JP5780911B2 - Wireless communication system, wireless communication apparatus, and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication system, a wireless communication apparatus, and a wireless communication method that contribute to improving responsiveness in low-consumption wireless communication.

  A slope monitoring system that detects in real time signs of slope collapse formed when laying roads and railways is a wireless ad hoc network technology represented by ZigBee (registered trademark) for cost reduction. Attempts have been made to construct a system using this.

  The wireless ad hoc network has a function of constructing a communication path from a packet source to a destination, and this communication path construction function only establishes a communication path in an initial state where the communication path is not constructed. Instead, this method is applied to a case where a communication error due to a link breakage occurs and an error is recovered by reconstructing a communication path effective at that time. In a system installed outdoors, the radio wave propagation state fluctuates due to the influence of vegetation and the weather, and link breakage may occur. Therefore, the communication path construction function is very useful.

  On the other hand, in order to construct a communication route, a route search message called “Route Request” is transmitted (flooded) to the entire network, and thus a very long time is required.

In a slope monitoring system, it is necessary to collect data from multiple sensors laid in a wide area, but it takes a lot of time to reconstruct the route due to link breakage due to fluctuations in radio wave propagation conditions. There was a problem that data collection could not be realized.
As a method for solving this problem, a method for reducing the time required for route reconstruction by limiting the range in which a Route Request message is transmitted to a route when reconstructing the route is disclosed (for example, see Patent Document 1).

  In this method, after the route request is first flooded once to construct the route, the created route is managed by grouping, and when link breakage occurs, partial repair is performed between the group boundary sensor nodes. A method for simplifying route reconstruction is disclosed. According to this method, although it takes a very long time for the first time, the path can be reconstructed after a relatively short time.

JP 2009-38511 A

  However, in the method described in Patent Document 1, even if partial repair is required, it takes a long time that is several times that of normal access, and cases where partial repair cannot be performed within a group, or a failure of a group boundary sensor node. When the link to the group boundary sensor node breaks, after giving up the partial repair, it is necessary to flood the Route Request as in the initial stage, so the penalty increases, that is, the time required for the repair increases. There is a problem.

  The present invention is intended to solve the above-described problems, and by reducing the number of times required to reconstruct the route of an ad hoc network due to link breakage, even when a plurality of errors occur at the same time, the system The purpose is to shorten the data collection time required by.

  The present invention relates to a sensor node composed of a sensor that outputs sensed data and a wireless communication function, and a group of sensor nodes arranged to provide redundancy for the sensed data for a single area. Based on the wireless communication block that transmits / receives data, the data received from each sensor node and the redundancy, it is judged whether it is normal or error, and if an error occurs, the data is sensed again for the sensor node that caused the communication error And a data collection procedure determination block for instructing to collect the master station.

  According to the present invention, a sensor node including a sensor that outputs sensed data and a wireless communication function, and a sensor node group that is arranged to provide redundancy for the sensed data for a single area. Based on the wireless communication block that transmits / receives data to / from each sensor node and the data received from each sensor node and redundancy, it is judged whether it is normal or error, and if an error occurs, the sensor node that caused the communication error is sensed again. By providing a master station consisting of a data collection procedure decision block that instructs to collect collected data, it is possible to reduce the number of times it takes to reconstruct the route of an ad hoc network due to link breakage. Data collection time required by the system can be shortened even if they occur at the same time

1 is a diagram illustrating an overall configuration of a wireless communication system according to Embodiment 1. FIG. FIG. 3 shows a configuration of a master station 100 of the wireless communication system in the first embodiment. FIG. 3 shows a configuration of a sensor node of the wireless communication system in the first embodiment. 3 is a flowchart showing an operation sequence of a data collection procedure determination block 102 of a master station 100 of the wireless communication system in the first embodiment. The figure which showed the data recorded on the slope state monitoring block 101 when it implements by each data collection period in the radio | wireless communications system in Embodiment 1, and the data collection process procedure error does not generate | occur | produce. The data recorded in the slope state monitoring block 101 in the case where an error occurs in access to the sensor node 110 and the sensor node 130 in the wireless communication system according to the first embodiment is shown in each data collection cycle. Figure. 9 is a flowchart showing an operation sequence of a data collection procedure determination block 102 of a master station 100 of a wireless communication system in a second embodiment. FIG. 6 is a configuration diagram of a master station 100 in a third embodiment. 9 is a flowchart showing an operation sequence of a data collection procedure determination block 102 of a master station 100 of a wireless communication system in a third embodiment. 9 is a flowchart showing an operation sequence of a data collection procedure determination block 102 of a master station 100 of a wireless communication system in a fourth embodiment. The figure which showed the data recorded on the slope state monitoring block 101 in the radio | wireless communications system in Embodiment 4. FIG. The figure which showed the example of recollection of the sensor node data by correction of a communication path | route in the radio | wireless communications system in Embodiment 4. FIG. The figure which shows the area division method different from FIG. 1 with respect to arrangement | positioning of the several sensor node of the several area in this Embodiment 5. FIG. 10 is a flowchart showing an operation sequence of a data collection procedure determination block 102 of a master station 100 of a wireless communication system in a fifth embodiment. The figure which showed the data recorded on the slope state monitoring block 101 in the radio | wireless communications system in Embodiment 5. FIG. The figure which shows an example of the hardware resource of the main | base station 100 and the sensor nodes 110-450 in embodiment.

Embodiment 1 FIG.
In the first embodiment, a radio communication system that reduces the number of times required to reconstruct the route of an ad hoc network due to a link break will be described.

FIG. 1 is a diagram showing an overall configuration of a wireless communication system in the first embodiment.
In FIG. 1, the master station 100 (wireless communication apparatus) includes sensor nodes (area 1 to 110, area 2 to 210 to 250, area 3 to 310 to 350, which are arranged on the slopes of area 1 to area 4, respectively. , Area 4 is arranged to communicate directly or indirectly with 410-450).

  The sensor nodes 110 to 450 are devices having a wireless communication function with a sensor for monitoring the state of the slope. The monitoring target is divided into four areas, and five sensor nodes are installed in each area. Although the area where the master station 100 can communicate, the four sensor node areas, and the number of five in each area are not limited to this, this embodiment will be described in the embodiment.

  In this embodiment, one redundant sensor node is installed in each of the areas 1 to 4, and the state of the slope can be determined if the values of at least four sensors can be read out. Suppose that That is, the required number of data in each area is 4, and the error tolerance for data acquisition in each area is 1. The number of necessary data in each area and the number of redundant sensor nodes are not limited to those described above.

FIG. 2 is a diagram showing a configuration of master station 100 of the wireless communication system in the first embodiment.
The master station 100 accesses the sensor nodes 410 to 450 via the wireless ad hoc network, reads the sensing data, and determines the state of the slope as a result of the reading.

The configuration of the master station 100 will be described.
The slope state monitoring block 101 determines the slope state based on slope monitoring data (sensing data) from the sensor node. In the determination, at least four pieces of sensing data are evaluated for each of the above-described areas at a fixed period, and it is determined whether or not the state of the slope is good in all the areas.

  The data collection procedure determination block 102 receives the sensor node arrangement information and an instruction of the required number of data from the slope state monitoring block 101, determines the data collection procedure, and sends the wireless communication block 103 to the sensor nodes 110 to 450. A communication transaction is instructed. The transaction execution result is received from the wireless communication block 103. The transaction types are a data collection transaction and an error recovery transaction. The data collection transaction is a transaction for issuing a data collection command to a designated sensor node and receiving sensing data. The error recovery transaction is a transaction that reconstructs a communication path to a specified sensor node and uses the reconstructed path to execute a data collection transaction in which an error has occurred.

  The wireless communication block 103 is a block that performs transmission / reception and relay processing of a wireless frame, and the data collection procedure determination block 102 executes a designated communication transaction and notifies the data collection procedure determination block 102 of the result. . At that time, the route information of the sensor node via the wireless communication block 103 is also included. This path information may include path information of all sensor nodes that reach the sensor node from which data is collected, or may include only a sensor node immediately before the sensor node from which data is collected. In the execution of the transaction, the received sensing data is output to the slope state monitoring block 101.

FIG. 3 is a diagram showing a configuration of a sensor node of the wireless communication system in the first embodiment.
The sensor nodes 110 to 450 are devices having sensors 111 to 451 for monitoring the state of a slope, slope state monitoring blocks 112 to 452, and wireless communication blocks 113 to 453 that are wireless communication function portions.

The slope state monitoring blocks 112 to 452 receive a data collection command from the master station 100, access the sensors 111 to 451, acquire sensing data, and transmit the data to the master station 100 as wireless communication blocks. 113 is a block for instructing 113 to 453.
The sensors 111 to 451 are sensors that output sensing data necessary for the slope state monitoring block 101 of the master station 100 to determine the slope state.
The wireless communication blocks 113 to 453 are blocks for performing transmission / reception of radio frames and relay processing. When a data collection transaction is received, a data collection command is output to the slope state monitoring blocks 112 to 452, When sensing data is received from the slope state monitoring blocks 112 to 452, the sensing data is transmitted to the master station 100. Also, if a route reconstruction process is being performed on the network, it participates.

Next, the operation will be described.
3 is a diagram illustrating a configuration of a sensor node of the wireless communication system according to Embodiment 1. FIG.
FIG. 4 is a flowchart showing an operation sequence of the data collection procedure determination block 102 of the master station 100 of the wireless communication system in the first embodiment. The data collection procedure for each area is performed according to this procedure.

  First, in step S101, the data collection procedure determination block 102 of the master station 100 selects one of the sensor nodes 110 to 450 belonging to the corresponding area as the sensor node 110 to 450 to be accessed. The selection method is arbitrary. For example, the sensor nodes 110 to 150 in the corresponding area 1 are selected in order.

In step S102, the data collection procedure determination block 102 issues a data collection transaction to the selected sensor node, notifies the selected sensor node via the wireless communication block 103, and collects data from the sensor node. To do.
As a result of executing the data collection transaction, the data collection procedure determination block 102 proceeds to step S103 if an error that requires path reconstruction occurs, and proceeds to step S105 if data acquisition is successful.
In this step, error recovery processing that does not involve path reconstruction may be performed.

  In step S103, the data collection procedure determination block 102 checks the error tolerance. Error tolerance is the number of nodes that can tolerate data collection errors for sensor nodes in the area. That is, the collected data is redundant. If the error tolerance is 1 or more, the data collection procedure determination block 102 can tolerate the error, so that the error recovery process with path reconstruction is not performed, and the process proceeds to step S106 and the error tolerance is redefined as -1. Then, the process returns to step S101. If the error tolerance is 0, the data collection procedure determination block 102 performs step S104.

  In step S104, the data collection procedure determination block 102 issues an error recovery transaction involving path reconstruction to the sensor node that has made an error in step S102, and performs data acquisition again. If the data acquisition is successful, the data collection procedure determination block 102 proceeds to step S105. If data acquisition fails, step S104 is performed again. When executing step S104, an error recovery transaction for another sensor node that occurs in the same data collection cycle may be executed instead of the error recovery transaction that occurred immediately before.

  In step S105, it is confirmed whether necessary data is prepared. In this embodiment, the required number of data is four. If the data is ready, the data collection procedure determination block 102 ends the data collection for the area, otherwise returns to step S101 and selects the next sensor node.

Hereinafter, an example of the data collection result in area 1 of the data collection processing procedure performed in each data collection cycle of the wireless communication system in the first embodiment will be shown.
FIG. 5 shows data recorded in the slope state monitoring block 101 in the wireless communication system according to the first embodiment, which is performed in each data collection cycle and no data collection processing procedure error occurs. It is a figure.

The upper stage data in FIG. 5 shows the data storage area for each data collection cycle, the middle stage shows the data area for each area in a certain period, and the lower stage shows the data area for the sensor node in area 1 in a certain period.
The data collection procedure determination block 102 of the master station 100 instructs the sensor nodes 110 to 150 in the area 1 to access in order, and when the sensor nodes 110 to 140 are accessed, four data are acquired. The data collection in area 1 has been terminated by canceling access to. In this case, the data collection processing to the sensor node 150 may be performed, but even if an error occurs, the error tolerance is 1, so that the error recovery processing with path reconstruction is not performed.

FIG. 6 is performed in each data collection period in the wireless communication system in the first embodiment, and is recorded in the slope state monitoring block 101 when an error occurs in access to the sensor node 110 and the sensor node 130. It is the figure which showed the data.
6 also shows the data storage area for each data collection period, the middle part shows the data area for each area in a certain period, the lower part shows the data area of the sensor node in the certain period, and in FIG. Is shown.

  If the data collection procedure determination block 102 of the master station 100 accesses the sensor node 110 and fails to acquire data, the system configuration of this embodiment has an error tolerance of 1, so that the sensor based on step S103 in FIG. For node 110, error recovery is not performed, and data collection of subsequent sensor nodes is continued. If an error occurs in the sensor node 130, the error tolerance has already become 0 in step S103 in FIG. 4, and the data collection procedure determination block 102 performs error recovery for the sensor node 130 based on step S104 in FIG. To implement. At this time, error recovery to the sensor node 110 may be performed instead of error recovery to the sensor node 130. If data can be acquired by error recovery based on step S104 in FIG. 4, the subsequent sensor node is accessed, and if four data are collected, the data collection for area 1 is terminated. When error recovery fails, error recovery is performed on a sensor node that is different from the sensor node that failed error recovery, thereby increasing the success rate of error recovery processing.

In this way, when an error occurs during access to the sensor node, the error tolerance is checked, and if the error is allowed, error recovery is not performed, thereby reducing the number of error recovery processes. It becomes possible to improve the real-time property of the entire system.
In other words, because it takes time to reconstruct the route of an ad hoc network due to link breakage, if multiple errors occur at the same time, data that can be collected from sensors to solve the problem that the data collection time required by the system cannot be met It is a feature of this embodiment that the error tolerance is provided by increasing the number to be more than the minimum number of each area to make it redundant.

  Therefore, in the present embodiment, the sensor nodes 110 to 450 configured by the sensors 111 to 451 that output the sensed data and the wireless communication function and the data sensed for a single area are made redundant. Wireless communication block 103 that transmits / receives data to / from sensor node groups arranged in the network, and determines whether sensor data of a single area is normal or error based on the received data and redundancy from each sensor node In the case of an error, the master station 100 including the data collection procedure determination block 102 that instructs the sensor node having a communication error to collect the sensed data again is provided. By reducing the number of times it takes to reconstruct the route of an ad hoc network, Even if the error occurs at the same time it is possible to shorten the data collection time required by the system.

Embodiment 2. FIG.
In the first embodiment, since the master station 100 only tries to collect data again for the sensor node in which an error has occurred, there may be a sensor node that does not recover from the error during the data collection period X.
In the second embodiment, when the data collection for all areas is completed in a time shorter than the data collection period X, the error is allowed because the remaining time is used during the data collection process of the individual area. An example will be described in which error recovery to a sensor node that has not been recovered is performed during a data collection period in another area.

The system configuration, the master station 100 configuration, and the sensor nodes 110 to 450 are the same as those in the first embodiment. In the present embodiment, the operation sequence of the data collection procedure determination block 102 of the master station 100 is added with FIG. 7 in addition to FIG. This procedure will be described below.
Next, the operation will be described.
First, from step 101 to step 106 in FIG. 4, the same operation as in the first embodiment is performed in the second embodiment. At this time, if the data collection procedure determination block 102 does not recover the error even if an error recovery transaction is issued in S104, the data collection procedure determination block 102 must abort the error recovery transaction if the data collection period X has passed. I don't get it. However, if data collection for another area is completed in a time shorter than the data collection period X, an error recovery transaction can be performed again for that area using the remaining time.
FIG. 7 is a flowchart showing an operation sequence of the data collection procedure determination block 102 of the master station 100 of the wireless communication system in the second embodiment.

  In step S107 of FIG. 7, the data collection procedure determination block 102 determines whether there is a sensor node in which an error has occurred in the data collection transaction in steps S102 to S104 but an error recovery transaction has not been performed in another area. If there is, the process proceeds to step S108. If not, the process ends.

  In step S102 to S104, the data collection procedure determination block 102 stores the presence / absence of processing in which an error has occurred in the data collection transaction but the error recovery transaction has not been executed in step S103.

  In step S108, the data collection procedure determination block 102 checks whether there is time to perform an error recovery transaction. The maximum time required for the error recovery transaction can be calculated by the system configuration and the route reconstruction method. If there is time to execute the error recovery transaction in the currently executing data collection cycle, the process proceeds to step S109, and if not, the process ends.

  In step S109, the data collection procedure determination block 102 issues an error recovery transaction. If the error recovery is successful, the process returns to step S107. If the error recovery is unsuccessful, step S108 is performed to perform a retry. Note that a general limit on the number of retries may be applied. If the number limit has been reached, the process proceeds to step S107.

A sensor node in which an error has occurred in a data collection transaction is highly likely to cause an error even in the subsequent data collection cycle.
Therefore, the data collection process succeeds without impairing real-time performance by performing error recovery processing to the sensor node in which an error has occurred using the idle time according to the procedure shown in this embodiment. The rate can be increased and the real-time property can be improved.

  Therefore, in the present embodiment, the sensor nodes 110 to 450 configured by the sensors 111 to 451 that output the sensed data and the wireless communication function and the data sensed for a single area are made redundant. Wireless communication block 103 that transmits / receives data to / from sensor node groups arranged in the network, and determines whether sensor data of a single area is normal or error based on the received data and redundancy from each sensor node And a data collection procedure determining block 102 for instructing the sensor node that has caused a communication error to collect the sensed data again in the case of an error. After the lapse of time, the vacancy in the data collection period after data collection for all areas is By using this during the data collection period, the number of times it takes to reconstruct the route of the ad hoc network due to link breakage is reduced, and error recovery processing is performed on the sensor node where the error has occurred, thereby improving real-time performance. Without impairing, the success rate of the data collection process can be increased, and the real-time property can be improved.

Embodiment 3 FIG.
In the third embodiment, when data collection for all areas and error recovery for all sensor nodes shown in the second embodiment are completed in a time shorter than the data collection period X, the remaining time is used. A method used for reconstructing a communication path to a sensor node whose link quality has deteriorated will be described.

Since the system configuration and the sensor node configuration are the same as those in the first embodiment or the second embodiment, description thereof is omitted.
FIG. 8 is a configuration diagram of the master station 100 according to the third embodiment.
In contrast to the first or second embodiment, a link state monitoring block 104 is newly configured in the master station 100 in the present embodiment.
The link state monitoring block 104 is a block for monitoring the link quality between individual sensor nodes. When the link quality deteriorates, the data collection procedure determination block 102 indicates the sensor node related to the link with the deteriorated link quality. Be notified. A description of the link quality monitoring method is omitted.
When the sensor node related to the link whose link quality has deteriorated is notified, the data collection procedure determination block 102 issues a route reconstruction transaction to the wireless communication block 103 if there is time for route reconstruction. The path reconstruction transaction is a transaction that omits the data collection processing of the error recovery try-in transaction.

In this embodiment, in addition to FIG. 4 which is the operation sequence of the data collection procedure determination block 102 of the master station 100 in Embodiment 1, at least the sequence described in FIG. 9 described below is added. explain.
In addition to the operation sequence of the data collection procedure determination block 102 of the master station 100 according to the second embodiment, the sequence described in FIG. 9 described below may be added.

FIG. 9 is a flowchart showing an operation sequence of the data collection procedure determination block 102 of the master station 100 of the wireless communication system in the third embodiment.
In step S110, the data collection procedure determination block 102 checks the output from the link state monitoring block 104 to determine whether there is a sensor node whose communication state has deteriorated due to a decrease in link quality. Proceed to If not, the process ends.

  Next, in step S111, the data collection procedure determination block 102 confirms whether there is time to perform a path reconfiguration transaction. The maximum time required for executing the path restructuring transaction can be calculated by the system configuration and the path restructuring method. If there is time to execute the path restructuring transaction in the currently executing data collection cycle, the process proceeds to step S112, and if not, the process ends.

  In step S <b> 112, the data collection procedure determination block 102 issues a path reconstruction transaction and is transmitted to each sensor node via the wireless communication block 103. If the path reconstruction is successful, the process returns to step S110. If the path reconstruction is unsuccessful, the process proceeds to step S111 to perform a retry. It should be noted that the number of times that is generally implemented may be limited for the retry. If the number limit has been reached, the process proceeds to step 110.

  In the system installed outdoors, the individual link quality may deteriorate due to a change in the external environment. In this way, when the decrease in link quality is recognized in the idle time, by performing path reconfiguration even if no error has occurred, the error occurrence rate is reduced in the subsequent data collection cycle, Real-time performance can be improved.

  Therefore, in the present embodiment, the sensor nodes 110 to 450 configured by the sensors 111 to 451 that output the sensed data and the wireless communication function and the data sensed for a single area are made redundant. Wireless communication block 103 that transmits / receives data to / from sensor node groups arranged in the network, and determines whether sensor data of a single area is normal or error based on the received data and redundancy from each sensor node And a data collection procedure determining block 102 for instructing the sensor node that has caused a communication error to collect the sensed data again in the case of an error. After the lapse of time, the vacancy in the data collection period after data collection for all areas is By using the data collection period, in the subsequent data collection period, to reduce the error occurrence rate, it is possible to improve real-time.

  In addition, when a decrease in link quality, which is one of the characteristic parts in the present embodiment, is recognized, using a free time to perform route reconstruction even if no error has occurred, Even when the sensor node group does not have redundancy for a single area, that is, even when the error tolerance of the system is 0, the error occurrence rate is reduced in the data collection cycle. Real-time performance can be improved.

Embodiment 4 FIG.
In the fourth embodiment, a method will be described in which data collection processing is not performed for each area, but all fields are collectively performed, and error recovery processing is efficiently performed.
The system configuration of the fourth embodiment is the same as that of FIG. 1 as in the first embodiment, and one redundant sensor node is installed in each area. The number of data is 4.
The configurations of the master station 100 and the sensor nodes 110 to 450 are the same as those in FIGS. 2 and 3 of the first embodiment.
Operations of the master station 100 and the sensor nodes 110 to 450 will be described.
FIG. 10 is a flowchart showing an operation sequence of the data collection procedure determination block 102 of the master station 100 of the wireless communication system in the fourth embodiment.

In step S201, the data collection procedure determination block 102 of the master station 100 issues a data collection transaction to the sensor nodes 110 to 450 in all areas, one sensor node at a time. Specifically, sensor nodes belonging to a plurality of areas are selected one by one. The sensor node selection method / order is arbitrary, for example, the order of sensor nodes 110 to 150 in area 1, the order of sensor nodes 210 to 250 in area 2, the order of sensor nodes 310 to 350 in area 3, and the sensor in area 4 The nodes 410 to 450 are selected in this order.
Then, it is determined whether or not a data collection transaction has been issued to all sensor nodes. If it has not been issued, the process proceeds to step S202. If it has been issued, the process proceeds to step S204.

In step S202, the data collection procedure determination block 102 of the master station 100 issues a data collection transaction for the selected sensor node via the wireless communication block 103, and then collects data for the sensor node.
When the data of the sensor node can be collected, the process returns to step S201, and the data collection procedure determination block 102 of the master station 100 selects another sensor node and issues a data collection transaction.
If an error has occurred in the data collection of the sensor node, the process proceeds to step S203. The wireless communication block 103 may perform error recovery that does not involve path reconstruction when an error occurs, that is, can be performed in a short time.
In step S203, when an error occurs in the data collection of the sensor node, the data collection procedure determination block 102 stores the generated error. The stored content is an identifier of the sensor node in which the error has occurred. After storing the error, the process returns to step S201.

  Next, after the data collection procedure determination block 102 issues data collection transactions to all sensor nodes, in step S204, the data collection procedure determination block 102 selects a sensor node that issues an error recovery transaction. The sensor node that issues the error recovery transaction is selected from the error occurrence sensor nodes stored in step S203. The selection method is arbitrary, but, for example, if the error recovery is likely to succeed, the number of error recovery processes can be reduced in order, reducing the overall processing time and improving the real-time performance. Can be made. As a condition for a sensor node having a low error recovery success rate, for example, a sensor node that has generated an error continuously over a plurality of times, a sensor node that has a high frequency of error occurrence in the past, or the like is applicable. Therefore, in order to select the one that is highly likely to succeed in error recovery, it is only necessary to select one that does not satisfy the condition of the sensor node having a low error recovery success rate.

In step S <b> 205, the data collection procedure determination block 102 issues an error recovery transaction involving path reconstruction to the selected error occurrence sensor node via the wireless communication block 103. If error recovery is successful and data can be acquired, the process proceeds to step S206. If data cannot be acquired, the process returns to step S204.
In step S206, the data collection procedure determination block 102 counts the number of data collected in steps S202 and S205, and whether the necessary number of data (data of four sensor nodes in each area in this embodiment) has been collected. Please check. If the necessary data is available, the data collection for the area is terminated. If the necessary data is not available, the process returns to step S204.

FIG. 11 is a diagram illustrating data recorded in the slope state monitoring block 101 in the wireless communication system according to the fourth embodiment.
The upper stage data in FIG. 11 indicates a data storage area for each data collection period, the middle stage indicates the data area for each area in a certain period, and the lower stage indicates the data area of the sensor node in area 1 in a certain period.
In FIG. 11, as a result of collecting data in steps S201 to S203 in FIG. 10, in area 1, the data is stored from the lower left side as shown in FIG. 11, and an error occurs in the data collection processing to the sensor nodes 110, 130, and 150. Suppose that occurs. Thereafter, after data collection for all areas is completed, data for all areas is collected again in step 204 to step 206 in FIG. 10. In area 1, as shown in FIG. The data is stored again in the slope state monitoring block 101.
In the case of FIG. 11, the data collection procedure determination block 102 selects in order from those that are likely to succeed in error recovery, and performs error recovery in the order of the sensor node 130 and sensor node 150. Since 4 has been acquired, the data collection processing for area 1 is terminated.

  Therefore, in this embodiment, it is possible to increase the success rate of error recovery processing in that the error occurrence probability of all the sensor nodes in one area can be grasped and the error recovery order of the sensor nodes can be determined for each area. It is possible to improve the real-time property in that the time required for the recovery process can be shortened.

  In addition, as described above, the priority order of sensor nodes for error recovery for each area was determined and implemented. However, after data collection for all areas was first performed, the priority of sensor nodes for error recovery for all areas was determined. The order may be determined and error recovery may be performed. In this way, it is possible to improve the efficiency of error recovery.

FIG. 12 is a diagram illustrating an example of re-collecting sensor node data by correcting a communication path in the wireless communication system according to the fourth embodiment.
For example, assume that the sensor node 150, the sensor node 320, and the sensor node 350 are relay stations and the communication path 500 is used as a communication path for collecting data of the sensor node 120 from the master station 100. When such a path is constructed, if a link break occurs between the sensor node 320 and the sensor node 350, an error occurs in the sensor nodes 320, 150, and 120 when data collection is performed for all areas. In this case, error recovery can be efficiently performed by partially repairing the path using the communication path 501 that is the sensor node 320 -the sensor node 330 -the sensor node 350 as an alternative path of the sensor node 320 -the sensor node 350. Is possible.

Specifically, in step S <b> 204 of FIG. 10, the data collection procedure determination block 102 searches for the common route from the route information of the error-processed sensor node included in the result from the wireless communication block 103. If the result from the wireless communication block 103 includes information on all sensor nodes that arrive at the sensor node from which data is collected, the common path may be searched from the error-processed result of the sensor node that is in error. Further, when the result from the wireless communication block 103 includes only the sensor node immediately before the sensor node from which data is collected, the path information included in the result of the sensor node in which the error has occurred is immediately before By checking whether an error has occurred in the sensor node, the common route can be searched.
The data collection procedure determination block 102 performs error recovery transactions based on step S205 in FIG. 10 from the shortest number of sensor nodes that pass through the master station 100, for example, for a plurality of error-processed sensor nodes having the searched common path. Is issued and error recovery processing is performed, so that error recovery can be performed efficiently.
As described above, the error recovery procedure over a plurality of areas can be determined by analyzing the error that has occurred after collecting data in the entire field.

  Therefore, in the present embodiment, the sensor nodes 110 to 450 configured by the sensors 111 to 451 that output the sensed data and the wireless communication function and the data sensed for a single area are made redundant. Wireless communication block 103 that transmits / receives data to / from sensor node groups arranged in the network, and determines whether sensor data of a single area is normal or error based on the received data and redundancy from each sensor node If there is an error, the master station 100 is configured to include a data collection procedure determination block 102 that instructs the sensor node having a communication error to collect the sensed data again. Know the number of sensor node errors, and determine the error recovery order of sensor nodes for each area. In point, it becomes possible to increase the success rate of the error recovery process.

  In addition, it is possible to grasp the error occurrence probability of all the sensor nodes in one area, and to determine the error recovery order of the sensor nodes based on the high possibility of the error recovery of the sensor node for each area. It is possible to increase the success rate of error recovery processing.

  Furthermore, it is possible to increase the success rate of error recovery processing by searching common paths of sensor nodes where errors have occurred in all areas and performing error recovery processing from multiple error-processed sensor nodes having common paths. It becomes.

Embodiment 5 FIG.
Embodiment 5 discloses a data access method and an error recovery method when a plurality of area division methods are selectively applied to the arrangement of a plurality of sensor nodes in a plurality of areas.
FIG. 1 in the first embodiment is first referred to as area dividing method No. 1 for the arrangement of a plurality of sensor nodes in a plurality of areas in the fifth embodiment.
FIG. 13 is a diagram showing an area division method different from that in FIG. 1 for the arrangement of a plurality of sensor nodes in a plurality of areas in the fifth embodiment.
In the area division method different from FIG. 1 shown in FIG. 13, the number of data necessary for determining the state of each area is 4 and the error tolerance is 1 as in FIG. 1.
It is assumed that the sensor nodes 110 to 450 and the master station 100 have the functions described in the first to fourth embodiments.
Next, a method for selectively applying a plurality of area division methods will be described.
FIG. 14 shows an operation sequence of the data collection procedure determination block 102 in the fifth embodiment. This will be described below.

In step 301, the data collection procedure determination block 102 of the master station 100 selects one sensor node from among all the sensor nodes 110 to 450 as a sensor node that is to issue a data collection transaction. The selection method is arbitrary. If a data collection transaction has been issued to the sensor nodes in all areas, the process proceeds to S304. If not selected, the process proceeds to step S302.
In step 302, the data collection procedure determination block 102 of the master station 100 issues a data collection transaction to the selected sensor node to perform data collection. . If data can be collected, the process returns to step S301. If an error has occurred during data collection, the slope state monitoring block 101 stores that the error processing has been performed in step S303, and then returns to step S301. The contents to be stored are the identifier of the sensor node where the error has occurred. At the same time, additional information that can be used to select an error recovery sensor node in step S305, such as an error type, may be stored.

  Next, in step S304, the data collection procedure determination block 102 of the master station 100 determines an area division method based on the error information collected in steps S301 to S303, that is, the identification information of the sensor node that could not collect data. select. In the fifth embodiment, two types of area division shown in FIGS. 1 and 13 are prepared in advance, and one of them is selected. The selection criterion is the division method that allows error recovery to be performed in a short time. For example, an area division method is selected so that one sensor node having an error is included in each area according to the number of error recovery transactions to be issued, that is, the error tolerance of each area.

In step S305, in accordance with the division method selected in step S304, a sensor node that issues an error recovery transaction is selected so as to acquire data necessary for determining the state of each area. The sensor node that issues the error recovery transaction is selected from the error occurrence sensor nodes stored in the slope state monitoring block 101 in step S303. The selection method is arbitrary.
In step S306, the data collection procedure determination block 102 issues an error recovery transaction to the sensor node selected in step S305. If error recovery is successful and data can be acquired, the process proceeds to step S307. If data cannot be acquired, the process returns to S305.

  In step S307, the data collection procedure determination block 102 counts the number of data collected in step S302 and this step, and confirms whether the number of data necessary for state determination is collected for each area, that is, 4 in the fifth embodiment. To do. If necessary data is available in all areas, the data collection for the data collection cycle is terminated. If the necessary data is not available, the process proceeds to step S305.

FIG. 15 is a diagram illustrating data recorded in the slope state monitoring block 101 in the wireless communication system according to the fifth embodiment.
The upper data in FIG. 15 shows a data storage area for each data collection period, and the lower part shows a data area for each sensor node in a certain period.

In the data collection cycle #n, it is assumed that the master station 100 collects data for all sensor nodes in steps S301 to S303, and a data acquisition error occurs in the sensor nodes 110, 130, and 150.
In this case, in step S304, the data collection procedure determination block 102 compares the area divisions of FIG. 1 and FIG. 13 and selects the area division of FIG. In the case of FIG. 1, since three data acquisition errors occur in the same area 1, it is necessary to acquire sensor values for at least two sensor nodes. In the case of FIG. 13, in the case of FIG. This is because two sensor data acquisition errors occur and it is sufficient to acquire sensor values for one sensor node.
Next, in step S305, as an error recovery process, the data collection procedure determination block 102 performs error recovery to the sensor node 130 in order to acquire necessary data for the area 2 ′. The process of data collection cycle #n is terminated.

  Therefore, in the present embodiment, the sensor nodes 110 to 450 configured by the sensors 111 to 451 that output the sensed data and the wireless communication function and the data sensed for a single area are made redundant. Wireless communication block 103 that transmits / receives data to / from sensor node groups arranged in the network, and determines whether sensor data of a single area is normal or error based on the received data and redundancy from each sensor node And a data collection procedure determination block 102 comprising a master station 100 comprising a data collection procedure determination block 102 for instructing a sensor node having a communication error to collect the sensed data again. To provide redundancy for the sensed data for a single area By the from location allows a plurality of areas divided how to select the area dividing method error recovery process is reduced, it is possible to reduce the number of error recovery processing.

FIG. 16 is a diagram illustrating an example of hardware resources of the master station 100 and the sensor nodes 110 to 450 in the embodiment.
In FIG. 16, the master station 100 and the sensor nodes 110 to 450 (an example of a computer) include a CPU 901 (Central Processing Unit). The CPU 901 is connected to hardware devices such as the ROM 903, the RAM 904, and the communication board 905 via the bus 902, and controls these hardware devices.
The ROM 903 and the RAM 904 are examples of a storage device (memory). The communication board 905 is an example of an input / output device.

  The communication board 905 is connected to the wireless ad hoc network described in the first to fifth embodiments.

  The ROM 903 or the RAM 904 stores an OS (Operating System), a program group, and a file group.

  The program group includes programs that execute the functions described as “˜blocks” in the embodiments. A program (for example, a wireless communication program) is read and executed by the CPU 901. That is, the program causes the computer to function as “˜block”, and causes the computer to execute the procedure and method of “˜block”.

  The file group includes various data (input, output, determination result, calculation result, processing result, etc.) used in “˜block” described in the embodiment.

In the embodiment, arrows included in the configuration diagrams and flowcharts mainly indicate input and output of data and signals.
The processing of the embodiment described based on the flowchart and the like is executed using hardware such as the CPU 901, a storage device, and input / output.

  What is described as “˜block” in the embodiments may be “˜part”, “˜circuit”, “˜device”, “˜device”, and “˜step”, “˜procedure”, “ ~ Process ". That is, what is described as “˜block” may be implemented by any of firmware, software, hardware, or a combination thereof.

  100 master station, 101 slope state monitoring block, 102 data collection procedure determination block, 103 wireless communication block, 104 link state monitoring block, 110-450 sensor node, 111-451 sensor, 112-452 slope state monitoring block, 113 ˜453 Wireless communication block, 500, 501 communication path, 901 CPU, 902 bus, 903 ROM, 904 RAM, 905 communication board.

Claims (15)

Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. a data acquisition procedure determining block that instructs to collect, and a composed master station from
Regardless of whether or not redundancy is ensured for sensor node groups arranged in a single area, all data collection periods in a plurality of areas including the single area are free after the data collection period of the area has elapsed. A wireless communication system, characterized in that, by using time, a communication path for accessing a sensor node having a link having a deteriorated communication quality is reconstructed. Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
When collecting the sensed data again for the sensor node that caused the communication error, after the data collection period of the corresponding area has elapsed, the free time of all the data collection periods of the multiple areas including the single area A wireless communication system that is used during a data collection period. Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
A wireless communication system characterized in that, after a data collection period of a corresponding area has elapsed, idle time of all data collection periods of a plurality of areas including the single area is used for route reconstruction. Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
When collecting data sensed again for sensor nodes with communication errors, grasp the number of error occurrences of all sensor nodes in a single area, and recover sensor node errors for each of multiple areas. A wireless communication system, characterized by determining the order. Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
When collecting data sensed again for sensor nodes with communication errors, grasp the number of error occurrences of all sensor nodes in a single area, and reduce the number of error occurrences for each area out of multiple areas. A wireless communication system, wherein error recovery is performed from a sensor node. Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
When collecting the data sensed again for the sensor node that caused the communication error, search the common path of the sensor node where the error occurred in all areas, and perform error recovery processing from the multiple sensor nodes where the error occurred with the common path A wireless communication system, characterized in that: Sends and receives data to and from sensor nodes that are composed of sensors that output sensed data and wireless communication functions, and sensor nodes that are arranged to provide redundancy for the sensed data for a single area. A wireless communication block to perform;
Based on the data received from each sensor node and the redundancy, it is determined whether the sensor data of the single area is normal or error. A data collection procedure decision block for instructing collection, and a master station comprising :
The data collection procedure determination block selects an area division method that reduces error recovery processing from a plurality of area division methods that can be arranged to provide redundancy for the sensed data for a single area. A wireless communication system. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
Regardless of whether or not redundancy is ensured for sensor node groups arranged in a single area, all data collection periods in a plurality of areas including the single area are free after the data collection period of the area has elapsed. A wireless communication apparatus that reconstructs a communication path for accessing a sensor node including a link having a deteriorated communication quality using time. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
When collecting the sensed data again for the sensor node that caused the communication error, after the data collection period of the corresponding area has elapsed, the free time of all the data collection periods of the multiple areas including the single area A wireless communication apparatus that is used during a data collection period. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
A wireless communication apparatus characterized in that, after a data collection period of a corresponding area has elapsed, idle time of all data collection periods of a plurality of areas including the single area is used for route reconstruction. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
When collecting data sensed again for sensor nodes with communication errors, grasp the number of error occurrences of all sensor nodes in a single area, and recover sensor node errors for each of multiple areas. A wireless communication apparatus characterized by determining the order of. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
When collecting data sensed again for sensor nodes with communication errors, grasp the number of error occurrences of all sensor nodes in a single area, and reduce the number of error occurrences for each area out of multiple areas. A wireless communication apparatus, wherein an error recovery instruction is issued from a sensor node. A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
When collecting the sensing data for the sensor node that caused the communication error again, search the common path of the sensor node where the error occurred in all areas, and issue an error recovery instruction from the multiple sensor nodes where the error occurred with the common path. A wireless communication device characterized in that: A wireless communication block that is arranged to provide redundancy for the sensed data for a single area, and that transmits and receives data to and from a sensor node group that outputs the sensed data;
Sensor data of the single area on the basis of the data and redundancy that each sensor node or we received, it is determined whether normal or error, if an error was again sensed to sensor node has become the communication error and a instruction data collection procedure decision block to collect data,
The data collection procedure determination block selects an area division method that reduces error recovery processing from a plurality of area division methods that can be arranged to provide redundancy for the sensed data for a single area. A wireless communication device. A data collection step for collecting data for sensor nodes arranged so as to provide redundancy for data sensed for a single area;
A judgment step in which the sensor data of the single area to determine the success or failure based on data and redundancy that if we receive each sensor node,
There redundancy Nitsu and a data reacquisition step of instructing to collect data again sensed to sensor node has become the communication error When an error occurs,
Regardless of whether or not redundancy is ensured for sensor node groups arranged in a single area, all data collection periods in a plurality of areas including the single area are free after the data collection period of the area has elapsed. A wireless communication method for reconfiguring a communication path for accessing a sensor node including a link having a deteriorated communication quality using time .