KR20170092241A - METHOD OF LOAD BALANCING AND ROUTING IN WIRELESS SENSOR NETWORKS BASED ON IoT - Google Patents

Abstract

The present invention relates to an internet of things (IoT)-based wireless sensor network and a routing method capable of ensuring uniformity of a load. According to one aspect of the present invention, a sink node of an IoT-based wireless sensor network includes a network communication module, and a processor for controlling an operation of the network communication module. At this time, the processor receives actual distance information of a first sensor node and a neighboring sensor node within a predetermined distance, based on the first sensor node among a plurality of sensor nodes, from a plurality of sensor nodes in a wireless sensor network field through a network communication module, selects a center node and a vertex node among a plurality of sensor nodes by using the distance information, then calculates a position of each of the plurality of sensor nodes by using positions of the sink node, the center node, and the vertex node, generates at least one cluster based on the calculated position value of the sensor node, transmits clustering information to each of the sensor nodes, and allocates the same number of sensor nodes among the sensor nodes to each cluster.

Description

[0001] METHOD OF LOADING BALANCING AND ROUTING IN WIRELESS SENSOR NETWORKS [0002] BASED ON IOT [0003]

The present invention relates to a routing method of a wireless Internet-based sensor network and an efficient load balancing method therefor.

Recently, the importance of Internet of things has been emphasized because of active communication between devices. The Internet of objects requires a new communication routing technique as a structure that not only has devices connected to the existing Internet but also devices that do not have a unique address and participates in communication.

The Internet is an environment where various networks are interlocked, and wireless sensor networks play a key role. Therefore, using LEACH (Low Energy Adaptive Clustering Hierarchy) protocol, which is one of the routing methods of wireless sensor networks, it is expected that it will solve the unbalance of energy consumption among sensor nodes and extend network life.

However, the Internet environment of objects has various forms and sizes of data ranging from sensing information to multimedia information. Therefore, it is difficult to apply the routing technique of the existing wireless sensor network, which has been studied on the assumption that only small sensing information is transmitted.

Specifically, when the LEACH protocol is applied to the Internet of objects, the number of members in each cluster is determined stochastically. In the head of a cluster in which many members are instantly allocated, the buffer finite becomes a problem, .

Therefore, in the Internet environment of objects, routing technology that can solve the unbalance of energy consumption and load unevenness between sensor nodes is needed.

Korean Patent Laid-Open Publication No. 10-2012-0113064 (entitled "Low-power Sensor Network System and Cluster Network Establishment Method Through Cluster Network Construction") relates to a coordinator that acts as a gateway between a sensor network configuration and an external network; A high performance router for routing data from the sensor node to a neighboring node or a coordinator; And a non-adjacent node includes a low-power router operating as a lower node of the cluster header, and the cluster header includes an upper network including a coordinator, a high-performance router, and a cluster header, And a bridge of a cluster network including a lower node of the cluster header.

Korean Patent Laid-Open No. 10-2012-0113064

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a routing method that considers location information of a sensor node in cluster-based routing, determines the number of members in each cluster by a deterministic method, .

In addition, through the initial communication between the sink node and the sensor node, a method of efficiently locating an approximate position without additional configuration such as additional equipment such as GPS, or inputting the position information of each sensor node to each sensor in advance is provided I want to.

It should be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

According to an aspect of the present invention, there is provided a sink node of an Internet-based wireless sensor network including a network communication module and a processor for controlling operations of the network communication module. At this time, the processor transmits, from the plurality of sensor nodes existing in the field of the wireless sensor network, the peripheral sensor nodes within a predetermined distance based on the first sensor node among the plurality of sensor nodes, The center node and the vertex node are selected from among the plurality of sensor nodes using the separation distance information and then the positions of the sink node, the center node, and the vertex node are used And generating clustering information for each of the plurality of sensor nodes, wherein each of the plurality of sensor nodes includes a plurality of sensor nodes, The same number of sensor nodes are allocated among the sensor nodes.

A cluster according to an embodiment of the present invention includes at least one cluster head node and a plurality of member nodes, and the processor receives data collected from the plurality of member nodes from the cluster head node via the receiving unit.

Here, the clustering information includes a transmission radius for transmitting the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, and the third advertisement message.

Also, the processor of the sink node calculates the distance of two member nodes located farthest among the member nodes included in the cluster, and transmits the first advertisement message, the second advertisement message, and the third advertisement message of the cluster head node Can be set to the transmission power for transmission.

The sink node according to an exemplary embodiment of the present invention is located at the upper center of the network field.

The processor of the sink node selects a sensor node located at the center of the network field as a center node based on the number of times of reception of the second advertisement message and selects one of the sensor nodes located at four vertices of the network field assuming a square As a vertex node.

In addition, the sink node according to an embodiment of the present invention may further include a memory in which information on the number of times of reception of the second advertisement message received from the plurality of sensor nodes existing in the wireless sensor network field and actual distance information is stored.

According to another aspect of the present invention, there is provided a method for operating a sink node in an Internet-based wireless sensor network, comprising the steps of: receiving, from a plurality of sensor nodes existing in a wireless sensor network field, Receiving actual distance information of the first sensor node and the surrounding sensor node in the first sensor node; Selecting a center node and a vertex node among the plurality of sensor nodes using the actual distance information; Calculating positions of each of the plurality of sensor nodes using the positions of the sink node, the center node, and the vertex node; Generating at least one cluster based on the position value of each of the plurality of calculated sensor nodes; And transmitting the clustering information to each of the plurality of sensor nodes. At this time, in the step of creating a cluster, the same number of sensor nodes are allocated to each cluster from among a plurality of sensor nodes.

At this time, based on the calculated position value of the sensor node, generating at least one cluster is to create a cluster including at least one cluster head node and a plurality of member nodes.

The method also includes receiving data collected from the plurality of member nodes from the cluster head node.

At this time, the clustering information includes the transmission radius for transmitting the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, and the third advertisement message.

Meanwhile, a method of operating a sink node according to an exemplary embodiment of the present invention calculates a distance between two member nodes located farthest among member nodes included in a cluster, and calculates a distance between a first advertisement message, a second advertisement message, And setting transmission power for transmission of any one of the third advertisement messages.

In addition, in the method of operating a sink node according to an embodiment of the present invention, the step of selecting a center node and a vertex node may be based on the number of times of reception of the second advertisement message, The center node is selected as the center node, or the sensor node located at the four vertexes of the square network field is selected as the vertex node.

Also, the step of calculating the position of all the sensor nodes based on the positions of the sink node, the center node, and the vertex node may be performed by using a trilateration method based on the positions of the sink node, the center node, and the vertex node, And calculates the positions of all the sensor nodes existing in the network field.

The method of operating a sink node according to an embodiment of the present invention may further include storing information on the number of times of receiving a second advertisement message received from a plurality of sensor nodes existing in a wireless sensor network field and actual distance information have.

In addition, the step of generating at least one cluster based on the position value of each of the sensor nodes includes the steps of: selecting k cluster heads based on the calculated position values of the plurality of sensor nodes; Dividing the sensor field into W zones horizontally and H zones vertically; Arranging a plurality of sensor nodes on the basis of y coordinates and dividing the sensor nodes into H groups; And H equally divided groups are sorted on the basis of the x coordinate and divided by W to generate a total of k sensor node groups.

According to another aspect of the present invention, a first sensor node of a wireless Internet-based sensor network includes a first advertisement message having a transmission radius of a diagonal length of a wireless sensor network field, A network communication module for transmitting a second advertisement message having a radius, and a processor for controlling the operation of the network communication module. At this time, the processor transmits, through the network communication module, a plurality of neighboring sensor nodes within a distance of the diagonal length of the wireless sensor network field from the plurality of sensor nodes existing in the wireless sensor network field, And calculates the actual distance information of the plurality of neighboring sensor nodes and the first sensor node based on the first advertisement message, A second advertisement message is received from a plurality of neighboring sensor nodes within a distance and a third advertisement message including the calculated distance information and the number of times of receipt of the second advertisement message is counted, .

Here, the clustering information includes a transmission radius for transmitting the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, and the third advertisement message.

Therefore, the processor selects the operation mode of the sensor node according to the configuration information of the cluster, and the operation mode of the sensor node may be any of the cluster head node and the member node.

In this case, when the first sensor node operates in the cluster head node mode, the processor receives data from a plurality of member nodes existing in the cluster including the first sensor node, The data is compressed and transmitted to the sink node.

Alternatively, when the first sensor node operates in the member node mode, the processor transmits the data of the first sensor node to the cluster head node existing in the cluster including the first sensor node.

According to still another aspect of the present invention, there is provided a method for operating a first sensor node in an Internet-based wireless sensor network, comprising the steps of: receiving a first advertisement message having a transmission radius of a diagonal length of a wireless sensor network field, Transmitting a second advertisement message having a transmission radius of 1/2 of the first advertisement message; A method for receiving a first advertisement message from a plurality of neighboring sensor nodes within a distance of a diagonal length of a wireless sensor network field based on a first sensor node among a plurality of sensor nodes existing in a wireless sensor network field, Calculating actual spacing distance information of the plurality of peripheral sensor nodes and the first sensor node; Receiving a second advertisement message from a plurality of neighboring sensor nodes within a half of the diagonal length of the wireless sensor network field based on the first sensor node and counting the number of times the second advertisement message is received; Transmitting the third advertisement message including the calculated distance information and the number of times the second advertisement message is received to the sink node; And receiving the clustering information from the sink node and transmitting the data according to the clustering information.

At this time, the clustering information includes the transmission radius for transmitting the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, and the third advertisement message.

According to the clustering information, the step of transmitting the data further includes selecting an operation mode of the first sensor node according to the configuration information of the cluster, wherein the operation mode of the first sensor node includes a cluster head node mode and a member node Mode. ≪ / RTI >

In this case, in the step of selecting the operation mode of the first sensor node, when the first sensor node is selected as the cluster head node mode, the step of transmitting data may include a step of transmitting a plurality of member nodes And transmits the data to the sink node by compressing the received data together with the data of the first sensor node.

Alternatively, in the step of selecting the operation mode of the sensor node, when the first sensor node is selected as the member node mode, the step of transmitting data includes transmitting the data of the first sensor node to the first sensor node To the cluster head node.

According to any one of the above-mentioned means for solving the problems, the position information of the node is considered in the cluster-based routing, and the number of clusters, the number of members of each cluster, and the order of the head roles in the cluster are deterministic By the method, it is possible to guarantee the uniformity of the load.

Also, through the initial communication between the sink node and the sensor node, it is possible to efficiently approximate the position without additional equipment or configuration.

Thus, there is an effect of reducing data loss that may occur in the process of receiving data of the general member node by the cluster head.

In addition, the message transmission range of the general sensor node is limited within a certain range, thereby reducing energy consumption and increasing the overall service life of the network.

FIG. 1 is a schematic view of a sensor node included in a wireless Internet-based sensor network according to an embodiment of the present invention. Referring to FIG.
FIG. 2 is a flowchart illustrating a method of operating a sensor node according to an exemplary embodiment of the present invention. Referring to FIG.
3 shows the reception density of a first advertisement message according to the location of each sensor node according to an embodiment of the present invention.
4 is a diagram schematically illustrating a configuration of a sink node according to an embodiment of the present invention.
5 is a flowchart illustrating a method of operating a sink node according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a method of setting a vertex node according to an embodiment of the present invention. Referring to FIG.
FIG. 7 illustrates an example of clustering based on the location of a sensor node of a sink node according to an embodiment of the present invention.
FIG. 8 shows a simulation setting value for examining a performance analysis result of a matter-based Internet-based wireless sensor network according to an embodiment of the present invention.
9 is a flowchart illustrating a method of routing a wireless Internet based sensor network according to an embodiment of the present invention and a number of sensor nodes having residual energy for each round in a wireless Internet based sensor network using a conventional LEACH protocol, And the results of comparing the life span.
10 is a graph illustrating a result of comparing the number of members of each cluster in a specific round in a wireless Internet based wireless sensor network using a conventional LEACH protocol and a routing method of a wireless Internet based sensor network according to an embodiment of the present invention.
FIG. 11 is a graph illustrating a change in the overall loss rate of a wireless Internet-based wireless sensor network according to an exemplary embodiment of the present invention and a wireless Internet-based wireless sensor network using a conventional LEACH protocol.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

In this specification, the term " part " includes a unit realized by hardware, a unit realized by software, and a unit realized by using both. Further, one unit may be implemented using two or more hardware, or two or more units may be implemented by one hardware.

In this specification, some of the operations or functions described as being performed by the terminal or the device may be performed in the server connected to the terminal or the device instead. Similarly, some of the operations or functions described as being performed by the server may also be performed on a terminal or device connected to the server.

The object-based wireless sensor network according to one embodiment of the present invention may be composed of a network field indicating a space where sensor nodes are arranged and a sink node connecting an external network. At this time, the sensor nodes are sporadically distributed in the network field.

The randomly distributed sensor nodes measure physical quantities such as temperature, humidity, and pressure to sense various environmental parameters, collect data, and transmit the collected data to the sink node via a network communication module.

The sink node manages and controls the sensor nodes of the wireless sensor network, and collects the data sensed by the sensor nodes. Also, it can receive data from the sink unit and send it to the appropriate sensor node.

Here, the network means a connection structure in which information can be exchanged between each node such as a terminal and a server. An example of such a network is a 3rd generation partnership project (3GPP) network, a long term evolution (LTE) network, a WIMAX world interoperability for microwave access networks, internet, local area network (LAN), wireless local area network (WLAN), wide area network (WAN), personal area network (PAN), bluetooth network, Broadcast networks, analog broadcast networks, digital multimedia broadcasting (DMB) networks, and the like.

On the other hand, in an embodiment of the present invention, it is assumed that a network is a square and a sink node is disposed at a center of one side of a network field. At this time, as described above, the plurality of sensor nodes may be randomly arranged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 is a schematic view of a sensor node included in a wireless Internet-based sensor network according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 1, a sensor node 100 according to an embodiment of the present invention includes a network communication module 110, a memory 120, and a processor 130.

First, the network communication module of the sensor node 110 includes a transmitting unit 112 and a receiving unit 114.

The sensor node 100 transmits a first advertisement advertisement ADV1 message, a second advertisement message ADV2 and a third advertisement message ADV3 through the transmitting unit 112 of the network communication module 110. [ . At this time, the transmission radius of the first advertisement message is the diagonal length of the network field, and the transmission radius of the second advertisement message is 1/2 of the radius of the first advertisement message transmission.

The sensor node 100 receives the first advertisement message and the second advertisement message from the neighboring sensor nodes regardless of the location of the wireless sensor network field in which the corresponding sensor node exists through the receiving unit 114 of the network communication module 110. [ And receive the second advertisement message.

Specifically, the sensor node 100 receives the first advertisement message from all the sensor nodes existing in the network field, and transmits the first advertisement message to the sensor node 100 within a half radius of the diagonal line length of the wireless sensor network field, Lt; RTI ID = 0.0 > 100 < / RTI >

The memory 120 of the sensor node 100 may store the data to be transmitted to the sink node 200 and the number of times the second advertisement message is received from other sensor nodes other than the sensor node.

Herein, the memory 120 is one of the computer storage media and includes volatile and nonvolatile, removable and nonvolatile memory devices implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. And a removable medium. For example, the storage device may be a ROM (Read Only Memory), a RAM (Random Access Memory), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device, a compact flash Such as a NAND flash memory, a hard disk drive (HDD), etc., such as a memory card, a memory stick, a solid-state drive (SSD) Magnetic computer storage devices, and the like.

The processor 130 of the sensor node 100 can calculate the distance between the corresponding sensor node and another sensor node existing around the sensor node. Also, the sensor node 100 transmits a third advertisement message including the distance between the calculated sensor node and the other sensor node, the position of the corresponding sensor node, and the identification information of the corresponding sensor node to a transmitter (not shown) of the network communication module 110 112 to the sink node 200.

The processor 130 of the sensor node 100 receives the clustering information from the sink node 200 and determines whether the corresponding sensor node participates in the routing process as a member node or the cluster head node You can determine if you want to participate.

That is, the clustering information may include a cluster head node included in the cluster, a member node, and a selection order of cluster head nodes determined for each round.

Accordingly, when the sensor node 100 participates in the routing process as a member node, the processor 130 of the sensor node 100 can transmit data to the cluster head node included in the clustering information.

On the other hand, when the sensor node 100 participates in the routing process as a cluster head node, the processor 130 of the sensor node 100 receives data from the member nodes included in the cluster, based on the clustering information. Thereafter, the received data is compressed together with its own sensing data, and is transmitted to the sink node 200

Hereinafter, an operation method of the sensor node according to an embodiment of the present invention will be described in more detail with reference to FIG.

FIG. 2 is a flowchart illustrating a method of operating a sensor node according to an exemplary embodiment of the present invention. Referring to FIG.

3 shows the reception density of a first advertisement message according to the location of each sensor node according to an embodiment of the present invention.

Referring to FIG. 2, a method of operating a sensor node according to an exemplary embodiment of the present invention includes: transmitting (S 110) a first advertisement message and a second advertisement message; (S120) receiving a first advertisement message from a plurality of neighboring sensor nodes and calculating a distance between the corresponding sensor node and the neighboring sensor node; Receiving a second advertisement message from the plurality of neighboring sensor nodes and counting the number of times of reception of the second advertisement message (S130); Transmitting a third advertisement message to a sink node (S140); And receiving the clustering information from the sink node and transmitting the data (S150).

2, a sensor node serving as a reference and a sensor node serving as a first sensor node are located in the vicinity of the corresponding sensor node and transmit and receive data to and from the corresponding sensor node as a peripheral sensor node However, in an embodiment of the present invention, the corresponding sensor node and the neighboring sensor node are only for explaining the relative concept. In other words, the peripheral sensor node may be any one of a plurality of sensor nodes existing in the network field except the corresponding sensor node, and the configuration of each sensor node is the same as that shown in FIG.

Hereinafter, in the detailed description, the reference sensor node is indicated by the corresponding sensor node, and the sensor node located in the vicinity of the corresponding sensor node is indicated by the surrounding sensor node. In addition, the sensor node collectively refers to the corresponding sensor node and the peripheral sensor node.

First, in step S110, the sensor node transmits a first advertisement message with a transmission radius of a diagonal length of a network field, and transmits a first advertisement message to the first advertisement message, 2 sends a 2 advertisement message in a radius.

In step S120, the sensor node receives a first advertisement message from a plurality of neighboring sensor nodes and calculates a distance between the corresponding sensor node and the neighboring sensor node, The distance between the corresponding sensor node and the neighboring sensor node can be calculated using the received first advertisement message. For example, supposing the corresponding sensor node is n _i , and the corresponding sensor node, n _i , receives a first advertisement message from n _j , which is one of a plurality of peripheral sensor nodes, n _i is n _i and n _j The distance d _{i, j} can be calculated.

Next, in step S130 of receiving a second advertisement message from a plurality of neighboring sensor nodes and counting the number of times of reception of the second advertisement message, the corresponding sensor node receives a second advertisement message from a plurality of neighboring sensor nodes , And counts the received second advertisement message so that the location where the corresponding sensor node exists can be grasped.

3, since the transmission radius of the second advertisement message is 1/2 of the first advertisement message, if it is assumed that all the sensor nodes 100 are uniformly arranged in the network field, The closer to the center, the greater the number of times the second advertisement message is received from the plurality of neighboring sensor nodes.

Conversely, as the sensor node is located at the edge of the network field, the number of times of reception of the second advertisement message received from the plurality of peripheral sensor nodes will be reduced. That is, the reception frequency distribution, i.e., the reception density, of the second advertisement message of the corresponding sensor node according to the position in the network field may be as shown in FIG. 3. The sensor node counts the number of times of reception of the second advertisement message, It is possible to grasp the position where the user is located within the network field.

Next, in step S140 of transmitting the third advertisement message to the sink node, the corresponding sensor node calculates the distance to the plurality of neighboring sensor nodes calculated based on the corresponding sensor node, To the sink node 200, the third advertisement message including the number of times of reception of the third advertisement message.

Finally, in step S150, the sensor node can determine whether the corresponding sensor node is a member node or a cluster head node by receiving the clustering information from the sink node in step S150. At this time, the clustering information may include information such as a cluster head node, a member node, and a selection order of cluster head nodes determined for each round.

In other words, the sensor node 100 can recognize a cluster including the corresponding sensor node, and can determine whether to operate as a member node or a cluster head node in each cluster every round. That is, all the sensor nodes 100 can operate as a member node or a cluster head node according to the order of selection of the cluster head node.

At this time, if the corresponding sensor node is determined as a member node through the clustering information, the corresponding sensor node can transmit data to the cluster head node included in the clustering information.

On the other hand, when the corresponding sensor node is determined to be a cluster head node, the corresponding sensor node receives data from the member nodes included in the cluster based on the clustering information. Then, the received data is compressed together with its own sensing data and transmitted to the sink node 200.

According to the above-described method of operating the sensor node 100, the sink node 200 according to an embodiment of the present invention can determine the location of all the sensor nodes 100 existing in the network field. Accordingly, the clustering information can be transmitted to each sensor node 100 after configuring the clusters based on the positions of the respective sensor nodes 100. That is, the sink node 200 may form a cluster so that the same number of sensor nodes 100 located in the periphery are included in one cluster.

At this time, a uniform number of sensor nodes 100 are allocated to the member nodes in the cluster, so that the load can be equalized. In addition, the message transmission range of the sensor node 100 can be limited within a certain range to reduce energy consumption. Therefore, it is possible to reduce the data loss rate and improve the average life span of the network in the object Internet based wireless sensor network environment.

Hereinafter, a sink node 200 according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5. FIG.

4 is a diagram schematically illustrating a configuration of a sink node according to an embodiment of the present invention.

4, a sink node 200 according to an exemplary embodiment of the present invention may include a network communication module 210, a memory 220, and a processor 230, similar to the sensor node 100.

The sink node 200 can transmit and receive data to and from the sensor node 100 through the network communication module 210. Specifically, the network communication module 210 of the sink node 200 transmits clustering information to each sensor node 100 through the transmitting unit 212, and transmits at least one And receives data from the sensor node 100 and distance information between the corresponding sensor node and the peripheral sensor node.

The memory 220 of the sink node 200 stores the number of times of reception of the second advertisement message received from the plurality of sensor nodes 100 existing in the network field and the number of times of reception of the second advertisement message, Distance information between sensor nodes, and the like can be stored.

The processor 230 of the sink node 200 transmits the position of the corresponding sensor node 100 received from each sensor node 100 and a plurality of (Center node, ncenter) 100A and vertex nodes (vertex node, nvertex) 100B1 to 100B4 (100B) among the plurality of sensor nodes existing in the network field using the distance information between the neighboring sensor nodes You can choose. Herein, the center node 100A refers to the sensor node 100 located closest to the center of the network field, and the vertex node 100B refers to the sensor node 100 located at the edge of the network field.

The processor 230 of the sink node 200 calculates the positions of all the sensor nodes 100 based on the positions of the sink node 200, the center node 100A and the vertex node 100B, One or more clusters may be created based on the position value. According to an embodiment of the present invention, the processor 230 of the sink node 200 determines the number of the sensor nodes 100 based on the position of each sensor node 100 so that the same number of sensor nodes 100 are allocated to each cluster Clustering is performed.

The processor 230 of the sink node 200 transmits the clustering information to each of the sensor nodes 100 through the transmitting unit 212 of the network communication module 210 so that each of the sensor nodes 100 transmits the clustering information Accordingly, it is possible to route packets or data.

At this time, the clustering information may include information such as a cluster head node, a member node, and a selection order of cluster head nodes determined for each round.

Hereinafter, a method of operating a sink node according to an embodiment of the present invention will be described in detail with reference to FIG.

5 is a flowchart illustrating a method of operating a sink node according to an embodiment of the present invention.

Referring to FIG. 5, a method of operating a sink node 200 according to an embodiment of the present invention includes receiving (S210) a third advertisement message from at least one sensor node; Selecting a center node and a vertex node among the plurality of sensor nodes (S220); Calculating (S230) positions of all the sensor nodes based on the positions of the sink node, the center node, and the vertex node; Generating (S240) one or more clusters based on the calculated position value; Transmitting the clustering information to each sensor node (S250); And receiving data from the cluster head node (S260).

First, in step S210 of receiving a third advertisement message from at least one sensor node, the sink node 200 acquires the number of times of reception of the second advertisement message received by the sensor from at least one sensor node 100, And receives a third advertisement message including distance information between the sensor and the peripheral sensor node. Accordingly, the sink node 200 can acquire the position of the sink node 200 itself and the distance information between the sink node 200 and each of the sensor nodes 100.

In step S220, the sink node 200 selects a center node and a vertex node among the plurality of sensor nodes. The sink node 200 selects a center node and a vertex node among the plurality of sensor nodes, 0.0 > 100A < / RTI > and the vertex node 100B.

FIG. 6 is a diagram illustrating a method of setting a vertex node according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 6, in the Internet based wireless sensor network according to the embodiment of the present invention, the network field may be square. Also, the sink node 200 is located at the center of the top of the network field, and the center node 100A is located at the center of the network field.

The sink node 200 may select a node that receives the second advertisement message from among the plurality of sensor nodes 100 as a center node and guess its position. For example, if the size of the network field is 200X200, the position of the center node (ncenter) can be estimated as (50, 50).

Then, the sink node 200 may select one of the sensor nodes at four corner positions as a vertex node (nvertex) as shown in FIG. At this time, the sink node 200 may select the vertex node considering the number of times of receiving the second advertisement message and the distance between the sensor node 100 and the sink node 200. [

Specifically, the sink node 200 draws a first circle having a radius (r) with a center node as its center (dcenter, vertex) between the vertex nodes at the center node. At this time, the distance between the center node and the vertex node may be obtained from dij, which is the distance information between each sensor node included in the third advertisement message received from the sensor node 100. [

Next, a second circle and a second third circle having a radius between the vertex nodes at the sink node 200 are drawn around the sink node 200. Since two sensor nodes 100 are located close to the sink node 200 and the remaining two sensor nodes are located far away from the sink node 200 in the square field, A short second circle and a third circle with a relatively long radius can be drawn. Hereinafter, the radius of the second circle is defined as R _s , and the radius of the third circle is defined as R _l .

The sink node 200 may then search for contacts of the first and second circles and contacts of the first and third circles. At this time, the contact point is located where A is indicated on the first circle and B is indicated on the third circle.

In FIG. 6, vertexes 100B ₁ to 100B ₄ nodes are displayed at four corners, but the sink node 200 can select only one of the four edge nodes as the vertex node 100B. On the other hand, when the sink node 200 selects a vertex node, it is not necessary to distinguish the left and right sides of the vertex node 100B, but it is necessary to distinguish whether the selected vertex node is a node close to the sink node 200 or a node located far away .

Next, in step S230 of calculating the positions of all the sensor nodes based on the positions of the sink node, the center node, and the vertex node, the sink node 200 calculates the position of the sink node 200, Position of the sensor node 100, and the position of the vertex node 100B.

More specifically, the sink node 200 is based on the position of the sink node 200 itself, the center node 100A, and the vertex node 100B, and the distances between the three nodes and the other sensor nodes 100 The position of all the sensor nodes 100 existing in the network field can be set.

The coordinates of the sink node 200, the center node 100A and the vertex node 100B are defined as (x _s , y _s ), (x _c , y _c ) and (x _v , y _v ) , Coordinates (x _i , y _i ) of the position (loc _i ) of an arbitrary sensor node, n _i , can be determined by the following equations (1) and (2).

In Equation (1), c represents a center, s represents a sink, v represents a vertex node, and the origin (0,0) represents the lower left end of a square field.

Next, in step S240 of creating one or more clusters based on the calculated position value, the sink node 200 calculates one or more clusters based on the position value of each sensor node 100 calculated by the preceding step S230 The above cluster can be created.

At this time, the sink node 200 can select k cluster heads in each round. Assuming that the sensor field is divided into W zones and H horizontally, the number of cluster heads (k) Can be selected by the following equation (3).

In Equation (3), W and H are positive integers.

When the number of heads of the cluster is determined, the sink node 200 sorts the sensor node 100 based on the yi coordinate and divides it into H sensor node groups. Thereafter, a group of H halves can be sorted on the basis of xi coordinates, and a total of k groups can be generated by dividing by W.

When the classification is completed according to the above-described method, each group has a uniform number of sensor nodes 100, and each sensor node 100 is located close to each other. And assign the sensor node 100 as a member of the cluster. At this time, the sink node 200 calculates and records the distance of two member nodes located farthest in one cluster. The sink node 200 may set the transmission power of the transmission of the advertisement message of the sensor node 100 serving as the cluster head within the cluster to the distance of the two member nodes located farthest in the cluster.

FIG. 7 illustrates an example of clustering based on the location of a sensor node of a sink node according to an embodiment of the present invention.

In the network field of FIG. 7, 60 sensor nodes are arranged, and the estimated positions of the sensor nodes 100 are indicated by black dots. According to one embodiment of the present invention, k is 20, W is 4, and H is 5 in the wireless sensor network of Fig. The sink node 200 may first sort each sensor node based on yi and then divide it into five groups of 12 sensor nodes.

Then, the sensor nodes belonging to the five groups are sorted by xi and divided into four groups. As shown in FIG. 7, a total of 20 clusters may be configured in the network field. Also, three sensor nodes 100 located close to each other can be uniformly allocated to each cluster.

Next, in step S250 of transmitting the clustering information to each sensor node, the sink node 200 may transmit the clustering information to the sensor node 100. [ At this time, the clustering information may include cluster configuration information, cluster head selection order, and transmission radius of the first to third advertisement messages of each sensor node.

Accordingly, according to the clustering information, the sensor node 100 can recognize the cluster including the corresponding sensor node and judge whether it will operate as a member node or a cluster head node in the corresponding cluster every round can do.

That is, when the sensor node 100 operates as a member node through the clustering information, the sensor node 100 can transmit data to the cluster head node included in the clustering information.

On the other hand, when the sensor node 100 operates as a cluster head node, the corresponding sensor node receives data from the member nodes included in the cluster based on the clustering information. Then, the received data is compressed together with its own sensing data and transmitted to the sink node 200.

Finally, in step S260 of receiving data from the cluster head node, the sink node 200 may receive data from a cluster head node included in the cluster.

Hereinafter, a performance analysis result of the Internet based wireless sensor network using the routing method according to an embodiment of the present invention will be described with reference to FIG. 8 to FIG.

In order to analyze the performance of the Internet based wireless sensor network using the routing method according to an embodiment of the present invention, simulation was performed using JAVA programming. At this time, considering the buffers of the Internet environment of objects, we confirmed how much the performance was improved compared with the conventional LEACH protocol.

FIG. 8 shows a simulation setting value for examining a performance analysis result of a matter-based Internet-based wireless sensor network according to an embodiment of the present invention.

Referring to FIG. 8, the size of the buffer allows only 20 data including the data of the cluster head itself to be stored in the conventional LEACH protocol, unlike the cluster head which received an infinite number of sensing data. In such a case, one cluster must be composed of 20 or fewer sensor nodes so that no data loss occurs.

9 is a flowchart illustrating a method of routing a wireless Internet based sensor network according to an embodiment of the present invention and a number of sensor nodes having residual energy for each round in a wireless Internet based sensor network using a conventional LEACH protocol, And the results of comparing the life span.

Referring to FIG. 9, the number of sensor nodes having residual energy for each round is determined and the network lifetime is compared. As a result, the routing method of the Internet-based wireless sensor network according to an embodiment of the present invention is based on the LEACH protocol and load It can be confirmed that it is more improved than the conventional techniques using the equalization method. On the other hand, the load equalization method is a method of seeking load equalization so that the distance between the cluster heads in the existing LEACH protocol does not become equal to or shorter than a predetermined interval.

10 is a graph illustrating a result of comparing the number of members of each cluster in a specific round in a wireless Internet based wireless sensor network using a conventional LEACH protocol and a routing method of a wireless Internet based sensor network according to an embodiment of the present invention.

Referring to FIG. 10, it can be confirmed that the number of members in each cluster in a certain round is not constant every round because the number of cluster heads is determined as stochastic in the LEACH protocol.

On the other hand, according to the routing method of the Internet-based wireless sensor network according to the embodiment of the present invention, since the sink node constitutes a cluster, the number of cluster heads selected per round is 20, which is 5% deterministic), which greatly affects load balancing.

Therefore, in the Internet-based wireless sensor network according to an embodiment of the present invention, the number of member nodes belonging to each cluster is uniformly 20, but in the case of the LEACH protocol, the number of member nodes belonging to the cluster is not uniform. Accordingly, when the data transmission / reception is performed, the loss rate of the wireless sensor network using the LEACH protocol may be about 18%. However, in the embodiment of the present invention, the loss rate is 0%.

FIG. 11 is a graph illustrating a change in the overall loss rate of a wireless Internet-based wireless sensor network according to an exemplary embodiment of the present invention and a wireless Internet-based wireless sensor network using a conventional LEACH protocol.

11 shows the result of checking the change of the overall loss rate, not the number of cluster members or the loss rate in a specific round, while proceeding the simulation. Here, the data loss rate is a ratio of data lost in the data merging process of the cluster head to the number of data generated in the network in each round. In this case, the loss rate can be expressed as 0 when there is no data loss and 1 when all data is lost.

Referring to FIG. 11, the loss rate increases as the round progresses for all the protocols. However, it can be seen that the routing method of the Internet-based wireless sensor network according to an embodiment of the present invention shows a lower loss rate than the LEACH protocol until about 1200 rounds of the loss rate reaches 1 from the beginning of the simulation. Therefore, it can be confirmed that the overall performance of the network is improved in the case of the Internet based wireless sensor network using the routing method according to an embodiment of the present invention. On the other hand, in the case of the load equalization method, since the number of clusters is very small as a method which does not take into consideration the loss of data at all, it can be confirmed that the data loss rate is the largest.

According to one embodiment of the present invention, when performing cluster-based routing in the Internet-based wireless sensor network, the sink node 200 considers the location information of each sensor node 100, The number of nodes, the number of member nodes, and the order of selection of cluster head nodes in the cluster are determined in a deterministic manner, so that load uniformity can be guaranteed.

Also, through the initial communication between the sink node 200 and the sensor node 100, it is possible to grasp the approximate position efficiently without additional equipment or configuration.

Thus, there is an effect of reducing data loss that may occur in the process of receiving data of the general member node by the cluster head.

In addition, the message transmission range of the sensor node 100 is limited within a certain range to reduce energy consumption and increase the service life of the entire network.

One embodiment of the present invention may also be embodied in the form of a recording medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer-readable medium may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes any information delivery media, including computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: sensor node
100A: center node
100B: Vertex Node
200: sink node

Claims (30)

Network communication module, and
And a processor for controlling operation of the network communication module, the sink node comprising:
The processor
From the plurality of sensor nodes existing in the wireless sensor network field through the network communication module,
Receiving an actual distance information of the first sensor node and a neighboring sensor node within a predetermined distance based on the first sensor node among the plurality of sensor nodes,
A center node and a vertex node are selected from a plurality of sensor nodes using the spacing distance information,
Calculating a position of each of the plurality of sensor nodes using the positions of the sink node, the center node, and the vertex node,
Generating at least one cluster based on the calculated position value of the sensor node and transmitting clustering information to each of the plurality of sensor nodes,
Wherein the same number of sensor nodes among the plurality of sensor nodes are allocated to each of the plurality of clusters.
A sink node of an Internet - based wireless sensor network. The method according to claim 1,
The cluster comprising at least one cluster head node and
Comprising a plurality of member nodes,
Wherein the processor receives data collected from the plurality of member nodes from the cluster head node via the receiving unit,
A sink node of an Internet - based wireless sensor network. The method according to claim 1,
The clustering information
And a transmission radius for transmitting either the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, or the third advertisement message is included in the sink node of the wireless sensor network. The method of claim 3,
The processor
A distance between two member nodes located farthest among the member nodes included in the cluster is calculated and set to a transmission power for transmission of one of the first advertisement message, the second advertisement message and the third advertisement message of the cluster head node In fact,
A sink node of an Internet - based wireless sensor network. The method according to claim 1,
Wherein the sink node is located at the top center of the network field.
A sink node of an Internet - based wireless sensor network. The method according to claim 1,
The processor
Selecting a sensor node located at the center of the network field as a center node based on the number of times of reception of the second advertisement message,
A sink node of an Internet - based wireless sensor network. The method according to claim 1,
The processor
A sink node of a wireless Internet-based sensor network, wherein one of the sensor nodes located at the edge of the network field is selected as a vertex node. The method according to claim 1,
And a memory for storing the number of times of reception of the second advertisement message and the actual distance information received from the plurality of sensor nodes existing in the wireless sensor network field. From a plurality of sensor nodes existing in a wireless sensor network field,
Receiving actual distance information of the first sensor node and a neighboring sensor node within a predetermined distance based on the first sensor node among the plurality of sensor nodes;
Selecting a center node and a vertex node among the plurality of sensor nodes using the actual distance information;
Calculating a position of each of the plurality of sensor nodes using a position of the sink node, the center node, and the vertex node;
Generating at least one cluster based on the position value of each of the plurality of calculated sensor nodes; And
And transmitting clustering information to each of the plurality of sensor nodes,
The step of creating the cluster
Wherein the same number of sensor nodes are assigned to the respective clusters.
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The step of generating at least one cluster based on the calculated position value of the sensor node
Creating a cluster comprising at least one cluster head node and a plurality of member nodes,
A method of operating a sink node in an Internet based wireless sensor network. 11. The method of claim 10,
Further comprising receiving data collected from the plurality of member nodes from the cluster head node,
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The clustering information
And a transmission radius for transmitting either the configuration information of the cluster, the first advertisement message of the cluster head node, the second advertisement message, or the third advertisement message. Way. 13. The method of claim 12,
The step of transmitting clustering information to each of the plurality of sensor nodes
A distance between two member nodes located farthest among the member nodes included in the cluster is calculated and set to a transmission power for transmission of one of the first advertisement message, the second advertisement message and the third advertisement message of the cluster head node Further comprising the steps of:
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The step of selecting the center node and the vertex node comprises:
Selecting a sensor node located at the center of the network field as a center node based on the number of times of reception of the second advertisement message,
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The step of selecting the center node and the vertex node comprises:
Selecting one of the sensor nodes located at the edge of the network field as a vertex node,
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The step of calculating the position of each of the plurality of sensor nodes using the position of the sink node, the center node, and the vertex node
Wherein the position of all the sensor nodes existing in the network field is calculated using the trilateration method based on the positions of the sink node, the center node, and the vertex node and the distance between the sensor nodes,
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
Further comprising storing the number of times of reception of the second advertisement message and the actual distance information received from the plurality of sensor nodes existing in the wireless sensor network field.
A method of operating a sink node in an Internet based wireless sensor network. 10. The method of claim 9,
The step of generating at least one cluster based on the calculated position value of each of the plurality of sensor nodes
Selecting k cluster heads based on the calculated position value of each of the plurality of sensor nodes;
Dividing the sensor field into W zones horizontally and H zones vertically;
Arranging the plurality of sensor nodes on the basis of y coordinates, and dividing the sensor nodes into H groups; And
And sorting the H halved groups by an x coordinate and dividing them by W to generate a total of k sensor node groups.
A method of operating a sink node in an Internet based wireless sensor network. A computer-readable recording medium recording a program for performing the method according to any one of claims 9 to 18 on a computer. A network communication module for transmitting a first advertisement message having a transmission radius of a diagonal length of a wireless sensor network field and a second advertisement message having a transmission radius of a half of a diagonal length of the wireless sensor network field,
And a processor for controlling operation of the network communication module, the first sensor node comprising:
The processor
Through the network communication module,
Wherein among the plurality of sensor nodes existing in the wireless sensor network field,
Receiving the first advertisement message from a plurality of neighboring sensor nodes within a distance of a diagonal length of the wireless sensor network field based on the first sensor node,
Calculating actual distance information of the plurality of neighboring sensor nodes and the first sensor node using the first advertisement message,
Receiving the second advertisement message from a plurality of neighboring sensor nodes within a half distance of a diagonal length of the wireless sensor network field based on the first sensor node,
Counting the number of times the second advertisement message is received,
And transmitting the third advertisement message including the calculated distance information and the number of times of reception of the second advertisement message to the outside.
A sensor node in a wireless Internet sensor network. 21. The method of claim 20,
The clustering information
Cluster head configuration information, a cluster head node first advertisement message, a second advertisement message, and a third advertisement message,
A sensor node in a wireless Internet sensor network. 22. The method of claim 21,
The processor
Selecting an operation mode of the sensor node according to the configuration information of the cluster,
Wherein the operation mode of the sensor node is one of a cluster head node and a member node.
A sensor node in a wireless Internet sensor network. 23. The method of claim 22,
When the first sensor node operates in a cluster head node mode,
The processor
After receiving data from a plurality of member nodes existing in a cluster including the first sensor node, compressing the received data together with the data of the first sensor node and transmitting the compressed data to the sink node.
A sensor node in a wireless Internet sensor network. 23. The method of claim 22,
When the first sensor node operates in the member node mode,
The processor
And transmitting data of the first sensor node to a cluster head node existing in a cluster including the first sensor node.
A sensor node in a wireless Internet sensor network. A first advertisement message having a transmission radius of a diagonal length of the wireless sensor network field and
Transmitting a second advertisement message having a transmission radius of 1/2 of a diagonal length of the wireless sensor network field;
Wherein among the plurality of sensor nodes existing in the wireless sensor network field,
Receiving the first advertisement message from a plurality of neighboring sensor nodes within a distance of a diagonal length of the wireless sensor network field based on the first sensor node, Calculating actual distance information of the first sensor node;
Receiving the second advertisement message from a plurality of neighboring sensor nodes within a half distance of the diagonal length of the wireless sensor network field based on the first sensor node and counting the number of times of reception of the second advertisement message ;
Transmitting a third advertisement message including the calculated distance information and the number of times of reception of the second advertisement message to the sink node; And
Receiving clustering information from a sink node and transmitting data according to the clustering information,
A method of operating a first sensor node of a wireless Internet-based sensor network. 26. The method of claim 25,
The clustering information
Cluster head configuration information, a cluster head node first advertisement message, a second advertisement message, and a third advertisement message,
A method of operating a sensor node in a wireless Internet based sensor network. 27. The method of claim 26,
According to the clustering information,
Further comprising: selecting an operation mode of the first sensor node according to configuration information of the cluster,
Wherein the operation mode of the first sensor node is one of a cluster head node mode and a member node mode.
A method of operating a first sensor node of a wireless Internet-based sensor network. 28. The method of claim 27,
In the step of selecting the operation mode of the first sensor node,
When the first sensor node is selected as the cluster head node mode,
The step of transmitting the data
After receiving data from a plurality of member nodes existing in a cluster including the first sensor node, compressing the received data together with the data of the first sensor node and transmitting the compressed data to the sink node.
A method of operating a first sensor node of a wireless Internet-based sensor network. 28. The method of claim 27,
In the step of selecting the operation mode of the sensor node,
When the first sensor node is selected as the member node mode,
The step of transmitting the data
And transmitting data of the first sensor node to a cluster head node existing in a cluster including the first sensor node.
A method of operating a sensor node in a wireless Internet based sensor network. 29. A computer-readable recording medium recording a program for performing the method of any one of claims 25 to 29 on a computer.

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