JP7508864B2 - COMMUNICATION SYSTEM AND COMMUNICATION METHOD - Google Patents

Description

The present invention relates to a communication system and a communication method.

Conventionally, in the event of a disaster such as an earthquake, tsunami, typhoon, or nuclear accident, it is necessary to reliably obtain necessary data (seismic intensity, flood depth, radiation level, etc.) from sensors placed at specified locations. If the communication lines between a disaster prevention center such as an administrative agency and each of the sensors acquiring data are cut off during such a disaster, it becomes impossible to obtain subsequent data. As a countermeasure to this, for example, as shown in Patent Document 1, there is a technology that provides a first communication path (first communication line) and a second communication path (second communication line). In Patent Document 1, by duplicating the communication lines between the parent station and the child station in a disaster prevention radio system, communication can be continued using the second communication path even if the first communication path is cut off due to some cause such as a malfunction.

JP 2018-133676 A

However, in Patent Document 1, when the first communication path is interrupted, communication is performed by switching to the second communication path. Therefore, even though multiple communication lines are secured, communication is always performed using only one line, so it is difficult to say that the multiple communication lines are used effectively. On the other hand, if communication is always continued using the second communication path that uses multiple communication lines, the power for the multiple lines is consumed, which increases the operating costs.

The present invention has been made in light of these circumstances. The object of the present invention is to provide a communication system and a communication method that can effectively utilize multiple communication lines while suppressing power consumption.

The communication system of the present invention is a communication system that uses two lines, a first communication line using a specified communication method and a second communication line using a LPWA standard communication method, to aggregate environmental data measured by sensor terminals in a server device, and is equipped with an activation determination unit that determines whether to activate the second communication line together with the first communication line based on a specified activation condition related to the occurrence of a disaster, and a communication control unit that controls communication via each of the first communication line and the second communication line based on the determination result by the activation determination unit.

The communication method of the present invention is a communication method in a communication system that uses two lines, a first communication line using a predetermined communication method and a second communication line using a LPWA standard communication method, to aggregate environmental data measured by sensor terminals in a server device, in which an activation determination unit determines whether or not to activate the second communication line together with the first communication line based on a predetermined activation condition related to the occurrence of a disaster, and a communication control unit controls communication via each of the first communication line and the second communication line based on the determination result by the activation determination unit.

The present invention makes it possible to effectively utilize multiple communication lines while reducing power consumption.

1 is a block diagram showing an example of the configuration of a communication system 1 according to an embodiment of the present invention. 1 is a block diagram showing an example of a configuration of a server device 10 according to an embodiment of the present invention. 2 is a block diagram showing an example of a configuration of a sensor terminal 30 according to an embodiment of the present invention. FIG. 11 is a diagram showing an example of a configuration of alarm table information 190 according to the embodiment of the present invention. FIG. 11 is a diagram showing an example of a configuration of environment table information 191 according to an embodiment of the present invention. FIG. FIG. 11 is a diagram showing an example of the configuration of threshold information 192 according to an embodiment of the present invention. 2 is a sequence diagram showing a flow of processing performed by the communication system 1 according to the embodiment of the present invention. FIG. 2 is a sequence diagram showing a flow of processing performed by the communication system 1 according to the embodiment of the present invention. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a communication system 1 according to an embodiment of the present invention. The communication system 1 includes, for example, a server device 10, a first communication network 20, a second communication network 21, a plurality of sensor terminals 30 (sensor terminals 30-1, 30-2, ..., 30-N), and an emergency alert server 40. N is any natural number.

In the communication system 1, the server device 10 and the sensor terminal 30 are connected to each other so as to be able to communicate with each other via the first communication network 20 and the second communication network 21. That is, in the communication system 1, the server device 10 and the sensor terminal 30 are capable of communicating with each other via the first communication network 20 and also via the second communication network 21. In addition, in the communication system 1, the server device 10 and the emergency alert server 40 are connected to each other so as to be able to communicate with each other.

The communication system 1 is a communication system that aggregates environmental data measured by the sensor terminals 30 in the server device 10. The environmental data is information about the environment, such as information indicating the radiation dose, the concentration of a certain type of toxic gas or a foul-smelling gas, the number of scattered pollen grains per unit area, the intensity of noise, the amount of matter scattered by exhaust smoke, or the concentration of other harmful substances.

The server device 10 is a computer device that controls the sensor terminals 30 and aggregates the environmental data measured by the sensor terminals 30. For example, the server device 10 transmits a control signal to the sensor terminals 30 and commands the sensor terminals 30 to communicate in accordance with the control signal. The control signal indicates the communication conditions between the server device 10 and the sensor terminals 30, such as the communication method to be used when transmitting, and the timing and frequency of transmission.

In particular, the server device 10 controls the communication lines depending on the situation of the disaster. The disasters assumed here are disasters that are expected to affect environmental data, such as nuclear accidents that are expected to spread radioactive materials, factory fires or earthquakes that are expected to generate specific toxic gases, or floods. When such a disaster occurs, the scale and situation of the disaster can be understood and the effects on the human body can be predicted by continuing to reliably and accurately measure environmental data. For this reason, the server device 10 controls the communication lines so that environmental data can be reliably aggregated depending on the situation of the disaster. The communication lines here are communication lines between the server device 10 and the sensor terminals 30, and control whether to use only the first communication network 20 or the first communication network 20 and the second communication network 21.

For example, the server device 10 controls the communication line based on the contents of the alert received from the emergency alert server 40. Alternatively, the server device 10 controls the communication path based on the contents of the environmental data received from the sensor terminal 30. The specific method by which the server device 10 controls the communication line will be described in detail later.

The first communication network 20 communicates using a predetermined communication method. The predetermined communication method here is a communication network that includes some or all of the following: the Internet, a Wide Area Network (WAN), a Local Area Network (LAN), a provider device, a wireless base station, a dedicated line, etc. The first communication network 20 may also communicate using a Low Power Wide Area (LPWA) standard communication method, which will be described later.

The second communication network 21 performs communication according to the LPWA standard communication method. The second communication network 21 performs communication according to a communication method conforming to, for example, Sigfox (registered trademark), LoRa (registered trademark), ZETA (registered trademark), or the like. The LPWA standard communication method is characterized in that it reduces power consumption compared to existing communication networks, such as LTE (Long Term Evolution), by suppressing the communication speed. In addition, it is characterized in that the communication distance is long, for example, from several tens of kilometers to about 100 kilometers, compared to short-range wireless communication such as Bluetooth (registered trademark). In addition, when ZETA is applied to the second communication network 21, multi-channel communication may be performed using an ultra-narrow band (UNB (Ultra Narrow Band)) in which the communication band is divided into multiple bands. In this case, the band of the channel used for communication may be fixed to the same band every time, or may be operated so as to change without being fixed every time. As a result, communication can be performed using an available band, and it is possible to suppress communication being restricted due to the band being used by another device.

In addition, in the communication system 1, a repeater may be disposed to relay communication between the server device 10 and the sensor terminal 30 via the second communication network 21. This makes it possible to set the communication distance longer.

The sensor terminal 30 is a device equipped with various sensors for measuring objects to be measured and communication functions. The various sensors here are sensors for measuring environmental data, such as radiation doses and specific types of toxic gases. The sensor terminal 30 transmits environmental data to the server device 10 under the control of the server device 10 by using the first communication network 20 or both the first communication network 20 and the second communication network 21.

The emergency alert server 40 is a computer device that transmits emergency alerts. The emergency alert server 40 is installed, for example, in a disaster countermeasure center of a government agency, and transmits an emergency alert when an emergency alert is issued in the event of a disaster, etc.

FIG. 2 is a block diagram showing an example of the configuration of a server device 10 according to an embodiment of the present invention. The server device 10 includes, for example, a main line communication unit 11, a sub-line communication unit 12, a start-up determination unit 13, a communication control unit 14, a retransmission determination unit 15, a data capacity monitoring unit 17, a device control unit 18, and a storage unit 19.

The main line communication unit 11 is a functional unit that communicates with the sensor terminal 30 via the first communication network 20, and is configured, for example, by an Internet communication module. The sub-line communication unit 12 is a functional unit that communicates with the sensor terminal 30 via the second communication network 21, and is configured, for example, by a communication module conforming to the LPWA standard.

The start-up determination unit 13 determines whether or not to start the communication line. The start-up determination unit 13 determines whether or not to start the second communication network 21 together with the first communication network 20 based on a predetermined start-up condition related to the occurrence of a disaster. For example, the start-up determination unit 13 determines to start only the first communication network 20 in normal times. Here, normal times refers to a situation in which no disaster has occurred, for example, a situation in which no warning is being sent by the emergency warning server 40, and further, a situation in which the environmental data measured by the sensor terminal 30 does not indicate abnormal values.

When an abnormality occurs, the activation determination unit 13 determines that the second communication network 21 should be activated together with the first communication network 20. An abnormality here refers to a situation in which a disaster has occurred, such as when an alarm is sent by the emergency alarm server 40 or when the environmental data measured by the sensor terminal 30 indicates an abnormal value.

Here, a specific method for controlling the communication line will be described. First, a method for controlling the communication line when an alarm is transmitted by the emergency alarm server 40 will be described. When an alarm is transmitted from the emergency alarm server 40, the start-up determination unit 13 acquires the alarm and refers to the alarm table information 190 based on the acquired alarm content. The alarm table information 190 is information stored in the storage unit 19, and is information in which the alarm content is associated with an alarm level. In this way, the start-up determination unit 13 acquires an alarm level corresponding to the alarm content. Furthermore, the start-up determination unit 13 refers to the threshold information 192 based on the acquired alarm level. The threshold information 192 is information stored in the storage unit 19, and is information indicating the threshold (minimum level) of the alarm level when the second communication network 21 is activated together with the first communication network 20. When the alarm level corresponding to the alarm content is equal to or higher than the alarm level indicated in the threshold information 192, the start-up determination unit 13 determines that the second communication network 21 is activated together with the first communication network 20.

Next, a method for controlling a communication line when the environmental data measured by the sensor terminal 30 indicates an abnormal value will be described. The start-up determination unit 13 acquires the environmental data notified from the sensor terminal 30, and refers to the environmental table information 191 based on the numerical value of the acquired environmental data. The environmental table information 191 is information stored in the storage unit 19, and is information in which the environmental level is associated with the numerical value of the environmental data. In this way, the start-up determination unit 13 acquires the environmental level corresponding to the value of the environmental data. Furthermore, the start-up determination unit 13 refers to the threshold information 192 based on the acquired environmental level. The threshold information 192 is information stored in the storage unit 19, and is information indicating the threshold (minimum level) of the environmental level when the second communication network 21 is activated together with the first communication network 20. The start-up determination unit 13 determines that the second communication network 21 is activated together with the first communication network 20 when the environmental level corresponding to the value of the environmental data is equal to or higher than the environmental level indicated in the threshold information 192.

The communication control unit 14 controls the communication line according to the judgment result of the start-up judgment unit 13. When the start-up judgment unit 13 judges that only the first communication network 20 should be started, the communication control unit 14 starts only the first communication network 20. When the start-up judgment unit 13 judges that both the first communication network 20 and the second communication network 21 should be started, the communication control unit 14 starts both the first communication network 20 and the second communication network 21.

The communication control unit 14 not only controls the communication line, but also controls the communication frequency and the conditions for retransmission. For example, when it is determined that detailed environmental data needs to be aggregated during an abnormality, the communication control unit 14 controls the communication frequency to be higher than normal. In this case, the communication control unit 14 instructs the sensor terminal 30 to make the transmission interval of the environmental data shorter than normal. Furthermore, after controlling the communication frequency to be higher, if it is determined that it is no longer necessary to aggregate detailed environmental data because, for example, the disaster situation has stabilized, the communication control unit 14 may control the communication frequency to be returned to the normal state.

In addition, when the retransmission determination unit 15 described later determines that it is necessary to retransmit the environmental data, the communication control unit 14 commands the sensor terminal 30 to retransmit the environmental data. In this case, the communication control unit 14 may specify a communication line to be used when retransmitting the environmental data. For example, the communication control unit 14 may specify that the environmental data is to be retransmitted using only the first communication network 20, may specify that the environmental data is to be retransmitted using only the second communication network 21, or may specify that the environmental data is to be retransmitted using both the first communication network 20 and the second communication network 21.

In addition, when the data capacity monitoring unit 17 described later determines that there is a possibility of insufficient capacity for storing environmental data, the communication control unit 14 commands the sensor terminal 30 to transmit the environmental data to a device other than the server device 10 (e.g., a database server such as a cloud). In this case, the communication control unit 14 may specify a communication line to be used when transmitting the environmental data to the other device. For example, the communication control unit 14 may specify that the environmental data notified using the first communication network 20 is to be transmitted to the other device, or that the environmental data notified using the second communication network 21 is to be transmitted to the other device, or that both the environmental data notified using the first communication network 20 and the second communication network 21 are to be transmitted to the other device.

The retransmission determination unit 15 determines whether or not to retransmit the environmental data. The retransmission determination unit 15 determines to retransmit the environmental data when the received environmental data is unreliable, for example, when the environmental data show different values depending on the communication line used to notify the environmental data. In this case, it is assumed that environmental data is being aggregated using both the first communication network 20 and the second communication network 21 due to the occurrence of a disaster, etc.

As methods for determining whether environmental data is reliable, the following two methods, method 1 and method 2, can be considered.

As a first judgment method, for example, the retransmission judgment unit 15 acquires environmental data (hereinafter referred to as first data) received via the first communication network 20 and environmental data (hereinafter referred to as second data) received via the second communication network 21 at the same time. The retransmission judgment unit 15 compares the first data with the second data, and calculates, for example, the difference between the first data and the second data. If the calculated difference is equal to or greater than a predetermined threshold, the retransmission judgment unit 15 judges to retransmit the environmental data. This is because it is considered that there is an error in either the first data or the second data, or in both. Possible causes of errors in the environmental data include the occurrence of a communication line malfunction, such as sudden noise on the communication line or a temporary disconnection of the line. If the difference between the retransmitted first data and the second data is less than a predetermined threshold, the retransmission judgment unit 15 considers that the communication line malfunction has been resolved, and stops retransmission of the environmental data, assuming that error-free environmental data has been acquired.

On the other hand, the retransmission determination unit 15 retransmits the environmental data each time if the difference between the retransmitted first data and the second data is equal to or greater than a predetermined threshold. If the difference between the retransmitted first data and the second data is equal to or greater than a predetermined threshold even after the retransmission is performed a predetermined number of times, the retransmission determination unit 15 determines that there is some kind of malfunction (such as an abnormality in the sensor or communication line) in the process of aggregating the environmental data. If the retransmission determination unit 15 determines that there is some kind of malfunction, it does not search further for the cause of the malfunction, and continues to acquire the environmental data via only the first communication network 20, or both the first communication network 20 and the second communication network 21. In this case, the retransmission determination unit 15 may add a message to the environmental data indicating that there is some kind of malfunction in the process of aggregating the environmental data. Alternatively, the retransmission determination unit 15 may stop the data aggregation from the sensor terminal 30 that measured the environmental data that is determined to have some kind of malfunction.

Alternatively, if the retransmission determination unit 15 determines that there is some kind of problem in the process of aggregating the environmental data, it may issue an alert to that effect and instruct the site to confirm. In this case, the site is the location where the sensor terminal 30 that measured the environmental data that is determined to have some kind of problem is installed.

In the second judgment method, the retransmission judgment unit 15 compares the first data and the second data with the environmental data notified from a nearby sensor terminal 30 (hereinafter referred to as the third data) when the difference between the first data and the second data is equal to or greater than a predetermined threshold. The nearby sensor terminal 30 here is a sensor terminal 30 installed near the location where the sensor terminal 30 that measured the first data and the second data is installed. The range of the nearby area may be any range in which the values of the environmental data can be considered to be approximately equivalent, and may be set arbitrarily depending on the measurement target measured by the sensor terminal 30 and the measurement performance of the sensor. It is preferable to use the third data here for which it has been confirmed that the difference between the environmental data received via the first communication network 20 and the environmental data received via the second communication network 21 is less than a predetermined threshold.

For example, the retransmission judgment unit 15 calculates the difference between the first data and the third data (hereinafter referred to as the first difference) and the difference between the second data and the third data (hereinafter referred to as the second difference). If the calculated first difference is less than a predetermined threshold and the second difference is equal to or greater than the predetermined threshold, the retransmission judgment unit 15 determines that there is an error in the second data. On the other hand, if the calculated first difference is equal to or greater than the predetermined threshold and the second difference is less than the predetermined threshold, the retransmission judgment unit 15 determines that there is an error in the first data. In this case, the retransmission judgment unit 15 causes the environmental data to be retransmitted via the communication circuit to which the environmental data deemed to be erroneous was notified.

In the above, an example has been described in which the sensor terminal 30 that measured the third data is installed near the sensor terminal 30 that measured the first data and the second data. However, this is not limited to this. If there is no other sensor terminal 30 near the sensor terminal 30 that measured the first data and the second data, the retransmission determination unit 15 may use any sensor terminal 30 to determine whether there is an error in the first data or the second data. In this case, for example, when aggregating environmental data measured by each of the multiple sensor terminals 30 under normal circumstances, the retransmission determination unit 15 keeps track of the relative relationship (hereinafter referred to as offset) between the respective environmental data.

If the difference between the first data and the second data is equal to or greater than a predetermined threshold, the retransmission determination unit 15 compares the first data with the environmental data (hereinafter referred to as the fourth data) notified from an arbitrary sensor terminal 30. The retransmission determination unit 15 calculates the difference between the first data and the fourth data (hereinafter referred to as the third difference) and the difference between the second data and the fourth data (hereinafter referred to as the fourth difference). If the calculated third difference is less than a predetermined offset threshold and the second difference is equal to or greater than a predetermined offset threshold, the retransmission determination unit 15 considers that there is an error in the second data. The offset threshold here is a predetermined threshold plus an offset that is grasped under normal circumstances between the sensor terminal 30 that measured the first data and the second data and the sensor terminal 30 that measured the fourth data. If the third difference is equal to or greater than a predetermined offset threshold and the fourth difference is less than a predetermined offset threshold, the retransmission determination unit 15 considers that there is an error in the first data.

The retransmission determination unit 15 may perform the above-mentioned determination method 1 and determination method 2 alone, or may perform the above-mentioned determination method 1 and determination method 2 in combination.

In this embodiment, environmental data collected from the sensor terminals 30 is stored. In particular, when a disaster occurs, environmental data is collected using both the first communication network 20 and the second communication network 21. This may cause a sudden increase in the amount of data stored in the memory unit 19. If the amount of data stored in the memory unit 19 increases suddenly, it may become difficult to continue storing environmental data in the memory unit 19. In this case, it will no longer be possible to grasp the scale and situation of the disaster or predict its impact on the human body.

As a countermeasure to this, the data capacity monitoring unit 17 monitors the capacity of the environmental data stored in the memory unit 19. For example, when environmental data is aggregated using both the first communication network 20 and the second communication network 21, the data capacity monitoring unit 17 acquires the capacity of the environmental data stored in the memory unit 19. If the acquired capacity is equal to or greater than a predetermined threshold, the data capacity monitoring unit 17 determines to limit the environmental data to be stored in the memory unit 19. In this case, the data capacity monitoring unit 17 controls, for example, via the communication control unit 14, the destination of the environmental data notified from the sensor terminal 30 to be notified to another device.

Alternatively, if there is no significant change in the environmental data notified from the sensor terminal 30, the data capacity monitoring unit 17 may thin out the environmental data notified from the sensor terminal 30 and store it in the storage unit 19. Alternatively, if there is no significant change in the environmental data notified from the sensor terminal 30, the data capacity monitoring unit 17 may control to reduce the notification frequency of the environmental data notified from the sensor terminal 30 via the communication control unit 14.

The device control unit 18 controls the server device 10 in an integrated manner. For example, the device control unit 18 outputs an alarm received from the emergency alarm server 40 to the activation determination unit 13. The device control unit 18 outputs the determination result determined by the activation determination unit 13 to the communication control unit 14. The device control unit 18 outputs the determination result determined by the retransmission determination unit 15 to the communication control unit 14. When the data capacity monitoring unit 17 determines that the environmental data to be stored in the storage unit 19 should be limited, the device control unit 18 performs processing according to the determination. For example, when the device control unit 18 changes the notification destination of the environmental data to the sensor terminal 30 or when the device control unit 18 reduces the frequency of notification of the environmental data, it outputs the same to the communication control unit 14. When the device control unit 18 thins out and stores the environmental data notified from the sensor terminal 30, it thins out the environmental data received by the main line communication unit 11 and the sub-line communication unit 12 and stores it in the storage unit 19.

The storage unit 19 is configured with a storage medium, for example, a hard disk drive (HDD), a flash memory, an electrically erasable programmable read only memory (EEPROM), a random access read/write memory (RAM), a read only memory (ROM), or any combination of these storage media. The storage unit 19 stores programs for executing various processes of the server device 10, and temporary data used when performing various processes.

The memory unit 19 stores, for example, alarm table information 190, environmental table information 191, and threshold information 192. The alarm table information 190 is information in which the content of an alarm corresponds to an alarm level. The environmental table information 191 is information in which the value of environmental data corresponds to an environmental level. The threshold information 192 is information indicating the alarm level and environmental level that activate the second communication network 21 together with the first communication network 20.

Figure 3 is a block diagram showing an example of the configuration of a sensor terminal 30 according to an embodiment of the present invention. The sensor terminal 30 includes, for example, a sensor unit 300 and a communication module 310. The sensor unit 300 is a type of sensor, such as a sensor that measures radiation levels or a sensor that measures gas concentrations. The communication module 310 includes a main line communication unit 31, a sub-line communication unit 32, a sensor information acquisition unit 33, a communication control unit 34, a control unit 37, and a memory unit 38.

The main line communication unit 31 communicates with the server device 10 via the first communication network 20. The main line communication unit 31 transmits environmental data to the server device 10 via the first communication network 20. The main line communication unit 31 receives, for example, a control signal from the server device 10.

The sub-line communication unit 32 communicates with the server device 10 via the second communication network 21. The sub-line communication unit 32 transmits environmental data to the server device 10 via the second communication network 21. The sub-line communication unit 32 may receive a control signal from the server device 10 in place of the main line communication unit 31 or together with the first communication network 20.

The sensor information acquisition unit 33 is, for example, an IO (Input Output) port that connects to the sensor unit 300, and by connecting to the sensor unit 300 via the IO port, acquires information (environmental data) measured by the sensor unit 300. The sensor information acquisition unit 33 stores the acquired environmental data in the memory unit 38.

The communication control unit 34 controls the notification of environmental data to the server device 10 according to the server device 10. The communication control unit 34 acquires a control signal transmitted from the server device 10 via the main line communication unit 31 or the sub-line communication unit 32. When the communication control unit 34 acquires a control signal to start the first communication network 20, the communication control unit 34 transmits environmental data to the server device 10 via the main line communication unit 31 and the first communication network 20. When the communication control unit 34 acquires a control signal to start the second communication network 21 together with the first communication network 20, the communication control unit 34 transmits environmental data to the server device 10 via the main line communication unit 31 and the first communication network 20, and transmits environmental data to the server device 10 via the sub-line communication unit 32 and the second communication network 21. When the communication control unit 34 acquires a control signal to change the frequency of transmission of environmental data, the communication control unit 34 changes the frequency of transmission of environmental data to the server device 10. When the communication control unit 34 acquires a control signal to change the notification destination to which environmental data is notified, the communication control unit 34 transmits environmental data to another device.

The control unit 37 performs overall control of the sensor terminal 30. The control unit 37 outputs the environmental data acquired by the sensor information acquisition unit 33 to the main line communication unit 31 and the sub-line communication unit 32 under the control of the communication control unit 34.

The storage unit 38 is configured with a storage medium, for example, a HDD, a flash memory, an EEPROM, a RAM, a ROM, or any combination of these storage media. The storage unit 38 stores programs for executing various processes of the sensor terminal 30, and temporary data used when performing various processes. The storage unit 38 stores environmental data 280. The environmental data 280 is information measured by the sensor unit 300.

FIG. 4 is a diagram showing an example of the configuration of alarm table information 190 according to an embodiment of the present invention. The alarm table information 190 includes items such as a table ID, alarm information, and alarm level. The table ID is identification information that uniquely identifies the table. The table here shows the correspondence between the content of the alarm and the alarm level. The alarm information is the specific content indicated by the alarm, and includes items such as information type and information content. The alarm type is information indicating the type of alarm, and in this example, indicates earthquake, tsunami, and furnace temperature. The furnace temperature indicates the internal temperature of the reactor of a nuclear power plant. The information content is information indicating the content of the alarm specified by the information type, and in this example, the earthquake's seismic intensity is indicated for an earthquake alarm. The alarm level is an alarm level associated with the alarm specified by the alarm information. In this example, when an alarm regarding the furnace temperature is issued as an alarm, if the furnace temperature is equivalent to a meltdown, the alarm level is level 5, and if it is a predetermined temperature (in the figure, it is written as "furnace temperature XX or higher"), the alarm level is level 3.

FIG. 5 is a diagram showing an example of the configuration of environmental table information 191 according to an embodiment of the present invention. In this example, an example of environmental table information 191 is shown when the environmental data is a radiation dose. In this way, the environmental table information 191 may be created for each measurement target that is measured as environmental data. The environmental table information 191 includes items such as a table ID, a radiation dose, and an environmental level. The table ID is identification information that uniquely identifies the table. The table here shows the correspondence between the environmental data value and the environmental level. The radiation dose is the amount of measured radiation. The environmental level is the environmental level associated with the radiation dose corresponding to the environmental data value. In this example, it is shown that if the radiation dose is equal to or greater than a predetermined threshold (shown as "XX or more" in the figure), the environmental level is level 5, and if the radiation dose is less than the predetermined threshold (shown as "less than XX to XX" in the figure), the environmental level is level 4.

Figure 6 is a diagram showing an example of the configuration of threshold information 192 according to an embodiment of the present invention. Threshold information 192 includes items such as a threshold ID, a target, and a threshold. The threshold ID is identification information that uniquely identifies a threshold. The target is an object for which a threshold specified by a threshold ID is set, and in the example of this figure, an alert level and an environmental level are shown as targets. The threshold is information indicating a threshold at which the second communication network 21 is started together with the first communication network 20 for the object specified by the threshold ID. In this example, it is shown that the second communication network 21 is started together with the first communication network 20 when both the alert level and the environmental level are level 4 or higher.

Figures 7 and 8 are sequence diagrams showing the flow of processing performed by the communication system 1 according to an embodiment of the present invention. Figure 7 shows the flow of processing to control a communication line when an alarm is sent. Figure 8 shows the flow of processing to control a communication line when environmental data indicates an abnormal value. Note that the flows in Figures 7 and 8 are based on the premise that normal operation is performed, that is, that environmental data is periodically collected using the first communication network 20. Also, the "sensor information" in the flows in Figures 7 and 8 is information measured by a sensor, and is an example of "environmental data".

First, using Figure 7, we will explain the process flow for controlling the communication line when an alarm is sent.

In step S10, the server device 10 stores the threshold information 192. For example, the threshold information 192 is stored in the server device 10 by an operator or the like setting the threshold information 192 via an input device such as a keyboard or a mouse.

In step S11, the emergency alert server 40 transmits an alert. In step S12, the alert transmitted by the emergency alert server 40 is received by the server device 10.

In step S13, the server device 10 determines whether the alarm level is equal to or higher than the threshold based on the content of the received alarm. The threshold here indicates the threshold of the alarm level at which it is determined that the second communication network 21 should be started together with the first communication network 20. The server device 10 refers to the alarm table information 190 based on the received alarm, and acquires the alarm level corresponding to the content of the alarm. The server device 10 refers to the threshold information 192 based on the acquired alarm level, and determines whether the alarm level is equal to or higher than the threshold. If the alarm level corresponding to the content of the received alarm is equal to or higher than the threshold, the server device 10 transmits a control signal to the sensor terminal 30 to start up the second communication network 21 together with the first communication network 20. On the other hand, if the alarm level corresponding to the content of the received alarm is less than the threshold, the server device 10 returns to step S12 and waits for reception of an alarm.

In step S14, the sensor terminal 30 starts the sub-line (second communication network 21) in accordance with the control signal from the server device 10. The control signal here is a signal indicating an instruction to start the second communication network 21 together with the first communication network 20.

In step S15, the sensor terminal 30 starts notifying the environmental data using the sub-line. The sensor terminal 30 transmits the sensor information (environmental data) to the server device 10 at a predetermined timing (transmission timing) using both the main line (first communication network 20) and the sub-line.

In step D16, the server device 10 receives sensor information from both the main line and the sub-line. In step S17, the server device 10 determines whether the received sensor information is reliable. For example, the server device 10 determines that the sensor information is reliable when the difference between the sensor information acquired via the main line and the sensor information acquired via the sub-line is less than a predetermined threshold, and determines that the sensor information is unreliable when the difference is equal to or greater than the predetermined threshold. If the received sensor information is unreliable, the server device 10 requests the sensor terminal 30 to resend the environmental data. On the other hand, if the received sensor information is reliable, the server device 10 proceeds to step S20.

In step S18, the sensor terminal 30 resends the sensor information in accordance with instructions from the server device 10. In the event of an abnormality, the processes shown in steps S15 to S18 are repeated.

In step S19, the emergency warning server 40 transmits a new warning (including the cancellation of the warning) if the disaster situation changes, such as if the warning is cancelled. In step S12, the server device 10 receives the warning. In step S13, the server device 10 determines whether the warning level is equal to or higher than the threshold based on the content of the received warning. If the warning level corresponding to the content of the received warning is equal to or higher than the threshold, the server device 10 returns to step S16 and continues aggregating sensor information from both the first communication network 20 and the second communication network 21. On the other hand, if the warning level corresponding to the content of the received warning is less than the threshold, the server device 10 transmits a control signal to the sensor terminal 30 to stop the second communication network 21. In step S22, the sensor terminal 30 stops notifying environmental data via the second communication network 21 under the control of the server device 10.

Next, the flow of the process for controlling the communication line when the environmental data indicates an abnormal value will be described with reference to FIG. 8. The process shown in steps S30 and S34 to S38 is the same as the process shown in steps S10 and S14 to S18, so the description thereof will be omitted.

In step S31, the sensor terminal 30 notifies the server device 10 of the measured sensor information. The notification here is performed using the main line (first communication network 20).

In step S32, the server device 10 receives the sensor information. In step S33, the server device 10 determines whether the environmental level is equal to or greater than the threshold based on the value of the received sensor information. The threshold here indicates the environmental level threshold at which it is determined to start the second communication network 21 together with the first communication network 20. The server device 10 refers to the environmental table information 191 based on the received sensor information, and acquires the environmental level corresponding to the value of the sensor information. The server device 10 refers to the threshold information 192 based on the acquired environmental level, and determines whether the environmental level is equal to or greater than the threshold. If the environmental level corresponding to the value of the received sensor information is equal to or greater than the threshold, the server device 10 transmits a control signal to the sensor terminal 30 to start the second communication network 21 together with the first communication network 20. On the other hand, if the alarm level corresponding to the content of the received alarm is less than the threshold, the server device 10 returns to step S32 and waits for notification of the sensor information.

In step S39, the server device 10 determines whether the environmental level is equal to or greater than the threshold based on the value of the sensor information notified from the sensor terminal 30. If the environmental level corresponding to the value of the received sensor information is equal to or greater than the threshold, the server device 10 returns to step S36 and continues aggregating sensor information from both the first communication network 20 and the second communication network 21. On the other hand, if the environmental level corresponding to the value of the received sensor information is less than the threshold, the server device 10 transmits a control signal to the sensor terminal 30 to stop the second communication network 21. In step S40, the sensor terminal 30 stops notifying environmental data via the second communication network 21 under the control of the server device 10.

As described above, the communication system 1 of the embodiment is a system that aggregates environmental data measured by the sensor terminal 30 in the server device 10 using two lines, the first communication network 20 and the second communication network 21. The communication system 1 includes an activation determination unit 13 and a communication control unit 14. The activation determination unit 13 determines whether to activate the second communication network 21 together with the first communication network 20 based on a predetermined activation condition related to the occurrence of a disaster. The communication control unit 14 controls communication via each of the first communication network 20 and the second communication network 21 based on the determination result by the activation determination unit 13. As a result, in the communication system 1 of the embodiment, it is possible to switch between aggregating environmental data using only the first communication network 20 or aggregating environmental data using both the first communication network 20 and the second communication network 21 depending on the situation of the disaster occurrence. That is, it is possible to suppress power consumption by using only the first communication network 20 during normal times, and to reliably and accurately measure environmental data during abnormal times. Therefore, it is possible to effectively utilize multiple communication lines while suppressing power consumption. Furthermore, because the second communication network 21 is an LPWA standard communication line, data aggregation with reduced power consumption is possible even when multiple lines are used.

The first communication network 20 is an example of a "first communication line."
The second communication network 21 is an example of a "second communication line."
In the above-described embodiment, the server device 10 is described as including the activation determination unit 13 and the communication control unit 14, but the present invention is not limited to this. The activation determination unit 13 and the communication control unit 14 may be provided in a computer device, such as a cloud device, different from the server device 10, and may control communication between the server device 10 and the sensor terminal 30 via the cloud device.

In addition, in the communication system 1 of the embodiment, the start-up determination unit 13 determines to start the first communication network 20 when it is determined that the start-up condition is not satisfied, and determines to start the second communication network 21 when it is determined that the start-up condition is satisfied, regardless of whether the first communication network 20 is activated or not. As a result, in the communication system 1 of the embodiment, environmental data can be aggregated via the second communication network 21 even when the first communication network 20 is not activated due to a malfunction or the like. Therefore, the second communication network 21 can be utilized more effectively compared to when it is simply used as a spare communication line.

The communication system 1 of the embodiment also includes a device control unit 18 and a storage unit 19. The device control unit 18 is an example of an "alarm acquisition unit" and acquires an alarm regarding the occurrence of a disaster. The storage unit 19 stores alarm table information 190 and threshold information 192. The alarm table information 190 is information that associates an alarm with an alarm level. The threshold information 192 is information that indicates the alarm level that activates the second communication network 21. The activation determination unit 13 refers to the alarm table information 190 and the threshold information 192 based on the alarm acquired by the device control unit 18, and determines to activate the first communication network 20 if the alarm level corresponding to the alarm is equal to or higher than the alarm level that activates the second communication network 21.

In addition, in the communication system 1 of the embodiment, the device control unit 18 is an example of an "environmental data acquisition unit" and acquires environmental data. The storage unit 19 stores environmental table information 191 and threshold information 192. The environmental table information 191 is information that associates environmental data with an environmental level. The threshold information 192 is information that indicates the environmental level at which the second communication network 21 is started. The start-up determination unit 13 refers to the environmental table information 191 and threshold information 192 based on the environmental data acquired by the device control unit 18, and determines to start the second communication network 21 if the environmental level corresponding to the environmental data is equal to or higher than the environmental level at which the second communication network 21 is started.

As a result, in the communication system 1 of the embodiment, it is possible to determine whether or not to start the first communication network 20 by a simple process of referencing a table and thresholds stored in advance. Moreover, by rewriting the table and thresholds, it is possible to respond to various alarms and change the criteria for starting the first communication network 20, allowing for flexible response.

In addition, in the communication system 1 of the embodiment, the environmental data is data indicating the amount of radiation measured by the sensor terminal 30. As a result, in the communication system 1 of the embodiment, it is possible to aggregate the amount of radiation by effectively using multiple communication lines in response to the occurrence of a disaster.

In addition, in the communication system 1 of the embodiment, the server device 10 includes a main line communication unit 11, a sub-line communication unit 12, and a retransmission determination unit 15. The main line communication unit 11 is an example of a "first acquisition unit" and acquires first data. The first data is environmental data notified from the sensor terminal 30 via the first communication network 20. The sub-line communication unit 12 is an example of a "second acquisition unit" and acquires second data. The second data is environmental data notified from the sensor terminal 30 via the second communication network 21. The retransmission determination unit 15 determines whether to retransmit the environmental data via at least one of the first communication network 20 or the second communication network 21 based on a comparison result of comparing the first data and the second data. As a result, in the communication system 1 of the embodiment, the environmental data can be retransmitted when the environmental data aggregated via multiple communication lines differs, and the environmental data can be aggregated more accurately.

The communication system 1 of the embodiment also includes a data volume monitoring unit 17. The storage unit 19 stores environmental data notified from the sensor terminal 30 using the second communication network 21. The data volume monitoring unit 17 controls the data volume of the environmental data stored in the storage unit 19 to be less than a predetermined threshold. As a result, the communication system 1 of the embodiment can control the data volume of data to be stored in the storage unit 19 even if the data volume of environmental data aggregated via the second communication network 21 suddenly increases during an abnormality. This makes it possible to prevent problems in data aggregation due to memory leaks, etc.

In the above-described embodiment, the server device 10 is described as having a retransmission determination unit 15, a data capacity monitoring unit 17, and a storage unit 19, but the present invention is not limited to this. The retransmission determination unit 15, the data capacity monitoring unit 17, or the storage unit 19 may be provided in a computer device, such as a cloud device, different from the server device 10, and the data to be retransmitted or stored to the server device 10 may be controlled via the cloud device. In addition, all or part of the environmental data may be stored in the database of the cloud device.

In addition, in the communication system 1 of the embodiment, when communication is performed via the second communication network 21 together with the first communication network 20, the communication control unit 14 controls communication so that the communication is performed at a different communication frequency than when communication is performed using only the first communication network 20. As a result, in the communication system 1 of the embodiment, data can be aggregated by changing the communication frequency between normal times and abnormal times, and data can be aggregated according to the situation of the disaster occurrence.

Furthermore, in the communication system 1 of the embodiment, the second communication network 21 performs communication conforming to ZETA (registered trademark) in the LPWA standard. As a result, the communication system 1 of the embodiment can perform data aggregation using ZETA.

The functions described in each of the above embodiments can be realized not only by using hardware, but also by loading a program that describes each function into a computer using software. Also, each function may be configured by selecting either software or hardware as appropriate.

The communication system 1 and the server device 10 in the above-mentioned embodiment may be realized in whole or in part by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into the computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into the computer system. Furthermore, the term "computer-readable recording medium" may include a medium that dynamically holds a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in such a case. Furthermore, the above-mentioned program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA.

The above describes an embodiment of the present invention in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and includes designs that do not deviate from the gist of the present invention.

REFERENCE SIGNS LIST 1 communication system 10 server device 11 main line communication unit 12 sub line communication unit 13 start determination unit 14 communication control unit 15 retransmission determination unit 17 data capacity monitoring unit 18 device control unit (alarm acquisition unit), (environmental data acquisition unit)
19: Storage unit 190: Alarm table information 191: Environmental table information 192: Threshold information 20: First communication network (first communication line)
21...Second communication network (second communication line)
30: Sensor terminal

Claims (10)

A communication system for aggregating environmental data measured by a sensor terminal in a server device using two lines, a first communication line using a predetermined communication method and a second communication line using a communication method conforming to the LPWA standard,
an activation determination unit that determines whether or not to activate the second communication line together with the first communication line based on a predetermined activation condition related to the occurrence of a disaster;
a communication control unit that controls communications performed via the first communication line and the second communication line based on a result of the determination by the activation determination unit;
A communication system comprising: the activation determination unit determines to activate the first communication line when it is determined that the activation condition is not satisfied, and determines to activate the second communication line when it is determined that the activation condition is satisfied, regardless of whether the first communication line is activated or not.
The communication system according to claim 1 . an alert acquisition unit that acquires an alert regarding the occurrence of a disaster;
a storage unit configured to store an alarm table in which the alarm acquired by the alarm acquisition unit is associated with an alarm level, and threshold information indicating an alarm level at which the second communication line is activated;
Equipped with
the activation determination unit refers to the alarm table and the threshold information based on the alarm acquired by the alarm acquisition unit, and determines to activate the second communication line when an alarm level corresponding to the alarm is equal to or higher than an alarm level for activating the second communication line;
The communication system according to claim 1 or 2. an environmental data acquisition unit for acquiring the environmental data;
a storage unit that stores an environment table in which the environment data acquired by the environment data acquisition unit is associated with an environment level, and threshold information that indicates an environment level at which the second communication line is activated;
Equipped with
the activation determination unit refers to the environment table and the threshold information based on the environmental data acquired by the environmental data acquisition unit, and determines to activate the second communication line when an environmental level corresponding to the environmental data is equal to or higher than an environmental level for activating the second communication line;
A communication system according to any one of claims 1 to 3. The environmental data is data indicating a radiation dose measured by a sensor terminal.
A communication system according to any one of claims 1 to 4. The server device includes:
a first acquisition unit that acquires first data, which is the environmental data notified from the sensor terminal via the first communication line;
a second acquisition unit that acquires second data, which is the environmental data notified from the sensor terminal via the second communication line;
a retransmission determination unit that determines whether or not to retransmit the environmental data via at least one of the first communication line or the second communication line based on a comparison result of comparing the first data and the second data;
A communication system according to any one of claims 1 to 5, comprising: a storage unit that stores the environmental data notified from the sensor terminal using the second communication line;
a data volume monitoring unit that controls the data volume of the environmental data stored in the storage unit so that the data volume is less than a predetermined threshold;
The communication system according to claim 1 , further comprising: the communication control unit controls, when communication is performed via the second communication line together with the first communication line, the communication to be performed at a communication frequency different from a communication frequency when communication is performed using only the first communication line.
A communication system according to any one of claims 1 to 7. The second communication line performs communication conforming to ZETA (registered trademark) in the LPWA standard.
A communication system according to any one of claims 1 to 8. A communication method in a communication system for aggregating environmental data measured by a sensor terminal in a server device using two lines, a first communication line using a predetermined communication method and a second communication line using a communication method conforming to the LPWA standard, comprising:
an activation determination unit determines whether or not to activate the second communication line together with the first communication line based on a predetermined activation condition related to the occurrence of a disaster;
a communication control unit that controls communications performed via the first communication line and the second communication line based on a result of the determination by the activation determination unit;
Communication method.

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