JP4808228B2 - Wireless communication apparatus, wireless communication method, and wireless communication control program - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication method, and a wireless communication control program, and particularly to a wireless communication device, a wireless communication method, and a wireless communication control program used in a wireless communication system in which a parent device and a plurality of child devices perform wireless communication.

  At present, wireless PANs (Personal Area Networks) in which short-range wireless communication devices are mounted on devices such as information home appliances and computers and information can be processed in cooperation with a plurality of devices are attracting attention. By using wireless PAN, for example, it is possible to easily realize a sensor network in which sensing data obtained from a sensor device such as a monitoring camera or a temperature sensor is transferred to a computer, and the computer analyzes the sensing data and controls various devices. Can do. For example, ZigBee is a short-range wireless communication method that can be used in a wireless PAN. ZigBee has the advantage that the communication speed is low and the communicable distance is short, while the power consumption required for wireless communication is small and the wireless communication device can be downsized (for example, see Non-Patent Document 1).

  Here, various connection forms (network topologies) of a plurality of wireless communication apparatuses in the wireless PAN can be considered. One of these is a star topology in which a wireless link is established between a parent device (coordinator) that manages a wireless PAN and a plurality of child devices (end devices), and the child device performs wireless communication via the parent device. . The star topology has an advantage that the power consumption of the entire wireless PAN system can be further reduced. On the other hand, however, there is a problem that communication between the slave units cannot be performed if the master unit fails. For this reason, in the star topology, it is necessary to take measures to restore the wireless communication function when the master unit fails.

The following are known as techniques for automatically recovering the communication function when some of the plurality of communication devices fail. In other words, there is a technique for monitoring the operation state of the master unit and automatically transferring the control function of the system from the master unit to another device when an abnormality is detected (see, for example, Patent Document 1). In addition, a plurality of transmission control devices are coupled in a loop shape, and when an abnormal operation is detected, the abnormality information is forwarded through the loop network, and each transmission control device autonomously establishes a data transmission path based on the abnormality information. There is a technique to change to (for example, see Patent Document 2).
JP 09-307572 A JP-A-60-140457 The Institute of Electrical and Electronics Engineers (IEEE), "Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs)", IEEE Std 802.15.4-2006.

  By the way, in a star topology network, a method of automatically recovering the communication function by any one of the slave units functioning as a new master unit when the master unit fails can be considered. However, when this method is applied to the wireless PAN, there is a problem in how to determine which child device is a new parent device. This is because, in the wireless PAN, each slave unit performs short-range wireless communication, and thus it is not always possible to wirelessly communicate with all other slave units. On the other hand, it is desirable that the recovered wireless PAN system can provide a wireless communication function as close as possible to the wireless PAN system before the failure.

  This case has been made in view of such points, and in a wireless communication system in which a parent device and a plurality of child devices perform wireless communication, an appropriate child device becomes a new parent device when the parent device fails. An object of the present invention is to provide a wireless communication device, a wireless communication method, and a wireless communication control program that are automatically selected.

  In order to solve the above-described problem, a plurality of slave units in a wireless communication system including a master unit and a plurality of slave units that perform wireless communication with the master unit and an information processing apparatus connected to at least one of the plurality of slave units A wireless communication device used as each is provided. The wireless communication apparatus includes a detection unit, a confirmation unit, and a determination unit. The detection means monitors communication with the parent device and detects a failure of the parent device. When the detecting unit detects a failure of the master unit, the checking unit checks other slave units that can wirelessly communicate with the own device and notifies the confirmation result, and confirms the slave unit notified by each of the other slave units. Receive the result. Based on the confirmation result obtained by the confirmation unit, the determining unit is capable of wireless communication with the slave unit to which the information processing device is connected, and other slave units capable of wireless communication with the slave unit to which the information processing device is connected. If it is determined that the number of communicable opponents is the largest, the own device is determined to be a new parent device and notified.

  According to such a wireless communication apparatus, the communication with the parent device is monitored by the detection means, and a failure of the parent device is detected. When a failure of the parent device is detected, the confirmation unit confirms other child devices that can wirelessly communicate with the own device, and receives confirmation results for each of the other child devices. Then, by the determining means, the number of counterparts that can communicate with the slave unit to which the information processing apparatus is connected and can communicate with the slave unit to which the information processing apparatus is connected can be compared with other slave units. Is determined to be the new master unit.

  In order to solve the above-described problem, a wireless communication method for a wireless communication system including a parent device and a plurality of child devices that perform wireless communication with the parent device, and an information processing apparatus connected to at least one of the plurality of child devices Is provided. In this wireless communication method, each of a plurality of child devices monitors communication with the parent device to detect a failure of the parent device. Next, when each of the plurality of slave units detects a failure of the master unit, the slave unit confirms the other slave units that can wirelessly communicate with its own device and notifies the confirmation result, and the slave unit notified by each of the other slave units Receive confirmation results for. Then, each of the plurality of slave units is wirelessly communicable with the slave unit to which the information processing apparatus is connected, based on the obtained confirmation result, and other slave units that are capable of wireless communication with the slave unit to which the information processing apparatus is connected. When it is determined that the number of communicable counterparts is the largest compared to the slave unit, the own device is determined and notified as a new master unit.

  According to such a wireless communication method, each slave unit monitors communication with the master unit and detects a failure of the master unit. Next, when a failure of the parent device is detected, other child devices capable of wireless communication with the own device are confirmed, and confirmation results for each of the other child devices are received. And, when there is the largest number of counterparts that can communicate wirelessly with the slave unit to which the information processing device is connected and compared to other slave units that are capable of wireless communication with the slave unit to which the information processing device is connected. When the determination is made, it is determined that the own device becomes a new parent device.

  In order to solve the above-described problem, a plurality of slave units in a wireless communication system including a master unit and a plurality of slave units that perform wireless communication with the master unit and an information processing apparatus connected to at least one of the plurality of slave units are provided. There is provided a wireless communication control program for controlling a wireless communication apparatus having a computer function used as each slave unit. A wireless communication apparatus having the function of a computer that executes the wireless communication control program includes a detection unit, a confirmation unit, and a determination unit. The detection means monitors communication with the parent device and detects a failure of the parent device. When the detecting unit detects a failure of the master unit, the checking unit checks other slave units that can wirelessly communicate with the own device and notifies the confirmation result, and confirms the slave unit notified by each of the other slave units. Receive the result. Based on the confirmation result obtained by the confirmation unit, the determining unit is capable of wireless communication with the slave unit to which the information processing device is connected, and other slave units capable of wireless communication with the slave unit to which the information processing device is connected. If it is determined that the number of communicable opponents is the largest, the own device is determined to be a new parent device and notified.

  According to the computer that executes such a wireless communication control program, the detection unit monitors the communication with the parent device and detects a failure of the parent device. When a failure of the parent device is detected, the confirmation unit confirms other child devices that can wirelessly communicate with the own device, and receives confirmation results for each of the other child devices. Then, by the determining means, the number of counterparts that can communicate with the slave unit to which the information processing apparatus is connected and can communicate with the slave unit to which the information processing apparatus is connected can be compared with other slave units. Is determined to be the new master unit.

  According to the wireless communication device, the wireless communication method, and the wireless communication control program, in a wireless communication system in which a parent device and a plurality of child devices perform wireless communication, an appropriate child device becomes a new parent device when the parent device fails. Automatically selected as the machine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an outline of the present invention will be described, and then specific contents of the embodiment will be described.
FIG. 1 is a diagram showing an outline of the present embodiment. The system shown in FIG. 1 is a wireless communication system in which a parent device and a plurality of child devices perform wireless communication. This wireless communication system includes an information processing apparatus 10, a master unit 20, and slave units 30, 30a, 30b, and 30c. The information processing apparatus 10 is connected to the slave unit 30c.

  The information processing apparatus 10 is an apparatus that performs data transmission / reception with the parent device 20 and the child devices 30, 30a, 30b, and 30c and performs predetermined information processing, and is, for example, a PC (Personal Computer). The information processing apparatus 10 collects data via the parent device 20 and the child devices 30, 30a, 30b, and 30c, for example.

  The base unit 20 is a wireless communication device that manages a network. Master device 20 performs wireless communication with slave devices 30, 30a, 30b, and 30c, and relays data transmitted and received by slave devices 30, 30a, 30b, and 30c. For example, when receiving data addressed to the information processing apparatus 10 from the slave units 30, 30a, 30b, the master unit 20 transfers the received data to the slave unit 30c.

  The subunit | mobile_unit 30,30a, 30b, 30c is a radio | wireless communication apparatus which transmits / receives data with the main | base station 20 by radio | wireless. The subunit | mobile_unit 30 has the detection means 31, the confirmation means 32, and the determination means 33. FIG. In addition, the subunit | mobile_unit 30a, 30b, 30c also has a means similar to these.

  The detection unit 31 continuously monitors the wireless communication between the parent device 20 and the child device 30, and determines whether or not the parent device 20 has a failure. For example, the detection unit 31 determines that the master unit 20 has failed when transmission from the slave unit 30 to the master unit 20 has failed continuously for a predetermined number of times. And if the detection means 31 detects the failure of the main | base station 20, it will notify the confirmation means 32 of failure occurrence.

  When the confirmation unit 32 receives the notification of the occurrence of the failure from the detection unit 31, the confirmation unit 32 confirms other slave units that exist within a range where wireless communication with the slave unit 30 is possible. This can be determined, for example, based on whether or not a predetermined radio signal transmitted by another slave unit has been detected. And the confirmation means 32 alert | reports the confirmation result of the communicable other party on radio. The notified confirmation result is received by the other handset that exists within the wireless communicable range with the handset 30. In addition, the confirmation unit 32 receives the confirmation result notified by other slave units in a similar manner. Thereafter, the confirmation unit 32 notifies the determination unit 33 of the confirmation results of the obtained slave unit 30 and other slave units.

  The determination unit 33 determines whether or not the child device 30 becomes a new parent device in place of the failed parent device 20 based on the confirmation result of the communicable partner acquired from the confirmation device 32. Specifically, the determining unit 33 is capable of wireless communication with the child device 30c connected to the information processing apparatus 10 and can communicate with the other child devices that can wirelessly communicate with the child device 30c. Is determined to be the new parent device. And when the determination means 33 determines that it becomes a new main | base station, it will alert | report that to radio | wireless. The slave unit that has received the notification recognizes the slave unit 30 as a new master unit and resumes wireless communication.

  In other words, if the handset 30 is not wirelessly communicable with the handset 30c, the handset 30 is not a new base unit. This can be determined from the confirmation result of the communicable counterpart of the slave unit 30. Even when the slave unit 30 is capable of wireless communication with the slave unit 30c, if there are those that can communicate wirelessly with the slave unit 30c and have more communication partners than the slave unit 30, the slave unit 30 30 is not a new parent machine. This can be determined from the confirmation results received from other slave units. On the other hand, when the above two conditions are satisfied, the slave unit 30 becomes a new master unit. In the slave units 30a, 30b, and 30c, the same determination process as described above is performed.

  According to such a wireless communication system, the detection unit 31 monitors communication with the parent device 20 and detects a failure of the parent device 20. When a failure of the parent device 20 is detected, the confirmation unit 32 confirms other child devices that can wirelessly communicate with the child device 30 and receives confirmation results for each of the other child devices. Then, the determining means 33 is capable of wireless communication with the child device 30c to which the information processing apparatus 10 is connected, and has the largest number of communicable counterparts compared to other child devices that are capable of wireless communication with the child device 30c. If it is determined, it is determined that the child device 30 becomes a new parent device.

  As a result, when the parent device 20 fails, an appropriate child device is automatically selected as a new parent device. That is, as a new parent device, one capable of wireless communication with at least the child device 30c to which the information processing apparatus 10 is connected is selected. At this time, when there are a plurality of devices (parent device candidates) that can wirelessly communicate with the child device 30c, the device with the largest number of communicable opponents is selected. Therefore, the wireless communication system after recovering from the failure has a connection form in which as many slave units as possible can communicate with the information processing apparatus 10, and the influence of the failure of the master unit 20 can be minimized. In addition, each of the slave units 30, 30a, 30b, and 30c can be independently performed by the determination process.

Hereinafter, the specific content of this Embodiment is demonstrated in detail with reference to drawings.
FIG. 2 is a diagram showing a system configuration of the present embodiment. The wireless communication system according to the present embodiment is a system that continuously transmits sensing data from a wireless communication device equipped with a sensor device to an information processing device. This wireless communication system includes wireless communication devices 100, 100 a, 100 b, 100 c, 100 d, 100 e, 100 f, 100 g and an information processing device 200. The information processing device 200 is connected to the wireless communication device 100b.

  The wireless communication devices 100, 100a, 100b, 100c, 100d, 100e, 100f, and 100g are communication devices that can wirelessly communicate with each other in accordance with a short-range wireless communication method defined in IEEE 802.15.4. The wireless communication devices 100, 100a, 100b, 100c, 100d, 100e, 100f, and 100g are equipped with a predetermined sensor device such as a monitoring camera or a temperature sensor.

  Here, the wireless communication devices 100, 100a, 100b, 100c, 100d, 100e, 100f, and 100g form one wireless PAN. The wireless communication device 100 functions as a coordinator that manages the wireless PAN, and holds wireless PAN management data. The wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g function as end devices that perform wireless communication with the coordinator.

  The wireless communication devices 100a, 100c, 100d, 100e, 100f, and 100g continuously transmit the sensing data obtained from the sensor device to the wireless communication device 100 wirelessly. The wireless communication device 100 connects the sensing data received from the wireless communication devices 100a, 100c, 100d, 100e, 100f, and 100g and the sensing data obtained from the sensor device mounted on the wireless communication device 100 to the information processing device 200. Wirelessly transmitted to the wireless communication apparatus 100b. The wireless communication device 100b outputs the sensing data received from the wireless communication device 100 and the sensing data obtained from the sensor device mounted on the wireless communication device 100b to the information processing device 200.

  The information processing device 200 is a device that collects and analyzes sensing data of sensor devices mounted on the wireless communication devices 100, 100a, 100b, 100c, 100d, 100e, 100f, and 100g, and is, for example, a PC. The information processing device 200 continuously acquires the sensing data via the wireless communication device 100b.

  FIG. 3 is a diagram illustrating a hardware configuration of the wireless communication apparatus. The wireless communication apparatus 100 includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 103, a sensor unit 104, a wireless communication unit 105, an input / output interface 106, and a bus 107. A CPU 101, a RAM 102, a ROM 103, a sensor unit 104, a wireless communication unit 105, and an input / output interface 106 are connected to a bus 107.

  The CPU 101 controls the entire wireless communication device 100. That is, the CPU 101 controls the RAM 102, ROM 103, sensor unit 104, wireless communication unit 105, and input / output interface 106 via the bus 107.

  The RAM 102 is a readable / writable memory accessed by the CPU 101. The RAM 102 temporarily stores at least part of an OS (Operating System) program and application programs to be executed by the CPU 101. The RAM 102 temporarily stores at least a part of various data necessary for processing by the CPU 101.

  The ROM 103 is a non-volatile memory that stores programs to be executed by the CPU 101 and various data necessary for processing. For example, a flash memory can be used as the ROM 103.

  The sensor unit 104 is a sensor device that monitors the external environment of the wireless communication device 100. For example, a monitoring camera that continuously acquires images of a predetermined location, or a temperature sensor that continuously measures the temperature of a predetermined object Etc. The sensor unit 104 outputs the obtained sensing data to the CPU 101.

  The wireless communication unit 105 performs wireless communication with other wireless communication devices in accordance with IEEE802.15.4. The wireless communication unit 105 demodulates and decodes a wireless signal received from another wireless communication device, and outputs the obtained data to the CPU 101. Further, the wireless communication unit 105 modulates and encodes transmission data acquired from the CPU 101, and wirelessly outputs the obtained transmission signal.

  The input / output interface 106 is an interface through which the information processing apparatus 200 can be connected by wire. When the information processing apparatus 200 is connected, the data acquired from the information processing apparatus is output to the CPU 101 and the data acquired from the CPU 101 is output to the information processing apparatus 200.

  FIG. 4 is a block diagram illustrating functions of the wireless communication device. The wireless communication device 100 includes a reception unit 110, a transmission unit 120, a PAN data storage unit 130, and a control unit 140. These functions are realized by the hardware shown in FIG. 3 by causing the CPU 101 to execute a predetermined control program stored in the ROM 103. The connection management unit 141 corresponds to the detection unit 31 in FIG. 1, and the coordinator determination unit 142 corresponds to the confirmation unit 32 and the determination unit 33 in FIG.

  The receiving unit 110 receives sensing data transmitted by another wireless communication device. Then, when the wireless communication device 100 functions as a coordinator, the reception unit 110 outputs the sensing data to the transmission unit 120 in order to transfer the sensing data to the information processing device 200. Further, when the information processing apparatus 200 is connected to the wireless communication apparatus 100, the sensing data is output to the information processing apparatus 200. In addition, the receiving unit 110 receives a control message transmitted by another wireless communication device. Then, the reception unit 110 outputs a control message to the control unit 140.

  When the wireless communication device 100 functions as a coordinator, the transmission unit 120 transmits the sensing data acquired from the reception unit 110 to the wireless communication device to which the information processing device 200 is connected. When the wireless communication apparatus 100 functions as an end device, the sensing data obtained by the sensor unit 104 is transmitted to the coordinator. In addition, the transmission unit 120 transmits a control message in response to an instruction from the control unit 140.

  The PAN data storage unit 130 stores PAN data for managing the wireless PAN. In the PAN data, for example, a PAN identifier (ID: IDentifier), a communication channel to be used, an end device participating in the PAN, and the like are defined. Here, when the wireless communication apparatus 100 functions as a coordinator, the PAN data storage unit 130 stores an original PAN data. On the other hand, when the wireless communication apparatus 100 functions as an end device, the PAN data storage unit 130 stores a copy of the PAN data that the coordinator has.

  The control unit 140 refers to the PAN data stored in the PAN data storage unit 130 and controls the reception process of the reception unit 110 and the transmission process of the transmission unit 120. The control unit 140 includes a connection management unit 141, a coordinator determination unit 142, and a PAN data management unit 143.

  The connection management unit 141 manages a wireless link between the wireless communication device 100 and another wireless communication device, and instructs the reception unit 110 and the transmission unit 120 to establish and disconnect the wireless link as necessary. That is, when the wireless communication apparatus 100 functions as a coordinator, the connection management unit 141 manages the wireless link between the wireless communication apparatus 100 and each end device. When the wireless communication apparatus 100 functions as an end device, the wireless link between the wireless communication apparatus 100 and the coordinator is managed.

  Further, when the wireless communication apparatus 100 functions as an end device, the connection management unit 141 continuously monitors the communication status between the wireless communication apparatus 100 and the coordinator, and confirms whether the coordinator has failed. . If the transmission process to the coordinator fails continuously for a predetermined number of times (for example, three times), it is determined that the coordinator has failed.

  The coordinator determining unit 142 is a wireless communication device for reconfiguring the wireless PAN when the wireless communication device 100 functions as an end device and the connection management unit 141 determines that the coordinator has failed. Determine if 100 should be the new coordinator. Details of the coordinator determination process will be described later. If it is determined that the wireless communication device 100 should become a new coordinator, the transmission unit 120 is instructed to notify other wireless communication devices as a control message.

  The PAN data management unit 143 manages the PAN data stored in the PAN data storage unit 130. When the wireless communication apparatus 100 functions as an end device, the PAN data management unit 143 stores a copy of the PAN data transmitted by the coordinator from the reception unit 110 in the PAN data storage unit 130. In addition, when the wireless communication apparatus 100 functions as a coordinator, the PAN data management unit 143 appropriately updates the PAN data stored in the PAN data storage unit 130 and transmits a copy of the PAN data to the end device. Instructs the transmission unit 120.

  4 shows the module configuration of the wireless communication device 100, the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g can also be realized by the same module configuration as the wireless communication device 100.

  FIG. 5 is a diagram illustrating a data structure of PAN data. The PAN data 131 is stored in the PAN data storage unit 130. The PAN data 131 includes items indicating a PAN-ID, a communication channel, and an end device. If the wireless communication apparatus 100 is participating in a plurality of PANs, PAN data for each PAN is stored in the PAN data storage unit 130. The PAN data 131 is appropriately updated by the PAN data management unit 143.

  In the item indicating the PAN-ID, identification information for identifying the wireless PAN is set. In the item indicating the communication channel, information on the communication channel used in the wireless PAN is set. According to the IEEE 802.15.4 regulations, 16 channels from 11 to 26 are permitted to be used as 2.6 GHz communication channels. In the item indicating an end device, identification information for identifying an end device participating in the wireless PAN is set. Furthermore, information indicating whether or not the information processing apparatus 200 is an end device connected is also set. Here, “Y” means that the information processing apparatus 200 is connected, and “N” means that the information processing apparatus 200 is not connected.

  Next, details of processing executed in a wireless communication system having the above-described configuration and data structure will be described. In the following, when the wireless PAN system has the connection relationship shown in FIG. 2, that is, the wireless communication device 100 functions as a coordinator, and the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g serve as end devices. Consider a functioning case.

FIG. 6 is a flowchart showing the procedure of the PAN reconfiguration process. In the following, the process illustrated in FIG. 6 will be described in order of step number.
[Step S1] The wireless communication device 100 distributes a copy of the PAN data to the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g. The wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g hold a copy of the PAN data received from the wireless communication device 100. This process is controlled by a module corresponding to the PAN data management unit 143 shown in FIG.

  [Step S2] The wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g monitor the communication status with the wireless communication device 100 and determine whether the coordinator (wireless communication device 100) has failed. If it is determined that a failure has occurred, the process proceeds to step S3. If it is determined that there is no failure, the process of step S2 is repeated. This process is controlled by a module corresponding to the connection management unit 141 shown in FIG.

  [Step S3] Each of the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g determines whether or not to become a new coordinator. In order to become a new coordinator, it is necessary to be able to wirelessly communicate with at least the end device (wireless communication apparatus 100b) to which the information processing apparatus 200 is connected. Details of the coordinator determination process will be described later. Here, it is assumed that the wireless communication device 100a becomes a new coordinator. This process is controlled by a module corresponding to the coordinator determining unit 142 shown in FIG.

  [Step S4] The wireless communication device 100a wirelessly notifies that it is a new coordinator. The end device that has received the notification information transmits a request to participate in the wireless PAN to the wireless communication apparatus 100a. Thereby, a new wireless PAN having the wireless communication device 100a as a coordinator is formed. This process is controlled by a module corresponding to the coordinator determining unit 142.

  [Step S5] The wireless communication devices 100b, 100c, 100d, 100e, 100f, and 100g each determine whether or not they can participate in the wireless PAN after the return. Whether or not to participate can be determined, for example, by whether or not broadcast information has been received from a new coordinator within a predetermined time after detecting a failure of the old coordinator (wireless communication apparatus 100). If there is an end device that cannot participate, the process proceeds to step S6. If there is no end device that cannot participate, the process proceeds to step S8. Here, it is assumed that the wireless communication devices 100d and 100e are unable to participate in the wireless PAN after the return. This process is controlled by a module corresponding to the coordinator determining unit 142.

  [Step S6] Each of the wireless communication devices 100d and 100e determines whether or not to become an additional coordinator. To become an additional coordinator, it is necessary to be able to wirelessly communicate with at least the end devices participating in the wireless PAN formed in step S4. Here, it is assumed that the wireless communication device 100e becomes an additional coordinator. This process is controlled by a module corresponding to the coordinator determining unit 142.

  [Step S7] The wireless communication device 100e wirelessly notifies that it is an additional coordinator. The end device that has received the broadcast information transmits a request for participation in the additional wireless PAN to the wireless communication apparatus 100e. As a result, a wireless PAN is formed with the wireless communication device 100e different from the wireless PAN formed in step S4 as a coordinator. Here, an end device capable of wireless communication with both the wireless communication device 100a and the wireless communication device 100e participates in both wireless PANs. This end device functions as a router that relays sensing data between two wireless PANs. This process is controlled by a module corresponding to the coordinator determining unit 142.

  [Step S8] The wireless communication device 100a acquires PAN data corresponding to the pre-failure wireless PAN distributed in step S1 from end devices belonging to the wireless PAN. Then, the wireless communication device 100a generates PAN data corresponding to the restored wireless PAN based on the acquired PAN data. When step S7 is executed, the wireless communication device 100e also executes the same process. This process is controlled by a module corresponding to the PAN data management unit 143 shown in FIG.

  In this way, if the coordinator fails, each end device determines whether it becomes a new coordinator. A condition for becoming a new coordinator is that wireless communication is possible with at least an end device to which the information processing apparatus 200 is connected. When a new coordinator is determined, a star topology wireless PAN is formed. At this time, if there is an end device that could not participate in the wireless PAN after return (an end device that is not capable of wireless communication with the new coordinator), a separate wireless PAN is formed. As a result, when a plurality of wireless PANs are formed, at least one wireless communication device functions as a router that relays sensing data between the wireless PANs.

  FIG. 7 is a flowchart showing the procedure of coordinator determination processing. This flowchart describes the process executed in step S3 in more detail. Here, attention is focused on the wireless communication device 100a. In the following, the process illustrated in FIG. 7 will be described in order of step number.

  [Step S31] The wireless communication device 100a notifies the confirmation request as a wireless signal. An end device that has received this confirmation request (an end device within the communicable range of the wireless communication device 100a) transmits a confirmation response to the wireless communication device 100a. The confirmation response includes at least identification information of the source end device.

  [Step S32] The wireless communication device 100a receives a confirmation response from an end device within the communicable range. Then, the wireless communication device 100a extracts the identification information of the transmission source end device from the confirmation response. Thereby, the wireless communication apparatus 100a can grasp the end device currently in the communicable range.

  [Step S33] The wireless communication device 100a collates the end device that has received the confirmation response so far with the copy of the PAN data after a predetermined time has passed since the confirmation request was notified in step S31. Then, the wireless communication device 100a determines whether or not confirmation responses have been received from all end devices other than itself participating in the original wireless PAN. If confirmation responses are obtained from all end devices, the process proceeds to step S37. If there is an end device that cannot obtain the confirmation response, the process proceeds to step S34.

  [Step S34] The wireless communication device 100a notifies a confirmation result of an end device capable of wireless communication as a wireless signal. This confirmation result includes identification information of each communicable partner.

  [Step S35] The wireless communication device 100a receives the confirmation result of the communicable partner of the end device notified by the other end device within the communicable range. This confirmation result includes identification information of each communicable partner.

  [Step S36] Whether or not the wireless communication device 100a has a condition to become a new coordinator based on the confirmation result of the communicable partner of itself and the confirmation result of the communicable partner of each end device received in step S35. Judge. The condition for becoming a new coordinator is that the wireless communication device 100a can wirelessly communicate with an end device (wireless communication device 100b) connected to the information processing device 200, and is wireless with the end device connected to the information processing device 200. The maximum number of communicable parties among communicable ones. If the conditions are satisfied, the process proceeds to step S37. If the conditions are not met, the coordinator process ends.

[Step S37] The wireless communication device 100a determines that it will become a new coordinator.
In this way, when it is determined that the wireless communication device 100a can communicate with all the end devices other than itself participating in the original wireless PAN, the wireless communication device 100a determines to become a new coordinator. Further, even when the wireless communication apparatus 100a cannot communicate with all end devices, the wireless communication apparatus 100a can communicate with the end devices connected to the information processing apparatus 200 and can communicate with candidates including other end devices. If it turns out that the number of opponents is the maximum, it decides to become a new coordinator.

  When there are a plurality of wireless communication apparatuses that can communicate with all end devices, or when there are a plurality of wireless communication apparatuses that can communicate with the end devices connected to the information processing apparatus 200 and have the maximum number of communicable parties. For example, when it is determined that a plurality of wireless communication apparatuses become coordinators, the one that has been notified quickly becomes the coordinator.

Next, an example of a specific process progress process when the PAN reconfiguration process shown in FIGS. 6 and 7 is executed in the wireless PAN system shown in FIG. 2 will be described.
FIG. 8 is a first schematic diagram illustrating an example of the PAN reconstruction process. As shown in FIG. 8, the wireless communication apparatus 100 as a coordinator distributes a copy of PAN data to the wireless communication apparatuses 100a, 100b, 100c, 100d, 100e, 100f, and 100g as end devices in advance. The wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g hold a copy of the PAN data received from the wireless communication device 100. Note that the wireless communication apparatus 100 may distribute only a part of the PAN data instead of distributing the entire managed PAN data. Different partial data may be distributed depending on the end device.

  FIG. 9 is a second schematic diagram illustrating an example of the PAN reconstruction process. As illustrated in FIG. 9, the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g continuously monitor wireless communication with the wireless communication device 100, and communication abnormality (for example, continuously) If it is found that the transmission process has failed a predetermined number of times, it is determined that a failure has occurred in the wireless communication apparatus 100. Note that, due to the timing of the monitoring process and the data transmission / reception process, the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g do not always detect the failure at the same time. Can occur.

  FIG. 10 is a third schematic diagram illustrating an example of the PAN reconstruction process. As illustrated in FIG. 10, when the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g detect a failure of the wireless communication device 100, they disconnect the wireless link with the wireless communication device 100, and Check the wireless communication devices located in the vicinity of.

  Here, the wireless communication device 100a can communicate with the four wireless communication devices 100b, 100c, 100f, and 100g. The wireless communication device 100b can communicate with the two wireless communication devices 100a and 100c. The wireless communication device 100c can communicate with the three wireless communication devices 100a, 100b, and 100f. The wireless communication device 100d can communicate with one wireless communication device 100e. The wireless communication device 100e can communicate with the two wireless communication devices 100d and 100f. The wireless communication device 100f can communicate with the four wireless communication devices 100a, 100c, 100e, and 100g. The wireless communication device 100g can communicate with the two wireless communication devices 100a and 100f.

  FIG. 11 is a fourth schematic diagram illustrating an example of the PAN reconstruction process. As shown in FIG. 10, there is no wireless communication device that can communicate with all other wireless communication devices, but there are two wireless communication devices that can communicate with the wireless communication device 100b to which the information processing device 200 is connected ( Wireless communication devices 100a, 100c). Of these two, the wireless communication device 100a has a larger number of communicable parties. Therefore, the wireless communication device 100a is selected as a new coordinator, and a new wireless PAN is formed with the wireless communication device 100a as a coordinator and the wireless communication devices 100b, 100c, 100f, and 100g as end devices.

  On the other hand, the two wireless communication devices (wireless communication devices 100d and 100f) cannot participate in the wireless PAN having the wireless communication device 100a as a coordinator. Therefore, the wireless communication device 100e that can communicate with the wireless communication device participating in the wireless PAN having the wireless communication device 100a as a coordinator is selected as an additional coordinator. As a result, a separate wireless PAN having the wireless communication device 100e as a coordinator and the wireless communication devices 100d and 100f as end devices is formed.

  At this time, the wireless communication device 100f functions as a router that participates in two wireless PANs and relays sensing data between the wireless PANs. FIG. 11 shows the network topology after two wireless PANs are formed.

  FIG. 12 is a fifth schematic diagram illustrating an example of the PAN reconstruction process. As illustrated in FIG. 12, the wireless communication device 100a serving as a coordinator acquires the PAN data of the wireless PAN before the failure from the wireless communication devices 100b, 100c, 100f, and 100g serving as end devices. Then, the wireless communication device 100a refers to the PAN data held by the wireless communication device 100a and the PAN data acquired from the wireless communication devices 100b, 100c, 100f, and 100g, and generates PAN data of a new wireless PAN. Thereafter, as shown in FIG. 8, the wireless communication device 100a distributes a copy of the generated new PAN data to the wireless communication devices 100b, 100c, 100f, and 100g.

  Similarly, the wireless communication device 100e as the coordinator acquires the PAN data of the wireless PAN before the failure from the wireless communication devices 100d and 100f as the end devices. Then, the wireless communication device 100e refers to the PAN data held by the wireless communication device 100e and the PAN data acquired from the wireless communication devices 100d and 100f, and generates PAN data of a new wireless PAN. Thereafter, the wireless communication device 100e distributes a copy of the generated new PAN data to the wireless communication devices 100d and 100f.

  As a result, the wireless communication device 100d transmits the measured sensing data to the wireless communication device 100e. The wireless communication device 100e transmits the measured sensing data and the sensing data received from the wireless communication device 100d to the wireless communication device 100f. The wireless communication device 100f transmits the measured sensing data and the sensing data received from the wireless communication device 100e to the wireless communication device 100a. The wireless communication devices 100c and 100g transmit the measured sensing data to the wireless communication device 100a. The wireless communication device 100a transmits the measured sensing data and the sensing data received from the wireless communication devices 100c, 100f, and 100g to the wireless communication device 100b. The wireless communication device 100b outputs the measured sensing data and the sensing data received from the wireless communication device 100a to the information processing device 200. In this way, sensing data obtained by the wireless communication devices 100a, 100b, 100c, 100d, 100e, 100f, and 100g is collected in the information processing device 200.

  By using such a wireless communication system, an appropriate end device is automatically selected as a new coordinator when the coordinator fails. In other words, a coordinator that can wirelessly communicate with an end device to which at least a predetermined information processing apparatus is connected is selected. At this time, when there are a plurality of devices (coordinator candidates) capable of wireless communication with an end device to which a predetermined information processing apparatus is connected, the device having the largest number of communicable partners is selected. Therefore, a wireless PAN including an end device to which a predetermined information processing apparatus is connected can have as many end devices as possible to participate.

  If there is an end device that could not participate in this wireless PAN, a separate wireless PAN is formed so that it can cooperate with the wireless PAN including the end device to which the predetermined information processing apparatus is connected. As a result, the wireless PAN is automatically reconfigured to minimize the influence of the coordinator failure. In addition, since a copy of the PAN data managed by the coordinator is distributed to the end device in advance, the new coordinator can update the PAN data more quickly and start controlling the wireless PAN.

  Note that although an example of a sensor network has been described in the present embodiment, the network reconfiguration function provided in the wireless communication apparatus can be applied to other types of networks. In the present embodiment, the IEEE 802.15.4 standard is adopted as a wireless communication method, but other wireless communication methods may be adopted.

  In the present embodiment, the processing function of each wireless communication device is implemented as software, but the processing function illustrated in FIG. 4 may be implemented as hardware. In this embodiment, one information processing apparatus is provided in the system. However, a plurality of information processing apparatuses may be provided. In this case, in order to become a coordinator, it may be a condition that communication is possible with all of the wireless communication devices to which the information processing device is connected, and communication with at least one of the wireless communication devices to which the information processing device is connected is possible. It is good also as a condition.

It is a figure which shows the outline | summary of this Embodiment. It is a figure which shows the system configuration | structure of this Embodiment. It is a figure which shows the hardware constitutions of a radio | wireless communication apparatus. It is a block diagram which shows the function of a radio | wireless communication apparatus. It is a figure which shows the data structure of PAN data. It is a flowchart which shows the procedure of a PAN reconstruction process. It is a flowchart which shows the procedure of a coordinator determination process. It is a 1st schematic diagram which shows the example of a PAN reconstruction process. It is a 2nd schematic diagram which shows the example of a PAN reconstruction process. It is a 3rd schematic diagram which shows the example of a PAN reconstruction process. It is a 4th schematic diagram which shows the example of a PAN reconstruction process. It is a 5th schematic diagram which shows the example of a PAN reconstruction process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Information processing apparatus 20 Parent | base_unit 30,30a, 30b, 30c Subunit 31 Detection means 32 Confirmation means 33 Determination means

Claims (5)

A wireless device that includes a parent device and a plurality of child devices that perform wireless communication with the parent device, and is used as each of the plurality of child devices in a wireless communication system in which an information processing device is connected to at least one of the plurality of child devices. A communication device,
Detecting means for monitoring communication with the parent device and detecting a failure of the parent device;
When the detection unit detects a failure of the parent device, it confirms the other child device that can wirelessly communicate with the own device and notifies the confirmation result, and the other child device notified by each of the other child devices. Confirmation means for receiving the confirmation result of
From the confirmation result obtained by the confirmation means, other slave units that are capable of wireless communication with the slave unit to which the information processing device is connected and that are capable of wireless communication with the slave unit to which the information processing device is connected, If it is determined that the number of communicable counterparts is the largest in comparison, a determination means for determining and notifying that the own device becomes a new parent device,
A wireless communication device.   The determination means is a wireless device managed by the new parent device when the own device does not become a new parent device and detects that wireless communication with the wireless communication device as a new parent device is not possible. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus determines to form a wireless communication system separate from the communication system. Each of the plurality of slave units has at least a copy of network information for managing the wireless communication system of the master unit,
When the determination unit determines to become a new parent device, a copy of the network information is acquired from the other child device, and network information corresponding to a new wireless communication system is generated based on the acquired information Further comprising means,
The wireless communication apparatus according to claim 1. A wireless communication method of a wireless communication system comprising a parent device and a plurality of child devices that perform wireless communication with the parent device, wherein an information processing device is connected to at least one of the plurality of child devices,
Each of the plurality of slave units monitors communication with the master unit to detect a failure of the master unit,
When each of the plurality of slave units detects a failure of the master unit, the slave unit confirms another slave unit that can wirelessly communicate with its own device and notifies the confirmation result, and the other slave unit notifies Receive confirmation results for
Each of the plurality of slave units can wirelessly communicate with the slave unit to which the information processing apparatus is connected and wirelessly communicate with the slave unit to which the information processing apparatus is connected based on the obtained confirmation result. If it is determined that the number of communicable counterparts is the largest compared to other slave units, it will be determined and notified that the own device will be a new master unit,
Wireless communication method. A computer used as each of the plurality of slave units in a wireless communication system including a master unit and a plurality of slave units that perform wireless communication with the master unit, and an information processing apparatus connected to at least one of the plurality of slave units A wireless communication control program for controlling a wireless communication device having the function of
A wireless communication device having the function of the computer,
Detecting means for monitoring communication with the parent device and detecting a failure of the parent device;
When the detection unit detects a failure of the parent device, it confirms the other child device that can wirelessly communicate with the own device and notifies the confirmation result, and the other child device notified by each of the other child devices. Confirmation means for receiving the confirmation result of
From the confirmation result obtained by the confirmation means, other slave units that are capable of wireless communication with the slave unit to which the information processing device is connected and that are capable of wireless communication with the slave unit to which the information processing device is connected, If it is determined that the number of communicable counterparts is the largest in comparison, a determining means for determining and notifying that the own device becomes a new parent device,
Wireless communication control program that functions as

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