The present invention relates to an access point that performs wireless communication, a terminal equipped with a sensor, an information collection system, and an information collection method to be applied to the information collection system.
In recent years, attention has been paid to information collection systems that collect environmental information from various sensors that measure, for example: the aging of social infrastructure such as roads, bridges, tunnels, and water and sewage systems; or damage caused by natural disasters; or the operating status of production facilities such as factories. The information collection system includes an access point and a terminal equipped with a sensor, and uses environmental information to detect an anomaly or to estimate a value that the environmental information can take. The access point collects environmental information from the terminal by using wireless communication. The terminal obtains environmental information by using the sensor. When the information collection system performs highly accurate detection or estimation, the access point needs to collect environmental information from the terminal with high frequency. The degree of freedom in installing the terminal is improved by use of wireless communication. Meanwhile, it is often difficult to supply power to the terminal. Therefore, the terminal includes a battery, and operates the sensor and each functional unit by using the battery. If the frequency of collecting environmental information from the terminal is increased, power consumption of the terminal increases and the battery drains more quickly. Thus, the operating time of the terminal is reduced.
Patent Literature 1 discloses an information collection system in which a management server that controls sensors operates as follows. The management server calculates remaining time during which a terminal equipped with a sensor can be driven, by using remaining battery life of the terminal. The management server controls measurement time of the sensor provided in the terminal, the number of times a report is made, output power of wireless communication, and the like become equal to the remaining time during which the terminal can be driven.
However, the information collection system described in Patent Literature 1 has a problem in that the frequency of communication with the management server does not decrease in the entire terminal, and therefore power to be consumed by communication between the entire terminal and the management server cannot be reduced.
The present invention has been made in view of the above, and an object of the present invention is to obtain an access point that reduces power consumption of a terminal that transmits a value detected by a sensor.
To solve the above problems and achieve the object an access point according to the present invention receives first information measured by a sensor from a terminal and transmits the first information as sensor information to a server. The access point includes: a measurement result estimator to estimate an estimation result that is information indicating an estimated value of the first information and is information to be used by the terminal to determine whether to transmit the first information; a first communicator to transmit the estimation result to the terminal; and a second communicator to transmit the estimation result as the sensor information to the server in a case where the first information is not received from the terminal for a certain period of time or longer after transmission of the estimation result to the terminal.
An access point according to the present invention reduces power consumption of a terminal that transmits a value detected by a sensor. The present invention achieves an effect of enabling such an access point to be obtained.
An access point, a terminal, an information collection system, and an information collection method according to an embodiment of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiment.
The access point 10 performs wireless communication with the sensor-equipped terminal 20. In addition, the access point 10 is connected to the server 32 via the wide area network 31. The access point 10 communicates with a wide area communication network 30 that includes the wide area network 31 and the server 32 by using a method such as a wide area network (WAN), which is a wired connection, wideband-code division multiple access (W-CDMA), which is used in a mobile phone, or long term evolution (LTE).
The sensor-equipped terminal 20a and the sensor-equipped terminal 20b obtain environmental information. The environmental information refers to information on, for example, the acceleration of an object, the temperature of an object, and soil moisture. Upon obtaining the environmental information, the sensor-equipped terminal 20a and the sensor-equipped terminal 20b transmit the environmental information to the access point 10a and the access point 10b, respectively. The access points 10 transmit the environmental information obtained by the sensor-equipped terminal 20a and the sensor-equipped terminal 20b to the wide area network 31 by using a wide area communication means such as a mobile phone. The environmental information: is transmitted via the wide area network 31 to the server 32a, the server 32b, and the server 32c, which provide services; and is accumulated therein. Examples of the services to be provided by the servers 32 include detecting an event according to purpose such as risk prediction by using environmental information and distributing the detected event to users. The environmental information is also referred to as first information. In addition, the environmental information is also referred to as sensor information.
The wide area network 31 is connected to the access point 10a. Processing relating to, for example, control of line connection between the access point 10a and the wide area network 31 and security are provided by a communication method supported by the wide area network 31. A wired line is mainly used for communication between the wide area network 31 and the server 32, and an internet protocol (IP) network is configured by use of a plurality of routers, optical lines, and the like. Note that communication using the IP as a communication protocol will be described as an example of communication via the wide area network 31. However, a communication protocol to be used in the communication via the wide area network 31 is not limited to the IP.
The server 32 accumulates the environmental information obtained by the sensor-equipped terminal 20. In addition, the server 32 provides service. Furthermore, the server 32 distributes programs related to the operations of the access point 10 and the sensor-equipped terminal 20. Moreover, the server 32 provides settings for the access point 10 and the sensor-equipped terminal 20. Furthermore, the server 32 has the function of monitoring the states of the access point 10 and the sensor-equipped terminal 20, and also has the function of displaying the obtained environmental information on a console screen or the like. Note that the number of the servers 32 is not limited to three, and four or more servers 32 may be provided in the information collection system 40 according to purpose. In addition, each server 32 can select the sensor-equipped terminal 20 from which environmental information is to be obtained and a sensor. Furthermore, the servers 32 can share the obtained environmental information among the servers 32. In addition, the servers 32 can separately cause software to operate on the sensor-equipped terminal 20 and the access point 10 in parallel. However, the servers 32 are not limited to devices having these functions.
The communicator 100 has: a wireless interface (IF) function for transmitting and receiving signals for communication with another access point 10 and the sensor-equipped terminal 20; and a modem function for performing control for wireless connection with the another access point 10 and the sensor-equipped terminal 20. The communicator 100 is also referred to as a first communicator. The antenna 101 communicates with the other access point 10 and the sensor-equipped terminal 20. The wide area interface 102 communicates with the wide area communication network 30, and relays environmental information received from the sensor-equipped terminal 20 to the wide area communication network 30. The wide area interface 102 is also referred to as a second communicator. Note that in the case where communication between the access points 10 is performed by a method different from a method of communication between the sensor-equipped terminal 20 and the access point 10, another communicator 100 adopting the different communication method may be newly added. The antenna 103 communicates with the wide area communication network 30. The software processor 104 collects environmental information transmitted from the other access point 10 or the sensor-equipped terminal 20. In addition, the software processor 104 includes a measurement result estimator 1041 and a sensing cycle controller 1042.
The measurement result estimator 1041 estimates an estimation result indicating an estimated value based on the assumption that the environmental information transmitted from the sensor-equipped terminal 20 falls within a certain error range. Furthermore, the measurement result estimator 1041 broadcasts the estimation result to the sensor-equipped terminals 20. The sensing cycle controller 1042 controls the acquisition cycle of the environmental information by a sensor 201 included in the sensor-equipped terminal 20. Furthermore, the sensing cycle controller 1042 specifies and manages a report determination cycle corresponding to a time interval between transmission of environmental information from the sensor-equipped terminal 20 to the access point 10. The report determination cycle is also referred to as a first cycle. In the case where environmental information is not received from the sensor-equipped terminal 20 at the transmission time specified by the sensing cycle controller 1042, the sensing cycle controller 1042 provides the server 32 with a proxy report of the result of estimation of environmental information made by the measurement result estimator 1041, as the result of measurement performed by the sensor-equipped terminal 20.
The database 105 stores: operational information on the sensor-equipped terminal 20; a program necessary for operation of the software processor 104; setting information such as parameters of wireless communication necessary for communication between the communicator 100 and the wide area interface 102; and a sensor-equipped terminal program to be downloaded to the sensor-equipped terminal 20. The software distributor 106 causes the sensor-equipped terminal 20 to download the sensor-equipped terminal program stored in the database 105. Information that associates the sensor-equipped terminal 20 with the sensor-equipped terminal program is registered in the operational information on the sensor-equipped terminal 20, stored in the database 105. Note that a configuration example in which the wide area interface 102 is included in the access point 10 is described in the present embodiment. Meanwhile, the wide area interface 102 may be provided outside the access point 10 to serve the function of connection with the wide area communication network 30.
The sensing unit 200 sets parameters of the sensors 201, and controls the sensors 201. In addition, the sensing unit 200 obtains environmental information from the sensors 201. Note that an acceleration sensor to be used for a clinometer or the like and a thermometer are taken as examples in describing the sensors 201 in the present embodiment. However, the sensors 201 are not limited to these sensors. The communicator 202 has a wireless IF function for transmitting and receiving signals for wireless communication with the access point 10 and a modem function for performing control for wireless connection with the access point 10. The antenna 203 communicates with the access point 10. The software processor 204 performs a process of collecting environmental information from the sensors 201, a process of transmitting the environmental information obtained from the sensors 201 to the access point 10, and a power saving process. In addition, the software processor 204 includes a measurement error determiner 2041 and a report determiner 2042.
The measurement error determiner 2041 estimates an error in the result of estimation by the measurement result estimator 1041 by using the environmental information obtained from the sensors 201. The report determiner 2042 determines whether it is necessary to transmit the environmental information to the access point 10, based on the error estimated by the measurement error determiner 2041. When the error in the result of estimation by the measurement error determiner 2041 falls within a certain error range, the report determiner 2042 does not transmit the environmental information to the access point 10. This achieves power saving of the battery 207 and prevention of use of a band for unnecessary wireless transmission. Meanwhile, when the error estimated by the measurement error determiner 2041 does not fall within the certain error range or when no estimation result has been delivered from the access point 10, the report determiner 2042 transmits the environmental information to the communicator 100 so as to correct the estimation result.
The storage 205 stores, for example: a program for the process of collecting environmental information; a program for the process of transmitting the environmental information obtained from the sensors 201 to the access point 10; a program relating to the power saving process; and setting information such as wireless parameters necessary for the communicator 202 in performing communication. The programs stored in the storage 205 are read out when the sensor-equipped terminal 20 is started. The program for the process of collecting environmental information is also referred to as a first program. Furthermore, the storage 205 temporarily stores the environmental information that the sensing unit 200 has obtained from the sensors 201. The software update unit 206 updates a program stored in the storage 205 such that the stored program is changed to a program to be uploaded by the software distributor 106 of the access point 10 illustrated in
The software processor 104, the software distributor 106, the software processor 204, and the software update unit 206 are implemented by a processing circuitry as an electronic circuit that performs each process.
The present processing circuitry may be dedicated hardware or a control circuit including a memory and a central processing unit (CPU) that executes a program stored in the memory. Here, the memory corresponds to, for example, a nonvolatile or volatile semiconductor memory, such as a random access memory (RAM), a read only memory (ROM), or a flash memory, a magnetic disk, or an optical disk. In the case where the present processing circuitry is a control circuit including a CPU, the control circuit is exemplified by a control circuit 300 with a configuration illustrated in
As illustrated in
After receiving the first program distributed from the access point 10, the sensor-equipped terminal 20 stores the first program in the storage 205 (step S106). The software update unit 206 makes a diagnosis of the program stored in the storage 205. When it is determined that the distribution source and the like are normal, the software update unit 206 deploys the program in the software processor 204 (step S107), activates the software (step S108), and notifies the software distributor 106 that the software has been activated (step S109). Upon receiving the notification of completion of software activation, the software distributor 106 deploys, in the software processor 104, the program that is stored in the database 105 and necessary for operation of the software processor 104, and starts to provide service (step S110).
When the software activation is completed in step S110, the access point 10 periodically broadcasts, to the sensor-equipped terminals 20, measurement error estimation parameters 400 to be used by the measurement result estimator 1041.
The number of information distributions refers to the number of the sensor-equipped terminals 20. The device ID refers to an ID for identifying the sensor-equipped terminal 20. The number of registered sensors refers to the number of sensors connected to the sensor-equipped terminal 20. The sensor ID refers to an ID for identifying each sensor (clinometer, thermometer, and the like) connected to the sensor-equipped terminal 20. The reference value refers to a value to be used for estimating an error in environmental information obtained from each sensor connected to the sensor-equipped terminal 20. Furthermore, the reference value corresponds to an average value of past environmental information obtained from the sensor-equipped terminal 20. When the sensor-equipped terminal 20 newly obtains environmental information, the reference value is updated by use of the new environmental information. In addition, when the access point 10 receives environmental information from the sensor-equipped terminal 20, the reference value is automatically updated by use of the environmental information received by the access point 10. The allowable error refers to a value to be used to evaluate whether the result of error estimation performed by the sensor-equipped terminal 20 falls within an allowable range. The change detection threshold refers to a value for determining whether environmental information obtained from the sensor 201 indicates that an anomaly has been detected. The transmission request refers to a request to be made by the access point 10 when the access point 10 requests the sensor-equipped terminal 20 to transmit environmental information.
When environmental information obtained from the sensor 201 is equal to or higher than the change detection threshold, or when the access point 10 has made a transmission request, the sensor-equipped terminal 20 transmits the environmental information to the access point 10 regardless of the result of estimation by the measurement error determiner 2041. For example, when the result of measurement by the clinometer is 0.1 degrees or more in a sensor with a sensor ID of 0x00010001 connected to a sensor-equipped terminal with a device ID of 0x00010000 as illustrated in the measurement error estimation parameters 400 of
Moreover, description is provided in the present embodiment, based on the assumption that the measurement error estimation parameters 400 correspond to values to be used for error estimation. However, the present invention is not limited to the measurement error estimation parameters 400, and other values may be used for error estimation as long as the values are parameters necessary for estimating an error of an estimation result, corresponding to a difference between the estimation result and environmental information. Furthermore, the measurement error estimation parameters 400 include numerical values designated as parameters necessary for error estimation. However, the parameters may be expressed by computational expressions or the like. In addition, the parameter necessary for error estimation may be information associated with time information or year/month information. Furthermore, the time or year/month information of the sensor-equipped terminal 20 may be used for error estimation. Moreover, a parameter related to, for example, sunshine conditions depending on the weather and the like, or seasons may also be used as the parameter necessary for error estimation.
The sensing cycle controller 1042 manages the environmental information acquisition cycle and report determination cycle of the sensor-equipped terminal 20, and generates an acquisition trigger to obtain environmental information, regardless of whether environmental information has been received from the sensor-equipped terminal 20. The acquisition trigger refers to a signal that causes the measurement result estimator 1041 to obtain environmental information. When the sensing cycle controller 1042 notifies the measurement result estimator 1041 of the acquisition trigger to obtain environmental information, the measurement result estimator 1041 confirms whether new environmental information has been received from the sensor-equipped terminal 20 (step S204). When the measurement result estimator 1041 has received no environmental information, the measurement result estimator 1041 uses the reference value included in the measurement error estimation parameters 400 as an estimation result (step S205), and broadcasts the estimation result to the sensor-equipped terminals 20 (step S206). When the measurement result estimator 1041 has received the environmental information, the measurement result estimator 1041 transmits the environmental information received from the sensor-equipped terminal 20, as a measurement result to the server 32 without performing the measurement result estimation process. Note that a case where the measurement result estimator 1041 receives no environmental information will be described in the embodiment. Details of the environmental information and the measurement result to be transmitted by the sensor-equipped terminal 20 will be described below.
Description is provided in the present embodiment by use of the configuration example of the estimation result 500. However, an estimation result to be distributed by the measurement result estimator 1041 is not limited to the estimation result 500 with the configuration example illustrated in
The measurement error determiner 2041 performs verification of an estimated error of the estimation result received from the access point 10, corresponding to a difference between the estimation result and the environmental information obtained from the sensing unit 200 (step S307). In the case where, as a result of verification of the estimated error, the measurement error determiner 2041 determines that the result of estimation by the access point 10 exceeds an allowable error range, the report determiner 2042 transmits the environmental information obtained from the sensor 201 and stored in the storage 205 to the access point 10 so as to correct the result of estimation by the access point 10 (step S308).
Only in the case where an error of the result of estimation by the access point 10, corresponding to a difference between the result of estimation and the environmental information measured by the sensor-equipped terminal 20 is out of the allowable range, the sensor-equipped terminal 20 can transmit the environmental information. Therefore, it is possible to reduce wireless transmission processing that requires more power consumption while maintaining the accuracy of environmental information that the access point 10 reports to the server 32 and reducing a band to be used for wireless communication. Note that in the case where the result of estimation by the access point 10 is frequently corrected based on environmental information of a plurality of the sensors 201 in step S310, the sensor-equipped terminal 20 may determine whether the estimation result falls within the allowable error range by assigning a degree of priority to each environmental information obtained from the plurality of sensors 201 and using only environmental information with high priority in the sensor-equipped terminal 20. Thus, it is possible to prevent an estimation result from being corrected based on environmental information with low priority, and to use a wireless communication band for transmitting environmental information with high priority.
As described above, according to the present embodiment, the access point 10 has the function of estimating environmental information and the function of providing a proxy report to the server 32. The sensor-equipped terminal 20 has the function of verifying the result of estimation by the access point 10 and the function of correcting the result of estimation by the access point 10. Therefore, it is possible to reduce a band to be used by the sensor-equipped terminal 20 for wireless communication, achieve power saving of the sensor-equipped terminal 20, and improve the accuracy of environmental information to be transmitted to the server 32.
The configuration described in the above embodiment illustrates an example of the subject matter of the present invention, and it is possible to combine the configuration with another technique that is publicly known, and is also possible to make omissions and changes to part of the configuration without departing from the gist of the present invention.
10, 10a, 10b access point; 20, 20a, 20b sensor-equipped terminal; 30 wide area communication network; 31 wide area network; 32, 32a, 32b, 32c server; 40 information collection system; 100, 202 communicator; 101, 103, 203 antenna; 102 wide area interface; 104, 204 software processor; 105 database; 106 software distributor; 200 sensing unit; 201, 201-1 to 201-n sensor; 205 storage; 206 software update unit; 207 battery; 300 control circuit; 300a processor; 300b memory; 400 measurement error estimation parameter; 500 estimation result; 600 environmental information; 1041 measurement result estimator; 1042 sensing cycle controller; 2041 measurement error determiner; 2042 report determiner.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/011126 | 3/20/2018 | WO | 00 |