in FIG. 6 and information related to a calculation method of line characteristic indexes for each control method as shown in FIG. 7. Note that instead of the proportion of packets to be allocated to each communication line, an upper limit proportion of packets to be allocated to each communication line may be used. For example, if transmission data occurs at 5 Mbps and the upper limit is 50%, 2.5 Mbps is allocated as the upper limit. Alternatively, the percentage of each communication line's resource usage or the upper limit percentage of each communication line's resource usage may be used. Here, "combination" includes the use of a single communication line as well as a combination of two or more communication lines. "Percentage" includes 0% and 100%.

[0054] In this embodiment, the policy determination unit 105 determines the order of search for each control method, i.e., simple transmission, bandwidth synthesis transmission, and redundant transmission, based on source device information and destination device information. FIG. 8 is a diagram showing the order of search for control methods when the policy determination unit 105 determines a policy. As already described, the required characteristics determination unit 103 determines required characteristics based on source device information and destination device information. In this embodiment, the policy determination unit 105 determines the order of search for control methods based on the required characteristics. In FIG. 8 , A indicates a case where strict requirements are placed on each index of the required characteristics, B indicates a case where normal requirements are placed on each index of the required characteristics, and C indicates a case where lenient requirements are placed on each index of the required characteristics. While FIG. 8 illustrates a case where evaluation is performed on a three-level scale, evaluation may be performed on a different number of levels, or evaluation may be performed using specific numerical values ​​and thresholds.

[0055] In Figure 8, when wide bandwidth and real-time performance are required, but packet loss can be tolerated to a certain extent and communication costs are not an issue, as in the remote driving application of Figure 4, the control method search order is bandwidth synthesis transmission, simple transmission, and redundant transmission. Also, in Figure 8, when speed and latency requirements are lenient, packet loss is required to a normal level, and communication costs are desired to be as low as possible, as in the big data analysis application of Figure 4, the control method search order is simple transmission, bandwidth synthesis transmission, and redundant transmission. Furthermore, in Figure 8, when communication speed is normal and communication costs are not an issue, real-time performance is required, and packet loss is desired to be as low as possible, the control method search order is redundant transmission, bandwidth synthesis transmission, and simple transmission. Of course, other orders may be used.

[0056] The details of the processing performed by the strategy determination unit 105 in this embodiment will be described in detail in the section on the operation of the communication device 100.

[0057] Transmission control unit 106 distributes packets to be transmitted to each communication line based on the policy determined by policy determination unit 105. Then, multiple second transmission units 107-1 to 107-L (L: number of communication lines) (corresponding to "transmission unit") are connected to communication lines 1 to 107-L, and transmit the packets distributed to each unit to counterparty device 200. Note that when the policy determined by policy determination unit 105 is simple forwarding, packets are not distributed to communication lines that are not in use, and second transmission units 107 connected to communication lines that are not in use do not transmit packets.

[0058] The second receiving units 108-1 to 108-L receive actual measurement values ​​of communication characteristics measured and transmitted by the counterpart device 200. In this embodiment, the actual measurement values ​​include speed (Mbps), delay (bps), and success rate (%). In addition, the second receiving units 108-1 to 108-L also receive data transmitted from the destination device to the source device.

[0059] The reception control unit 109 outputs the actual measurement values ​​of the communication characteristics received by the second reception units 108-1 to 108-L to the line information update unit 111. In addition, the reception control unit 109 rearranges the packets received by the second reception units 108-1 to 108-L and outputs them to the first transmission unit 110.

[0060] The first transmitting unit 110 transmits the packets rearranged by the reception control unit 109 to the source device.

[0061] The line characteristic information update unit 111 updates the line characteristics of the line characteristic information using actual measurement values ​​of communication characteristics received from the counterpart device 200. For example, the line characteristic information update unit 111 periodically receives communication speed (Mbps), delay (ms), and success rate (%) from the counterpart device 200 and updates the line characteristics of the line characteristic information by calculating a moving average for each. Alternatively, the line characteristics of the line characteristic information are updated by filtering each of these taking into account an observation error.

[0062] The line characteristic information change unit 112 changes the line characteristics of the line characteristic information based on at least one input of the vehicle speed, the vehicle position, and the current time. For example, multiple sets of line characteristics are prepared for one line in advance, and the line characteristic information is changed by appropriately switching the set of line characteristics based on the input information.

[0063] For example, the faster the vehicle speed, the more likely it is to switch to a set including line characteristics with a lower success rate. The vehicle speed can be determined using inputs such as the vehicle speed detected by a wheel speed sensor or position information measured using GNSS. For example, when the vehicle moves to a specific location, the set is switched to including line characteristics with a slow communication speed. The vehicle position can be determined using inputs such as position information measured using GNSS. For example, when it is a time period when there is a high traffic congestion of vehicles on the road, the set is switched to including line characteristics with a slow communication speed. The current time can be determined using inputs such as a clock installed in the vehicle or the current time measured using GNSS. Additionally, when connected using a specific communication standard, the set may be switched to including line characteristics with a slow communication speed.

[0064] In this embodiment, the line characteristic information updating unit 111 and the line characteristic information changing unit 112 may have any configuration.

[0065] 9 is a block diagram showing the configuration of the counterparty device 200 in this embodiment. The counterparty device 200 has receiving units 201-1 to 201-L, a communication characteristics measuring unit 202, transmitting units 203-1 to 203-L, and an alignment unit 204.

[0066] The receiving units 201-1 to 201-L receive packets transmitted from the second transmitting units 107-1 to 107-L of the communication device 100 via the respective communication lines.

[0067] Communication characteristic measurement unit 202 measures the communication characteristics of each communication line based on packets received by receiving units 201-1 to 201-L. For example, communication characteristic measurement unit 202 measures the communication speed (Mbps) based on the amount of data of packets received in a predetermined period, the packet delay (ms) based on transmission time information included in the packets and the reception time at which the packets were received, and the success rate (%) based on the number of packets transmitted from communication device 100 and the number of packets received by receiving units 201-1 to 201-L. The number of packets transmitted from communication device 100 can be found using the first sequence number and second sequence number included in the packets.

[0068] Transmitting units 203-1 to 203-L transmit the actual measured values ​​of the communication characteristics measured by communication characteristics measuring unit 202 to communication device 100. For example, the actual measured values ​​of the communication characteristics are stored in packets and transmitted. In addition, transmitting units 203-1 to 203-L also transmit data received from a destination device by a receiving unit (not shown) and transmitted from the destination device to the source device.

[0069] Alignment unit 204 rearranges the packets received by receiving units 201-1 to 201-L based on the second sequence number etc. included in each packet, and then transmits the packets from a transmitting unit (not shown) to a destination device.

[0070] (3) Operation of Communication Device 100 Next, the operation of communication device 100 will be described with reference to Figures 10 to 14. Figures 10 to 14 not only show the communication method executed by communication device 100, but also show the processing procedure of a communication program that can be executed by communication device 100. These processes are not limited to the order shown in Figures 10 to 14. In other words, the order may be changed as long as there are no constraints, such as a relationship in which a certain step uses the result of the previous step.

[0071] (a) Overall Operation of Communication Device 100 FIG. 10 is a flow diagram illustrating the overall operation of the communication device 100. The first receiving unit 101 receives a packet from a source device (S101). The required characteristics determining unit 103 determines required characteristics for communication based on source device information indicating the source device identified from the packet received in S101 and destination device information indicating the destination device identified from the packet received in S101 (S102). The strategy determining unit 105 determines a strategy, which is a combination of one or more communication lines to be used for communication, based on the required characteristics determined in S102 (S103). The strategy determining unit 105 determines one of the following strategies: simple transmission, which transmits packets using a single communication line; bandwidth combining transmission, which distributes packets to multiple communication lines; and redundant transmission, which transmits the same packet over multiple communication lines. The transmission control unit 106 distributes packets to each communication line based on the strategy determined in S103 (S104). Second transmitting units 107-1 to 107-L transmit the packets allocated in S104 using the respective communication lines (S105).

[0072] (b) Operation of the Required Characteristics Determining Unit 103 FIG. 11 is a flow diagram illustrating the details of the operation of the required characteristics determining unit 103, that is, the operation of S102. Note that the numbers in parentheses around the required characteristics candidates indicate the IDs in FIG. 5. The required characteristics determining unit 103 identifies the source device, destination device, and protocol from the packet received in S101 (S111). The required characteristics determining unit 103 reads the required characteristics information from the required characteristics information storage unit 102 (S112). The required characteristics determining unit 103 determines whether the source device, destination device, and protocol identified in S111 are all included in the required characteristics information read in S112 (S113). If included, the required characteristics determining unit 103 uses the required characteristics information to determine the required characteristics candidate (1-) corresponding to the source device, destination device, and protocol as the required characteristics Cr (S114). If not included, the process proceeds to S115. The required characteristics determination unit 103 determines whether the protocol identified in S111 is included in the required characteristics information read in S112 (S115). If included, the required characteristics determination unit 103 uses the required characteristics information to determine the required characteristics candidate (101, 102) corresponding to the protocol as the required characteristics Cr (S116). If not included, the required characteristics determination unit 103 determines the required characteristics candidate (103) as the required characteristics Cr (S117).

[0073] (c) Operation of the Policy Determination Unit 105 FIG. 12 is a flow diagram illustrating the details of the operation of S103, which is the operation of the policy determination unit 105. The policy determination unit 105 determines the search order of the control methods of simple transmission, bandwidth synthesis transmission, and redundant transmission based on the source device information and the destination device information (S121). The policy determination unit 105 searches for a policy using control method 1, which was determined to be searched first (S121). If a candidate policy that satisfies the required characteristics is found (S123: Yes), the candidate policy is determined as the policy (S128) and the process ends. If no candidate policy that satisfies the required characteristics is found (S123: No), the process proceeds to S124. The policy determination unit 105 searches for a policy using control method 2, which was determined to be searched second (S124). If a candidate policy that satisfies the required characteristics is found (S125: Yes), the candidate policy is determined as the policy (S128) and the process ends. If there is no candidate measure that satisfies the required characteristics (S125: No), the process proceeds to S126. The measure decision unit 105 searches for a measure using control method 3, which was determined to be the third to be searched for (S126). If there is a candidate measure that satisfies the required characteristics (S127: Yes), the candidate measure is decided as the measure (S128), and the process ends. If there is no candidate measure that satisfies the required characteristics (S127: No), the process ends.

[0074] In addition, a time limit may be set for the processing of S101 to S128, and if a measure cannot be determined within the time limit, a candidate measure that does not satisfy the required characteristics as the limit value but has characteristics closest to the required characteristics may be determined as the measure.

[0075] As described above, in this embodiment, the policy decision unit 105 does not extract policy characteristic candidates for all control methods and decide on a policy. Instead, when a policy candidate that satisfies the required characteristics as limit values ​​is found for the first time, the search ends and this policy candidate is decided as the policy. Then, a search for the next control method is not performed. Furthermore, in the search for each control method, when a policy candidate that satisfies the required characteristics as limit values ​​is found for the first time, the search ends and this policy candidate is decided as the policy. Then, thereafter, other policy candidates for the same control method are not searched for. As a result, in this embodiment, a policy can be decided quickly and communication can be started.

[0076] The determined measure is stored as previous measure information in the line characteristics information storage unit 104. Then, when searching for a next measure, the measure stored as the previous measure information may be applied with priority.

[0077] In the case of bandwidth synthesis transmission, the search may not be terminated when a candidate strategy is first found, but may be continued until the search at a predetermined granularity is completed. The search method in this case will be described with reference to FIG. 13 .

[0078] 13 and 14 are flow diagrams illustrating a strategy determination method of the strategy determination unit 105 when the control method is bandwidth synthesis transmission, and correspond to S122, S124, or S126 in FIG. 12. The symbols used in FIGS. 13 and 14 are as follows: p: strategy p(opt): strategy p previously adopted (corresponding to "previous strategy information") p(ok): set of strategy candidates that satisfy the required characteristics (corresponding to "previous strategy candidate information") p(ng): set of strategy candidates that do not satisfy the required characteristics r: granularity of the ratio at which packets are distributed to each communication line Note that these values ​​are assumed to be updated during the previous search and saved.

[0079] The previous policy information p(opt) is set as a tentative policy p, and the granularity r is set to an initial value (S131). The granularity r indicates the ratio of packets to be distributed to each communication line. For example, when communication line 1 and communication line 2 are used, if the granularity r is 0.5, the candidate ratios to be distributed to communication line 1 and communication line 2 are (0.5, 0.5). If the granularity r is 0.25, the candidate ratios are (0.25, 0.75), (0.5, 0.5), and (0.75, 0.25). If the granularity r is 0.125, the candidate ratios are (0.125, 0.875), (0.25, 0.75), (0.375, 0.625), (0.5, 0.5), (0.625, 0.375), (0.75, 0.25), and (0.875, 0.125). The initial value of the granularity r may be a value that is fixed each time, such as 0.5, or may be the granularity used when the policy p was found in the previous search.

[0080] If a candidate measure p(ok) that satisfies the required characteristics exists in the previous search (S132: Yes), the process proceeds to the measure selection process (S139). If no candidate measure p(ok) exists (S132: No), the search from S133 onwards is performed.

[0081] If the granularity r is equal to or less than a predetermined minimum value (S133: Yes), the policy p is selected from among the policy characteristic candidates p(ng) that do not satisfy the requirements, and the process is terminated (S141). If the granularity r is equal to or greater than a predetermined minimum value (S133: No), policy candidates that achieve the desired ratio with the granularity r are extracted (S134). Next, among the extracted policy candidates, those included in p(ng) are deleted (S135). Then, among the remaining policy candidates, those that satisfy the desired characteristics are saved in p(ok) (S136).

[0082] If p(ok) includes a candidate measure (S137: Yes), the process proceeds to the policy selection process (S139). If p(ok) does not include a candidate measure (S137: No), the granularity r is set to a value smaller than the current granularity r (S138), and the process returns to S133. In the example of FIG. 13, the granularity r is halved. Note that, from the second extraction in S134 onwards, it is desirable to omit the candidate measures of granularity r that have been extracted up to that point.

[0083] The policy selection process (S139) calculates the distance between the tentative policy p and the policy candidates included in p(ok) (S139). Then, the policy candidate with the largest "distance" is designated as policy p (S140). The distance can be, for example, Euclidean distance. Note that policy p is saved as previous policy information p(opt) for the next search, and p(ok) is also saved as previous policy candidate information p(ok) for the next search. Here, "distance" indicates the degree of deviation between the policy characteristics of the past policy and the policy characteristics of the past policy candidate, and can be defined, for example, by a norm, which is the length of a geometric vector in a plane or space.

[0084] Instead of S139, the previously adopted measure p(opt) may be given priority as the current measure p.

[0085] The above-described policy determination unit 105 and its operation can achieve the following technical effects. Specifically, a ratio of packet distribution to each communication line is determined at a predetermined granularity (S131, S133), a policy is determined from among policy candidate options that satisfy the required characteristics as limit values ​​(S136), and the policy is saved as previous policy information and the policy candidate options are saved as policy candidate information (S140). This allows the previous search results to be used next time, thereby shortening the time required for the search. If a policy candidate option that satisfies the required characteristics at the predetermined granularity is not found (S137), a policy candidate option that satisfies the required characteristics is searched for at a smaller granularity than the predetermined granularity (S138). This allows the search to proceed from a coarse search to a fine search, resulting in efficient search. If policy information or policy candidate information is saved from a past search (S131), a policy is determined from the past policy indicated in the previous policy information or the past policy candidate options indicated in the previous policy candidate information (S132, S139). This makes it possible to shorten the time required for the search by utilizing the results of the previous search. The past policy candidate with the greatest distance from the past policy indicated in the previous policy information is determined as the policy (S140). This allows communication lines with a high previous usage rate to be placed under a low load, and communication lines with a low previous usage rate to be placed under a high load, thereby preventing excessive load on a specific communication line.

[0086] (4) Invention Disclosed in This Embodiment This embodiment discloses the following invention in addition to the inventions set forth in the claims: A communication device (100) capable of communicating with a counterpart device connected to a destination device using one or more communication lines in order to transmit a packet including data received from a source device to the destination device, the communication device (100) comprising: a receiving unit (101) that receives the packet from the source device; a required characteristics determining unit (103) that determines required characteristics for the communication based on source device information indicating the source device identified from the packet and destination device information indicating the destination device identified from the packet; a policy determining unit (105) that determines a policy, which is a combination of one or more of the communication lines to be used for the communication, based on the required characteristics; a transmission control unit (106) that distributes the packet to each communication line based on the policy; and a plurality of transmission units (107) connected to the communication lines and that transmit the packet.

[0087] (5) Summary As described above, the communication device 100 of this embodiment determines the required characteristics for communication based on source device information and destination device information, and distributes packets to each line based on these required characteristics, so that multi-link communication suitable for the type of packet, the type of data contained in the packet, etc. The communication device 100 of this embodiment determines a strategy from among simple transmission, bandwidth synthesis transmission, and redundant transmission, so that it is possible to determine the optimal strategy for each control method of multiple communication lines.

[0088] 3. Summary The features of the communication devices and the like in each embodiment of the present disclosure have been described above.

[0089] The terms used in each embodiment are merely examples and may be replaced with synonymous terms or terms having the same functions.

[0090] The block diagrams used to explain the embodiments classify and organize the device configuration by function. The blocks representing each function can be realized by any combination of hardware or software. Furthermore, because they represent functions, the block diagrams can also be understood as disclosures of method inventions and program inventions that realize the methods.

[0091] The order of the functional blocks that can be understood as the processes, flows, and methods described in each embodiment may be changed as long as there are no constraints, such as one step utilizing the results of another step that precedes it.

[0092] The terms first, second, through Nth (N is an integer) used in each embodiment and in the claims are used to distinguish between two or more configurations or methods of the same type, and do not limit the order or superiority or inferiority.

[0093] Examples of the form of the communication device and the counterpart device of the present disclosure include the following: Examples of the form of components include semiconductor elements, electronic circuits, modules, and microcomputers; Examples of the form of semi-finished products include electronic control devices (ECUs (Electric Control Units)) and system boards; Examples of the form of finished products include mobile phones, smartphones, tablets, personal computers (PCs), workstations, and servers; and Other devices with communication functions, such as video cameras, still cameras, and car navigation systems.

[0094] Furthermore, necessary functions such as an antenna and a communication interface may be added to the communication device.

[0095] The communication device of the present disclosure is expected to be used, particularly on the server side, to provide various services, and the communication device of the present disclosure, the method of the present disclosure, and / or the program of the present disclosure will be used in providing these services.

[0096] In addition, the present disclosure can be realized not only by dedicated hardware having the configuration and functions described in each embodiment, but also by a combination of a program for realizing the present disclosure recorded on a recording medium such as a memory or a hard disk, and general-purpose hardware having a dedicated or general-purpose CPU and memory that can execute the program.

[0097] A program stored in a non-transient physical recording medium (for example, an external storage device (hard disk, USB memory, CD / BD, etc.) or an internal storage device (RAM, ROM, etc.)) of dedicated or general-purpose hardware can be provided to the dedicated or general-purpose hardware via the recording medium, or via a communication line from a server without using a recording medium. This makes it possible to always provide the latest functions through program upgrades.

[0098] The communication device of the present disclosure may be used in a mobile phone or smartphone that supports multi-SIM.

Claims

1. A communication device (100) capable of communicating with a counterpart device connected to a destination device using one or more communication lines in order to transmit a packet including data received from a source device to the destination device, the communication device having: a receiving unit (101) that receives the packet from the source device; a required characteristics determining unit (103) that determines required characteristics for the communication based on source device information indicating the source device identified from the packet and destination device information indicating the destination device identified from the packet; a policy determining unit (105) that determines a policy, which is a combination of one or more of the communication lines to be used for the communication, based on the required characteristics; a transmission control unit (106) that distributes the packet to each communication line based on the policy; and a plurality of transmission units (107) connected to each communication line and that transmit the packet, wherein the policy determining unit determines the policy from among simple transmission that transmits the packet using a single communication line, bandwidth synthesis transmission that distributes the packet to multiple communication lines and transmits it, and redundant transmission that transmits the same packet over multiple communication lines. A communication device (100).

2. The communication device according to claim 1, wherein the required characteristics determination unit determines the required characteristics based on a protocol identified from the packet.

3. The communication device of claim 1 further comprises a required characteristic information storage unit (102) that stores required characteristic information linking source device candidates and destination device candidates with required characteristic candidates, and the required characteristic determination unit uses the required characteristic information to determine the required characteristic candidate corresponding to the source device information and the destination device information as the required characteristic.

4. A communication device as described in claim 1, further comprising a line characteristic information storage unit (104) that stores line characteristic information indicating the line characteristics of one or more of the communication lines, and the strategy determination unit uses the line characteristic information to determine the strategy from among candidate strategies that satisfy the required characteristics as limit values.

5. The communication device according to claim 4, wherein the strategy determination unit determines the order of searching for the simple transmission, the bandwidth synthesis transmission, and the redundant transmission based on the source device information and the destination device information.

6. The communication device according to claim 4, wherein when the candidate policy is first found that satisfies the required characteristics as limit values, the policy decision unit terminates the search, decides on the candidate policy as the policy, and saves the policy as previous policy information.

7. The communication device of claim 5, wherein when searching for the bandwidth synthesis transmission, the policy decision unit determines the usage ratio of each communication line at a predetermined granularity, decides on the policy from among the policy candidate options that satisfy the required characteristics as limit values, and saves the policy as previous policy information and the policy candidate options as previous policy candidate information.

8. The communication device according to claim 7, wherein, if the policy decision unit cannot find a policy candidate that satisfies the required characteristics at the predetermined granularity, it searches for a policy candidate that satisfies the required characteristics at a granularity smaller than the predetermined granularity.

9. The communication device of claim 7, wherein the measure determination unit determines the measure from among the past measures indicated in the previous measure information or the past measure candidates indicated in the previous measure candidate information when previous measure information or previous measure candidate information is saved from a past search.

10. The communication device according to claim 7, wherein the policy decision unit decides, as the policy, the past policy candidate having the greatest distance from the past policy indicated in the previous policy information.

11. The communication device according to claim 1, wherein the policy determination unit determines the policy, which is a combination of one or more communication lines to be used for the communication and a ratio at which the packets are distributed, based on the required characteristics.

12. A communication device according to any one of claims 4 to 11, further comprising a line characteristic information update unit (111) that updates the line characteristics of the line characteristic information using actual measurement values ​​of communication characteristics received from the counterpart device.

13. A communication device according to any one of claims 4 to 11, wherein the communication device is mounted on a mobile body, and further comprises a line characteristic information change unit (112) that changes the line characteristics of the line characteristic information based on at least one of the speed of the mobile body, the position of the mobile body, and the current time.

14. A communication method executed by a communication device (100) capable of communicating with a counterpart device connected to a destination device using one or more communication lines in order to transmit a packet including data received from a source device to the destination device, the method comprising: receiving the packet from the source device (S101); determining required characteristics for the communication based on source device information indicating the source device identified from the packet and destination device information indicating the destination device identified from the packet (S102); determining a strategy, which is a combination of one or more of the communication lines to be used for the communication, based on the required characteristics (S103); allocating the packet to each communication line based on the strategy (S104); and transmitting the packet using each of the communication lines (S105); determining the strategy from among simple transmission, which transmits the packet using a single communication line, bandwidth synthesis transmission, which allocates and transmits the packet to multiple communication lines, and redundant transmission, which transmits the same packet using multiple communication lines.

15. A communication program executable by a communication device (100) capable of communicating with a counterpart device connected to a destination device using one or more communication lines in order to transmit a packet including data received from a source device to the destination device, the communication program causing the communication device to execute the following process: receive the packet from the source device (S101); determine required characteristics for the communication based on source device information indicating the source device identified from the packet and destination device information indicating the destination device identified from the packet (S102); determine a strategy, which is a combination of one or more communication lines to be used for the communication, based on the required characteristics (S103); allocate the packet to each communication line based on the strategy (S104); and transmit the packet using each communication line (S105); the strategy determination is made from simple transmission, which transmits the packet using a single communication line, bandwidth synthesis transmission, which allocates and transmits the packet to multiple communication lines, and redundant transmission, which transmits the same packet using multiple communication lines. Communications program.

16. A communication system (1) comprising a communication device (100) and a counterpart device (200) that communicates with the communication device, wherein the communication device is capable of communicating with the counterpart device connected to the destination device using one or more communication lines in order to transmit packets containing data received from the source device to the destination device, and comprises: a receiving unit (101) that receives the packets from the source device; a required characteristics determining unit (103) that determines required characteristics for the communication based on source device information indicating the source device identified from the packets and destination device information indicating the destination device identified from the packets; a policy determining unit (105) that determines a policy, which is a combination of one or more communication lines to be used for the communication, based on the required characteristics; a transmission control unit (106) that distributes the packets to each communication line based on the policy; and a plurality of transmission units (107) that are connected to the respective communication lines and transmit the packets. The strategy determination unit determines the strategy from among simple transmission, which transmits the packet using a single communication line, bandwidth synthesis transmission, which distributes the packet among multiple communication lines and transmits it, and redundant transmission, which transmits the same packet over multiple communication lines; and the other device has: a receiving unit (201) that receives the packet; a communication characteristic measurement unit (201) that measures communication characteristics of each communication line based on the received packet; and a transmitting unit (203) that transmits the communication characteristics to the communication device.

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