KR100872706B1 - Operating method for wireless sensor network and system thereof - Google Patents

Abstract

The present invention relates to a method and system for operating a wireless sensor network.

In accordance with another aspect of the present invention, a method for operating a wireless sensor network includes transmitting a control message at a base node; Passing the control message to each other between hierarchical sensor nodes, wherein each sensor node is configured with a correlation level between a parent node and a child node; And transmitting data in a round robin manner by using a path between a sensor node configured as a correlation level of a child node and a parent node.

Sensor network, routing, multipath

Description

Operating method for wireless sensor network and system thereof

1 is a view showing the configuration of a sensor network according to an embodiment of the present invention.

2 is a detailed configuration diagram of a sensor node according to an embodiment of the present invention.

3 is a diagram illustrating an example of building a sensor network according to an embodiment of the present invention.

4 is a diagram illustrating an example of data transmission through multiple paths in a sensor node according to an embodiment of the present invention.

5 is a diagram illustrating an example of link error detection between sensor nodes according to an exemplary embodiment of the present invention.

6 illustrates a message format used in a sensor network according to an embodiment of the present invention.

7 is a block diagram of a parent table according to an embodiment of the present invention.

8 is a flowchart illustrating an example of a network configuration in a sensor network according to an embodiment of the present invention.

9 is a flowchart illustrating an example of data transmission according to an embodiment of the present invention.

10 is a flowchart illustrating an example of a network configuration according to an embodiment of the present invention.

11 is a flowchart illustrating an example of managing a parent node according to an embodiment of the present invention.

 <Explanation of symbols for the main parts of the drawings>

110: base node 101: sensor node

102: control message processing unit 103: data message processing unit

104: sensed data processing unit 105: forwarding processing unit

106: path selection processing unit 107: link detection processing unit

108: parent table 200: wired network

The present invention relates to a method and system for operating a wireless sensor network.

The wireless sensor network is composed of military operation areas, natural environments such as forests and rivers that are hard to reach, or bridges and buildings, and is actively used to monitor specific areas by collecting various data required for each application. It consists of a sensor node that collects data and a base node that receives data from the sensor nodes and delivers the data to a device accessible to the user.

In general, a node constituting a wireless sensor network includes a sensor that collects data, a computing device that processes the collected data, a storage device that stores the data, and a transceiver that transmits and receives data to and from the radio. They have the same power.

Low-Energy Adaptive Clustering Hierarchy (LEACH) distributes the transmission load of a wireless sensor network across the entire sensor network using a clustering method, but the limitation is that all sensor nodes must be able to communicate with the base node. In order to reduce the duplication of data transmission and improve reliability, the message is lost.

MultiHop LQI is a multi-hop routing protocol provided by TinyOS that transmits data in a single path by setting a routing path in a least cost manner based on radio strength received from neighbor nodes. However, when the routing path is determined by the least cost method, data processing and transmission loads are concentrated on a specific node according to the phase of the sensor node constituting the wireless sensor network. This causes a shortening of the lifetime of the wireless sensor network.

The present invention provides a method and system for operating a wireless sensor network.

The present invention configures a self-network using a parent-child node relationship level using a periodic transmission message, and selects a next hop and transmits data in a round robin manner. Provides an operation method and a system thereof.

The present invention provides a method and system for operating a wireless sensor network to manage a parent node according to a transmission error degree of the parent node.

In accordance with another aspect of the present invention, a method for operating a wireless sensor network includes transmitting a control message at a base node; Passing the control message to each other between hierarchical sensor nodes, wherein each sensor node is configured with a correlation level between a parent node and a child node; And transmitting data in a round robin manner by using a path between a sensor node configured as a correlation level of a child node and a parent node.

A wireless sensor network operating system according to an exemplary embodiment of the present invention includes a base node transmitting a control message for configuring a wireless sensor network; The node information is updated according to the received control message, and the control message reflecting the updated node information is transmitted to other neighbor nodes to form a parent-child node relationship, and the detected data is transmitted to the base node. Sensor nodes.

Hereinafter, with reference to the accompanying drawings as follows.

1 is a diagram illustrating a concept of a sensor network according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a sensor network includes a plurality of sensor nodes 101, a base station 110, and a wired network 200. The sensor node 101 is nodes that collect data of interest to the sensor node 100 and wirelessly transmit it to another sensor node or the base node 110 in the sensing field 100, and the base node 110 is a sensor node. Collecting data transmitted from these devices is a node that can be accessed by a user, for example, a server or a terminal connected to the wired network (200).

The sensor node 101 may operate as a source node of specific data or a routing node constituting a data transmission path. That is, node 1 may be a source node, and nodes 2 to 7 may be routing nodes.

If the source node is located within a certain distance from the base node, the source node can deliver data directly to the base node, if not located within a certain distance so that the source node can deliver data to the base node through one or more routing nodes do. That is, since the transmission distance and energy of the nodes constituting the wireless sensor network are limited, the data measured by the sensor node far from the base node is transmitted to the base node through multi-hop.

The base node 110 transmits a message for network configuration, and sets a parent-child relationship, that is, a hierarchical correlation level, between nodes receiving the message. In such a sensor network environment, the sensor node 101 transmits the collected data to a neighboring node (eg, a parent node) that is hierarchically correlated with a data message, and the base node 110 transmits the sensor node ( 101 receives the data message transmitted from the data message to provide to the user.

2 is a detailed configuration diagram of a sensor node 101 according to an exemplary embodiment of the present invention.

Referring to FIG. 2, each sensor node 101 includes a control message processor 102, a data message processor 103, and a parent table 108, and the control message processor 102 forms a wireless sensor network. As a processor, the wireless sensor network is self-established by comparing the level and sequence number of control messages received from neighbor nodes with its node information (ie, level and sequence numbers) and updating the parent table 109. That is, the wireless sensor network may be built on its own based on the node's level and the transmission period of the control message transmitted between the nodes.

The data message processing unit 103 includes a sensing data processing unit 104, a forwarding processing unit 105, a path selection processing unit 106, and a link sensing processing unit 107. The sensing data processing unit 104 measures at a corresponding sensor node. One data is transmitted to the next hop, and the forwarding processor 105 forwards the data received from the child node to the next hop to transmit the data to the base node. The path selection processor 106 checks the number of errors of the parent node in the parent table and selects a next hop node next round in a round robin manner among the parent nodes of the parent table. The link error processor 107 determines the link state between the child node and the parent node based on the time required when the parent node receives the data from the child node during data forwarding to the next hop. Increase the transmission error count with the parent node.

3 is a diagram illustrating a configuration example of a sensor network according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the base node BS periodically broadcasts and transmits a control message to configure a wireless sensor network. Here, the transmission period may be adjusted according to the type of application.

The control message is composed of the information of the transmitting node and is used for network configuration. As shown in (c) of FIG. 6, the ID (addr) of the node and the sequence number of the control message are shown. number, level. The ID of the node is the address of the transmitting node, the sequence number of the control message represents the period of the control message and is incremented only at the base node, and the level represents the level of the sensor node transmitting the control message including the base node.

In this case, the level represents a depth (or distance) from the base node based on the communication distance of each node, and the depth of the base node is 0, and the level increases by 1 toward the lower node hierarchically (LV1, LV2, LV3). That is, the node receiving the control message from the node having the level i compares the level i stored in the control message with the level of the control message receiving node itself, and if the level of the control message receiving node is greater than i, receiving the control message. The level of the node is i + 1.

In addition, whenever the base node BS transmits a control message, the base node BS broadcasts the sequence number of the control message by increasing the sequence number.

After receiving the control message, the sensor nodes E and F update their node information with reference to the information of the control message, and then the lower control node B, C, and D change the control message with the node information. Will be sent. In this manner of transmitting the control message, the control message can be transmitted to the sensor node A of the final source, and the construction of the hierarchical self network is completed.

At this time, the node sending the control message becomes the parent node, and the node receiving the control message becomes the child node, and the hierarchical correlation level for the parent-child node is determined. The node receiving the control message may be a node that is one hop away from the parent node.

Each sensor node compares the sequence number and level of the received control message with its own sequence number and level, and if the sequence number of the received control message is large, the sequence number of the received control message. Change to the number, and ignore if the sequence number is the same or smaller. That is, if the sequence numbers are the same or smaller, no routing path is established between the two nodes. In addition, when the level of the received control message is smaller than its level, it modifies its level to the level + 1 of the received control message. That is, the correlation level of the parent-child node.

On the other hand, even when the level of the received control message is greater than its level, no routing path is established between the two nodes.

At this time, the sensor node adds the node that sent the control message to its parent table, and it broadcasts again after modifying the control message with the level and ID. In this manner, the base node BS and the sensor nodes E and F, or the parent-child nodes B, C, and D between the sensor nodes are E and F (the parent node of A is B and C). The network is constructed with a correlation level of, D). In addition, when the sensor node receives the control message, the sensor node maintains or updates its level and sequence number. That is, at least one level difference is adjusted between the parent and child nodes, and the sequence number is changed according to the received control message.

Also, the node that receives the control message from the base node BS is the sensor nodes E and F of the first level LV1, and the control message retransmitted from the sensor nodes E and F of the first level LV1. Is a lower node that receives the control message retransmitted by the sensor nodes B, C and D of the second level LV2, and the sensor nodes B, C and D of the second level LV2. The level of the node may be determined by the sensor node A of the third level LV3 or the like. At this time, whether or not the control message is received between the nodes may use the reception strength of the RF power.

On the other hand, each sensor node (A-F) includes a parent table that stores the information of the parent node. The parent table is represented by an ID (addr) of the parent node, an error value for each parent node, and flag information as shown in FIG. 7, wherein an address of one or more parent nodes is stored in the ID of the parent node, respectively. The error value stores the number of transmission errors with each parent node, and the flag information is a value indicating whether the transmission succeeds when a specific parent node is selected as the next hop and transmits data. The child node may delete the parent node when a link error with the parent node reaches a predetermined number or more.

The present invention can configure the network with only the control message sent from the base node to minimize the number of messages required for the network configuration, thereby saving energy required for message transmission / reception.

As such, when the self network using the control message is configured, as shown in FIG. 4, the source sensor node A may transmit data through a multi-path using a round robin method. The round robin method alternately transmits data using a predetermined order of parent nodes in a parent table. Each sensor node records the next node (next_hop) and previous node (pre_hop) information in the data message when receiving and retransmitting the data message.

Herein, the data message is composed of information necessary for transmission of sensed data and detection of a released link. As shown in FIG. Level, sensed data (reading), the next hop (next_hop) of the sensed node, the previous hop (pre_hop) of the current node, and the sequence number (data_seq_no) of the sensed data.

As shown in FIG. 4, node A transmits a data message to a corresponding path (P1, P2, P3) in a round robin manner using B, C, and D, and B round robins its parent nodes, E, F. The data messages are sequentially transmitted using the scheme, and E and F transmit the data messages to the base node BS, which is the parent node, thereby transmitting the data to the final base node using the configured network and round robin scheme. I can do it.

5 is an example of detecting a link error between sensor nodes.

Referring to FIG. 5, when the data message Data1 is transmitted from the child node A to the parent node B (S11), the parent node B receives the data message and forwards it to the next node, E node. In operation S13, the data message is simultaneously received by the child node A by setting the previous hop of the data message to the node A (S12). Accordingly, the child node A checks the link state between the two nodes according to whether the forwarding message corresponding to the transmitted data message is valid within a valid time, and detects whether the link is an error link.

In the message of the present invention, as shown in FIG. 6, a control message and a data message are added based on a Tiny os message. (a) is a Tiny os message (Tos_msg), and the data of the message is a multi-hop message (Tos_MhopMsg) of (b), and the data of this message is used as a control message of (c) or a data message of (d). . The control message includes address, sequence number, and level information as described above, and the data message includes type, level, reading, next hop and previous hop, and data sequence number. Here, Tiny os is network-based, so messages are handled in bytes.

The present invention is a level based multi-path routing (LMPR) protocol, which minimizes the types of messages in consideration of the characteristics of a wireless network with a lot of message loss, and uses only control and data messages to configure the network. It is designed to perform data transmission and transmission error detection. In addition, only the minimum number of messages can be transmitted / received, saving the energy required for transmission / reception.

FIG. 8 is a flowchart illustrating a multi-path routing method of a sensor network according to the present invention, and uses a control message transmitted from a base node to configure a network corresponding to a transmission path between a node receiving the control message and nodes retransmitting the control message. It is made (S110).

Then, the data is transmitted through the multi-path in a round robin manner (S120), and when the transmission error occurs more than a predetermined time, the corresponding parent node is deleted and the entire network is updated (S130).

9 is a flowchart illustrating an example of a configuration of a self-network in FIG. 8.

Referring to FIG. 9, when the control node periodically broadcasts a control message (S111), the broadcast message is received by a sensor node within a predetermined distance (S112). At this time, the sensor node updates its sequence number and level with reference to the sequence number and level of the control message (S113). That is, the node receiving the control message compares its level with that of the node sending the control message, and if its level is large, modifies its level to +1 of the level of the node sending the control message. When the sequence number of the control message is large, the sequence number of the control message is changed to the sequence number of the control message.

Then, the node (that is, the transmitting node) that has transmitted the control message is added to the parent table to update the parent table (S114).

In operation S115, the control message is modified with the level and ID of the sensor node. By repeating this procedure, a self network having a hierarchical correlation level of parent-child nodes is constructed.

FIG. 10 is a flowchart illustrating an example of data transmission according to an embodiment of the present invention. In the case where data is collected at a source node and the collected data is to be transmitted (S121 and S122), it corresponds to a sequence in a parent table using a round robin method. The selected parent node is selected (S123), and a data message is transmitted to the selected parent node (S124). Here, the sensor node of the starting point may transmit data periodically.

11 is a flowchart illustrating an example of managing a parent node according to an embodiment of the present invention.

Referring to FIG. 11, the child node transmits a data message to the parent node (S131), and then confirms whether the received message is a response message received from the parent node (S132). At this time, if the received response message is not received within the valid time (S133), increase the number of errors and compare whether the error number exceeds the predetermined criteria (S134, S135), and if the error number exceeds the predetermined criteria, the corresponding parent node It is deleted from the parent table (S136). At this time, if data is transmitted within the specified number of errors, the error value is initialized.

According to the present invention, based on Tiny 0S, which is an embedded operating system, multipath applications can be distributed about 4.6 times or more than Surge applications using the MultiHop LQI method, which determines the path in the least cost method. The average reception rate of the node is about 91.32%.

The present invention has been described above with reference to the preferred embodiments, which are merely examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component specifically shown in the embodiment of the present invention can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

The present invention is a level based multi-path routing (LMPR) protocol, which minimizes the types of messages in consideration of the characteristics of a wireless network with a lot of message loss, and uses only control and data messages to configure the network. It is designed to perform data transmission and transmission error detection. In addition, only the minimum number of messages can be transmitted / received, saving the energy required for transmission / reception.

By decentralizing data transmission and processing, the energy of the entire network can be efficiently consumed to extend the life of the wireless sensor network.

In addition, by adjusting the control message cycle according to the type of application, it is possible to collect various data desired by the user in various environments such as home, school, and office to monitor the area.

Claims (24)

Transmitting a control message at the base node; Passing the control message to each other between hierarchical sensor nodes, wherein each sensor node is configured with a correlation level between a parent node and a child node; The sensor node uses a path between the sensor node configured as the correlation level of the child node and the parent node, selecting a parent node of the parent table in a round robin manner and transmitting the sensed data. Operating method. The method of claim 1, And the base node periodically broadcasts a control message. The method of claim 1, The control message includes a node ID, a sequence number of the control message, and a level of the node transmitting the control message. The method of claim 3, wherein And the base node increases a sequence number value at every transmission period of a control message. The method of claim 1, The configuring of the correlation level between the nodes may include: updating a sequence number and level of the node with reference to the sequence number and level of the control message in the sensor node receiving the control message; Storing the node sending the control message as a parent node; And modifying the control message with the updated level and ID of the mobile station and broadcasting to a lower node. The method of claim 5, The sensor node that receives the control message changes its sequence number to the sequence number of the control message when the sequence number of the control message is large. A method of operating a wireless sensor network that modifies the control message to level + 1 of the node that sent it. The method according to claim 1 or 6, The level of each node is the base node is the smallest value, the next level of relationship between the parent node and child nodes are differentiated from each other by one difference. The method of claim 1, Each sensor node transmits data by selecting a next hop from a parent table by using a round robin method each time data is transmitted. The method of claim 1, The sensor node includes transmitting data from a child node to a corresponding parent node, and checking a link state between two nodes according to whether a message received from the parent node is a response message of the parent node. Operating method. The method of claim 9, And checking a link state between the two nodes and deleting a corresponding parent node from a parent table if the number of errors is a predetermined number or more. The method of claim 1, The data message includes a type of data message, a level of a node that senses data, a sensed data, a next hop of a sensed node and a previous hop of a current node, and a number of sensed data. The method of claim 8, The parent table includes a flag information indicating whether the ID of the parent node, the number of transmission errors with the parent node, the success of the transmission when the parent node is selected as the next hop and transmitted data. The method of claim 1, And a distance of one hop between the parent node and the child node. The method according to claim 5 or 9, The sensor node collecting data, selecting a parent node corresponding to an order in a parent table using a round robin method when transmitting the collected data, and transmitting the data message to the selected parent node. Wireless sensor network operating method comprising the step of. The method of claim 14, The sensor node transmitting data to a corresponding parent node in a child mode, checking whether a message received from the parent node is a response message of the parent node, and checking whether the response message has been received within a valid time period Increasing the number of errors if not received within the valid time, and deleting the corresponding parent node from the parent table if the number of errors exceeds a predetermined number of times. The method of claim 1, And a method for operating a wireless sensor network based on a correlation level between the sensor nodes and a transmission period of a control message. A base node for transmitting a control message for configuring a wireless sensor network; The node information is updated according to the received control message, and a control message reflecting the updated node information is transmitted to other neighboring nodes to form a parent-child node relationship, and the detected data is stored in the parent node of the parent table. Wireless sensor network operating system including sensor nodes that select and transmit in a round robin manner. The method of claim 17, The sensor node compares the level and sequence number of the control message received from the neighbor node with its node information, updates the control message processor and establishes a wireless sensor network, and transmits the detected data and forwarding data to the next hop and links. Wireless sensor network operating system including a data message processing unit for detecting an error. The method of claim 18, The control message processing unit changes its sequence number to the sequence number of the received control message if the sequence number of the received control message is larger and the level is lower, and changes its level to level + 1 of the received control message. Wireless sensor network operating system. The method of claim 18, The control message processing unit adds the node that sent the control message to the parent table, the wireless sensor network operating system for transmitting again after reflecting the control message with its level and ID. The method of claim 18, The data message processor includes a sensing data processor for transmitting the sensed data to the next hop, a forwarding processor for transmitting the data received from the child node to the next hop to transmit the data to the base node, and checks the error count of the parent node. Path selection processing unit that selects the next hop in the round robin manner among the parent nodes of the table, and when the parent node receives the data from the child node when data forwarding to the next hop. And a link error processing unit for determining a link state between the child node and the parent node based on the time required to increase the number of transmission errors with the corresponding parent node. The method of claim 17, And the base node and sensor node transmit a control message in a broadcast manner. The method of claim 17, The wireless sensor network operating system of the wireless sensor network is configured based on the correlation level between nodes and the transmission period of the control message. The method according to any one of claims 17 to 23, And the base node increases a sequence number value in every transmission period of a control message.

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