KR100987492B1 - Method for organizing logical group in wireless sensor network and wireless sensor network system using the same and managing group - Google Patents

Abstract

The present invention provides a method for forming a logical group in a wireless sensor network, and a wireless sensor network system for managing a group using the same, wherein a new sensor node is introduced into the wireless sensor network, and the new sensor node is an adjacent sensor node as a parent sensor node. Selecting, and determining whether the new sensor node is within the group range to which the parent sensor node belongs, and if the result is within the group range, the new sensor node belongs to the group to which the parent sensor node belongs, and does not belong to the group range. In this case, a method of forming a logical group in a wireless sensor network including generating a fragment group for creating a new group and a wireless sensor network system for managing a group using the same are provided.

Wireless sensor network. Group header, sensor node, sink node, received signal strength, group formation, group management

Description

Method for organizing logical group in wireless sensor network and wireless sensor network system using the same and managing group}

The present invention relates to a method for forming a logical group in a wireless sensor network and a wireless sensor network system for managing a group using the same. More particularly, the present invention relates to a method of forming a group using a logical relationship between sensor nodes without using location recognition technology. A method of forming a logical group in a managing wireless sensor network and a wireless sensor network system managing a group using the same.

Wireless Sensor Network (WSN) is a network formed by numerous sensor nodes spread around like countless dust floating in the air. Sensor nodes distribute information like Grid Computing due to the network that connects each other, and unlike a personal computer with a limited interface, it has excellent situational awareness with various kinds of sensors and a large number of sensor nodes. Wireless sensor networks are considered the best technology for ubiquitous environments.

Wireless sensor networks extend radially around sink nodes and form networks on their own. After that, depending on the purpose of the application, the main focus is to collect information from a particular zone into the sink node. Although large in size, a large number of packets continue to flow through the network, while the sensor nodes that process them have very limited performance and capacity, large networks are less reliable.

Group-based network management is required because of the burden of broadcast, various network overheads, and security threats.

As a method of forming and managing networks according to the prior art in groups, there are a method of using configuration information of a sensor node and a method of using location recognition technology.

The method of using sensor node placement information is to divide all sensor nodes into an appropriate number of groups and place them in a predetermined position for each group. This method is used to determine the size, group, and physical location of a group. Since there is only a limited method of designing all in advance and deploying a group of networks, there is a problem in that there is a lack of flexibility in dynamic change of sensor nodes.

The method of using location recognition technology is a method of forming and managing a group of networks by mounting a location awareness module in some or all sensor nodes.

In general, through a method using a global positioning system (GPS) and a location recognition technology using an ad-hoc location recognition system, a wireless sensor network manages sensor nodes inside a boundary by defining a group boundary in a square or hexagon shape as shown in FIG. However, the cost of attaching GPS to all sensor nodes is too high. Attaching GPS to only some of the group header nodes introduces another problem. The same problem occurs with the ad-hoc location recognition system, which is the lifetime expiration of the GPS attachment node or the reference node that knows its location. These nodes, the core of location-aware systems, have a lot of battery consumption for that purpose, which cannot guarantee the stability of the network.

The present invention is to overcome the above-mentioned conventional problems, the problem to be solved by the present invention is a wireless sensor network that can form and manage a group with only general sensor nodes without additional equipment, such as GPS or ad-hoc location recognition system To provide a logical group forming method and a wireless sensor network system to manage the group using the same.

According to an exemplary embodiment of the present invention, a step of introducing a new sensor node into a wireless sensor network; The new sensor node selecting an adjacent sensor node as a parent sensor node; Determining whether the new sensor node is within a radio propagation range of a group header to which the parent sensor node belongs; And the determination result. The new sensor node belongs to the group to which the parent sensor node belongs when it is within the radio wave propagation range of the group header, and if the new sensor node does not belong to the radio propagation range of the group header to generate a fragment group for generating a new group. A method of forming a logical group in a wireless sensor network is provided.

After creating the fragment group, creating a new group through consolidation of the fragment group; And determining a belonging group of the general sensor node.

The determining may include measuring received signal strength between the new sensor node and the group header; Deriving a distance between the group header and the new sensor node using the measured received signal strength; And comparing the derived distance with a radio propagation range of the group header.

Generating a new group through merging the fragment group may include: checking whether a group header of the fragment group exists around another group; And merging the group header of the fragment group into a group by measuring a received signal strength with the group header of the neighboring group and when the distance between the fragment groups is within a predetermined distance. Includes merging the group to the group header side having a relatively low depth and a relatively small short address.

In the determining of the belonging group of the general sensor node, the belonging group of the general sensor node is determined by comparing the received signal strength value of the group header of the new group and the group header of the group to which the parent sensor node belongs.

The selecting a neighbor sensor node as a parent sensor node by the new sensor node may include determining whether a parent sensor node to be selected by the new sensor node exists; And if the parent sensor node exists, inherits the group ID of the parent sensor node, and if the parent sensor node does not exist, proceeding to generating a fragment group for creating the new group. Include.

The group ID is expressed hierarchically by dividing a predetermined bit or represented by a short address of a group header.

According to another embodiment of the present invention, there is provided a method, comprising changing or destroying a group header within any group of a wireless sensor network; And reconstructing the arbitrary group by using the received signal strength value of the group header or the new group header.

Reconfiguring the arbitrary group when the group header is changed includes: determining whether a sensor node adjacent to the changed group header is within a radio propagation range of the changed group header; And as a result of the determination, the sensor node belonging to the radio wave propagation range of the changed group header belongs to the group to which the group parent sensor node of the changed group header belongs, and the sensor node not belonging to the radio wave propagation range of the changed group header is new. Creating a fragment group for creating a group or belonging to a neighboring group.

The determining may include measuring received signal strength between the adjacent sensor node and the changed group header; Deriving a distance between the changed group header and the adjacent sensor node using the measured received signal strength; And comparing the derived distance with a radio propagation range of the modified group header.

Reconstructing the arbitrary group when the group header is expired, the sensor nodes belonging to the group of the expired group header to generate a fragment group for creating a new group; Creating a new group through consolidation of the created fragment groups; And determining a belonging group of sensor nodes.

Generating a new group by merging the generated fragment group may include: checking whether a group header of the fragment group exists near another group; And the group header of the fragment group includes merging the received signal strength with the group header of the peripheral group and merging it into one group when the mutual distance is within a predetermined distance, and determining a belonging group of the sensor nodes. The determining of the belonging group of the sensor node may be performed by comparing the received signal strength value of the group header of the new group and the group header of the adjacent group.

According to another embodiment of the present invention, a wireless sensor network system composed of a plurality of groups, each group controlling a group header, a plurality of sensor nodes and the sensor node, and a sink for collecting data sensed by the sensor node And a sensor node to determine a belonging group by comparing the received signal strength values of the group headers of each group, and the group header of an arbitrary group is assigned to a group according to the received signal strength values of the group headers of neighboring groups. Merged with a wireless sensor network system that maintains the number and size of groups.

As in the present invention, if the group is formed using the logical relationship between the sensor nodes and the received signal strength value, it is possible to form an efficient size group and maintain the size of the group appropriately without an additional location recognition system.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a flow diagram of a method for performing logical grouping in a wireless sensor network in accordance with an embodiment of the present invention.

Looking at the process of performing logical group formation in the wireless sensor network with reference to Figure 2, first, a new sensor node is introduced into the wireless sensor network (S201).

The new sensor node determines whether a parent sensor node to be selected exists in the group (S202).

As a result, if there is a parent sensor node to be selected in the group, the new sensor node inherits the group ID of the parent sensor node and primarily belongs to the group of the parent sensor node (S203).

On the other hand, if there is no parent sensor node to select in the group as a result of the determination proceeds to step S207 described below to create a fragment group for creating a new group.

After the step S203, in order to determine whether the new sensor node is within the radio propagation range of the group header of the group to which the parent sensor node belongs, the distance between the group header to which the parent sensor node belongs and the new sensor node is measured (S204). In this case, the distance measurement measures the received signal strength between the new sensor node and the group header, and derives the distance between the group header and the new sensor node using the measured received signal strength and the following Equation 1.

[Equation 1]

Pr: Received Power [w]

K: wavelength used (c / f) [m]

R: Distance between transmission and reception [m]

Gt: transmit antenna power gain [dB]

Gr: Receive Antenna Power Gain [dB]

Pt: transmit power [w]

Then, the process of determining whether the new sensor node is within the radio propagation range of the group header of the group to which the parent sensor node belongs (S205). By comparing the radio propagation range of the group header with the distance between the group header and the new sensor node derived through the process S204, if the derived distance is within the radio propagation range of the group header, the new sensor node is the group of the parent sensor node. It is determined that it belongs to the radio propagation range of the group header. On the other hand, if the derived distance falls outside the radio propagation range of the group header, the new sensor node determines that it exists outside the group range to which the parent sensor node belongs.

As a result of the determination, when belonging to the group range, the new sensor node belongs to the group to which the parent sensor node belongs (S206).

On the other hand, when it is determined that it does not belong to the group range, a fragment group for generating a new group is generated (S207). Sculpture group refers to a new group that is created separately from an existing group, and is a group that is in a state before becoming an independent group through integration process with surrounding groups.

After the step S207, the group header of the fragment group checks whether or not there is another group around (S208).

Then, a new group is created through fragment group merging (S209). At this time, the group header of the fragment group checks whether there is another group nearby, and then measures the received signal strength with the group header of the neighboring group and merges the fragment group into one group when the distance between the fragment groups is within a predetermined distance. Will be integrated. Further, when merging into any one group, the group can be merged to the group header side having a relatively low depth and a relatively short short address.

After the process of S209, a process of determining a group to which the general sensor node belongs is performed (S210). At this time, the general sensor node measures and compares the received signal strengths of the group header of the new group and the group header of the group to which the parent sensor node belongs. Then, the general sensor node belongs to the group of the group header with a large received signal strength value.

3 is a diagram illustrating the expansion of a group of a wireless sensor network through the inflow of a new sensor node, and FIG. 4 is a diagram illustrating hierarchical notation among group ID notation methods. FIG. 5 is a diagram illustrating a state in which a new fragment group is formed, FIG. 6 is a diagram illustrating a state in which a group independent of the merge of a fragment group is formed, and FIG. 7 is a diagram illustrating a state in which a general sensor node determines a belonging group. 3 to 7 conceptually illustrate a main process of a method of performing logical group formation in the wireless sensor network shown in FIG. 2. Hereinafter, the main process will be described with reference to FIGS. 3 to 7. do.

3 is a conceptual diagram illustrating a state in which a group is expanded through steps S201 to S203. When the sensor node A enters the wireless sensor network, the group ID is inherited from the group ID of the group header GH, which is a parent sensor node, and belongs to the same group as the parent node. The group ID of the sensor node A, which is a node, is inherited and belongs to the same group as the parent sensor node.

At this time, there are two ways to indicate group ID. One of them is a method of hierarchically expressing a group ID of 16/32 bits in total by dividing a predetermined bit as shown in FIG. 4 to indicate a sub-group. This is a method of writing a bit short address.

Referring to FIG. 4, in the ZigBee standard, a default maximum number of routers (Rm) that can form a relationship with a sensor node is set to 0x06. Therefore, GroupId is indicated by dividing each sub-group by 3 bits (= log ₂ 6).

In the case of the short address, only 16 bits are required for the group ID, but the hierarchy of the group cannot be indicated. However, a technique of dividing a group ID into predetermined bits may not properly reflect a dynamically changing group configuration due to a change in a group header.

Therefore, it is preferable to apply a technique of dividing a group ID into predetermined bits in a wireless sensor network in which the group header does not change, and in a highly dynamic wireless sensor network, grouping is performed using a 16-bit short address of a group header. It is advisable to apply the ID notation technique.

5 illustrates a state in which a fragment group for generating a new group is formed by deriving a distance between a new sensor node and a group header through steps S204, S205, and S207.

After entering the wireless sensor network, the sensor node P and the sensor node Q may measure a distance from the group header GH _A of the group to which the parent sensor node belongs by using a received signal strength (RSSI) value. Through this, the sensor node Q may be located far from the group header GH _A , unlike the sensor node Q located close to the group header GH _A. As such, the sensor nodes P that are far apart from the range of the group header GH _A form a fragment group to form a new group.

6 shows a state in which a group independent of the merge of the fragment group is formed through the process S208 to S209.

Since all sensor nodes located at the edge of the group header with weak radio wave reception strength are all trying to form a new group, the number of sensor nodes that do not belong to the existing group and form a new fragment group is quite large. Thus, the integration of numerous fragment groups created around existing groups is required. The group header of the fragment group checks for the presence of other groups around it and merges the group towards the group header with a lower depth and a shorter short address. In this process, the group header of the fragment group that can be merged is measured by merging the group header of the neighboring group and the received signal strength (RSSI) value if it is at a short distance, and forming a separate group from the fragment group if the distance is far.

Referring to FIG. 6, fragment group headers pGH _B , pGH _C , and pGH _D are all fragment group headers of newly formed fragment groups that are far from the group header GH _A. The fragment group header (pGH _D ) forms an independent group because there are no mergeable groups around it. However, since the fragment group headers pGH _B and PGH _C are close to each other, the depth of the fragment group header and the 16-bit short address are compared and absorbed and merged into one side to form a group.

7 shows a state in which the general sensor node determines the belonging group through the process S210.

The formation of a new group affects all sensor nodes around it. A general sensor node belongs to a group formed by a group header of a short distance, thereby efficiently managing power. The general sensor node determines the group to which it belongs according to the group header having the strongest signal strength in the vicinity.

As shown in FIG. 7, two group headers generate portions in which a propagation range overlaps. Sensor nodes in this intersection compare the received signal strength values of the two group headers to determine which group they belong to. Based on the dotted line, the sensor node in the X direction is close to the group header GH _A , so the received signal strength belongs to the group of the strong group header GH _A , whereas the sensor node in the Y direction is the group header GH _B. Since the signal strength is strong, it belongs to the group of GH _B.

8 is a flowchart illustrating a method of performing logical group formation in a wireless sensor network when a group header is changed according to another embodiment of the present invention, and FIG. 9 is a diagram illustrating a state in which a group is reconfigured according to replacement of a group header.

Referring to FIG. 8, a method of forming a logical group in a wireless sensor network when changing a group header is described. First, a group header is changed in an arbitrary group of a wireless sensor network composed of a plurality of groups (S801).

The distance between the sensor nodes adjacent to the changed group header is measured (S802). In this case, the distance measurement measures the received signal strength between the sensor node and the changed group header as in the above-described embodiment, and derives the distance from the measured received signal strength.

Then, it is determined whether the distance between the sensor node and the changed group header is within the radio propagation range of the changed group header (S803). That is, it is determined whether the sensor node belongs to the group of the changed group header.

As a result of the determination, when the sensor node belongs to the group of the changed group header, it belongs to the group of the changed group header (S804). If the sensor node does not belong to the group of the changed group header, the sensor node belongs to an adjacent group or creates a new group (S805).

9 illustrates a change in the group configuration sensor node due to a change in the group header. Sensor nodes in the lower right that are close to the modified group header GH` belong to the group of the group header GH`, and sensor nodes in the upper left that are far from the modified group header GH` belong to the surrounding group or are new. To form a group.

FIG. 10 is a flowchart illustrating a method of performing logical group formation in a wireless sensor network when a group header is destroyed according to another embodiment of the present invention, and FIG. 11 is a diagram illustrating a state in which a group is reconfigured according to group header destruction.

Referring to FIG. 10, a method of forming a logical group in a wireless sensor network when a group header is destroyed, first, an arbitrary group header is destroyed in a wireless sensor network including a plurality of groups (S1001).

If any group header expires, the sensor nodes in the group of the expired group header create a fragment group for creating a new group (S1002).

Then, the group header of the fragment group checks whether there is another group around (S1003).

A new group is created through the integration of the fragment group (S1004). At this time, the group header of the fragment group measures the received signal strength with the group header of the peripheral group and merges into one group when the distance between the fragment groups is within a predetermined distance.

Then, the belonging group of the sensor nodes is determined (S1005). As described in the above embodiment, the belonging group determination is determined by comparing the received signal strength value of the group header of the new group with the group header of the adjacent group.

When Referring to Figure 11, a group header (GH _A) of the group located at the center in a wireless sensor network of six groups each formed of a circular shape is destroyed, the peripheral of the sensor node in the group of the group header (GH _A) The sensor nodes that were located at the intersection with the groups of are belong to the near group. In addition, the sensor nodes in the center form a group of pieces and go through an integration process, but they cannot form a group of the same type as before but form a similar group. In other words, the group located in the center is changed from a circular shape to a polygonal shape such as a pentagon, and the remaining peripheral groups are also changed in some forms from the original form, but the overall group configuration remains similar.

What has been described above is merely an exemplary embodiment of a method for forming a logical group in a wireless sensor network according to the present invention and a wireless sensor network system for managing a group using the same, and the present invention is not limited to the above-described embodiment. As claimed in the claims, any person of ordinary skill in the art without departing from the gist of the present invention will have the technical spirit of the present invention to the extent that various modifications can be made.

1 is a schematic diagram illustrating a group management technique of a wireless sensor network according to the prior art.

2 is a flow diagram of a method for performing logical grouping in a wireless sensor network in accordance with an embodiment of the present invention.

3 is a diagram illustrating the expansion of a group of wireless sensor networks through the introduction of new sensor nodes.

4 is a diagram illustrating hierarchical notation among group ID notation methods.

5 is a view showing a state in which a new piece group is formed.

6 is a view showing a state in which a group independent of the merging of fragment groups is formed.

7 is a diagram illustrating a state in which a general sensor node determines a belonging group.

8 is a flowchart of a method of performing logical group formation in a wireless sensor network when a group header is changed according to another embodiment of the present invention.

9 is a diagram illustrating a state in which a group is reconfigured according to replacement of a group header.

10 is a flowchart of a method for performing logical group formation in a wireless sensor network upon group header destruction according to another embodiment of the present invention.

11 is a diagram illustrating a state in which a group is reconfigured according to the disappearance of a group header.

Claims (13)

In the method of forming a logical group in a wireless sensor network, (a) introducing a new sensor node into the wireless sensor network; (b) the new sensor node selecting an adjacent sensor node as a parent sensor node; (c) determining whether the new sensor node falls within a radio propagation range of a group header of a group to which the parent sensor node belongs; (d) If the new sensor node belongs to the group to which the parent sensor node belongs when it is within the radio wave propagation range of the group header, and generates a fragment group if it is not within the radio wave propagation range of the group header. Making; (e) creating a new group by merging the created fragment groups; And (f) determining a belonging group of the sensor node belonging to the created new group and the neighboring group of the new group, Creating the new group, (e1) checking whether the group header of the fragment group exists near the group of the fragment group; And (e2) the group header of the fragment group includes a step of measuring received signal strength with the group header of the peripheral group and merging into one group when the mutual distance is within a predetermined distance, The merging into any one of the groups comprises merging the group into a group header having a lower depth and a smaller short address among the fragment group and the neighboring groups of the fragment group. Way. delete The method of claim 1, wherein step (c) (c1) measuring a received signal strength between the new sensor node and the group header; (c2) deriving a distance between the group header and the new sensor node using the measured received signal strength; And (c3) comparing the derived distance with a radio propagation range of the group header. delete The method of claim 1, wherein step (f) In the wireless sensor network, the new group and the sensor node belonging to the group adjacent to the new group compare the received signal strength values of the header of the new group with the header of the group adjacent to the new group to determine the belonging group of the sensor node. How to form a logical group. The method of claim 1, wherein step (b) Determining whether there is a parent sensor node to be selected by the new sensor node; And And if the parent sensor node exists, inheriting the group ID of the parent sensor node; and if the parent sensor node does not exist, generating a fragment group for creating the new group. How to form a logical group in a wireless sensor network. The method of claim 6, The group ID is expressed in a hierarchical manner by dividing a predetermined bit or by a short address of a group header. The method of claim 1, Determining whether a group header has changed within any group of the wireless sensor network; When the group header is changed, determining whether a sensor node adjacent to the changed group header is within a radio propagation range of the changed group header; As a result of the determination, the sensor node belonging to the radio wave propagation range of the changed group header generates a second fragment group from the sensor nodes belonging to the group to which the changed group header belongs, and are not within the radio propagation range of the changed group header. Making; Generating a second new group by generating the generated second fragment group; And And determining a belonging group of the sensor node belonging to the created second new group and the neighboring group of the second new group. The method of claim 1, Determining whether a group header has expired in any group of the wireless sensor network; Creating a third fragment group from sensor nodes belonging to the group of expired group headers; Generating a third new group by integrating the created third piece group; And And determining a belonging group of the sensor node belonging to the created third new group and the neighboring group of the third new group. delete delete delete delete

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