JP6707570B2 - Wireless communication device, wireless communication system, wireless communication method, and program - Google Patents

Description

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

2. Description of the Related Art A wireless communication system in which a plurality of wireless communication devices having a hierarchical structure are connected under an aggregating device is conventionally known. A wireless communication device 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 Japanese Patent No. 4517885

However, with the conventional technology, it is difficult to further reduce the power consumption of the wireless communication system.

The wireless communication device according to the embodiment is a wireless communication device 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 it is connected to the first parent node based on the data transmitted from the first parent node. The communication unit, when the connection with the first parent node is disconnected, while repeated a predetermined communication processing, the search process of searching for candidates of the second parent node. The predetermined communication process includes a first parent node data transmission process of transmitting data to the first parent node, a child node data reception process of receiving data transmitted from the child node, and the child node. This is a child node data transmission process for transmitting data.

The figure which shows the example of a device structure of the radio|wireless communications system of 1st Embodiment. The schematic diagram which showed the wireless communication system of FIG. 1 in the form of network topology. The figure which shows the example of a function structure of the radio|wireless communication apparatus of 1st Embodiment. 3 is a flowchart showing an example of a wireless communication method according to the first embodiment. The figure which shows the example of a function structure of the radio|wireless communication apparatus of 2nd Embodiment. The flowchart which shows the example of the wireless communication method of 2nd Embodiment. The figure which shows the example of a function structure of the radio|wireless communication apparatus of 3rd Embodiment. The flowchart which shows the example of the radio|wireless communication method of 3rd 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 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 wireless communication method of 5th Embodiment. The figure which shows the example 1 of the hardware constitutions of the radio|wireless communication apparatus and aggregation apparatus of 1st thru|or 5th embodiment. The figure which shows the example 2 of the hardware constitutions of the radio|wireless communication apparatus and aggregation apparatus of 1st thru|or 5th embodiment.

Embodiments of a wireless communication device, a wireless communication system, a wireless communication method, and a program will be described in detail below with reference to the accompanying drawings.

(First embodiment)
First, the device 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 a 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, 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 arranged 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 the 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). The arrows indicate the information transmission paths. The source of the arrow indicates the information transmission source (child node), and the arrow destination indicates the information transmission destination (parent node).

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

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

[Example of functional configuration]
FIG. 3 is a diagram illustrating 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. Further, 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 it is connected to the parent node based on the data transmitted from the parent node. For example, when the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

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

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

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

The predetermined cycle is, for example, a cycle indicating the timing at which the wireless communication device 10 generates data. Further, for example, the predetermined cycle is a cycle indicating the timing at which the wireless communication device 10 transmits data. Further, for example, the predetermined cycle is a cycle indicating the timing at which the wireless communication device 10 receives data. Further, 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 of 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, the determination unit 2 determines whether or not the parent node is connected to the parent node based on the result of the parent node data reception process of step S1 (step S2). For example, when the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

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

When it is not connected to 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 by, for example, whether or not the predetermined cycle is measured j times (j is an integer of 1 or more).

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

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 node of the wireless communication device 10. The determination unit 2 determines whether or not it is connected to the parent node based on the data transmitted from the parent node. Then, the communication unit 1 repeats a predetermined communication process when the connection with the parent node is disconnected.

In the conventional technique, in the case of the network topology as shown in FIG. 2 described above, for example, when the node F detects a disconnection with the node D that is the parent node of the node F, the node F performs the parent node search process. Then, the nodes H and J cannot transmit/receive data to/from the node F. Therefore, also in the nodes H and J, disconnection of the parent node is detected, and the parent node search process is performed. As a result, communication disconnection occurs in the lower nodes of the node F. When the communication disconnection occurs in the lower nodes of the node F, the power consumption of the wireless communication system 100 becomes larger than that in the case where the communication is maintained. Specifically, for example, due to the influence of a parent node search process that is performed in a chain of lower nodes, a reacquisition process and a retransmission process of data that could not be transmitted due to disconnection of communication, and the like of the wireless communication system 100. Power consumption increases.

According to the wireless communication device 10 of the first 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 connection with the child node of the wireless communication device 10 is maintained. can do. As a result, 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, description similar to that of the first embodiment will be omitted, and only different points 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.

When the connection with the parent node (first parent node) is disconnected, the communication unit 1-2 searches for a candidate for a new parent node (second parent node) while repeating a predetermined communication process. Perform processing. Note that the new parent node may be the same parent node as before the connection was disconnected. The description of the predetermined communication process is the same as the description of the first embodiment, and will be omitted.

Since the description of the determination unit 2 is the same as the description of the first embodiment, the description thereof 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 process. 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 forming 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 1. 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 the wireless communication method of 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 the data transmitted from the parent node (first parent node) (step S11).

Next, the determination unit 2 determines whether or not it is connected to the parent node, based on the result of the parent node data reception process of step S11 (step S12). For example, when the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

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

When not connected to the parent node (No in step S12), the communication unit 1-2 repeats a predetermined communication process and performs a search process for searching for a new parent node candidate (step S13). The predetermined communication process includes, for example, a parent node data transmission process of transmitting data to a parent node (first parent node), a child node data reception process of receiving data transmitted from a child node, and a data transmission to a child node. It is a child node data transmission process for transmitting. If no new parent node candidate can be received in the search process of step S13, the communication unit 1-2 again receives a new parent node candidate node. Further, the communication unit 1-2 may fail to receive the candidate node of the parent node, and may preset the number of times of continuing the transmission/reception process for the child node when receiving 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, the 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, reception success probability, and the like. The reception success probability is calculated based on, for example, the ratio of the amount of data scheduled to be received to the amount of data that was actually successfully received. The same parent node as before disconnection may be selected as the new parent node.

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

The time information includes, for example, the time indicating the 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 the communication disconnection 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 for identifying a parent node of the wireless communication device 10-2 and identification information for identifying a child node of the wireless communication device 10-2.

Next, the communication unit 1-2 performs communication processing based on the parameter information generated by the processing 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. The communication unit 1-2 also transmits the changed hop count to the child node. When the parent node has a change in the hop count and receives the hop count from the parent node, the wireless communication device 10-2 performs transmission/reception processing with respect to the parent node based on the hop count, and transmits the received hop count to the child node connected to itself. Then, the hop count is transmitted. As a result, the hop count of the wireless communication device 10-2 included in the wireless communication system 100 forming 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 disconnecting the communication with the lower node, and to connect to the new parent node having 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 the parameters used by the new parent node (second parent node) for transmission processing and reception processing with the parent node. When the information (first parameter information) is received, the parent node data transmission process and the parent node data reception process are repeated based on the parameter information.

(Third Embodiment)
Next, a third embodiment will be described. In the description of the third embodiment, description similar to that of the first and second embodiments will be omitted, and only different points from the first and second embodiments will be described.

[Example of functional configuration]
FIG. 7 is a diagram showing an example of the 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 a predetermined communication process based on the instruction from the instruction unit 7. Alternatively, when the connection with the parent node (first parent node) is cut off, the communication unit 1-3 repeats a predetermined communication process based on the instruction of the instruction unit 7, and then the new parent node (second Search process for searching for a candidate for the parent node of. The description of the predetermined communication process is the same as the description of the first embodiment, and will be omitted. Note that the new parent node may be the same parent node as before the connection was disconnected.

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

The measurement 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 that have passed 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 the communication unit 1-3 to repeat a predetermined communication process, for example, based on the statistical information. Further, for example, when the connection with the parent node (first parent node) is cut off, the instruction unit 7 notifies the communication unit 1-3 of the new parent node (second parent node) based on the statistical information. An instruction to execute a search process for searching a candidate and an instruction to repeat a predetermined communication process are given.

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

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

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

Next, the determination unit 2 determines whether or not the parent node is connected to the parent node based on the result of the parent node data reception process of step S21 (step S22). For example, when the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

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

When it is not connected to the parent node (step S22, No), the measurement unit 6 adds the number of disconnections of communication with the parent node (step S23). The measuring unit 6 increases the number of cuts by 1, for example.

Next, the instruction unit 7 determines whether or not the number of disconnections is equal to or greater than the threshold value (step S24). The reason for determining the disconnection count threshold value is that, for example, it is assumed that the larger the number of disconnections, the lower the possibility that the connection with the parent node (first parent node) will be restored.

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

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

As described above, in the wireless communication device 10-3 according to the third embodiment, the communication with the parent node to which the wireless communication device 10-3 is connected is continued according to the statistical information of the wireless communication by the communication unit 1-3, 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 that the connection will be restored is low, the data can be transmitted to the new parent node newly discovered by the search processing. On the other hand, when there is a high possibility that the connection will be restored, it is possible to continue the power-saving operation without executing the search process 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, description similar to that of the first embodiment will be omitted, and only different points from the first embodiment will be described. In the fourth embodiment, a case where the communication system is a time division system will be described as an example of a specific communication system of the wireless communication system 100.

[Example of functional configuration]
FIG. 9 is a diagram illustrating 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 connection with the parent node (first parent node) is disconnected, the communication unit 1-4 repeats a predetermined communication process according to 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 process is the same as the description of the first embodiment, and will be omitted.

The determination unit 2 determines whether or not it is connected to the parent node based on the data transmitted from the parent node. When the data (radio signal) transmitted from the parent node cannot be received in the time slot assigned to the transmission of the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

The setting unit 8 sets a time slot indicating the timing of executing a predetermined communication process when the connection with the parent node is disconnected.

Next, an example of the 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 the data transmitted from the parent node (first parent node) (step S31).

Next, the determination unit 2 determines whether or not the parent node is connected to the parent node based on the result of the parent node data reception process of step S31 (step S32). When the data (radio signal) transmitted from the parent node cannot be received in the time slot assigned to the transmission of the parent node, the determination unit 2 determines that the connection with the parent node has been disconnected.

If it is connected to the parent node (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 process is, for example, a parent node data reception process of receiving data transmitted from the parent node.

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

The communication unit 1-4 repeats a 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, it is possible to continue the predetermined communication process even when the communication system of the wireless communication system 100 is the time division system. With this, according to the wireless communication device 10-4 of the fourth embodiment, it is possible to further reduce the power consumption of the wireless communication system 100 even when the communication system of the wireless communication system 100 is the time division system.

(Fifth Embodiment)
Next, a fifth embodiment will be described. In the description of the fifth embodiment, description similar to that of the first embodiment will be omitted, and only different points from the first embodiment will be described.

[Example of functional configuration]
FIG. 11 is a diagram showing an example of the 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 a communication unit 1, a determination unit 2-2, and a control unit 3-2.

When the connection with the parent node (first parent node) is cut off, the communication unit 1 repeats the predetermined communication process until the predetermined cycle has reached the standby count (repetition count). The description is the same as that of the first embodiment, and will not be repeated.

The number of times of waiting is determined by the determination unit 2-2. The number of waits is a value set before the power of the wireless communication device 10-5 is turned on, a value notified from the aggregation device 20 that aggregates the data transmitted from the wireless communication device 10-5, and the parent node (first Parent node) of at least one of the communication qualities.

The communication quality with the parent node (first parent node) is, for example, the number of times that the communication quality with the parent node is below a threshold, the number of times the communication quality with the parent node is above the threshold, Is represented by the received signal strength of, and the number of disconnections from the parent node.

The determination unit 2-2 determines whether or not it is connected to the parent node based on the data transmitted from the parent node. If the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2-2 determines that the connection with the parent node has been disconnected.

The determination unit 2-2 determines the number of waits when the connection with the parent node (first parent node) is disconnected. The number of times of waiting may be a different value for each target parent node, or may be a uniform value such as a value set before power-on. Further, the determination unit 2-2 stores, for each parent node, the disconnection count at which the connection with the parent node has been disconnected, and updates the standby count by subtracting the disconnection count from the standby count. 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 period, and when the predetermined period has passed the number of times of waiting described above, stops the predetermined communication process executed by the communication unit 1. The description of the predetermined cycle is the same as the description of the first embodiment, and will be omitted.

Next, an example of the wireless communication method of 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 a parent node data reception process of receiving data transmitted from the parent node (first parent node) (step S41).

Next, the determination unit 2-2 determines whether or not the parent node is connected to the parent node based on the result of the parent node data reception process of step S41 (step S42). If the data (radio signal) of the parent node cannot be received at the timing of receiving the data from the parent node, the determination unit 2-2 determines that the connection with the parent node has been disconnected.

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

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

Next, the determination unit 2-2 determines whether or not the standby count j updated by the process of step S44 is 0 or less (step S45). When the standby count j is 0 or less (step S45, Yes), the standby count j is set to 0 (step S48), and the process ends.

When the number of times of waiting j is not 0 or less (step S45, No), the communication unit 1 performs a predetermined communication process at a timing of once 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. Further, the predetermined communication process is, for example, a parent node data reception process for receiving data transmitted from the parent node, a parent node data transmission process for transmitting data to the parent node, and a child node for receiving data transmitted from the child node. A data reception process and a child node data transmission process for transmitting data to the child node.

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

When the predetermined cycle has been repeated the number of times of waiting j (step S47, Yes), the process ends.

When the predetermined cycle has not been repeated for the number of times of waiting 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, the search process for searching for the parent node is not performed at the timing when the connection with the parent node is disconnected, so the operation before disconnection is performed. (Predetermined communication processing) 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.

In addition, in the wireless communication device 10-5 of the fifth embodiment, the determination unit 2-2 changes the standby count (repetition count) according to the disconnection count with the parent node (first parent node). In general, it is considered that the connection with the parent node becomes unstable as the number of disconnections with the parent node increases. The number of times the determination unit 2-2 repeats the predetermined communication process performed with respect to the parent node as the number of disconnections with the parent node increases by changing the number of times of standby as in the process of step S44 described above. Is reduced. When the number of waiting times becomes 0, for example, the communication unit 1 performs a search process for searching for a new parent node (second parent node).

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

[Example 1 of hardware configuration]
FIG. 13 is a diagram illustrating a first example of the hardware configuration of the wireless communication device 10 and the aggregation device 20 of the embodiment. In Example 1 of FIG. 13, the wireless communication device 10 and the aggregation device 20 include a CPU (Central Processing Unit) 101, a main storage device 102, an external storage device 103, a communication interface 104, and a wireless device 105. The CPU 101, main storage device 102, external storage device 103, communication interface 104, and 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 executing the program, data generated by executing the program, and the like. The main storage device 102 may be arbitrary. The main storage device 102 is, for example, a RAM (Random Access Memory), a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), or the like.

The main storage device 102 stores information such as programs, relay information, frame information, node IDs, hop numbers, parent nodes and child nodes. The relay information is, for example, data received from another node. Specifically, the relay information is, for example, sensor information acquired by another node. The parent node is a node having a hop count smaller than that of the own node by one, and is a destination node of the own node. The child node is a node whose hop number is one larger than that of its own node, and which has determined the destination node as its own node.

Further, the main storage device 102 may store an OS (Operating System), a BIOS (Basic Input Output System), various middleware, and the like.

The external storage device 103 stores a program, data necessary for executing the program, data generated by executing the program, and the like. These programs and data are expanded in the main storage device 102 when the programs are executed. The external storage device 103 may be arbitrary. 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 programs, relay information, frame information, node IDs, hop counts, parent nodes and child nodes.

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. Further, for example, the external storage device 103 may install the program in the external storage device 103 by storing the program transmitted from another device to the aggregation device 20 via 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, Ethernet (registered trademark) port, or the like.

The wireless device 105 is a device for the wireless communication device 10 and the aggregation device 20 to wirelessly communicate with another device. Moreover, 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 than the first wireless device 105. The second wireless device 105 is, for example, cellular communication, Wi-Fi, or the like.

Next, a second example of the hardware configuration of the wireless communication device 10 and the aggregation device 20 of the embodiment will be described.

[Example 2 of hardware configuration]
FIG. 14 is a diagram illustrating a second example of the hardware configuration of the wireless communication device 10 and the aggregation device 20 of 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, main storage device 102, external storage device 103, communication interface 104, input interface 106, and graphic processing device 107 are connected via a bus 120.

Further, in the example 2 of FIG. 14, the sensor 108 and the wireless communication module 109 are connected to the communication interface 104. The input device 110 is connected to the input interface 106. Further, the 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 received 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 for displaying a video or an image on the display 111 based on the video 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 (cathode ray tube), a PDP (plasma display), or the like.

The sensor 108 may be optional. The sensor 108 is, for example, an illuminance sensor, a temperature/humidity sensor, an acceleration sensor, an angular velocity sensor, or the like. Further, 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 does not necessarily have the same 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, similarly to the wireless device 105 in FIG. 13.

Note that the power source of the hardware in FIGS. 13 and 14 described above may be arbitrary. The power source of the hardware in FIGS. 13 and 14 described above is, for example, a battery, a generator, a power generation module, a commercial power source, or the like.

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

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

DESCRIPTION OF SYMBOLS 1 communication part 2 determination part 3 control part 4 selection part 5 generation part 6 measurement part 7 instruction part 8 setting part 10 wireless communication device 20 aggregation device 100 wireless communication system

Claims (16)

A wireless communication device connected to a multi-hop network,
A first parent node of the wireless communication device, and a communication unit that wirelessly communicates with a child node of the wireless communication device;
A determination unit that determines whether or not the device is connected to the first parent node, based on data transmitted from the first parent node,
The communication unit, when the connection with the first parent node is disconnected, while repeated a predetermined communication process, performs a search process of searching for candidates of the second parent node,
The predetermined communication process includes a first parent node data transmission process of transmitting data to the first parent node, a child node data reception process of receiving data transmitted from the child node, and the child node. It is a child node data transmission process that transmits data,
Wireless communication device. The communication unit, when the connection with the first parent node is disconnected, the predetermined communication processing is repeated a predetermined period a predetermined number of times, until passage,
The wireless communication device according to claim 1. The predetermined cycle is a cycle indicating a timing at which the wireless communication device generates data, a cycle indicating a timing at which the wireless communication device transmits data, a cycle indicating a timing at which the wireless communication device receives data, or Is a preset period,
The wireless communication device according to claim 2 . Further comprising a selection unit that selects the second parent node based on the search process,
The communication unit, when the connection with the first parent node is disconnected and the second parent node is selected, the child node data receiving process, the child node data transmitting process, and the second node data receiving process. A second parent node data receiving process for receiving data transmitted from the parent node and a second parent node data transmitting process for transmitting data to the second parent node are repeated.
The wireless communication device according to claim 1 . The communication unit receives, from the second parent node, first parameter information used in a transmission process and a reception process with the second parent node, and based on the first parameter information, the first parameter information. The second parent node data transmission process and the second parent node data reception process are repeated.
The wireless communication device according to claim 4 . Further comprising a generation unit that generates second parameter information used in 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 5 . The first and second parameter information are time information indicating timing at which the wireless communication device transmits and receives, the number of hops from an aggregation device that aggregates data transmitted from the wireless communication device, and the first parent node. The difference between the number of hops before the connection is disconnected and the new number of hops, the frequency used for communication, and at least one of the connection destination information of the wireless communication device,
The wireless communication device according to claim 6 . A wireless communication device connected to a multi-hop network,
A first parent node of the wireless communication device, and a communication unit that wirelessly communicates with a child node of the wireless communication device;
A determination unit that determines whether or not the device is connected to the first parent node based on the data transmitted from the first parent node;
A measuring unit that measures statistical information of wireless communication by the communication unit,
If the connection between the first parent node is disconnected, on the basis of the statistical information, to repeat the previous SL second run and Jo Tokoro communication processing of the search process of searching for candidate parent node to the communication unit and a instruction unit for performing instructions,
The communication unit repeats the predetermined communication process when the connection with the first parent node is disconnected,
No line communication device. The statistical information includes the number of disconnections with the first parent node, the number of frames that have passed since the last communication with the first parent node, and a received signal of data received from the first parent node. Strength and at least one of the average received signal strength of the data received from the parent node,
The wireless communication device according to claim 8 . The communication method of the multi-hop network is a time division method,
When the connection with the first parent node is disconnected, a setting unit for setting a time slot indicating the timing of executing the predetermined communication process is further provided.
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 waits 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 cycle has reached the standby count,
The wireless communication device according to claim 2 . The standby count is a value set before powering on 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 qualities,
The wireless communication device according to claim 11 . The determination unit stores, for each of the first parent nodes, the number of disconnections when the connection with the first parent node is disconnected, and subtracts the number of disconnections from the number of waits to determine the number of waits. Update,
The wireless communication device according to claim 11 . A wireless communication system that forms a multi-hop network by a plurality of wireless communication devices and an aggregation device that aggregates data transmitted from the plurality of wireless communication devices,
The wireless communication device,
A first parent node of the wireless communication device, and a communication unit that wirelessly communicates with a child node of the wireless communication device;
A determination unit that determines whether or not the device is connected to the first parent node, based on data transmitted from the first parent node,
The communication unit, when the connection with the first parent node is disconnected, while repeated a predetermined communication process, performs a search process of searching for candidates of the second parent node,
The predetermined communication process includes a first parent node data transmission process of transmitting data to the first parent node, a child node data reception process of receiving data transmitted from the child node, and the child node. It is a child node data transmission process that transmits data,
Wireless communication system. A wireless communication method for a wireless communication device 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 whether or not it is connected to the first parent node based on the data transmitted from the first parent node,
Wherein the step of wireless communication, if the connection between the first parent node is disconnected, while repeated a predetermined communication process, performs a search process of searching for candidates of the second parent node,
The predetermined communication process includes a first parent node data transmission process of transmitting data to the first parent node, a child node data reception process of receiving data transmitted from the child node, and the child node. It is a child node data transmission process that transmits data,
Wireless communication method. A wireless communication device connected to a multi-hop network,
A first parent node of the wireless communication device, and a communication unit that wirelessly communicates with a child node of the wireless communication device;
Causing the first parent node to function as a determination unit that determines whether or not the node is connected to the first parent node based on the data transmitted from the first parent node,
The communication unit, when the connection with the first parent node is disconnected, while repeated a predetermined communication process, performs a search process of searching for candidates of the second parent node,
The predetermined communication process includes a first parent node data transmission process of transmitting data to the first parent node, a child node data reception process of receiving data transmitted from the child node, and the child node. It is a child node data transmission process that transmits data,
program.

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