JP5678647B2 - Communication device - Google Patents

Description

  The present invention relates to a communication device.

  When a wireless communication device establishes communication with another wireless communication device in the vicinity of the boundary of the communicable area, the communication may be interrupted due to the movement of a person having the wireless communication device. If communication is interrupted, data must be retransmitted and power is wasted.

  In addition, a communication base station and a plurality of sensor terminals that communicate with each other are provided, and a totaling server connected to the communication base station via a network is provided, and the sensor terminal measures data related to the environment where it is installed. Data measuring means, sensor identification data storage means for storing sensor identification data unique to the sensor terminal, and measurement data transmission means for transmitting the measured environmental data to the communication base station as measurement data together with the sensor identification data. An environmental data measurement system is known (see, for example, Patent Document 1).

  An information reading device connected to the network by activating the fixed sensor device wirelessly by the mobile terminal, transmitting environment information collected by the fixed sensor device to the center device via the network, storing the environment information in the center device There is known an information collecting / providing system provided with information collecting / providing means for providing accumulated environmental information based on a request from (see, for example, Patent Document 2).

  Further, when the locator node intercepts sensing information (first transmission data) transmitted from the sensor node to the base station, the locator node includes a node ID extracted from the information transmitted by the sensor node and its own locator node ID. The data (second transmission data) is transmitted to the base station, and the base station transmits ID information extracted from at least one of the first transmission data and the second transmission data to the server. There is known a sensor network system that identifies the position of a node using a table that associates locator node ID information with the position of the locator (see, for example, Patent Document 3).

  Also, a position detecting means for detecting the position of a human or animal and transmitting it as a position detection signal, a posture / behavior detecting means for detecting the posture and / or action state of a human or animal, and the posture and / or action A terminal that can be worn on a human or an animal and that has a detection signal transmission means for transmitting a state detection signal based on the detection of the state, and is provided in a predetermined area for receiving and processing the position detection signal and the state detection signal. There is known a state information collection system that includes signal reception processing means and obtains state information indicating the state of a human or an animal based on the processing result (see, for example, Patent Document 4).

Japanese Patent Laid-Open No. 2005-147953 JP 2005-311716 A JP 2007-300571 A JP 2002-132948 A

  An object of the present invention is to provide a communication apparatus capable of expanding an effective communicable area and preventing a communication error due to movement of the communication apparatus.

The communication device is a communication device that performs wireless communication, a motion detection unit that detects a motion of the communication device, and wirelessly transmits a communication request to another communication device, and from the other communication device for the communication request A communication unit that wirelessly receives a response, and when the motion detected by the motion detection unit is less than a threshold, the reception strength of the response from the other communication device is a first reception strength. It is determined whether or not it is equal to or greater than the above, and when it is equal to or higher than the first reception strength, wireless communication is performed with the other communication device, and when it is less than the first reception strength, wireless communication with the other communication device is performed. Without performing, when the motion detected by the motion detection unit is equal to or greater than a threshold, whether the reception strength of the response from the other communication device is equal to or greater than a second reception strength that is greater than the first reception strength. And determine the second When more than the reception strength with which performs the other communication apparatus and radio communication, does not perform the other communication apparatus and the wireless communication when a less than the second reception strength.

  The effective communicable area can be expanded according to the movement of the communication device detected by the motion detector, and a communication error due to movement of the communication device can be prevented.

1A and 1B are diagrams illustrating a communication system according to the first embodiment. 2A and 2B are diagrams showing a communication system according to the first embodiment. FIG. 3A is a block diagram illustrating a configuration example of the sensor unit, and FIG. 3B is a block diagram illustrating a configuration example of the communication device. 4A and 4B are diagrams showing a communication system according to the second embodiment. 5A and 5B are diagrams showing a communication system according to the third embodiment.

(First embodiment)
1A and 1B are diagrams showing a communication system according to the first embodiment. A farm field 101 is a field for cultivating crops, and is divided by a road 102. The sensor unit 111 is a communication device that is provided for each farm field 101, periodically detects the temperature and humidity of the soil of the farm field 101, stores data such as the temperature and humidity, and performs communication. The worker 113 carries the communication device 112 and looks around the farm field 101. The communication device 112 automatically connects to the sensor unit 111 installed on the farm field 101 by wireless communication, and wirelessly receives data in the sensor unit 111. By collecting data such as temperature and humidity, it can be used for the cultivation method of the crops cultivated in each field 101. The communication device 112 can perform wireless communication if the distance from the sensor unit 111 is short. However, if the distance from the sensor unit 111 is long, the wireless signal becomes weak and communication is not possible. The communication device 112 can communicate with the sensor unit 111 as long as the communication device 112 is located within the communication limit area 124 centering on the sensor unit 111. On the other hand, the communication device 112 cannot communicate with the sensor unit 111 if it is located outside the communication limit area 124 centering on the sensor unit 111.

  FIG. 1B is a diagram showing the relationship of the radio wave intensity of the received signal with respect to the distance between the communication device 112 and the sensor unit 111. The longer the distance, the smaller the radio field intensity of the received signal. The communication device 112 determines that the communication device 112 is located in the communication limit region 124 if the radio wave intensity of the reception signal from the sensor unit 111 is equal to or higher than the first communication strength Th1, and the communication device 112 determines that the reception signal from the sensor unit 111 is If the radio wave intensity is less than the first communication intensity Th1, it can be determined that the communication device 112 is located outside the communication limit area 124.

  However, the worker 113 having the communication device 112 can move. When the communication device 112 establishes wireless communication in the vicinity of the boundary of the communication limit area 124 with respect to the sensor unit 111, the communication device 112 moves out of the communication limit area 124 due to the subsequent movement of the worker 113, and wireless communication is performed. May be interrupted. When communication is interrupted, the sensor unit 111 needs to retransmit data to the communication device 112, which wastes power.

  In order to solve this problem, the communication stable area 114 is set. The communication stable region 114 is a safe region that allows for a margin that allows wireless communication to continue even if the communication device 112 moves, and is a region that is narrower than the communication limit region 124. The communication stable region 114 is a region closer to the communication limit region 124 from the sensor unit 111. When the communication device 112 is located in the communication stable region 114, the communication device 112 establishes communication with the sensor unit 111 and receives data from the sensor unit 111. On the other hand, the communication device 112 does not communicate with the sensor unit 111 when located outside the stable communication region 114.

  Specifically, as illustrated in FIG. 1B, the communication device 112 has the communication device 112 in the stable communication region 114 if the radio wave intensity of the received signal from the sensor unit 111 is equal to or higher than the second communication strength Th2. If the radio wave intensity of the received signal from the sensor unit 111 is less than the second communication intensity Th2, it can be determined that the communication device 112 is located outside the communication stable region 114. The second communication strength Th2 is larger than the first communication strength Th1 by a margin 130. Since the communication device 112 performs communication only when the radio wave intensity of the received signal is sufficiently high, communication errors due to movement of the communication device 112 can be reduced.

  However, when the communication device 122 possessed by the worker 123 is located in the communication limit area 124 and outside the communication stable area 114, the worker 123 can communicate with the communication stable area 114 even if communication is inherently possible. If it does not move in, data cannot be acquired from the sensor unit 111. For example, even if the worker 123 wants to acquire data from the position of the road 102, if the communication device 122 is located outside the stable communication area 114, the worker 123 must move to the position of the worker 113 in the farm field 101. Don't be. If the worker 113 does not enter the field 101, it is inconvenient that data cannot be acquired.

  Therefore, even if the communication device 122 is located in the communication limit region 124 even outside the stable communication region 114, if it is predicted that the worker 123 will not move, the communication device 122 will detect the sensor unit 111. Data may be obtained from As a result, the communication device 122 does not need to move from the road 102 into the field 101, and an effective communicable area can be expanded and a communication error accompanying the movement of the communication device 122 can be prevented. Hereinafter, a communication system for realizing this will be described.

  2A and 2B are diagrams showing a communication system according to the first embodiment. FIG. 2A is a diagram showing the farm field 101 in FIG. Hereinafter, a point of difference in FIG. 2A compared with FIG. 1A will be described. The sensor unit 201 corresponds to the sensor unit 111 in FIG. 1A, and the communication device 202 and the worker 203 correspond to the communication device 122 and the worker 123 in FIG. 1A, respectively. The sensor unit 201 is a communication device that is provided for each farm field 101 and can periodically detect the temperature and humidity of the soil of the farm field 101, store data such as the temperature and humidity, and perform communication. The communication device 202 automatically connects to the sensor unit 201 installed in the field 101 by wireless communication, and wirelessly receives data in the sensor unit 201.

  FIG. 3A is a block diagram illustrating a configuration example of the sensor unit 201 in FIG. The sensor unit 201 includes a microprocessor unit (MPU) 301, a communication control unit 302, a communication circuit 303, a sensor control unit 304, a data storage unit 305, a first sensor 306, and a second sensor 307. The MPU 301 controls the communication control unit 302, the sensor control unit 304, and the data storage unit 305. The first sensor 306 is, for example, a temperature sensor, and detects the temperature of the soil of the farm field 101. The second sensor 307 is a humidity sensor, for example, and detects the humidity of the soil in the field 101. The sensor control unit 304 controls the first sensor 306 and the second sensor 307. The communication circuit 303 performs wireless transmission and wireless reception with respect to the communication device 202. The communication control unit 302 controls the communication circuit 303. The MPU 301 periodically reads the temperature data detected by the first sensor 306 and the humidity data detected by the second sensor 307 and stores them in the data storage unit 305. When wirelessly receiving the data request signal from the communication device 202, the communication circuit 303 wirelessly transmits the data stored in the data storage unit 305 to the communication device 202.

  FIG. 3B is a block diagram illustrating a configuration example of the communication device 202 in FIG. The communication device 202 includes an MPU 311, a communication control unit 312, a communication circuit 313, a motion detection unit 314, and a data storage unit 315. The MPU 311, the communication control unit 312, and the communication circuit 313 are communication units that perform communication. The communication control unit 312 includes a reception intensity processing unit 321 and a transmission output control unit 322. The communication circuit 313 includes a reception circuit 323 and a transmission circuit 324. The motion detection unit 314 includes a sensor control unit 325, an acceleration sensor 326, a geomagnetic sensor 327, and a GPS (Global Positioning System) 328. The MPU 311 controls the communication control unit 312, the sensor control unit 325, and the data storage unit 315. The acceleration sensor 326 detects the acceleration of the communication device 202. The geomagnetic sensor 327 detects the direction of the communication device 202. The GPS 328 detects the position of the communication device 202. The acceleration sensor 326, the geomagnetic sensor 327, and the GPS 328 periodically detect acceleration, direction, and position, respectively. The motion detection unit 314 detects a change in the acceleration of the communication device 202 detected by the acceleration sensor 326, a change in the direction of the communication device 202 detected by the geomagnetic sensor 327, or a change in the position of the communication device 202 detected by the GPS 328. Based on this, the movement of the communication device 202 is detected. The reception circuit 323 performs wireless reception processing on the sensor unit 201. The reception strength processing unit 321 determines whether the reception strength of the signal received by the reception circuit 323 is equal to or higher than the first communication strength Th1 or the second communication strength Th2 in FIG. The transmission circuit 324 performs wireless transmission processing on the sensor unit 201. The transmission output control unit 322 sets the transmission intensity transmitted by the transmission circuit 324 to the first communication intensity or the second communication intensity. The MPU 311 stores the data received from the sensor unit 201 via the receiving circuit 323 in the data storage unit 315.

  FIG. 2B is a flowchart showing a processing method of the communication apparatus 202. The communication device 202 periodically performs the process of FIG. Specifically, the communication device 202 starts the processing in FIG. 2B when a predetermined time has elapsed by the timer. In step S211, the MPU 311 of the communication apparatus 202 determines whether or not the fluctuation of the acceleration of the communication apparatus 202 periodically detected by the acceleration sensor 326 is less than the acceleration fluctuation threshold. If the motion detected by 314 is less than the threshold value, the process proceeds to step S212. If the motion detected by the motion detection unit 314 is equal to or greater than the threshold value, the process proceeds to step S214.

  In step S212, the MPU 311 of the communication device 202 determines whether or not the change in the direction of the communication device 202 periodically detected by the geomagnetic sensor 327 is less than the direction variation threshold. The process proceeds to step S213 on the assumption that the motion detected by 314 is less than the threshold value, and proceeds to step S214 on the assumption that the motion detected by the motion detection unit 314 is greater than or equal to the threshold value when the motion is greater than or equal to the threshold value.

  In step S214, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is greater than or equal to the threshold value, and therefore determines that the communication device 202 is likely to move out of the communication limit region 124. Then, the second communication strength Th2 (FIG. 1B) is set for the reception strength processing unit 321 as a large reception threshold. Thereafter, the process proceeds to step S215.

  In step S213, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is less than the threshold value, and thus determines that the possibility that the communication device 202 moves outside the communication limit region 124 is small. Then, the first communication strength Th1 (FIG. 1B) is set for the reception strength processing unit 321 as a small reception threshold. The first communication strength Th1 does not need to be the communication strength in the communication limit region 124, and may be a communication strength in a communicable region narrower than the communication limit region 124 with a margin. However, the second communication strength Th2 needs to be larger than the first communication strength Th1. Thereafter, the process proceeds to step S215.

  In step S <b> 215, the MPU 311 of the communication apparatus 202 wirelessly transmits a communication request signal to the sensor unit 201 via the transmission circuit 324. When the sensor unit 201 wirelessly receives a communication request signal from the communication device 202, the sensor unit 201 wirelessly transmits a response signal to the communication device 202.

  Next, in step S <b> 216, the MPU 311 of the communication apparatus 202 wirelessly receives a response signal from the sensor unit 201 via the reception circuit 323. When the communication device 202 is present at a position close to the sensor unit 201, the intensity of the response signal received by the wireless device 202 is large. On the other hand, when the communication device 202 is located far from the sensor unit 201, the strength of the response signal received by the wireless device 202 is small.

  Next, in step S217, the MPU 311 of the communication apparatus 202 determines whether or not the reception strength of the response signal received from the sensor unit 201 is greater than or equal to the reception threshold via the reception strength processing unit 321. If there is, it is determined that the communication device 202 is located within the communicable area, and the process proceeds to step S218. If it is less than the reception threshold, it is determined that the communication apparatus 202 is located outside the communicable area and wireless data communication with the sensor unit 201 is performed. The process is terminated without performing the process.

  Specifically, when the reception threshold is set to the first communication strength Th1 in step S213, the MPU 311 of the communication device 202 has the response strength received from the sensor unit 201 as the first communication strength Th1. If it is equal to or greater than the first communication strength Th1, it is determined that the communication device 202 is located in the communication limit region 124, and the process proceeds to step S218, where the communication strength is less than the first communication strength Th1. Sometimes, it is determined that the communication device 202 is located outside the communication limit area 124, and the processing is terminated without performing wireless data communication with the sensor unit 201.

  When the reception threshold is set to the second communication strength Th2 in step S214, the MPU 311 of the communication device 202 has a response strength received from the sensor unit 201 that is greater than or equal to the second communication strength Th2. If it is equal to or greater than the second communication strength Th2, it is determined that the communication device 202 is located in the communication stable region 114, and the process proceeds to step S218. If it is less than the second communication strength Th2, the communication device It is determined that 202 is located outside the stable communication area 114, and the processing is terminated without performing wireless data communication with the sensor unit 201.

  In step S <b> 218, the MPU 311 of the communication apparatus 202 wirelessly transmits a data request signal to the sensor unit 201 via the transmission circuit 324. When wirelessly receiving a data request signal from the communication device 202, the sensor unit 201 reads data such as temperature and humidity stored in the data storage unit 305 and wirelessly transmits the data to the communication device 202 via the communication circuit 303. The MPU 311 of the communication apparatus 202 wirelessly receives data from the sensor unit 201 via the receiving circuit 323, stores the received data in the data storage unit 315, and ends the process.

  As described above, when the motion is greater than or equal to the threshold, it is determined whether or not the received signal is greater than or equal to the second communication strength (large reception threshold) Th2, and only when the communication device 202 is located in the communication stable region 114. Perform data communication. On the other hand, when the movement is less than the threshold, it is determined whether or not the received signal is equal to or higher than the first communication strength (small reception threshold) Th1, and data communication is performed only when the communication device 202 is located in the communication limit area 124. I do. If the movement is less than the threshold value, data communication is performed if the position of the communication device 202 is outside the stable communication area 114 and within the communication limit area 124, so that the effective communicable area can be expanded. it can. If the operator does not move the communication device 202, the data of the sensor unit 201 can be acquired from the road 102 without entering the agricultural field 101.

(Second Embodiment)
4A and 4B are diagrams showing a communication system according to the second embodiment. FIG. 4A is a diagram illustrating the sensor unit 201 and the communication device 202, as in FIG. FIG. 4B is a flowchart illustrating a processing method of the communication device 202. FIG. 4B is different from FIG. 2B in that steps S413, S414, and S417 are provided instead of steps S213, S214, and S217. Hereinafter, the points of the present embodiment different from the first embodiment will be described. Steps S211 and S212 are the same as those in FIG.

  Step S413 is provided instead of step S213 in FIG. In step S413, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is less than the threshold value, and thus determines that the possibility that the communication device 202 moves outside the communication limit region 124 is small. Then, the first communication strength is set for the transmission output control unit 322 as the standard transmission power. Thereafter, in step S215, the MPU 311 of the communication device 202 wirelessly transmits a communication request signal to the sensor unit 201 with the first communication strength (standard transmission power) via the transmission circuit 324. By setting the first communication strength, the sensor unit 201 can receive a communication request from the communication device 202 when the communication device 202 is located in the communication limit region 124. When the sensor unit 201 wirelessly receives a communication request signal from the communication device 202, the sensor unit 201 wirelessly transmits a response signal to the communication device 202. Next, in step S216, as described above, the MPU 311 of the communication apparatus 202 determines whether or not a response signal is wirelessly received from the sensor unit 201 via the reception circuit 323. Next, in step S417, when the MPU 311 of the communication device 202 receives a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located within the communication limit region 124, and in step S218, the same as above. In addition, wireless communication of data is performed with the sensor unit 201. On the other hand, when the MPU 311 of the communication device 202 does not receive a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located outside the communication limit area 124 and transmits wireless data to and from the sensor unit 201. The process ends without performing communication.

  Step S414 is provided instead of step S214 in FIG. In step S414, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is greater than or equal to the threshold value, and therefore determines that the communication device 202 is likely to move outside the communication limit region 124. Then, the second communication strength is set for the transmission output control unit 322 as a small transmission power. In the present embodiment, the second communication strength needs to be smaller than the first communication strength. Thereafter, in step S215, the MPU 311 of the communication apparatus 202 wirelessly transmits a communication request signal to the sensor unit 201 with the second communication strength (small transmission power) via the transmission circuit 324. By setting the second communication strength, the sensor unit 201 can receive a communication request from the communication device 202 when the communication device 202 is located in the communication stable region 114. When the sensor unit 201 wirelessly receives a communication request signal from the communication device 202, the sensor unit 201 wirelessly transmits a response signal to the communication device 202. When the communication device 202 is located outside the communication stable region 114, the sensor unit 201 cannot receive a communication request and does not need to wirelessly transmit a response signal, thereby reducing unnecessary transmission power. can do. Next, in step S216, as described above, the MPU 311 of the communication apparatus 202 determines whether or not a response signal is wirelessly received from the sensor unit 201 via the reception circuit 323. Next, in step S417, when the MPU 311 of the communication device 202 receives a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located in the communication stable region 114, and in step S218, the same as above. In addition, wireless communication of data is performed with the sensor unit 201. On the other hand, when the MPU 311 of the communication device 202 does not receive a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located outside the stable communication region 114, and transmits wireless data to and from the sensor unit 201. The process ends without performing communication.

  As described above, the present embodiment can obtain the same effects as those of the first embodiment. Further, by setting the second communication strength (small transmission power) in step S414, when the communication device 202 is located outside the stable communication region 114, the sensor unit 201 may receive a communication request. Can not. In this case, the sensor unit 201 does not need to wirelessly transmit a response signal, so that useless transmission power can be reduced.

(Third embodiment)
5A and 5B are diagrams illustrating a communication system according to the third embodiment. FIG. 5A is a diagram illustrating the sensor unit 201 and the communication device 202 as in FIG. FIG. 5B is a flowchart showing a processing method of the communication apparatus 202. FIG. 5B is different from FIG. 4B in that steps S501 to S503 are provided instead of step S211. Hereinafter, the points of the present embodiment different from the second embodiment will be described.

  Similarly to the above, the communication device 202 periodically repeats the process of FIG. First, in step S501, the MPU 311 of the communication device 202 acquires the position 500 of the communication device 202 that has been periodically detected by the GPS 328 in the past, as shown in FIG. Next, in step S502, the MPU 311 of the communication apparatus 202 calculates the moving direction of the communication apparatus 202 based on the position 500 of the communication apparatus 202 detected in the past. In the case of FIG. 5A, it can be seen that the communication device 202 is moving in the direction toward the sensor unit 201.

  Next, in step S503, it is determined whether or not the change in the position 500 of the communication device 202 detected by the GPS 328 is within a threshold range in the direction toward the sensor unit 201. If it is within the threshold range, the motion detection unit 314 is detected. The process proceeds to step S212 on the assumption that the motion detected by is less than the threshold, and proceeds to step S414 if the motion detected by the motion detection unit 314 is greater than or equal to the threshold when it is outside the threshold range.

  In step S212, similarly to the above, the MPU 311 of the communication device 202 determines whether or not the variation in the direction of the communication device 202 periodically detected by the geomagnetic sensor 327 is less than the direction variation threshold. If there is, the process proceeds to step S413 on the assumption that the motion detected by the motion detection unit 314 is less than the threshold, and proceeds to step S414 if the motion detected by the motion detection unit 314 is greater than or equal to the threshold.

  In step S413, as described above, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is less than the threshold, and thus the communication device 202 can move out of the communication limit region 124. The first communication strength is set to the transmission output control unit 322 as the standard transmission power. Thereafter, in step S215, the MPU 311 of the communication device 202 wirelessly transmits a communication request signal to the sensor unit 201 with the first communication strength (standard transmission power) via the transmission circuit 324. Next, in step S216, as described above, the MPU 311 of the communication apparatus 202 determines whether or not a response signal is wirelessly received from the sensor unit 201 via the reception circuit 323. Next, in step S417, when the MPU 311 of the communication device 202 receives a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located within the communication limit region 124, and in step S218, the same as above. In addition, wireless communication of data is performed with the sensor unit 201. On the other hand, when the MPU 311 of the communication device 202 does not receive a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located outside the communication limit area 124 and transmits wireless data to and from the sensor unit 201. The process ends without performing communication.

  In step S414, as described above, the MPU 311 of the communication device 202 determines that the motion detected by the motion detection unit 314 is equal to or greater than the threshold, and thus the communication device 202 can move out of the communication limit area 124. The second communication strength is set to the transmission output control unit 322 as a small transmission power. Thereafter, in step S215, the MPU 311 of the communication apparatus 202 wirelessly transmits a communication request signal to the sensor unit 201 with the second communication strength (small transmission power) via the transmission circuit 324. Next, in step S216, as described above, the MPU 311 of the communication apparatus 202 determines whether or not a response signal is wirelessly received from the sensor unit 201 via the reception circuit 323. Next, in step S417, when the MPU 311 of the communication device 202 receives a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located in the communication stable region 114, and in step S218, the same as above. In addition, wireless communication of data is performed with the sensor unit 201. On the other hand, when the MPU 311 of the communication device 202 does not receive a response signal from the sensor unit 201, the MPU 311 determines that the communication device 202 is located outside the stable communication region 114, and transmits wireless data to and from the sensor unit 201. The process ends without performing communication.

  As described above, according to the first to third embodiments, when the motion detected by the motion detection unit 314 is less than the threshold, the MPU 311 of the communication device 202 uses the sensor unit (others It is determined whether or not wireless communication with the communication device 201 is possible. The MPU 311 of the communication device 202 performs wireless communication with the sensor unit 201 when wireless communication with the sensor unit 201 is possible with the first communication strength, and performs sensor communication when wireless communication with the sensor unit 201 is not possible with the first communication strength. Wireless communication with the unit 201 is not performed.

  Also, the MPU 311 of the communication device 202 can wirelessly communicate with the sensor unit 201 with the second communication strength different from the first communication strength when the motion detected by the motion detection unit 314 is equal to or greater than the threshold. Determine. The MPU 311 of the communication device 202 performs wireless communication with the sensor unit 201 when wireless communication with the sensor unit 201 is possible with the second communication strength, and performs sensor communication when wireless communication with the sensor unit 201 is not possible with the second communication strength. Wireless communication with the unit 201 is not performed.

  According to the first to third embodiments, an effective communicable area can be expanded according to the movement of the communication apparatus 202 detected by the movement detection unit 314, and a communication error due to movement of the communication apparatus 202 Can be prevented.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof. Various combinations of the first to third embodiments are possible.

201 Sensor unit 202 Communication device 301 MPU
302 communication control unit 303 communication circuit 304 sensor control unit 305 data storage unit 306 first sensor 307 second sensor 311 MPU
312 Communication control unit 313 Communication circuit 314 Motion detection unit 315 Data storage unit 321 Reception intensity processing unit 322 Transmission output control unit 323 Reception circuit 324 Transmission circuit 325 Sensor control unit 326 Acceleration sensor 327 Geomagnetic sensor 328 GPS

Claims (4)

A communication device for performing wireless communication,
A motion detector for detecting the motion of the communication device;
A communication unit that wirelessly transmits a communication request to another communication device and wirelessly receives a response from the other communication device to the communication request;
The communication unit is
When the motion detected by the motion detection unit is less than a threshold value, it is determined whether or not the reception strength of the response from the other communication device is equal to or higher than the first reception strength, and is equal to or higher than the first reception strength. When it is, perform wireless communication with the other communication device, when not less than the first reception strength, do not perform wireless communication with the other communication device,
When the motion detected by the motion detector is greater than or equal to a threshold, it is determined whether or not the reception strength of the response from the other communication device is greater than or equal to a second reception strength that is greater than the first reception strength. The communication device performs wireless communication with the other communication device when the second reception strength is higher than the second reception strength, and does not perform wireless communication with the other communication device when the second reception strength is lower than the second reception strength. . The motion detection unit is based on a change in acceleration of the communication device detected by an acceleration sensor, a change in orientation of the communication device detected by a geomagnetic sensor, or a change in position of the communication device detected by GPS. the communication apparatus according to claim 1, wherein the detecting the movement of the communication device. When the movement detection unit detects a movement of the communication device based on a change in acceleration of the communication device detected by an acceleration sensor and a change in orientation of the communication device detected by a geomagnetic sensor,
The communication unit, when the fluctuation of the acceleration of the communication device detected by the acceleration sensor is greater than or equal to an acceleration fluctuation threshold, or when the fluctuation of the direction of the communication device detected by the geomagnetic sensor is greater than or equal to a direction fluctuation threshold, communication apparatus according to claim 1 or 2, wherein the motion said detected by the motion detection unit is characterized in that determined to be equal to or larger than the threshold value. When the movement detection unit detects the movement of the communication device based on the change in the position of the communication device detected by GPS and the change in the direction of the communication device detected by a geomagnetic sensor,
In the communication unit, the change in the position of the communication device detected by the GPS is out of a threshold range in the direction toward the other communication device, or the change in the direction of the communication device detected by the geomagnetic sensor is changed in the direction. when the threshold value or more, the communication apparatus according to claim 1 or 2, wherein the motion said detected by the motion detection unit, characterized in that determined to be equal to or larger than the threshold value.

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