Communication system and repeater

Abstract

To provide a communication system capable of suppressing inconvenience such as the suspension of communication itself due to a temporary interruption of communication.SOLUTION: A PU 12 of a first communication device 10 transmits data including a detection value of a sensor 20 to a second communication device 30. When the second communication device 30 receives the data transmitted by the first communication device 10, the second communication device transmits response data to the first communication device 10. The repeater 60 mediates communication between the first communication device 10 and the second communication device 30. When the PU 62 of the repeater 60 does not receive data from the first communication device 10, the PU transmits data to the second communication device 30 in place of the data that should have been transmitted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a communication system and a repeater. [Background technology]

[0002] Patent Document 1 below describes a system in which a communication terminal provided in a mobile body and an application server communicate via a mobile gateway. In this system, data transmitted from the application server is stored in a buffer of the mobile gateway. The mobile gateway sequentially transmits the data stored in the buffer to the communication terminal. Here, when the communication terminal notifies the mobile gateway of the time when communication will be interrupted, the mobile gateway instructs the application server to reduce the communication speed. Thereafter, when the notified time has elapsed, the mobile gateway sequentially transmits the data stored in the buffer to the communication terminal. Then, when the data accumulated in the buffer has been sufficiently reduced, the mobile gateway instructs the application server to restore the communication speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-196678 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have considered performing a fail-safe process when communication is interrupted in a system in which two communication devices periodically communicate with each other, and have found that in such a case, a temporary interruption of communication may cause the fail-safe process to be performed, which may prevent a smooth return to a normal communication state. [Means for solving the problem]

[0005] Means for solving the above problems and their effects will be described below. 1. A communication system comprising a first communication device, a second communication device, and a repeater, the first communication device configured to execute a first transmission process and a first reception process, the second communication device configured to execute a second transmission process, the first transmission process being a process of periodically transmitting data to the second communication device by wireless communication via the repeater, the first reception process being a process of receiving data transmitted by the second transmission process, the second transmission process being a process of transmitting data responding to the first transmission process via the repeater after receiving the data transmitted by the first transmission process, and the repeater configured to execute a proxy process, the proxy process including at least one of two processes: a process of transmitting to the second communication device data replacing the data to be transmitted by the first transmission process when data to be transmitted by the first transmission process is not received, and a process of transmitting to the first communication device data replacing the data to be transmitted by the second transmission process when data to be transmitted by the second transmission process is not received.

[0006] When the repeater executes a process of transmitting data to the second communication device when the data to be transmitted by the first transmission process is not received, it is possible to prevent inconveniences such as communication being stopped due to a temporary interruption of communication. Also, when the repeater executes a process of transmitting data to the first communication device when the data to be transmitted by the second transmission process is not received, it is possible to prevent inconveniences such as communication being stopped due to a temporary interruption of communication.

[0007] 2. A communication system as described in claim 1, wherein the first transmission process includes a process of periodically transmitting data regarding a detection value of a specified physical quantity, and the proxy process includes an extrapolation process of transmitting to the second communication device data regarding the physical quantity set in accordance with data regarding the detection value transmitted by the first transmission process in the past when data to be transmitted by the first transmission process is not received.

[0008] In the above configuration, it is possible to transmit to the second communication device data close to the detection value that would have been transmitted by the first transmission process. 3. A communication system as described in 1 or 2 above, wherein the proxy processing includes a process of transmitting data indicating that the data transmitted by the first transmission processing cannot be received to the second communication device, instead of the data transmitted by the first transmission processing, when the data to be transmitted by the first transmission processing is not received.

[0009] In the above configuration, data that allows the second communication device to recognize the current situation can be transmitted. 4. A communication system described in any one of 1 to 3 above, wherein the proxy processing includes a process of transmitting data indicating that the data transmitted by the second transmission processing cannot be received to the first communication device, instead of the data transmitted by the second transmission processing, when the data to be transmitted by the second transmission processing is not received.

[0010] In the above configuration, data that allows the first communication device to recognize the current situation can be transmitted. 5. The communication system according to any one of 1 to 4 above, wherein the first communication device executes a fail-safe process when the first communication device is unable to receive data transmitted by the second transmission process for a predetermined period of time.

[0011] In the above configuration, even if the first communication device does not receive data to be transmitted by the second transmission process for a predetermined period of time, the proxy process prevents the first communication device from performing the fail-safe process.

[0012] 6. The communication system according to any one of 1 to 5 above, wherein the second communication device executes a fail-safe process when the second communication device is unable to receive data transmitted by the first transmission process for a predetermined period of time.

[0013] In the above configuration, even if the second communication device does not receive data to be transmitted by the first transmission process for a predetermined period of time, the proxy process prevents the second communication device from performing the fail-safe process.

[0014] 7. The repeater in the communication system according to any one of 1 to 6 above. [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram showing a configuration of a communication system according to an embodiment; [Diagram 2] 6 is a flowchart showing a procedure of a process executed by a first communication device and a second communication device according to the embodiment. [Diagram 3] 4 is a flowchart showing a procedure of a process executed by a repeater according to the embodiment; [Figure 4] 4 is a time chart illustrating the process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment will be described with reference to the drawings. "Prerequisite configuration" FIG. 1 shows a communication system.

[0017] The first communication device 10 acquires a detection value of a predetermined physical quantity by the sensor 20. The first communication device 10 is arranged in a factory as an example. In that case, the sensor 20 may be a sensor that detects a state quantity of a processing object in the factory. Also, the first communication device 10 is arranged in a plant cultivation area as an example. In that case, the sensor 20 may be a sensor that detects state quantities such as the ambient temperature, illuminance, and humidity. Also, the first communication device 10 is arranged in an animal breeding area as an example. In that case, the sensor 20 may be a sensor that detects state quantities of the environment surrounding the animal such as the ambient temperature and humidity. Also, the sensor 20 may be a sensor that detects state quantities of the animal such as the pulse, body temperature, and activity level of the animal. Also, the first communication device 10 may be arranged in a house that is comprehensively managed using IOT as an example. In that case, the sensor 20 may be a sensor that detects state quantities such as the temperature and humidity in the house. Also, the sensor 20 may be a human sensor that detects whether or not a person is present in the house.

[0018] The first communication device 10 includes a PU 12, a storage device 14, and a communication device 16. The PU 12 is a software processing device such as a CPU, a GPU, or a TPU. The storage device 14 may be an electrically non-rewritable non-volatile memory. The storage device 14 may also be an electrically rewritable non-volatile memory, or a storage medium such as a disk medium.

[0019] The second communication device 30 is configured to periodically communicate with the first communication device 10. The second communication device 30 notifies a person of the result of communication with the first communication device 10 via a user interface 40 under a predetermined condition.

[0020] The second communication device 30 includes a PU 32, a storage device 34, and a communication device 36. The PU 32 is a software processing device such as a CPU, a GPU, or a TPU. The storage device 34 may be an electrically non-rewritable non-volatile memory. The storage device 34 may also be an electrically rewritable non-volatile memory, or a storage medium such as a disk medium.

[0021] The repeater 60 is configured to intermediate communication between the first communication device 10 and the second communication device 30. That is, the repeater 60 receives data transmitted from the first communication device 10 via the network 50. The repeater 60 transmits the received data to the second communication device 30. The repeater 60 also receives data transmitted from the second communication device 30 via the network 50. The repeater 60 transmits the received data to the first communication device 10.

[0022] The repeater 60 includes a PU 62, a storage device 64, and a communication device 66. The PU 62 is a software processing device such as a CPU, a GPU, or a TPU. The storage device 64 may be an electrically non-rewritable non-volatile memory. The storage device 64 may also be an electrically rewritable non-volatile memory or a storage medium such as a disk medium. The storage device 64 stores a repeater program 64a.

[0023] "Preliminary processing" Fig. 2 shows the procedure of the process executed by the first communication device 10 and the second communication device 30. The process shown on the left side of Fig. 2 is realized by the PU 12 repeatedly executing a program stored in the storage device 14 of the first communication device 10, for example, at a predetermined cycle. The process shown on the right side of Fig. 2 is realized by the PU 32 repeatedly executing a program stored in the storage device 34 of the second communication device 30, for example, at a predetermined cycle. In the following, the step number of each process is represented by a number preceded by "S".

[0024] 2, the PU 12 of the first communication device 10 first acquires a detection value of the sensor 20 (S10). Next, the PU 12 generates data for transmission including the detection value (S12). The PU 12 then operates the communication device 16 to transmit the generated data to the second communication device 30 (S14).

[0025] On the other hand, the PU 32 of the second communication device 30 determines whether or not data transmitted at a predetermined period from the first communication device 10 has been received (S30). If the PU 32 determines that the data has been received (S30: YES), the PU 32 operates the communication device 36 to transmit data to the first communication device 10 in response to the reception of the data (S34).

[0026] On the other hand, the PU 12 of the first communication device 10 judges whether or not the response data has been received (S16). When the PU 12 judges that the response data has not been received (S16: NO), the PU 12 judges whether or not a predetermined time has elapsed (S18). Here, the predetermined time may be set to a time equal to or longer than the period in which the first communication device 10 periodically transmits data. However, the predetermined time may be set to a time shorter than the period in which the first communication device 10 periodically transmits data. When the PU 12 judges that the predetermined time has not elapsed (S18: NO), the PU 12 returns to the process of S16. On the other hand, when the PU 12 judges that the predetermined time has elapsed (S18: YES), the PU 12 executes a fail-safe process (S20). Here, the fail-safe process includes a process of terminating the periodic communication with the second communication device 30. The fail-safe process includes a process of notifying a person of the occurrence of an abnormality without going through the second communication device 30. For example, if the first communication device 10 is installed in a house and the owner of the house has a contract with a specific management center, the fail-safe process may include a process of transmitting a signal for the notification to the management center. Also, if the first communication device 10 is owned by an organization that has bases other than a factory and a management building of the factory and the first communication device 10 is a device that transmits information about the factory to the management building, the fail-safe process may be a process of transmitting a signal for the notification to a base other than the management building.

[0027] When the PU 12 completes the process of S20 or when a positive determination is made in the process of S16, the PU 12 temporarily ends the series of processes shown on the left side of FIG. On the other hand, when the PU 32 of the second communication device 30 determines that the data has not been received yet (S30: NO), it determines whether or not a predetermined time has elapsed (S32). Here, the predetermined time may be set to a time equal to or longer than the period in which the first communication device 10 periodically transmits data. However, the predetermined time may be set to a time shorter than the period in which the first communication device 10 periodically transmits data. When the PU 32 determines that the predetermined time has not elapsed (S32: NO), it returns to the process of S30. On the other hand, when the PU 32 determines that the predetermined time has elapsed (S32: YES), it executes a fail-safe process (S36). The fail-safe process includes a process of terminating the periodic communication with the first communication device 10. The fail-safe process includes a process of notifying a person that an abnormality has occurred by operating the user interface 40.

[0028] When the PU 32 completes the processes of S34 and S36, the PU 32 temporarily ends the series of processes shown on the right side of FIG. "Repeater processing" Fig. 3 shows the procedure of the process executed by the repeater 60. The series of processes shown in Fig. 3 is realized by the PU 62 repeatedly executing the repeater program 64a, for example, at a predetermined interval.

[0029] 3, the PU 62 first determines whether or not the data to be transmitted in the process of S14 has been received (S40). If the PU 62 determines that the data has been received (S40: YES), the PU 62 operates the communication device 66 to transmit the data to the second communication device 30 (S42).

[0030] On the other hand, when the PU 62 determines that data has not been received (S40: NO), it determines whether or not the specified time has elapsed (S44). The specified time is set to a time shorter than the period in which the first communication device 10 periodically transmits data. In particular, the specified time is set to a time shorter than the predetermined time in S32. When the PU 62 determines that the specified time has not yet elapsed (S44: NO), it returns to the process of S40.

[0031] On the other hand, when the PU 62 determines that the specified time has elapsed (S44: YES), it increments the counter C1 (S46). Then, the PU 62 determines whether the counter C1 is equal to or less than the threshold C1th (S48). The threshold C1th is set according to the upper limit of the time during which the temporary communication interruption between the first communication device 10 and the repeater 60 continues. When the PU 62 determines that the counter C1 is equal to or less than the threshold C1th (S48: YES), it executes an extrapolation calculation to predict the current detection value according to a predetermined number of detection values ​​most recently included in the data transmitted by the first communication device 10 in the past (S50). The PU 62 may predict the current detection value, for example, by linearly approximating the relationship between the time and the detection value from the predetermined number of detection values ​​according to the least squares method.

[0032] The PU 62 generates data to be transmitted to the second communication device 30, including data of the predicted detection value and temporary interruption notification data (S52). The temporary interruption notification data is data notifying that a temporary interruption of communication with the first communication device 10 has occurred. The PU 62 then operates the communication device 66 to transmit the data generated by the process of S52 to the second communication device 30 (S54).

[0033] On the other hand, when completing the process of S42, the PU 62 stores data indicating the detection value included in the received data together with the timestamp in the storage device 64, and initializes the counter C1 (S56). Instead of using the timestamp, the PU 62 may update all data in a predetermined storage area in the storage device 64. That is, the PU 62 erases data older than the most recent predetermined number of pieces, and stores the predetermined number of pieces of data in chronological order in the predetermined storage area.

[0034] When the processing of S54 and S56 is completed, the PU 62 judges whether or not the response data transmitted by the second communication device 30 has been received (S58). When the PU 62 judges that the response data has not yet been received (S58: NO), the PU 62 judges whether or not a prescribed time has elapsed (S60). The prescribed time is set to a time shorter than the period in which the first communication device 10 periodically transmits data. In particular, the prescribed time is set to a time shorter than the predetermined time in S18. When the PU 62 judges that the prescribed time has not yet elapsed (S60: NO), the PU 62 returns to the processing of S58.

[0035] On the other hand, when the PU 62 determines that the specified time has elapsed (S60: YES), it increments the counter C2 (S62). Then, the PU 62 determines whether the counter C2 is equal to or less than the threshold C2th (S64). The threshold C2th is set according to the upper limit of the time that the temporary communication interruption between the second communication device 30 and the repeater 60 continues. When the PU 62 determines that the counter C2 is equal to or less than the threshold C2th (S64: YES), it generates data to be transmitted to the first communication device 10 so as to include the temporary interruption notification data (S66). The temporary interruption notification data is data that notifies that a temporary interruption of communication with the second communication device 30 has occurred. Then, the PU 62 transmits the data generated by the process of S66 to the first communication device 10 by operating the communication device 66 (S68).

[0036] On the other hand, when the PU 62 determines that the response data has been received (S58: YES), it initializes the counter C2 (S70). When the PU 62 completes the processes of S68 and S70, or when a negative determination is made in the processes of S48 and S64, the PU 62 temporarily ends the series of processes shown in FIG.

[0037] "Actions and Effects of the Present Embodiment" FIG. 4 illustrates a periodic communication process between the first communication device 10 and the second communication device 30. As shown in FIG. 4, when communication between the first communication device 10 and the repeater 60 is interrupted, the repeater 60 transmits to the second communication device 30, at time t2, data to replace the data to be transmitted from the first communication device 10 to the second communication device 30. As a result, the PU 32 of the second communication device 30 makes a positive determination in the process of S30. The PU 32 then transmits data to the first communication device 10 in response to the fact that the data has been received.

[0038] Therefore, even if the communication between the first communication device 10 and the repeater 60 is merely interrupted temporarily, the PU 32 can be prevented from executing the fail-safe process. 4, when communication between the second communication device 30 and the repeater 60 is interrupted, the PU 62 of the repeater 60 transmits alternative data for the response data to the first communication device 10 at time t4. As a result, the PU 12 of the first communication device 10 receives the alternative data as the response data, and makes a positive determination in the process of S16. Therefore, even if communication between the second communication device 30 and the repeater 60 is merely temporarily interrupted, the PU 12 can be prevented from executing the fail-safe process.

[0039] According to the present embodiment described above, the following actions and effects can be obtained. (1) When the PU 62 of the repeater 60 cannot receive data from the first communication device 10, the PU 62 predicts the current detection value based on the detection value data included in the previously received data. Then, the PU 62 transmits data related to the predicted detection value to the second communication device 30. This enables the second communication device 30 to execute normal processing as much as possible.

[0040] (2) When the PU 62 of the repeater 60 cannot receive data from the first communication device 10, the PU 62 transmits data indicating that communication has been temporarily interrupted to the second communication device 30. This allows the second communication device 30 to grasp the situation.

[0041] (3) When the PU 62 of the repeater 60 cannot receive data from the second communication device 30, the PU 62 transmits data to the first communication device 10 indicating that communication has been temporarily interrupted. This allows the first communication device 10 to grasp the situation.

[0042] <Correspondence> The correspondence between the matters in the above embodiment and the matters described in the above "Means for solving the problem" column is as follows. Below, the correspondence is shown for each number of the means for solving the problem described in the "Means for solving the problem" column. [1,7] The first transmission process corresponds to the process of S14. The first reception process corresponds to the process of S16. The second transmission process corresponds to the process of S34. The proxy process corresponds to the processes of S48 to S54 and S66 and S68. [2] The detection value of the predetermined physical quantity corresponds to the detection value obtained by the process of S10. The extrapolation process corresponds to the process of S50. [3] In the process of S52, temporary interruption notification data is included in the transmission data. [4] The proxy process corresponds to the processes of S66 and S68. [5] The fail-safe process corresponds to the process of S20. [6] The fail-safe process corresponds to the process of S36.

[0043] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0044] "About proxy processing" The proxy process of the first transmission process does not necessarily include both the extrapolation process and the process of transmitting temporary outage notification data. For example, the above two processes may be performed in a process of performing only one of them. Note that, when performing the extrapolation process, the PU 62 of the repeater 60 may generate and transmit pseudo data equivalent to the data other than the detection value transmitted by the first transmission process.

[0045] The proxy process for the second transmission process does not necessarily have to include a process for transmitting temporary interruption notification data. For example, the proxy process for the second transmission process may be a process for transmitting data that responds to the fact that the data has been received.

[0046] "Fail-safe processing" In the above embodiment, the fail-safe process executed by the first communication device 10 includes a process of notifying a person that an abnormality has occurred, but is not limited to this. If a state where communication is not possible continues for a predetermined time, the second communication device 30 executes a fail-safe process, so that a person can be notified.

[0047] "About communication systems" The communication system is not limited to a system in which the second communication device 30 executes a process of notifying a person of the communication result with the first communication device 10 via the user interface 40 under a predetermined condition. For example, the communication system may further be a system in which the first communication device 10 executes a process of notifying a person of the communication result with the second communication device 30 via the user interface under a predetermined condition. This system is effective in cases where the first communication device 10 and the second communication device 30 execute a process of transmitting detection values ​​of predetermined physical quantities in the vicinity to each other. In that case, the communication system may execute the process illustrated in FIG. 2 and a process in which the roles of the first communication device 10 and the second communication device 30 are swapped in FIG. 2. The swapped process is a process in which the first communication device 10 receives data related to the detection value transmitted from the second communication device 30 and the first communication device 10 transmits response data to the second communication device 30.

[0048] "About repeaters" The repeater is not limited to a device that executes software processing. For example, the repeater may include a dedicated hardware circuit, such as an ASIC, that executes at least a part of the processing executed in the above embodiment. That is, the repeater may include a processing circuit having any of the following configurations (a) to (c). (a) A processing circuit including a processing device that executes all of the above processing according to a program, and a program storage device, such as a storage device, that stores the program. (b) A processing circuit including a processing device and a program storage device that executes part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A processing circuit including a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software execution devices that include a processing device and a program storage device. Also, there may be multiple dedicated hardware circuits.

[0049] "Regarding the first and second communication devices" The above repeater-related modifications can also be applied to the configuration of the first communication device. The above repeater-related modifications can also be applied to the configuration of the second communication device. [Explanation of symbols]

[0050] 10…First communication device 14...Storage device 16...Communication device 20…Sensor 30…Second communication device 34…Storage device 36…Communication device 40...User interface 50…Network 60…Repeater 64…Storage device

Claims

1. A first communication device, a second communication device, and a repeater, The first communication device is configured to perform a first transmission process and a first reception process; The second communicator is configured to perform a second transmission process; the first transmission process is a process of periodically transmitting data to the second communication device by wireless communication via the repeater; the first reception process is a process of receiving data transmitted by the second transmission process, the second transmission process is a process of receiving data transmitted by the first transmission process and then transmitting data in response to the first transmission process via the repeater; The relay is configured to perform proxy processing; The proxy processing includes at least one of two processings: a processing of transmitting to the second communication device data replacing the data to be transmitted by the first transmission processing when data to be transmitted by the first transmission processing is not received, and a processing of transmitting to the first communication device data replacing the data to be transmitted by the second transmission processing when data to be transmitted by the second transmission processing is not received.

2. the first transmission process includes a process of periodically transmitting data regarding a detection value of a predetermined physical quantity, The communication system according to claim 1, wherein the proxy processing includes an extrapolation process for transmitting data regarding the physical quantity set in accordance with data regarding the detection value transmitted by the first transmission process in the past to the second communication device when data to be transmitted by the first transmission process is not received.

3. The communication system of claim 1, wherein the proxy processing includes a process of transmitting data indicating that the data by the first transmission processing cannot be received to the second communication device instead of the data to be transmitted by the first transmission processing when the data to be transmitted by the first transmission processing is not received.

4. The communication system of claim 1, wherein the proxy processing includes a process of transmitting data indicating that the data by the second transmission processing cannot be received to the first communication device instead of the data to be transmitted by the second transmission processing when the data to be transmitted by the second transmission processing is not received.

5. The communication system according to claim 1 , wherein the first communication device executes a fail-safe process when the first communication device is unable to receive the data transmitted by the second transmission process for a predetermined period of time.

6. The communication system according to claim 1 , wherein the second communication device executes a fail-safe process when the second communication device is unable to receive the data transmitted by the first transmission process for a predetermined period of time.

7. The repeater in the communication system according to claim 1.

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