JP6329744B2 - Node device and network system - Google Patents

Description

  The present invention relates to a node device and a network system.

  A network system including sensor nodes that collect data is generally called a wireless sensor network. It is known that a wireless sensor network can improve the performance of a communication system by multipath for selecting a plurality of paths between sensor nodes and multichannel wireless communication using a plurality of channels simultaneously. In a network layer higher than IEEE 802.15.4 that defines the physical layer and the MAC layer, various network topologies such as a mesh type, a star type, and a tree type can be constructed according to a protocol to be used.

  Usually, in a wireless sensor network, a node that relays data communicates with any one of a plurality of sensor nodes using a common wireless channel to collect data. Furthermore, a wireless sensor network that collects data by communicating simultaneously with other sensor nodes by using another wireless channel is disclosed (for example, Patent Document 1).

  Also disclosed is a wireless sensor network having a hierarchical structure in which data is collected from nearby peripheral nodes using an omnidirectional antenna, while data is transferred to a destination node in a specific direction using the directional antenna. (For example, Non-Patent Document 1). In wireless sensor networks, by dynamically controlling the communication direction, the communication distance is extended, and the interference between the communication radio waves from the directional antenna and the communication radio waves between adjacent sensor nodes is reduced, and the transmission efficiency is improved. Can do.

JP 2012-50089

Hiroshi Sakamoto et al. “S-UNAGI: Implementation of Hierarchical Sensor Network Using Smart Antenna”, “Multimedia, Distributed, Cooperation and Mobile (DICOMO2008) Symposium” July 2008, pp. 2020-2024

  However, in the case of the above-mentioned Patent Document 1, it is complicated to determine and control spatially and temporally whether a node communicates using a common channel or communicates using another channel. Although the efficiency of data collection is improved, when data is propagated (hopped) further away, reception (data collection) and transmission cannot be performed simultaneously as shown in FIG. Transmission can be a bottleneck. In addition, when performing wide-area transmission by multi-hop (overlapping propagation), it is inevitable that the number of nodes that transmit and receive data increases along the route and the frequency of data communication becomes dense. However, there is a problem that the throughput decreases as the data is transmitted.

  Moreover, in the case of the said nonpatent literature 1, it is necessary to specify the position of the other party node which a directional antenna points, and the problem which should still be solved is included in practical use. Further, in order to extend the communication distance without specifying the direction, it is necessary to increase the output of the radio wave. However, uniformly increasing the output of the radio wave extends the range of radio wave interference.

  Therefore, an object of the present invention is to provide a node device and a network system that can suppress a decrease in throughput.

  A node device according to the present invention includes a first communication unit that receives data collected by a sensor node from a plurality of sensor nodes, and a second communication unit that transfers the data to a higher-level backbone network, The first communication unit and the second communication unit can communicate simultaneously.

  A network system according to the present invention is a basic system including the node device, a plurality of sub-networks configured by a plurality of sensor nodes, a plurality of the node devices, and a management node device that manages the node devices. And a network.

  According to the present invention, data collection and data frame transfer can be performed at the same time, so that a reduction in throughput can be suppressed.

It is a mimetic diagram showing the whole network system composition concerning this embodiment. It is a figure where it uses for description of the communication layer of the node apparatus which concerns on this embodiment. It is a block diagram which shows the structure of the node apparatus which concerns on this embodiment. It is a figure with which it uses for description of the table which concerns on this embodiment. It is a flowchart which shows the table edit process procedure of the node apparatus which concerns on this embodiment. It is a flowchart which shows the association processing procedure of the node apparatus which concerns on this embodiment. It is a flowchart which shows the transfer processing procedure of the node apparatus concerning this embodiment. It is a timing chart in the transfer processing of the node device according to the present embodiment. It is a figure where it uses for description of the scheduling of the node apparatus which concerns on this embodiment. It is a figure with which it uses for description of the scheduling of the conventional node.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(overall structure)
A network system 10 shown in FIG. 1 includes a plurality (four in the case of this figure) of sub-networks 12 and a backbone network 14 that is higher in hierarchy than the sub-networks 12. The subnetwork 12 includes one node device 18A to 18D, respectively. A plurality of sensor nodes 16 are provided under the node devices 18A to 18D. The node devices 18A to 18D and the subordinate sensor node 16 are formed to be capable of wireless communication in both directions by transmitting and receiving radio waves to and from each other. Although not shown, sensor node 16 is provided with a sensor and a communication device that performs wireless communication with node devices 18A to 18D. As the sensor, for example, a sensor that collects information such as temperature, humidity, speed, and video is used.

  The backbone network 14 is composed of node devices 18A to 18D belonging to each sub-network 12. In the backbone network 14, any one of the plurality of node devices 18 </ b> A to 18 </ b> D is set as a management node device (also called a coordinator) 20. The node devices 18A to 18D and the management node device 20 are configured to be capable of wireless communication in both directions by transmitting and receiving radio waves to and from each other. The management node device 20 is connected to the gateway 21. The gateway 21 is, for example, a personal computer that can be connected to a public line.

  The sub-network 12 and the backbone network 14 are configured to perform wireless communication based on the IEEE 802.15.4 standard. The network system 10 transfers the data collected by the sub-network 12 to the gateway 21 through the backbone network 14. Thereby, the data collected in the sub-network 12 is transmitted from the gateway 21 to the user terminal 24 via the Internet network 22.

  As illustrated in FIG. 2, the node devices 18 </ b> A to 18 </ b> D include a first communication unit 26 and a second communication unit 28. In the first communication unit 26 and the second communication unit 28, PHY (Physical layer) 60A and 60B, MAC (Media Access Control) layers 58A and 58B, and NW layers (Network layers) 56A and 56B are mounted, respectively. Furthermore, the node device is mounted with a common application layer 54 and transaction layer 52 in the first communication unit 26 and the second communication unit 28. The PHYs 60A and 60B and the MAC layers 58A and 58B are defined in the IEEE 802.15.4 standard. Any communication standard can be used for the NW layers 56A and 56B. In addition to the routing process, the application layer 54 performs a transfer identification registration process for associating data collected from the sensor nodes 16 belonging to the subnetwork 12 and a transfer destination of the data. The transaction layer 52 performs data reception processing and transmission processing.

  In practice, the node devices 18A to 18D include a first communication unit 26, a second communication unit 28, and a control unit 30, as shown in FIG. The first communication unit 26 is formed to be able to wirelessly communicate with the sensor node 16 within the sub-network 12. The second communication unit 28 is configured to be able to wirelessly communicate with the other node devices 18A to 18D and the management node device 20 in the backbone network 14. The first communication unit 26 and the second communication unit 28 use different radio channels.

  The control unit 30 includes an MPU (Micro-Processing Unit) 32 and an I / O 34 as an interface. The I / O 34 is connected to the gateway 21 (not shown in the figure). In the node devices 18 </ b> A to 18 </ b> D, the control unit 30 reads a program stored in a ROM (Read Only Memory) 36 into a RAM (Random Access Memory) 38. The control unit 30 expands the read program on the RAM 38 and executes various processes according to the expanded program. The memory 40 in the RAM 38 includes a management table 42, transaction rules 44, a proximity frame buffer 46 as a first storage unit, a wide area frame buffer 48 as a second storage unit, and an I / O frame buffer 50. Yes. The transaction rule 44 manages a rule that collectively handles a plurality of processes from collecting and transferring data as one process.

  The MPU 32 converts the data collected from the sensor node 16 into a data frame and temporarily stores it in the proximity frame buffer 46. In accordance with an instruction from the management node device 20, the MPU 32 registers transfer identification information that associates a data frame temporarily stored in the proximity frame buffer 46 with a transfer destination of the data frame. More specifically, in accordance with an instruction from the management node device 20, the MPU 32 edits the transfer identification information shown in FIG. 4A with reference to the transfer destination address information shown in FIG. 4B. Note that the transfer destination address information is set based on addresses assigned by the management node device 20 to the node devices 18A to 18D.

  As described above, the MPU 32 performs processing for assigning transfer destination address information to the data frame temporarily stored in the proximity frame buffer 46 based on the management table 42, and moves the data frame to the wide area frame buffer 48. . The MPU 32 transfers the data frames to the other node devices 18A to 18D according to the transfer identification information in the order stored in the wide area frame buffer 48.

  The MPU 32 registers the transfer identification information described above, thereby specifying the final data collection point of the data collected by the sensor node 16 and grasping the state of each sensor node 16.

  In the backbone network 14, a data frame created based on data collected in any of the plurality of sub-networks 12 is transmitted from the node devices 18 </ b> A to 18 </ b> D belonging to the sub-network 12 to the node device 18 </ b> A belonging to the other sub-network 12. To 18D. Therefore, the data frames collected in the subnetwork 12 and transferred to the backbone network 14 and the node devices 18A to 18D belonging to the other subnetwork 12 are transferred to the wide area frame buffer 48 via the backbone network 14. Data frames are temporarily stored.

(Data collection procedure)
Next, the data collection processing procedure of the node devices 18A to 18D will be described. The MPU 32 performs a table editing process for rewriting the management table 42 in accordance with an instruction from the management node device 20 according to the processing program.

  Next, the MPU 32 performs association processing for associating the data received from the sensor node 16 in the subnetwork 12 to which the MPU 32 belongs and the transfer destination of the data. In parallel, the MPU 32 transfers the data received from the sensor node 16 in the subnetwork 12 to which the MPU 32 belongs and the data transferred from the node devices 18A to 18D belonging to the other subnetwork 12 to the next node devices 18A to 18D. Perform the transfer process.

(Table editing procedure)
Next, the table editing processing procedure will be described with reference to the flowchart of FIG. The MPU 32 starts the table editing processing procedure RT1 shown in this figure and proceeds to step SP10.

  In step SP10, the MPU 32 waits for a command sent from the management node device 20, and proceeds to step SP11.

  In step SP11, the MPU 32 determines whether or not a command has been sent from the management node device 20. If a positive result is obtained in step SP11, this means that there is a processing request from the management node device 20, and at this time, the MPU 32 proceeds to step SP12.

  On the other hand, if a negative result is obtained in step SP11, it means that there is no processing request from the management node device 20, and the MPU 32 repeats step SP10 and waits until a command is sent from the management node device 20.

  In step SP12, the MPU 32 analyzes the contents of the sent command and proceeds to step SP13. In step SP13, the MPU 32 performs processing in accordance with the contents of the command, and proceeds to step SP15. Specifically, in order to register transfer identification information that associates data collected in the subnetwork 12 with a transfer destination of the data, the MPU 32 edits the table in step SP14.

  In step SP15, the MPU 32 performs a response process for notifying the management node device 20 that the table editing has been completed in accordance with the command, and proceeds to step SP16. In step SP16, the MPU 32 ends the table editing process procedure.

(Association procedure)
Next, the association processing procedure of the node devices 18A to 18D will be described with reference to the flowchart of FIG. The MPU 32 starts the association processing procedure RT2 shown in this figure and proceeds to step SP20. In step SP20, the MPU 32 waits until the data transmitted from the sensor node 16 in the subnetwork 12 to which the MPU 32 belongs is stored in the proximity frame buffer 46, and proceeds to step SP21.

  In step SP21, the MPU 32 determines whether the data storage is completed. If a positive result is obtained in step SP21, the MPU 32 proceeds to step SP22. In practice, the MPU 32 converts the data received from the sensor node 16 into a data frame and stores it in the proximity frame buffer 46.

  On the other hand, if a negative result is obtained in step SP21, the MPU 32 repeats step SP20 and waits until data storage is completed.

  In step SP22, the MPU 32 takes out the data frame stored in the adjacent frame buffer 46, and proceeds to step SP23.

  In step SP23, the MPU 32 extracts a transmission destination. Specifically, the MPU 32 collates the data frame with the table (step SP24), extracts the data frame transmission destination, and proceeds to step SP25.

  In step SP25, the MPU 32 determines whether or not the data frame transfer destination has been registered as a result of the collation. If a positive result is obtained in step SP25, the MPU 32 proceeds to step SP27.

  In step SP27, the MPU 32 temporarily stores the data frame in the wide area frame buffer 48, and proceeds to step SP28. In practice, the MPU 32 performs processing for assigning transfer destination address information to the data frame extracted from the close frame buffer 46 based on the management table 42 and stores the processed data frame in the wide area frame buffer 48.

  On the other hand, if a negative result is obtained in step SP25, this means that unrequested data has been collected, and the MPU 32 proceeds to step SP26. In step SP26, the MPU 32 performs error processing. Specifically, the MPU 32 deletes the data frame and moves to step SP28. In step SP28, the MPU 32 ends the association processing procedure.

(Transfer procedure)
Next, the transfer processing procedure of the node devices 18A to 18D will be described with reference to the flowchart shown in FIG. The MPU 32 starts the transfer processing subroutine RT3 shown in FIG. 8 and proceeds to step SP30. In step SP30, the MPU 32 waits for the data frame to be stored in the wide area frame buffer 48, and proceeds to step SP31. In practice, the data frame stored in the wide area frame buffer 48 includes a data frame created from data collected from the sensor node 16 and a data frame transferred from the other node devices 18A to 18D.

  In step SP31, the MPU 32 determines whether or not a data frame is stored in the wide area frame buffer 48. If a positive result is obtained in step SP31, the MPU 32 proceeds to step SP32. On the other hand, if a negative result is obtained in step SP31, the MPU 32 repeats step SP30 and waits until a data frame is stored.

  In step SP32, the MPU 32 takes out the data frame stored in the wide area frame buffer 48, and proceeds to step SP33. In practice, when a plurality of data frames are stored in the wide area frame buffer 48, the MPU 32 sequentially extracts from the previously stored data frames.

  In step SP33, the MPU 32 extracts the transfer destination of the data, and proceeds to step SP34. More specifically, the MPU 32 extracts transfer destination information from the data frame.

  In step SP34, the MPU 32 performs a transfer process. Specifically, the MPU 32 cuts out a data frame with the transfer destination as one segment, and proceeds to step SP35.

  In step SP35, the MPU 32 determines whether a data frame remains after being cut out. If a positive result is obtained in step SP35, this means that the dequeued data frame has become empty, and the process proceeds to step SP36.

  On the other hand, if a negative result is obtained in step SP36, this means that data frames with different transfer destinations remain, and the process returns to step SP33, and steps SP33 to SP35 are repeated.

  In step SP36, the MPU 32 sets a position to be dequeued next, and proceeds to step SP37. In step SP37, the MPU 32 determines whether or not the remaining data frame is stored in the storage queue. If a positive result is obtained in step SP37, this means that the storage queue is emptied, and the process proceeds to step SP38.

On the other hand, if a negative result is obtained in SP37, this means that the storage queue is not empty, the process returns to step SP32, and steps SP32 to SP37 are repeated. In step SP38, the MPU 32 ends the transfer processing procedure.

(Operation and effect)
Since the operations of the node devices 18A to 18D constituting the network system 10 are all the same, the description will be made with reference to FIG. 8 focusing on the node device 18A.

  When the node device 18A receives a command transmitted from the management node device 20, the node device 18A starts processing based on the command. Specifically, based on the command, the node device 18A collects predetermined data from the predetermined sensor node 16 in the subnetwork 12 to which the node device 18A belongs via the first communication unit 26. The collected data is converted into a data frame and temporarily stored in the adjacent frame buffer 46 in the node device 18A.

  Next, the node device 18A takes out the data frame temporarily stored in the adjacent frame buffer 46, and performs processing for assigning transfer destination address information to the data frame based on the management table 42. The processed data frame is temporarily stored in the wide area frame buffer 48. The node device 18A repeats the above operation as long as the request from the management node device 20 continues. As a result, the wide area frame buffer 48 sequentially stores the data frames to which the transfer destination address information is assigned.

  In parallel, the node device 18A transfers the data frame temporarily stored in the wide area frame buffer 48 to the predetermined node device 18C via the second communication unit 28 according to the transfer identification information. In this case, the node device 18A sequentially transfers data frames stored in the wide area frame buffer 48 in order.

  As described above, the node device 18A includes the first communication unit 26 that performs bidirectional communication with the sensor node 16, and the second communication unit 28 that performs bidirectional communication with the other node devices 18B, 18C, and 18D. The unit 26 and the second communication unit 28 use different radio channels. As a result, the node device 18A can simultaneously collect data and transfer data frames. That is, as shown in FIG. 9, the node device 18A collects data from a plurality of sensor nodes 16 (node 1 and node 2 in the figure), and simultaneously transmits data frames already stored in the wide area frame buffer 48 to other frames. It can be transferred to the node device 18C. Therefore, the node device 18A can transfer other data that has already been collected without waiting for the completion of data collection to the other node device 18C, so that a decrease in throughput can be suppressed. Here, the throughput refers to a data transfer amount per unit time.

  The node device 18A relays the data frame created based on the data collected by the other node device 18B. That is, the node device 18B collects data from the sensor node 16 in the subnetwork 12 to which the node device 18B belongs, via the first communication unit 26, according to the command transmitted by the management node device 20. In accordance with the transfer identification information, the node device 18B transfers the data frame whose destination is the node device 18A to the node device 18A via the second communication unit 28 (FIG. 8).

  When the node device 18A receives the data frame via the second communication unit 28, the node device 18A temporarily stores it in the wide area frame buffer 48 and sequentially transfers it to the other node device 18C according to the transfer identification information. Accordingly, since the node device 18A collects data from the sensor node 16 and simultaneously transfers the data frame transferred from the other node device 18B to the other node device 18C, the network system 10 suppresses a decrease in throughput. be able to.

  When receiving the data frame transmitted from each of the node devices 18A to 18C, the management node device 20 (node device 18C) temporarily stores it in the I / O frame buffer 50. Next, the management node device 20 takes out the data frame stored in the I / O frame buffer 50 in accordance with a request from the gateway, and transfers it to the gateway 21 via the I / O. In this way, the data collected in the sub-network 12 is transmitted from the gateway 21 to the user terminal 24 via the Internet network 22.

(Modification)
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the gist of the present invention.

  In the above-described embodiment, the case where the first communication unit 26 and the second communication unit 28 use different wireless channels has been described. A band may be used.

  In the above embodiment, the case where the management node device 20 is connected to the gateway 21 has been described. However, the present invention is not limited thereto, and the node devices 18A to 18D other than the management node device 20 may be connected to the gateway 21. Good.

  In the above embodiment, the numbers of the subnetwork 12 and the sensor nodes 16 are specified for convenience of explanation, but the present invention is not limited to this, and the numbers of the subnetwork 12 and the sensor nodes 16 can be appropriately selected.

DESCRIPTION OF SYMBOLS 10 Network system 12 Subnetwork 14 Core network 16 Sensor node 18A, 18B, 18C, 18D Node apparatus 20 Management node apparatus 21 Gateway 26 1st communication part 28 2nd communication part 34 I / O (interface)
42 Management table 46 Proximity frame buffer (first storage unit)
48 Wide area frame buffer (second storage)

Claims (6)

A first communication unit that receives data collected by the sensor node from a plurality of sensor nodes;
A second communication unit for transferring the data to a higher-level backbone network ;
A first storage unit for storing data collected from the plurality of sensor nodes;
A second storage unit for storing data received through the second communication unit and transferred to the backbone network;
A management table indicating a transfer destination of the data ;
Wherein the first communication unit and the second communication unit, unlike the channel or frequency band to each other state, and are capable of communicating at the same time,
The data is retrieved from the first storage unit, the data stored in the first storage unit is associated with the transfer destination of the data, stored in the second storage unit, and concurrently in the second storage unit node and wherein that you transfer from the data previously stored in this order. Claim 1 Symbol placement node device, characterized in that it comprises a communicable interface with the gateway. The claims 1 or 2 SL placing node device, and a plurality of sub-networks made up of a plurality of sensor nodes,
A backbone network including a plurality of the node devices and a management node device that manages the node devices ;
The management node device, a network system, characterized that you manage the transfer destination address information of the management table. The network system according to claim 3 , wherein the management node device is one of the plurality of node devices. The node device converts the data received from the sensor node in the subnetwork to which the node device belongs to into a data frame, stores the data frame in the first storage unit, collates the data frame with the management table, and stores the data frame 5. The network system according to claim 3, wherein a transmission destination is extracted, transfer destination address information is added to the data frame, and the data is stored in the second storage unit. The node device sequentially retrieves previously stored data frames from the second storage unit, extracts transfer destination information from the data frames, and transfers the data frame to a transfer destination address. 6. The network system according to claim 5, wherein the network system is repeated until the data frame stored in the storage unit is exhausted.

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