COMMUNICATION DEVICE, COMMUNICATION PROGRAM, COMMUNICATION METHOD, AND COMMUNICATION SYSTEM

Abstract

To provide a communication apparatus capable of preventing battery consumption by an unintended packet from the outside while using a public communication line with low communication costs.SOLUTION: A communication apparatus connecting with a server for collecting sensing data through a low power wide area communication network comprises: a sensing data creation unit for creating and outputting the sensing data; an overload detection unit that detects overload of a battery for driving the apparatus and outputs an overload signal; a state management unit that outputs a non-communication state indication signal when the overload signal is input; and a wide area communication core unit that when the non-communication state indication signal is input, transits to a non-communication state in which any packet transmission / reception is temporarily impossible.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication device, a communication program, a communication method, and a communication system, and can be applied to a sensor network that aggregates sensing data using a public network such as LTE (Long Term Evolution) / 4G, for example. [Background technology]

[0002] As IoT (Internet of Things) related technologies continue to develop, many sensor networks have been proposed in which sensor nodes are placed under a gateway (see Patent Document 1).

[0003] Fig. 3 shows an example of the configuration of a sensor network typified by Patent Document 1. In Fig. 3, the sensor network 100 includes a wide-area communication node Z1 that uses a mobile communication service such as 3G / 4G / 5G to transmit upstream data as one type of transmitted / received data and receive downstream data as one type of transmitted / received data, and a DB server Z2 that receives the upstream data and transmits the downstream data as one type of transmitted / received data, and stores the sensing data included in the upstream data in a DB (Database) or visualizes it.

[0004] Here, sensing data refers to electronic data acquired from electronic devices that sense the state of the installation environment. For example, sensing data is electronic data acquired from acceleration sensors, temperature sensors, humidity sensors, illuminance sensors, displacement sensors, and sensors that sense voltage or current (including electronic data processed by signal processing).

[0005] The upstream data may be generated sensing data, while the downstream data may be data that stores settings on how the wide-area communication node Z1 should operate, or data that requests retransmission of a packet.

[0006] The wide-area communication node Z1 has a sensing data generation unit B11 that generates and outputs sensing data, and a wide-area communication unit B12 that transmits uplink data (sensing data) as one of the transmitted and received data and receives downlink data as one of the transmitted and received data.

[0007] Figure 3 does not specifically show how the sensing data is generated, but it is conceivable that the sensing data may be obtained, for example, from an electronic device that senses the state of the installation environment and is wired to the wide-area communication node Z1, or that the sensing data may be data collected using a private wireless communication system that utilizes the 920 MHz band.

[0008] The latter configuration is generally used when talking about sensor networks, and the previous example also uses this configuration. In this latter configuration, wide-area communication node Z1 acts as a gateway.

[0009] The wide-area communication node Z1 may be configured to use both electronic data acquired from an electronic device that senses the state of the wired-connected installation environment and data collected using a private wireless communication system as sensing data. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-122310 Summary of the Invention [Problem to be solved by the invention]

[0011] The function of sensing the state of the installation environment is realized as expected with the conventional configuration.

[0012] However, if it is assumed that the wide-area communication node Z1 operates on a battery alone or on a battery combined with an environmentally-powered source such as a solar panel, it is possible to use a mobile communication service characterized by low power consumption with defined active and sleep states, such as LTE Category M1, as a line for connecting the wide-area communication node Z1 to the DB server Z2. LTE Category M1 is a type of LPWA (Low Power Wide Area) wireless communication technology for IoT.

[0013] In addition, LTE Category M1 consumes low power in sleep mode, transitioning to a high-power active mode only when there are received or transmitted packets, and can transition back to sleep mode after clearing all received and transmitted packets. Whether or not there are received packets while in sleep mode is checked at pre-set intervals using a mechanism called eDRX (extended Discontinuous Reception). Specifically, the terminal attempts to receive downlink messages from the network once per fixed period (DRX period). If there is a message addressed to it, the terminal will wake up from sleep mode and transition to active mode.

[0014] When a mobile communication service characterized by low power consumption with defined active and sleep states is used as a line to connect a wide-area communication node Z1 to a DB server Z2, if unintended packets continue to arrive from outside, the packets will increase the active state time, causing a problem in which the battery of the wide-area communication node Z1 will be depleted.

[0015] One effective solution to this issue would be to connect using private LTE, which prevents unintended packet transmissions, but this would increase communication costs.

[0016] Therefore, there is a demand for a communication device, a communication program, a communication method, and a communication system that can prevent battery drain due to unintended packets from outside while using public communication lines with low communication costs. This is the problem that the present invention solves. [Means for solving the problem]

[0017] The first invention is a communication device connected to a server that collects sensing data via a low-power wide-area communication network, characterized by having: (1) a sensing data generation unit that generates and outputs the sensing data; (2) an overload detection unit that detects an overload on a battery that drives the device and outputs an overload signal; (3) a state management unit that outputs a non-communication state indication signal when the overload signal is input; and (4) a wide-area communication core unit that, when the non-communication state indication signal is input, transitions to a non-communication state in which no packets can be sent or received temporarily.

[0018] The second communication program of the present invention is characterized in that it causes a computer installed in a communication device connected to a server that collects sensing data via a low-power wide-area communication network to function as (1) a sensing data generation unit that generates and outputs the sensing data, (2) an overload detection unit that detects an overload on the battery that drives the device and outputs an overload signal, (3) a state management unit that outputs a non-communication state indication signal when the overload signal is input, and (4) a wide-area communication core unit that, when the non-communication state indication signal is input, transitions to a non-communication state in which no packets can be sent or received temporarily.

[0019] The third invention is a communication method used for a communication device connected to a server that collects sensing data via a low-power wide-area communication network, characterized in that (1) a sensing data generation unit generates and outputs the sensing data, (2) an overload detection unit detects an overload of a battery that drives the device and outputs an overload signal, (3) a state management unit outputs a non-communication state indication signal when the overload signal is input, and (4) when the non-communication state indication signal is input, the wide-area communication core unit transitions to a non-communication state in which no packets can be sent or received temporarily.

[0020] A fourth aspect of the present invention is a communication system having a communication device and a server, wherein said communication device is the communication device of the first aspect of the present invention. [Effects of the Invention]

[0021] According to the present invention, it is possible to prevent battery consumption due to unintended packets from outside while using public communication lines with low communication costs. [Brief explanation of the drawings]

[0022] [Figure 1] 1 illustrates an example of the configuration of a sensor network (sensor network system) according to an embodiment. [Figure 2] 10 is a flowchart illustrating a characteristic operation of a wide-area communication unit of the wide-area communication node according to the embodiment. [Figure 3] 1 shows an example of the configuration of a conventional sensor network (sensor network system). DETAILED DESCRIPTION OF THE INVENTION

[0023] (A) Main embodiment Hereinafter, embodiments of a communication device, a communication program, a communication method, and a communication system according to the present invention will be described in detail with reference to the drawings.

[0024] (A-1) Configuration of the embodiment FIG. 1 shows an example of the configuration of a sensor network (sensor network system) according to an embodiment.

[0025] 1, a sensor network 1 includes a wide-area communication node A1 and a DB server A2. The following description will focus on the wide-area communication node A1 and the DB server A2, focusing on differences from the wide-area communication node Z1 and the DB server Z2 described above.

[0026] [Wide area communication node] The wide-area communication node A1 has a sensing data generation unit B11 that generates and outputs sensing data, and a wide-area communication unit B12 that transmits upstream data as one of the transmitted and received data and receives downstream data as one of the transmitted and received data, and also controls the communication state according to the load on the battery of the wide-area communication node A1.

[0027] The wide-area communication node according to the embodiment may be configured as hardware such as a dedicated IC chip equipped with each component shown in FIG. 1, or may be configured as software centered around a CPU and a program executed by the CPU, but functionally it can be represented as shown in FIG. 1.

[0028] The wide area communication unit B12 includes an overload detection unit C121 that detects an overload on the battery of the wide area communication node A1 and outputs an overload signal, a state management unit C122 that outputs a non-communication state indication signal when an overload signal is input, and a wide area communication core unit C123 that transmits upstream data as one of the transmitted and received data and receives downstream data as one of the transmitted and received data using a line that defines an active state and a sleep state and is characterized by low power consumption by transitioning between the active state and the sleep state depending on the presence or absence of packets, and that temporarily transitions to a non-communication state when a non-communication state indication signal is input.

[0029] Here, battery overload refers to a state in which the battery has been depleted to the point where it can no longer meet the design value for battery life. A non-communication state refers to a state in which no packets can be sent or received, such as a state in which power is cut off to an electronic device that handles the lowest physical layer in the OSI layer model. On the other hand, a line in an active or sleep state is called a communication state.

[0030] The overload detection unit C121 can apply a variety of detection methods, for example, the following methods to detect the load. First, the overload detection unit C121 monitors the current supplied from the battery of the wide-area communication node A1 and outputs an overload signal if the current is higher than a threshold. The allowable current consumption is determined as a design value based on the battery capacity and designed operating time of the wide-area communication node A1, so this design value is used as the threshold, for example. The current consumption can also be monitored by monitoring the battery voltage, which is correlated with the current consumption, and comparing it with the battery specifications. Battery voltage monitoring can be achieved using an analog-to-digital conversion circuit.

[0031] The second method is for the overload detection unit C121 to monitor whether the line is in an active state or a sleep state, and output an overload signal if the line's active state continues for a longer period than the threshold. For example, if a DoS attack or DDoS attack occurs, the communication line will never be able to enter a sleep state, and the battery will continue to be consumed. Even in such cases, this can be avoided by outputting an overload signal when the active state continues for more than the threshold.

[0032] A third method is for the overload detection unit C121 to monitor whether the line is in an active state or a sleep state and whether the wide-area communication core unit C123 is in a non-communicating state, and to output an overload signal if the ratio R of active time to inactive time for the past N seconds (N is a positive real number) exceeds a threshold. Here, inactive time refers to the total time when the line is in a sleep state and when the wide-area communication core unit C123 is in a non-communicating state. The limit value of the ratio R that satisfies the specifications is determined, for example, by the battery capacity and designed operating time of the wide-area communication node A1, and this limit value is used as the threshold. When the wide-area communication node A1 also operates using energy harvesting, the limit value of the ratio R is determined, for example, by the battery capacity and designed operating time of the wide-area communication node A1, as well as the amount of power generated at the installation location and the allowable non-communicating time, and this limit value is used as the threshold.

[0033] [Supplementary explanation of the sensing data generation unit, state management unit, etc.] As shown in Fig. 1, the sensing data generation unit B11 may output alert information along with the sensing data. In this case, the wide-area communication unit B12 may control the communication state in accordance with the alert information. That is, the state management unit C122 may determine whether or not to output a non-communication state instruction signal using the overload signal and the alert information. Specifically, the state management unit C122 may output a non-communication state instruction signal only when the alert information indicates a non-alert state and an overload signal is input.

[0034] Alert information is information derived from sensing data, for example. For example, when the sensing data is water level, the information indicates a non-alert state under normal circumstances, but indicates an alert state when the water level rises, i.e., when the water level exceeds a certain level. For example, when the sensing data is slope, the information indicates a non-alert state under normal circumstances, but indicates an alert state when there is a possibility of a landslide or the like occurring, i.e., when the slope changes beyond a certain level. Various combinations are possible.

[0035] In the case of an alert state due to flooding or a landslide, for example, there may be cases where low-latency, timely information is required, even if the battery is overloaded and only a shorter operating time than designed.The state management unit C122 also references the alert information to determine whether or not to output a non-communication state indication signal, making it possible to transmit upstream and downstream data with low latency in situations where timely information is required.

[0036] [DB Server] The DB server A2 has a transmission / reception unit B21 that relays transmission / reception data as internal transmission / reception data, and a DB server core unit B22 that receives uplink data and transmits downlink data as one type of internal transmission / reception data, and stores the sensing data included in the uplink data in a DB or visualizes it. Details will be described in the section on operation, but in this embodiment, the wide area communication unit B12 may disconnect communication, in which case the transmission / reception unit B21 buffers the downlink data.

[0037] (A-2) Operation of the embodiment Next, the operation of the sensor network 1 according to the embodiment will be described in detail with reference to the drawings.

[0038] 2 is a flowchart showing the characteristic operation of the wide-area communication unit of the wide-area communication node according to the embodiment. In the following, in addition to the processing of the wide-area communication node A1, the processing of the DB server A2 will also be described as appropriate.

[0039] <S101、S102> The overload detection unit C121 detects an overload on the battery of the wide-area communication node A1 and outputs an overload signal to the state management unit C 122. The method of detecting an overload is, for example, the method described in the section on configuration.

[0040] <S103、S104> The state management unit C122 determines whether or not to output a non-communication state indication signal. When an overload signal is input from the overload detection unit C121, the state management unit C122 outputs the non-communication state indication signal to the wide-area communication core unit C123. As described above, when alert information is also input, the state management unit C122 determines whether or not to output a non-communication state indication signal in accordance with the overload signal and the alert information.

[0041] <s105> When a non-communication state instruction signal is input from the state management unit C122, the wide area communication core unit transmits a non-communication notification as one of the transmission and reception data to the transmission and reception unit B21 of the DB server A2, and then transitions to the non-communication state. Note that in order to transition the wide area communication core unit C123 to the non-communication state after reliably delivering the non-communication notification, the wide area communication core unit C123 may transition to the non-communication state after receiving a response to the non-communication notification from the transmission and reception unit B21.

[0042] <s106> The wide-area communication core unit C123 buffers the upstream data generated during the non-communication state. Meanwhile, the transceiver unit B21 of the DB server A2 buffers the downstream data after receiving the non-communication notification.

[0043] <S107、S108> When the wide-area communication core unit C123 is in a non-communication state, it returns to a communication state at a predetermined timing. In order to notify the transmitting / receiving unit B21 of the DB server A2 of the timing of returning to the communication state, the wide-area communication core unit C123 transmits a communication notification notifying the return to the transmitting / receiving unit B21 of the DB server A2 as one of the transmission / reception data.

[0044] <S109、S110> When the communication state is restored, the wide-area communication core unit C123 transmits the buffered uplink data to the wide-area communication core unit C123. Meanwhile, the transceiver unit B21 of the DB server A2 receives the communication notification and transmits the buffered downlink data, and the wide-area communication core unit C123 receives the downlink packets.

[0045] The predetermined timing for returning to the aforementioned communication state (the return timing in step S107) can be, for example, the timing when a predetermined time has elapsed since the non-communication state was entered, or the timing when the ratio S of active time to inactive time in the past M seconds (M is a positive real number) becomes equal to or less than the return threshold.

[0046] In addition to these methods, the sensing data input from the sensing data generation unit B11 to the wide area communication core unit C123 may also include the above-mentioned alert information, and the system may be restored when the alert information indicates that the system is in an alert state. As a derivative example of this, a certain degree of effectiveness can be achieved by restoring the system only when the alert information indicates that the system is in an alert state.

[0047] Although the risk of packet loss increases with the transmission notification, a certain effect of this embodiment can be obtained by notifying the transmission / reception unit B21 of the DB server A2 of the return by notifying the expected return time at the same time as the non-communication notification.

[0048] After step S110 (after returning to a communication state), the wide-area communication node A1 returns to step S101 again and monitors the load.

[0049] (A-3) Effects of the embodiment According to this embodiment, the following effects are achieved.

[0050] The wide-area communication node A1 uses public communication lines with low communication costs, while preventing battery drain due to unintended packets from outside.Furthermore, when utilizing alert information, it can transmit upstream and downstream data with low latency in situations where timely information is required.

[0051] By preventing battery consumption, the wide-area communication node A1 can operate for a long time on a battery alone or on a battery combined with an energy harvester such as a solar panel. Also, when the wide-area communication node A1 is combined with a solar panel, the solar panel can be made smaller.

[0052] (B) Other embodiments The present invention is not limited to the above-described embodiment, and modified embodiments such as those exemplified below can also be mentioned.

[0053] (B-1) In the above embodiment, the wide-area communication core unit C123 can enter a non-communication state upon receiving a non-communication state instruction signal. However, some electronic devices that handle the physical layer record base station information and the like in a non-volatile recording component such as a flash ROM when communication is cut off, but the recording component has a limit to the number of times it can be rewritten. If such an electronic component is used, excessive transitions to a non-communication state will shorten the life of the device.

[0054] Therefore, the number of times the non-communication state has been transitioned to can be recorded in a recording component such as RAM that has no limit on the number of times it can be rewritten, and if the number of times the non-communication state has been transitioned to exceeds a threshold, the conditions for transitioning to the non-communication state can be tightened to extend the time until the transition to the non-communication state, or the conditions for transitioning to the communication state can be tightened to extend the time until the state returns to the communication state, or the restriction on the non-communication state can be prohibited, thereby reducing the number of times the non-communication state is transitioned to, and thereby solving this problem.

[0055] (B-2) If the number of times the node has transitioned to a non-communication state exceeds a threshold, electronic data for warning the administrator of the wide-area communication node A1 may be transmitted as one of the upstream data.

[0056] (B-3) In the above embodiment, the sensing data generation unit B11 outputs alarm information, but as a modified example, this alarm information does not need to be output. In this case, the state management unit C122 does not need to process the alarm information. [Explanation of symbols]

[0057] 1, 100...sensor network, A1...wide area communication node, A2...DB server, B11...sensing data generation unit, B12...wide area communication unit, B21...transmitter / receiver unit, B22...DB server core unit, C121...overload detection unit, C122...status management unit, C123...wide area communication core unit, Z1...wide area communication node, Z2...DB server.

Claims

1. A communication device connected to a server that collects sensing data via a low-power wide-area communication network, a sensing data generation unit that generates and outputs the sensing data; an overload detection unit that detects an overload of a battery that drives the device and outputs an overload signal; a state management unit that outputs a non-communication state indication signal when the overload signal is input; When the non-communication state instruction signal is input, the wide-area communication core unit transitions to a non-communication state in which no packets can be sent or received temporarily. A communication device comprising:

2. The communication device described in claim 1, characterized in that the wide area communication core unit defines communication states of a sleep state with low power consumption and an active state with high power consumption, and transmits upstream data as one of the transmitted and received data and receives downstream data as one of the transmitted and received data using a line that achieves low power consumption by transitioning between the active state and the sleep state depending on the presence or absence of packets.

3. 3. The communication device according to claim 2, wherein the overload detection unit monitors the current supplied from the battery, and outputs the overload signal when the current is higher than a first threshold value.

4. the sensing data generation unit outputs alarm information together with the sensing data, The state management unit determines whether or not the non-communication state indication signal needs to be output using the overload signal and the alarm information.

4. The communication device according to claim 2 or 3.

5. The communication device according to claim 4, characterized in that the status management unit outputs the non-communication state indication signal only when the alert information indicates a non-alert state and the overload signal is input.

6. The wide area communication core unit When the non-communication state instruction signal is input from the state management unit, a non-communication notification is transmitted to the server as one of the transmission / reception data, and then the state transitions to the non-communication state; Upstream data generated during the non-communication state is buffered, When the non-communication state instruction signal is input from the state management unit, the non-communication notification is transmitted to the server as one of the transmission / reception data, and then the state transitions to the non-communication state; In the case of the non-communication state, the communication state is restored at a predetermined timing, and a communication notification informing the server of the timing of the restoration to the communication state is transmitted as one of the transmission and reception data; After returning to the communication state, the buffered uplink data is transmitted.

6. The communication device according to claim 4 or 5.

7. 7. The communication device according to claim 6, wherein the predetermined timing is a timing when a predetermined time has elapsed since the non-communication state was established.

8. The communication device according to claim 6 , wherein the predetermined timing is a timing when a ratio of active time to inactive time in the past M seconds (M is a positive real number) becomes equal to or less than a fourth threshold.

9. 7. The communication device according to claim 6, wherein the predetermined timing is a timing when the alert information indicates that an alert state exists.

10. The wide area communication core unit A communication device as described in any one of claims 1 to 9, characterized in that the number of times the non-communication state is transitioned to is recorded in a recording unit, and if the number of times the non-communication state is transitioned to exceeds a fifth threshold, the number of times the non-communication state is transitioned to is reduced.

11. 11. The communication device according to claim 10, wherein the wide-area communication core unit transmits electronic data for issuing a warning when the number of times the device has transitioned to the non-communication state exceeds the fifth threshold value.

12. A communication device described in any one of claims 1 to 11, characterized in that the communication device is connected to a communication line that can receive unintended packets from the outside, and is powered by the battery in combination with environmental power generation.

13. a computer installed in a communication device connected to a server that collects sensing data via a low-power wide-area communication network; a sensing data generation unit that generates and outputs the sensing data; an overload detection unit that detects an overload of a battery that drives the device and outputs an overload signal; a state management unit that outputs a non-communication state indication signal when the overload signal is input; When the non-communication state instruction signal is input, the wide-area communication core unit transitions to a non-communication state in which no packets can be sent or received temporarily. A communication program characterized by functioning as follows.

14. A communication method used in a communication device connected to a server that collects sensing data via a low-power wide area communication network, comprising: the sensing data generation unit generates and outputs the sensing data; The overload detection unit detects an overload of the battery that drives the device and outputs an overload signal; the state management unit outputs a non-communication state indication signal when the overload signal is input; When the non-communication state instruction signal is input, the wide-area communication core unit transitions to a non-communication state in which no packets can be sent or received temporarily. A communication method comprising:

15. A communication system having a communication device and a server, The communication device is a communication device according to any one of claims 1 to 12. A communication system comprising:

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