JP2019121899A - Radio communication device, radio communication system, radio communication method, and program - Google Patents

Abstract

To further reduce the power consumption of a radio communication system.SOLUTION: A radio communication device of an embodiment is a radio communication device connected to a multi-hop network and includes a communication unit and a determination unit. The communication unit performs radio communication with a first master node of the radio communication device and a slave node of the radio communication device. The determination unit determines whether the radio communication device is connected with the first master node on the basis of data transmitted from the first master node. The communication unit repeats prescribed communication processing if the connection with the first master node is disconnected.SELECTED DRAWING: Figure 3

Description

  Embodiments of the present invention relate to a wireless communication apparatus, a wireless communication system, a wireless communication method, and a program.

  A wireless communication system in which a plurality of wireless communication devices having a hierarchical structure are connected under an aggregation device is conventionally known. A wireless communication apparatus used in a wireless communication system is often driven by limited power such as a battery, and a technique for reducing power consumption of the wireless communication system is required.

JP, 2016-54349, A Patent No. 4517885 gazette

  However, in the prior art, it has been difficult to further reduce the power consumption of the wireless communication system.

  The wireless communication apparatus according to the embodiment is a wireless communication apparatus connected to a multi-hop network, and includes a communication unit and a determination unit. The communication unit wirelessly communicates with a first parent node of the wireless communication device and a child node of the wireless communication device. The determination unit determines whether or not the first parent node is connected based on the data transmitted from the first parent node. The communication unit repeats predetermined communication processing when the connection with the first parent node is disconnected.

FIG. 2 is a diagram showing an example of a device configuration of the wireless communication system of the first embodiment. FIG. 2 is a schematic diagram showing the wireless communication system of FIG. 1 in the form of a network topology. FIG. 2 is a view showing an example of the functional configuration of the wireless communication apparatus of the first embodiment. 3 is a flowchart showing an example of a wireless communication method according to the first embodiment. A figure showing an example of functional composition of a radio communication apparatus of a 2nd embodiment. 6 is a flowchart illustrating an example of a wireless communication method according to a second embodiment. The figure which shows the example of a function structure of the radio | wireless communication apparatus of 3rd Embodiment. 9 is a flowchart showing an example of a wireless communication method according to a third embodiment. The figure which shows the example of a function structure of the radio | wireless communication apparatus of 4th Embodiment. The flowchart which shows the example of the radio | wireless communication method of 4th Embodiment. The figure which shows the example of a function structure of the radio | wireless communication apparatus of 5th Embodiment. The flowchart which shows the example of the radio | wireless communication method of 5th Embodiment. The figure which shows Example 1 of the hardware constitutions of the radio | wireless communication apparatus of 1st thru | or 5th embodiment, and a concentration apparatus. FIG. 7 is a diagram showing a second example of the hardware configuration of the wireless communication devices and the aggregation device according to the first to fifth embodiments.

  Hereinafter, embodiments of a wireless communication device, a wireless communication system, a wireless communication method, and a program will be described in detail with reference to the attached drawings.

First Embodiment
First, an apparatus configuration of the wireless communication system according to the first embodiment will be described.

[Example of device configuration]
FIG. 1 is a diagram illustrating an example of a device configuration of the wireless communication system 100 according to the first embodiment. The wireless communication system 100 according to the first embodiment includes wireless communication devices 10A to 10P and an aggregation device 20. Hereinafter, when the wireless communication devices 10A to 10P are not distinguished from one another, they are simply referred to as the wireless communication device 10.

  In the wireless communication system 100, the wireless communication device 10 and the aggregation device 20 disposed within a predetermined range can wirelessly communicate with each other. The data transmitted by each wireless communication device 10 is transmitted to the aggregation device 20 via another wireless communication device 10 or directly. The aggregation device 20 aggregates data transmitted from each wireless communication device 10.

  FIG. 2 is a schematic diagram showing the wireless communication system 100 of FIG. 1 in the form of a network topology. The alphabet indicates the wireless communication device 10 (wireless node), and the root indicates the aggregation device 20 (root node). Also, arrows indicate transmission paths of information. The origin of the arrow indicates the information transmission source (child node), and the point of the arrow indicates the information transmission destination (parent node).

  The wireless communication system 100 of the first embodiment configures a multi-hop network. The communication method of the wireless communication system 100 may be arbitrary. As a specific example of the communication method of the wireless communication system 100, an example in which the communication method is a time division method will be described in the fourth embodiment.

  Next, an example of a functional configuration of the wireless communication device 10 according to the first embodiment will be described.

[Example of functional configuration]
FIG. 3 is a diagram showing an example of a functional configuration of the wireless communication device 10 according to the first embodiment. The wireless communication device 10 of the first embodiment includes a communication unit 1, a determination unit 2, and a control unit 3.

  The communication unit 1 performs wireless communication by transmitting and receiving radio waves between a parent node of the wireless communication device 10 and a child node of the wireless communication device 10. For example, in the example of FIG. 1, the parent node of the wireless communication device 10A is the aggregation device 20, and the child nodes of the wireless communication device 10A are the wireless communication devices 10C and 10E. Also, for example, the parent node of the wireless communication device 10E is the wireless communication device 10A, and the child node of the wireless communication device 10E is the wireless communication device 10G.

  The determination unit 2 determines whether or not the parent node is connected based on the data transmitted from the parent node. For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2 determines that the connection with the parent node is disconnected.

  When the connection with the parent node is disconnected, the communication unit 1 repeats predetermined communication processing.

  The predetermined communication process may be optional. The predetermined communication process is, for example, the same process as the process performed before the connection with the parent node is disconnected. Specifically, the predetermined communication process is, for example, parent node data reception process for receiving data transmitted from a parent node (first parent node). Also, for example, the predetermined communication processing is parent node data transmission processing for transmitting data to the parent node. Further, for example, the predetermined communication processing is child node data reception processing for receiving data transmitted from a child node, and child node data transmission processing for transmitting data to a child node. Also, for example, the predetermined communication processing is any combination of parent node data transmission processing, parent node data reception processing, child node data transmission processing, and child node data reception processing.

  The control unit 3 stops the predetermined communication process being executed by the communication unit 1 when the predetermined period has elapsed. For example, the control unit 3 measures a predetermined cycle, and stops the predetermined communication process executed by the communication unit 1 when the predetermined cycle has passed a predetermined number of times.

  The predetermined cycle is, for example, a cycle indicating the timing at which the wireless communication device 10 generates data. Also, for example, the predetermined cycle is a cycle that indicates the timing at which the wireless communication device 10 transmits data. Also, for example, the predetermined cycle is a cycle that indicates the timing at which the wireless communication device 10 receives data. Also, for example, the predetermined cycle is a cycle set in advance.

  Next, an example of the wireless communication method according to the first embodiment will be described.

[Example of wireless communication method]
FIG. 4 is a flowchart showing an example of the wireless communication method according to the first embodiment. First, the communication unit 1 performs a parent node data reception process of receiving data transmitted from a parent node (first parent node) (step S1).

  Next, based on the result of the parent node data reception process of step S1, the determination unit 2 determines whether or not the parent node is connected (step S2). For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2 determines that the connection with the parent node is disconnected.

  If it is connected to the parent node (step S2, Yes), the process ends.

  When it is not connected with the parent node (Step S2, No), the control unit 3 determines whether a predetermined period has elapsed (Step S3). The elapse of the predetermined period is determined based on, for example, whether a predetermined period has been measured j times (j is an integer of 1 or more).

  When the predetermined period has elapsed (Yes in step S3), the process ends. When the predetermined period has not elapsed (No in step S3), the communication unit 1 repeats the predetermined communication process (step S4). The predetermined communication processing includes, for example, parent node data reception processing for receiving data transmitted from a parent node, parent node data transmission processing for transmitting data to a parent node, child node data reception for receiving data transmitted from a child node Processing and child node data transmission processing for transmitting data to child nodes.

  As described above, in the wireless communication device 10 of the first embodiment, the communication unit 1 wirelessly communicates with the parent node of the wireless communication device 10 and the child nodes of the wireless communication device 10. The determination unit 2 determines whether or not the parent node is connected based on the data transmitted from the parent node. Then, when the communication unit 1 is disconnected from the parent node, the communication unit 1 repeats predetermined communication processing.

  In the prior art, in the case of the network topology as shown in FIG. 2 described above, for example, when node F detects disconnection with node D which is a parent node of node F, node F searches for a parent node. If this is done, the nodes H and J can not exchange data with the node F. Therefore, disconnection of the parent node is detected also in the nodes H and J, and the search processing of the parent node is performed. As a result, disconnection of communication occurs in cascade at lower nodes of the node F. When disconnection of communication occurs in cascade in lower nodes of the node F, power consumption of the wireless communication system 100 becomes larger than when communication is maintained. Specifically, for example, in the wireless communication system 100 due to the influence of a search process of parent nodes, which is sequentially performed by lower nodes, and reacquisition process and retransmission process of data that can not be transmitted due to disconnection of communication. Power consumption increases.

  According to the wireless communication device 10 of the first embodiment, the connection with the child node of the wireless communication device 10 is maintained because the search process for searching for the parent node is not performed at the timing when the connection with the parent node is disconnected. can do. Thereby, according to the wireless communication device 10 of the first embodiment, the power consumption of the wireless communication system 100 can be further reduced.

Second Embodiment
Next, a second embodiment will be described. In the description of the second embodiment, the same descriptions as those of the first embodiment will be omitted, and parts different from the first embodiment will be described.

[Example of functional configuration]
FIG. 5 is a diagram illustrating an example of a functional configuration of the wireless communication device 10-2 according to the second embodiment. The wireless communication device 10-2 according to the second embodiment includes a communication unit 1-2, a determination unit 2, a selection unit 4, and a generation unit 5.

  The communication unit 1-2 is a search for searching for a candidate for a new parent node (second parent node) while repeating predetermined communication processing when the connection with the parent node (first parent node) is disconnected. Do the processing. Note that the new parent node may be the same parent node as before the disconnection. The description of the predetermined communication processing is the same as the description of the first embodiment, and thus will not be described.

  The description of the determination unit 2 is the same as the description of the first embodiment and thus will be omitted.

  The selection unit 4 selects a parent node using a predetermined parent node selection method based on the result of the above-described search processing. Details of the processing of the selection unit 4 will be described later with reference to the flowchart of FIG.

  The generation unit 5 generates parameter information (second parameter information). The parameter information is information necessary for the wireless communication device to communicate. The parameter information includes, for example, the number of hops of the wireless communication device 10-2 configuring the multi-hop network. The number of hops is determined based on the connection relationship with the aggregation device 20. For example, the number of hops of the wireless communication device 10-2 directly connected to the aggregation device 20 is one. When the number of hops of the wireless communication device 10-2 is changed, for example, the timing at which the wireless communication device 10-2 performs transmission / reception processing is changed.

  Next, an example of a wireless communication method according to the second embodiment will be described.

[Example of wireless communication method]
FIG. 6 is a flowchart showing an example of the wireless communication method of the second embodiment. First, the communication unit 1-2 performs a parent node data reception process of receiving data transmitted from a parent node (first parent node) (step S11).

  Next, based on the result of the parent node data reception processing of step S11, the determination unit 2 determines whether or not the connection with the parent node is made (step S12). For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2 determines that the connection with the parent node is disconnected.

  If the parent node is connected (step S12, Yes), the process ends.

  When the communication unit 1-2 is not connected to the parent node (No in step S12), the communication unit 1-2 performs search processing for searching for a new parent node candidate while repeating predetermined communication processing (step S13). The predetermined communication processing includes, for example, parent node data transmission processing for transmitting data to a parent node (first parent node), child node data reception processing for receiving data transmitted from a child node, and data to a child node Child node data transmission processing to transmit. When the communication unit 1-2 can not receive even one new parent node candidate in the search process of step S13, the communication unit 1-2 receives the new parent node candidate node again. Further, the communication unit 1-2 may fail to receive the candidate node of the parent node, and may set the number of times to continue the transmission and reception process with respect to the child node in advance when performing reception again.

  Next, the selection unit 4 selects a parent node using a predetermined parent node selection method based on the result of the search process of step S13 (step S14). The result of the search process includes, for example, data received from the parent node candidate. The selection unit 4 selects a new parent node based on, for example, communication quality, received signal strength, and reception success probability. The reception success probability is calculated based on, for example, the ratio between the amount of data scheduled to be received and the amount of data actually successfully received. The same parent node as that before disconnection may be selected as a new parent node.

  Next, the generation unit 5 generates parameter information based on the new parent node selected in the process of step S14 (step S15). The generation unit 5 generates, for example, parameter information including the changed number of hops. The parameter information may include time information, a difference in the number of hops (change amount), frequency information, connection destination information, and the like.

  The time information includes, for example, a time indicating a timing at which the wireless communication device 10-2 transmits and receives. The difference in the number of hops indicates the difference between the number of hops before disconnection of the communication of the wireless communication device 10-2 and the number of new hops. The frequency information indicates the frequency used for communication. The connection destination information includes, for example, identification information that identifies a parent node of the wireless communication device 10-2, and identification information that identifies a child node of the wireless communication device 10-2.

  Next, the communication unit 1-2 performs a communication process based on the parameter information generated by the process of step S15 (step S16). Specifically, the communication unit 1-2 performs transmission / reception processing for the connected child node and transmission / reception processing for the newly selected parent node. Also, the communication unit 1-2 transmits the changed hop number to the child node. When there is a change in the number of hops in the parent node and the number of hops is received from the parent node, the wireless communication device 10-2 performs transmission / reception processing with respect to the parent node based on the number of hops to child nodes connected to itself. And further transmit the number of hops. Thus, the number of hops of the wireless communication device 10-2 included in the wireless communication system 100 configuring the multi-hop network is updated.

  As described above, the wireless communication device 10-2 according to the second embodiment continues the operation with the child node even after the communication with the parent node is disconnected, and further searches for a new parent node. According to the wireless communication device 10-2 of the second embodiment, it is possible to continue the operation without causing the disconnection with the lower node, and to connect to a new parent node with good communication quality. Thereby, the power consumption of the wireless communication system 100 can be further reduced.

  In the wireless communication device 10-2 according to the second embodiment, the communication unit 1-2 uses parameters from the new parent node (second parent node) for transmission processing and reception processing with the parent node. When information (first parameter information) is received, parent node data transmission processing and parent node data reception processing are repeated based on the parameter information.

Third Embodiment
Next, a third embodiment will be described. In the description of the third embodiment, the same descriptions as those of the first and second embodiments will be omitted, and parts different from the first and second embodiments will be described.

[Example of functional configuration]
FIG. 7 is a diagram showing an example of a functional configuration of the wireless communication device 10-3 according to the third embodiment. The wireless communication device 10-3 of the third embodiment includes a communication unit 1-3, a determination unit 2, a control unit 3, a selection unit 4, a generation unit 5, a measurement unit 6, and an instruction unit 7.

  When the connection with the parent node (first parent node) is disconnected, the communication unit 1-3 repeats predetermined communication processing based on the instruction of the instruction unit 7. Alternatively, when the communication unit 1-3 disconnects the connection with the parent node (first parent node), the communication unit 1-3 repeats a predetermined communication process based on the instruction of the instruction unit 7, and thus the new parent node (second Search processing for searching for the candidate of the parent node of The description of the predetermined communication processing is the same as the description of the first embodiment, and thus will not be described. Note that the new parent node may be the same parent node as before the disconnection.

  The description of the determination unit 2 and the control unit 3 is the same as the description of the first embodiment and thus will be omitted. The description of the selection unit 4 and the generation unit 5 is the same as the description of the second embodiment and thus will be omitted.

  The measuring unit 6 measures statistical information of wireless communication by the communication unit 1-3. The statistical information includes, for example, the number of disconnections of communication with the parent node (first parent node), the number of frames elapsed since the last communication with the parent node (first parent node), and the parent node (first parent node) And at least one of the average received signal strength of the data received from the parent node (first parent node).

  When the connection with the parent node (first parent node) is disconnected, the instruction unit 7 instructs, for example, the communication unit 1-3 to repeat predetermined communication processing based on the statistical information. Further, for example, when the connection with the parent node (first parent node) is disconnected, the instruction unit 7 transmits the new parent node (second parent node) to the communication unit 1-3 based on the statistical information. An instruction to execute a search process for searching for a candidate and an instruction to repeat a predetermined communication process are performed.

  Next, an example of a wireless communication method according to the third embodiment will be described.

[Example of wireless communication method]
FIG. 8 is a flowchart showing an example of a wireless communication method according to the third embodiment. In the example of FIG. 8, the case where the number of disconnections of communication with the parent node (first parent node) is used as statistical information measured by the measurement unit 6 will be described.

  First, the communication unit 1-3 performs parent node data reception processing for receiving data transmitted from the parent node (first parent node) (step S21).

  Next, based on the result of the parent node data reception processing of step S21, the determination unit 2 determines whether or not the connection with the parent node is made (step S22). For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2 determines that the connection with the parent node is disconnected.

  If it is connected to the parent node (Yes in step S22), the process ends.

  When not connected with the parent node (Step S22, No), the measuring unit 6 adds the number of disconnections of communication with the parent node (Step S23). The measuring unit 6 increases the number of disconnections by one, for example.

  Next, the instruction unit 7 determines whether the number of disconnections is equal to or more than a threshold (step S24). The reason for determining the threshold of the number of disconnections is that, for example, it is assumed that the possibility of re-establishing the connection with the parent node (the first parent node) is lower as the number of disconnections increases.

  When the number of disconnections is not equal to or more than the threshold (No in step S24), the communication unit 1-3 repeats predetermined communication processing according to an instruction of the instruction unit 7 (step S25). The predetermined communication processing includes, for example, parent node data reception processing for receiving data transmitted from a parent node, parent node data transmission processing for transmitting data to a parent node, child node data reception for receiving data transmitted from a child node Processing and child node data transmission processing for transmitting data to child nodes.

  When the number of disconnections is equal to or more than the threshold (Yes in step S24), the communication unit 1-3 performs a search process for searching for a candidate of a new parent node (second parent node) according to an instruction of the instruction unit 7 and a predetermined process. A communication process is performed (step S26). The predetermined communication processing includes, for example, parent node data reception processing for receiving data transmitted from a parent node, parent node data transmission processing for transmitting data to a parent node, child node data reception for receiving data transmitted from a child node Processing and child node data transmission processing for transmitting data to child nodes.

  As described above, in the wireless communication device 10-3 of the third embodiment, according to the statistical information of the wireless communication by the communication unit 1-3, the communication with the connected parent node is continued, or It is possible to change whether to search for a new parent node while continuing communication with the connected parent node. As a result, when the possibility of connection recovery is low, data can be transmitted to a new parent node newly discovered by the search process. On the other hand, when there is a high possibility that the connection will be restored, the power saving operation can be continued without executing the search processing with high power consumption. Therefore, according to the wireless communication device 10-3 of the third embodiment, the power consumption of the wireless communication system 100 can be further reduced.

Fourth Embodiment
Next, a fourth embodiment will be described. In the description of the fourth embodiment, the same descriptions as those of the first embodiment will be omitted, and parts different from the first embodiment will be described. In the fourth embodiment, as an example of a specific communication method of the wireless communication system 100, a case where the communication method is a time division method will be described.

[Example of functional configuration]
FIG. 9 is a diagram showing an example of a functional configuration of the wireless communication device 10-4 according to the fourth embodiment. The wireless communication device 10-4 according to the fourth embodiment includes a communication unit 1-4, a determination unit 2, and a setting unit 8.

  When the communication unit 1-4 disconnects from the parent node (first parent node), the communication unit 1-4 repeats predetermined communication processing in accordance with the time slot set by the setting unit 8. The time slot indicates the timing of executing a predetermined communication process. The description of the predetermined communication processing is the same as the description of the first embodiment, and thus will not be described.

  The determination unit 2 determines whether or not the parent node is connected based on the data transmitted from the parent node. For example, when the data (wireless signal) transmitted from the parent node can not be received in the time slot assigned to the transmission of the parent node, for example, the determination unit 2 determines that the connection with the parent node is disconnected.

  When the connection with the parent node is disconnected, the setting unit 8 sets a time slot indicating timing to execute predetermined communication processing.

  Next, an example of a wireless communication method according to the fourth embodiment will be described.

[Example of wireless communication method]
FIG. 10 is a flowchart showing an example of the wireless communication method of the fourth embodiment. First, the communication unit 1-4 performs a parent node data reception process of receiving data transmitted from a parent node (first parent node) (step S31).

  Next, based on the result of the parent node data reception processing of step S31, the determination unit 2 determines whether or not the connection with the parent node is made (step S32). For example, when the data (wireless signal) transmitted from the parent node can not be received in the time slot assigned to the transmission of the parent node, for example, the determination unit 2 determines that the connection with the parent node is disconnected.

  If the parent node is connected (step S32, Yes), the process ends.

  If not connected to the parent node (step S32, No), the setting unit 8 sets a time slot indicating the timing of executing a predetermined communication process (step S33). The predetermined communication processing is, for example, parent node data reception processing for receiving data transmitted from a parent node.

  As predetermined communication processing, parent node data transmission processing for transmitting data to a parent node, child node data reception processing for receiving data transmitted from a child node, and child node data transmission for transmitting data to a child node A time slot for further processing may be set. In addition, the setting unit 8 may set a reception time slot for searching for a new parent node and a connection acceptance time slot for connecting to a new child node in the process of step S33.

  The communication unit 1-4 repeats the predetermined communication process according to the time slot set by the process of step S33 (step S34).

  As described above, according to the wireless communication device 10-4 of the fourth embodiment, even when the communication system of the wireless communication system 100 is a time division system, predetermined communication processing can be continued. Thereby, according to the wireless communication device 10-4 of the fourth embodiment, even when the communication system of the wireless communication system 100 is a time division system, the power consumption of the wireless communication system 100 can be further reduced.

Fifth Embodiment
Next, a fifth embodiment will be described. In the description of the fifth embodiment, the same descriptions as those of the first embodiment will be omitted, and parts different from the first embodiment will be described.

[Example of functional configuration]
FIG. 11 is a diagram illustrating an example of a functional configuration of the wireless communication device 10-5 according to the fifth embodiment. The wireless communication device 10-5 of the fifth embodiment includes the communication unit 1, a determination unit 2-2, and a control unit 3-2.

  When the communication unit 1 disconnects the connection with the parent node (first parent node), the communication unit 1 repeats the predetermined communication process until the predetermined number of cycles (waiting number of repetitions) elapses in the predetermined communication process. The description is the same as the description of the first embodiment and thus will be omitted.

  The number of times of waiting is determined by the determination unit 2-2. The number of times of standby may be a value set before power-on of the wireless communication device 10-5, a value notified from the aggregation device 20 that aggregates data transmitted from the wireless communication device 10-5, and a parent node (first Of the communication quality with the parent node of

  The communication quality with the parent node (first parent node) is, for example, the number of times the communication quality with the parent node is below the threshold, the number of times the communication quality with the parent node is above the threshold, with the parent node And the number of disconnections with the parent node.

  The determination unit 2-2 determines whether or not the parent node is connected based on the data transmitted from the parent node. For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2-2 determines that the connection with the parent node is disconnected.

  When the connection with the parent node (first parent node) is disconnected, the determination unit 2-2 determines the number of times of waiting. The number of times of waiting may be a value different for each target parent node, or may be a uniform value such as a value set before power-on. Furthermore, the determination unit 2-2 stores, for each parent node, the number of disconnections in which the connection with the parent node is disconnected, and updates the number of waits by subtracting the number of disconnections from the number of waits. The determination unit 2-2 notifies the control unit 3-2 of the number of times of waiting.

  The control unit 3-2 measures a predetermined cycle, and stops the predetermined communication process being executed by the communication unit 1 when the predetermined cycle has passed the above-described standby number. The description of the predetermined cycle is the same as the description of the first embodiment, and is thus omitted.

  Next, an example of a wireless communication method according to the fifth embodiment will be described.

[Example of wireless communication method]
FIG. 12 is a flowchart showing an example of the wireless communication method of the fifth embodiment. First, the communication unit 1 performs parent node data reception processing for receiving data transmitted from a parent node (first parent node) (step S41).

  Next, based on the result of the parent node data reception processing of step S41, the determination unit 2-2 determines whether or not the connection with the parent node is made (step S42). For example, when the data (wireless signal) of the parent node can not be received at the timing when the data from the parent node is received, the determination unit 2-2 determines that the connection with the parent node is disconnected.

  If it is connected to the parent node (Yes in step S42), the process ends.

  When it is not connected with the parent node (Step S42, No), the determination unit 2-2 increments and stores the number of disconnections in which the connection with the parent node is disconnected (Step S43). Next, the determination unit 2-2 updates the number of waits j by subtracting the number of disconnections stored in the process of step S43 from the number of waits j (step S44).

  Next, the determination unit 2-2 determines whether the number of times of waiting j updated by the process of step S44 is 0 or less (step S45). If the number of times of waiting j is 0 or less (Yes in step S45), the number of times of waiting j is set to 0 (step S48), and the process ends.

  If the number of times of waiting j is not 0 or less (No at Step S45), the communication unit 1 performs a predetermined communication process at one timing in a predetermined cycle (Step S46). The predetermined cycle is, for example, a cycle indicating the timing at which the wireless communication device 10-5 generates data. The predetermined communication processing includes, for example, parent node data reception processing for receiving data transmitted from a parent node, parent node data transmission processing for transmitting data to a parent node, and a child node for receiving data transmitted from a child node Data reception processing and child node data transmission processing for transmitting data to child nodes.

  Next, the control unit 3-2 determines whether or not the predetermined cycle has been repeated the number of times of waiting j (j is an integer of 1 or more) (step S47).

  If the predetermined cycle is repeated for the number of times j (step S47, Yes), the process ends.

  If the predetermined cycle has not been repeated for the number of times j (step S47, No), the process returns to step S46.

  As described above, according to the wireless communication device 10-5 of the fifth embodiment, since the search process for searching for the parent node is not performed at the timing when the connection with the parent node is disconnected, the operation before the disconnection is performed. (Predetermined communication process) can be continued. Thereby, according to the wireless communication device 10-5 of the fifth embodiment, the power consumption of the wireless communication system 100 can be further reduced.

  Further, in the wireless communication device 10-5 of the fifth embodiment, the determination unit 2-2 changes the number of times of waiting (the number of repetitions) in accordance with the number of disconnections with the parent node (first parent node). Generally, it is considered that the connection with the parent node is unstable as the number of disconnections with the parent node increases. The determination unit 2-2 changes the number of times of waiting as in the process of step S44 described above, and as the number of disconnections with the parent node increases, the number of times of repeating predetermined communication processing performed on the parent node Is reduced. When the number of times of waiting becomes 0, for example, the communication unit 1 performs a search process for searching for a new parent node (second parent node).

  Finally, an example of the hardware configuration of the wireless communication device 10 and the aggregation device 20 according to the first to fifth embodiments will be described.

[Hardware configuration example 1]
FIG. 13 is a diagram illustrating an example 1 of the hardware configuration of the wireless communication device 10 and the aggregation device 20 according to the embodiment. In Example 1 of FIG. 13, the wireless communication device 10 and the aggregation device 20 include a central processing unit (CPU) 101, a main storage device 102, an external storage device 103, a communication interface 104, and a wireless device 105. The CPU 101, the main storage device 102, the external storage device 103, the communication interface 104, and the wireless device 105 are connected by a bus 120.

  The CPU 101 reads a program from a storage medium such as the external storage device 103 and executes the program on the main storage device 102.

  The main storage device 102 stores a program, data necessary for the execution of the program, data generated by the execution of the program, and the like. The main storage 102 may be optional. The main storage device 102 is, for example, a random access memory (RAM), a dynamic random access memory (DRAM), a static random access memory (SRAM), or the like.

  The main storage unit 102 stores information such as a program, relay information, frame information, node ID, number of hops, parent node and child node. The relay information is, for example, data received from another node. Specifically, relay information is sensor information etc. which were acquired by other nodes, for example. The parent node is a node whose number of hops is smaller than that of its own node by one and is a transmission destination node of its own node. A child node is a node whose hop number is larger than that of its own node by one and is a node which determines the transmission destination node as its own node.

  Also, the main storage device 102 may store an operating system (OS), a basic input output system (BIOS), various middleware, and the like.

  The external storage device 103 stores a program, data required to execute the program, data generated by the execution of the program, and the like. These programs and data are expanded in the main storage device 102 when the program is executed. The external storage device 103 may be optional. The external storage device 103 is, for example, a hard disk, an optical disk, a flash memory, a magnetic tape, or the like. The external storage device 103 stores information such as program, relay information, frame information, node ID, number of hops, parent node and child node.

  The programs executed by the wireless communication device 10 and the aggregation device 20 may be installed in advance in the external storage device 103, for example. Also, for example, the external storage device 103 may install the program in the external storage device 103 by storing a program transmitted from another device to the aggregation device 20 through another wired or wireless network.

  The communication interface 104 is a general-purpose I / F for communicating with an external device. The communication interface 104 is, for example, a UART, I2C, SPI, CAN, RS232 and Ethernet (registered trademark) port.

  The wireless device 105 is a device for the wireless communication device 10 and the aggregation device 20 to wirelessly communicate with other devices. Further, the wireless communication device 10 and the aggregation device 20 may include a plurality of wireless devices 105. When the wireless communication device 10 and the aggregation device 20 include, for example, two wireless devices 105, the second wireless device 105 may transmit the data collected by the first wireless device 105. The second wireless device 105 may be any device as long as it uses a different radio frequency from the first wireless device 105. The second wireless device 105 is, for example, cellular communication and Wi-Fi.

  Next, an example 2 of the hardware configuration of the wireless communication device 10 and the aggregation device 20 according to the embodiment will be described.

[Hardware configuration example 2]
FIG. 14 is a diagram of a second example of the hardware configuration of the wireless communication device 10 and the aggregation device 20 according to the embodiment. In Example 2 of FIG. 14, the wireless communication device 10 and the aggregation device 20 include a CPU 101, a main storage device 102, an external storage device 103, a communication interface 104, an input interface 106, and a graphic processing device 107. The CPU 101, the main storage device 102, the external storage device 103, the communication interface 104, the input interface 106, and the graphic processing device 107 are connected via a bus 120.

  Further, in Example 2 of FIG. 14, the sensor 108 and the wireless communication module 109 are connected to the communication interface 104. An input device 110 is connected to the input interface 106. Further, a display 111 is connected to the graphic processing device 107.

  The description of the CPU 101, the main storage device 102, the external storage device 103, and the communication interface 104 is the same as that of FIG.

  The input interface 106 receives from the input device 110 an operation signal corresponding to the input operation accepted by the input device 110. The input device 110 may be optional. The input device 110 is, for example, a keyboard and a mouse.

  The graphic processing device 107 is a device that causes the display 111 to display an image or an image based on the image signal and the image signal generated by the CPU 101. The display 111 may be optional. The display 111 is, for example, an LCD (Liquid Crystal Display), a CRT (Brown Tube), or a PDP (Plasma Display).

  The sensor 108 may be optional. The sensor 108 is, for example, an illuminance sensor, a temperature and humidity sensor, an acceleration sensor, and an angular velocity sensor. Also, the sensor 108 may be a pseudo sensor. The pseudo sensor is, for example, another computer device that outputs data. Since the aggregation device 20 is a device that aggregates data from the wireless communication device 10, the aggregation device 20 may not include the sensor 108.

  The wireless communication module 109 plays the role of the wireless device 105 of FIG. 13 described above. The wireless communication module 109 is not necessarily the same in hardware configuration as the wireless device 105 described above. Further, the wireless communication device 10 and the aggregation device 20 may include a plurality of wireless communication modules 109 as in the wireless device 105 of FIG. 13.

  The power supply of the hardware in FIG. 13 and FIG. 14 described above may be arbitrary. The power supplies of the hardware in the above-mentioned FIG. 13 and FIG.

  However, since the power supply of the wireless communication device 10 relates to the power saving property of the wireless communication device 10, it is mainly assumed that the power supply is driven by energy supply by a battery, a power generation element, or the like. However, even if the power source of the wireless communication device 10 is a commercial power source, the effect of suppressing power consumption can be obtained by the wireless communication methods of the first to fifth embodiments described above.

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Reference Signs List 1 communication unit 2 determination unit 3 control unit 4 selection unit 5 generation unit 6 measurement unit 7 instruction unit 8 setting unit 10 wireless communication device 20 aggregation device 100 wireless communication system

Claims (20)

A wireless communication apparatus connected to a multi-hop network, comprising:
A communication unit that wirelessly communicates with a first parent node of the wireless communication device, and a child node of the wireless communication device;
A determination unit that determines whether or not the first parent node is connected based on data transmitted from the first parent node;
The communication unit repeats predetermined communication processing when the connection with the first parent node is disconnected.
Wireless communication device. The predetermined communication process is a first parent node data reception process for receiving data transmitted from the first parent node.
The wireless communication device according to claim 1. The predetermined communication process is a first parent node data transmission process for transmitting data to the first parent node.
The wireless communication device according to claim 1. The predetermined communication process is a child node data reception process for receiving data transmitted from the child node, and a child node data transmission process for transmitting data to the child node.
The wireless communication device according to claim 1. The communication unit repeats a predetermined communication process until a predetermined cycle elapses a predetermined number of times, when the connection with the first parent node is disconnected.
The wireless communication device according to claim 1. The predetermined cycle is a cycle indicating the timing at which the wireless communication device generates data, a cycle indicating the timing at which the wireless communication device transmits data, or a cycle indicating the timing at which the wireless communication device receives data. It is a preset cycle,
The wireless communication device according to claim 5. The communication unit is configured to transmit data to the first parent node when the connection with the first parent node is disconnected, and the data transmitted from the child node is received. Performing a search process for searching for a second parent node candidate while repeating a child node data reception process to be performed and a child node data transmission process to transmit data to the child node;
The wireless communication device according to claim 1. And a selection unit that selects the second parent node based on the search processing,
The communication unit, when the connection with the first parent node is disconnected and the second parent node is selected, the child node data reception process, the child node data transmission process, the second A second parent node data reception process for receiving data transmitted from a parent node, and a second parent node data transmission process for transmitting data to the second parent node are repeated.
The wireless communication device according to claim 7. The communication unit receives, from the second parent node, first parameter information used for transmission processing and reception processing with the second parent node, and based on the first parameter information, the communication unit receives the first parameter information. Repeating the second parent node data transmission process and the second parent node data reception process;
The wireless communication device according to claim 8. The apparatus further comprises a generation unit that generates second parameter information used for the child node data transmission process and the child node data reception process,
The communication unit transmits the second parameter information to the child node, and repeats the child node data transmission process and the child node data reception process based on the second parameter information.
The wireless communication device according to claim 9. The first and second parameter information includes time information indicating a timing at which the wireless communication apparatus transmits and receives, the number of hops from an aggregation apparatus for aggregating data transmitted from the wireless communication apparatus, and the first parent node The difference between the number of hops before the disconnection of the connection and the number of new hops, the frequency used for communication, and at least one of connection destination information of the wireless communication device,
The wireless communication device according to claim 10. A measurement unit configured to measure statistical information of wireless communication by the communication unit;
When the connection with the first parent node is disconnected, an instruction to cause the communication unit to repeat the predetermined communication process is searched based on the statistical information, or the communication unit searches for a candidate for the second parent node. An instruction unit that performs either one of execution of search processing and instruction to repeat the predetermined communication processing;
The wireless communication device according to claim 1, further comprising: The statistical information includes the number of disconnections from the connection with the first parent node, the number of frames elapsed since the last communication with the first parent node, and a received signal of data received from the first parent node And at least one of an intensity and an average received signal strength of data received from a parent node,
A wireless communication device according to claim 12. The communication method of the multi-hop network is a time division method,
And a setting unit configured to set a time slot indicating a timing to execute the predetermined communication process when the connection with the first parent node is disconnected.
The communication unit repeats the predetermined communication process according to the time slot when the connection with the first parent node is disconnected.
The wireless communication device according to claim 1. The determination unit determines the number of times of waiting when the connection with the first parent node is disconnected,
When the connection with the first parent node is disconnected, the communication unit repeats a predetermined communication process until a predetermined number of cycles of the waiting period elapses.
The wireless communication device according to claim 5. The number of times of standby may be a value set before power-on of the wireless communication device, a value notified from an aggregation device that aggregates data transmitted from the wireless communication device, and communication with the first parent node Determined based on at least one of the quality,
The wireless communication device according to claim 15. The determination unit stores, for each of the first parent nodes, the number of disconnections in which the connection with the first parent node is disconnected, and subtracting the number of disconnections from the number of standbys. Update,
The wireless communication device according to claim 15. What is claimed is: 1. A wireless communication system, comprising: a plurality of wireless communication devices, and an aggregation device for aggregating data transmitted from the plurality of wireless communication devices, the multi-hop network being configured,
The wireless communication device is
A communication unit that wirelessly communicates with a first parent node of the wireless communication device, and a child node of the wireless communication device;
A determination unit that determines whether or not the first parent node is connected based on data transmitted from the first parent node;
The communication unit repeats predetermined communication processing when the connection with the first parent node is disconnected.
Wireless communication system. A wireless communication method of a wireless communication apparatus connected to a multi-hop network, comprising:
Wirelessly communicating with a first parent node of the wireless communication device and a child node of the wireless communication device;
Determining based on data transmitted from the first parent node whether or not it is connected to the first parent node;
The wireless communication step repeats predetermined communication processing when the connection with the first parent node is disconnected.
Wireless communication method. A wireless communication device connected to a multi-hop network,
A communication unit that wirelessly communicates with a first parent node of the wireless communication device, and a child node of the wireless communication device;
It functions as a determination unit that determines based on data transmitted from the first parent node whether it is connected to the first parent node or not.
The communication unit repeats predetermined communication processing when the connection with the first parent node is disconnected.
program.

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