KR101482145B1 - Apparatus and method for energy-saving and reliable data communication in Wireless Sensor Networks - Google Patents

Abstract

When a sensor node is installed in a cluster environment based on clusters, a node that has frequent data loss or damage due to a different link quality of each node is avoided in header selection, and reliable transmission of data and unnecessary retransmission The present invention provides an apparatus and method for energy saving and reliable information transmission in a wireless sensor network for reducing overall occurrence time of a wireless sensor network, A link quality information measuring unit for measuring a link quality of each of the sensor nodes, a remaining energy information and link quality information of each of the estimated sensor nodes, collecting remaining energy information of each sensor node, Through the combination of link quality information, weights for each sensor node A cluster header selecting unit for selecting a sensor node having the highest weight value as a cluster header node through comparison between the sensor nodes based on the calculated weight value; And a link quality information update unit updating the link quality measurement result measured by the link quality information measurement unit by updating information on the number of times the header node is selected as the cluster header and the number of retransmission times generated when the information is transmitted to the base station .

Description

[0001] The present invention relates to a wireless sensor network, and more particularly, to an apparatus and a method for energy saving and reliable information transmission in a wireless sensor network,

The present invention relates to an apparatus and method for efficient energy management in an environment using wireless sensor networks, and more particularly, to an apparatus and method for efficiently managing energy in an environment using wireless sensor networks, To an apparatus and method for energy saving and reliable information transmission in a wireless sensor network capable of reliable information transmission.

Wireless sensor networks are used for collecting various information by using sensor nodes having wireless communication function and are applied to various fields. For example, in the ubiquitous era, electronic tags are attached to all objects to recognize objects and environments, and real-time information is constructed and utilized through sensor networks.

Basically, the wireless sensor network includes at least one normal node group (cluster) composed of a plurality of normal nodes for collecting physical environmental information around the nodes, and at least one node group And a cluster header (node) responsible for direct communication between the normal nodes and the sink node.

In a wireless sensor network, it is an important task that the sensor nodes performing such a specific operation survive for a longer time based on limited and limited resources to perform the mission. Many studies have been carried out to improve this survival time and many technologies have been developed.

However, when a wireless sensor network is constructed in a real environment, sensor nodes have different link quality due to environmental factors such as obstacles and terrain. In this case, in a clustering method, which is a hierarchical structure widely used in a wireless sensor network, a cluster head for collecting information of neighboring sensor nodes and transmitting the information to a base station is required, In the case of quality, there is a high possibility that data is lost or damaged when data is transmitted to the base station. This requires a separate mechanism, such as retransmission, to ensure the data collection rate. In this case, additional energy consumption is inevitable, which is an inefficient operation in a wireless sensor network for maintaining limited energy for a longer time.

Accordingly, there are various alternative technologies for reducing energy consumption and efficient management in a wireless sensor network. However, energy management techniques using retransmission are not common based on link quality, and most studies utilizing link quality such as retransmission Because of its focus on routing, it is rarely utilized in cluster header selection techniques. In addition, sensor nodes in wireless sensor networks have a limitation in that it is not easy to use information such as precise energy measurement, location, and distance due to the main task of long-time survival with low power.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems and to improve the technology. When a sensor node is installed in a cluster environment, And to provide an apparatus and method for energy saving and reliable information transmission in a wireless sensor network for improving the overall survival time of a network by reducing the occurrence of unnecessary retransmission by reliably delivering data by avoiding header selection .

Another object of the present invention is to provide an apparatus and method for energy saving and reliable information transmission in a wireless sensor network capable of saving energy and reliably transmitting information by selecting cluster header nodes by adjusting energy remaining amount and link quality information of nodes together Method.

According to another aspect of the present invention, there is provided an apparatus for energy saving and reliable information transmission in a wireless sensor network, the apparatus including: an energy remaining amount estimating unit estimating residual energy of each sensor node included in a wireless sensor network; A link quality information measuring unit for measuring a link quality of each sensor node; and a controller for collecting remaining energy information and link quality information of each of the estimated sensor nodes and obtaining a combination of remaining energy information and link quality information of each sensor node And a cluster header for selecting a sensor node having the highest weight value as a cluster header node by comparing the calculated weight value with each sensor node based on the calculated weight value, A cluster selection unit configured to select the cluster header node as a cluster header; Number information and may update the retransmission times information generated when delivering the information to the base station is composed by including the link quality information updating unit for updating the link quality measurement results measured by the link quality information measuring unit.

Preferably, the energy remaining amount estimating unit estimates residual energy of each sensor node using an operating voltage value measured using an ADC (Analog-to-Digital Converter) provided by an MCU (Micro Controller Unit) of a sensor node .

Preferably, the estimation of the residual energy of the sensor node is performed using the equation Is used.

Preferably, the link quality information measuring unit measures the link quality information using the number of times that the sensor node is selected as the cluster header and the number of retransmission times when the information is transmitted to the base station.

According to an aspect of the present invention, there is provided a method for energy saving and reliable information transmission in a wireless sensor network, including the steps of: (A) estimating remaining energy of each sensor node included in a wireless sensor network; (B) measuring link quality information of each of the sensor nodes; (C) collecting residual energy information and link quality information of the estimated sensor nodes; Calculating a weight value for each sensor node through a combination of quality information, and (D) comparing sensor nodes having the highest weight value among the sensor nodes based on the calculated weight value, And a step of selecting the step of selecting the step.

Preferably, the step (B) is characterized in that the link quality information is obtained by using the number of times that the sensor node is selected as the cluster header and the number of retransmission times when the information is transmitted to the base station.

을 이용하여 산출하며, 이때, 상기 w는 잔여 에너지와 링크 품질의 적용 가중치인 것을 특징으로 한다.Preferably, the weight value (sensor node weight value) of the sensor node in the step (C)

, Where w is an applied weight of residual energy and link quality.

Preferably, the application weight w is set to be lower as the round progresses, and the link weight is set to be higher than the energy remaining energy as the round progresses.

Preferably, the step (D) is performed for one round.

Preferably, the step (D) includes the steps of: (D1) comparing (competing) sensor nodes using the calculated weight value of each sensor node; and (D2) comparing the highest weight value The method comprising the steps of: (D3) sending a notification message to the sensor nodes in the cluster to indicate that the cluster header node is a cluster header node in the cluster; and (D3) (D4) collecting information of the transmitted sensor nodes and transferring the collected information to a base station; (D5) receiving a connection message including information to be transmitted, And the number of retransmission times generated when information is transmitted to the base station is updated, and in the step (B), the link quality is updated in the next round Characterized by including the step of providing to also be utilized to establish.

Preferably, the step (D1) stops the competition when the sensor nodes are compared with the sensor node having a weight value higher than the sensor node and maintains the sensor node state. If the sensor node is compared with the sensor node having a weight value lower than the sensor node, And changing the header node to a header node.

The apparatus and method for energy saving and reliable information transmission in the wireless sensor network according to the present invention as described above have the following effects.

First, it avoids nodes that have frequent loss or damage of data due to header selection, thereby reducing the occurrence of reliable data transmission and unnecessary retransmission, thereby improving the overall lifetime of the network.

Secondly, the ADC used as the residual energy measurement method according to the present invention is often provided by many MCUs, and practical implementation is easy since there is no need for a circuit design requiring additional energy consumption.

Third, retransmission information to use link quality is easy to implement because it is a part that can easily obtain and utilize information due to a mechanism such as Ack processing for data transmission, which is widely used in communication field.

Fourth, a sensor node using a finite energy source such as a battery can be utilized and applied to a wireless sensor network utilizing a hierarchical structure such as a cluster.

Fifth, the system can be applied to a wireless sensor network which is used in a non-mobility sensor node and is used for military intrusion monitoring, sensing, or for monitoring and detecting natural phenomena such as earthquakes and floods. Can be utilized.

1 is a block diagram illustrating a configuration of an apparatus for energy saving and reliable information transmission in a wireless sensor network according to an embodiment of the present invention;
2 is a block diagram showing a preferred embodiment showing the configuration of the energy remaining amount estimating unit of FIG.
3 is a flowchart illustrating a method for energy saving and reliable information transmission in a wireless sensor network according to an embodiment of the present invention.
FIG. 4 is a flow chart for explaining the process of selecting a cluster header node in FIG. 3
5 is a diagram for explaining a process of measuring link quality information of a sensor node in FIG.
FIGS. 6 and 7 are diagrams for explaining a process of selecting a cluster header node in FIG.
FIG. 8 is a diagram illustrating an example for showing different link quality information generated when a cluster header node selected for each cluster in this round transmits information to a base station
Fig. 9 is a diagram showing an example for showing the phenomenon occurring in the next round when the situation shown in Fig. 8 occurs

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an apparatus and method for energy saving and reliable information transmission in a wireless sensor network according to the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

1 is a block diagram illustrating a configuration of an apparatus for energy saving and reliable information transmission in a wireless sensor network according to an embodiment of the present invention.

As shown in FIG. 1, the apparatus for transmitting information includes an energy remaining amount estimating unit 100 for estimating remaining energy of each sensor node included in a wireless sensor network, a link quality information measuring unit 100 for measuring a link quality of each sensor node, The remaining energy information of each sensor node estimated by the remaining energy estimating unit 100 and the link quality information of each sensor node measured by the link quality information measuring unit 200 are collected, A weight calculation unit 300 for calculating a weight value for each sensor node through a combination of remaining energy information and link quality information of the sensor node, and a weight value calculation unit 300 for calculating, based on the weight value calculated by the weight calculation unit 300, A cluster header node selection unit 400 for selecting a sensor node having the highest weight value through comparison as a cluster header node, Updates the link quality measurement result measured by the link quality information measurement unit 200 by updating the number of times that the cluster header node selected by the cluster head node 400 is selected as the cluster header and the number of retransmission times generated when the information is transmitted to the base station And a link quality information update unit 500.

At this time, the energy remaining amount estimating unit 100 calculates an energy remaining amount based on an operating voltage value measured using an ADC (Analog-to-Digital Converter) commonly provided in an MCU (Micro Controller Unit) 1, the residual energy of each sensor node is estimated.

FIG. 2 is a diagram showing an embodiment for measuring residual energy using an ADC. Since ADC values provided for each MCU used in each sensor node are different, the ADC pins of the MCU are connected to different resistance values (x, y) To measure the ADC value for the minimum operating power and the ADC value for the maximum operating power. In this configuration, to measure the minimum operating power and the maximum operating power, the resistance values x and y should be appropriately adjusted to the appropriate values.

The link quality information measurement unit 200 obtains link quality information using the number of times that the sensor node is selected as the cluster header and the number of retransmission times that occurs when information is transmitted to the base station. The smaller the link quality value thus obtained, the better the link quality.

The operation of the apparatus for energy saving and reliable information transmission in the wireless sensor network according to the present invention will now be described in detail with reference to the accompanying drawings. Like reference numerals in FIG. 1 or FIG. 2 denote the same members performing the same function.

3 is a flowchart illustrating a method for energy saving and reliable information transmission in a wireless sensor network according to an embodiment of the present invention.

3, the measurement of the operating voltage value is performed using an ADC (Analog-to-Digital Converter) provided by an MCU (Micro Controller Unit) used in each sensor node through the energy remaining amount estimating unit 100 And ADC values for the minimum and maximum operating power are applied to the equations shown in Equation (1) to estimate remaining energy of each sensor node (S100). In this case, sensor nodes in a wireless sensor network generally have a simple and simple structure for low power, and it is difficult to perform accurate residual energy measurement. Further, for the accurate energy measurement, additional circuits or a separate sensing chip (ADC), which is used in each sensor node, is used to calculate the operating voltage value (ADC) by using an ADC (Analog-to-Digital Converter) To estimate the energy remaining amount.

Next, the link quality is measured using the number of retransmission times information and the number of times selected by the cluster header, which occur when each sensor node included in the wireless sensor network transmits information to the base station through the link quality information measuring unit 200 S200). At this time, as shown in FIG. 5A, the retransmission number information is calculated as a retransmission ratio occurring in the relevant round, as a ratio obtained by dividing by the number of retransmissions occurring in the total number of transmissions. The number of times information selected as the cluster header is calculated as the number of times of header selection in accordance with the total operation round N as shown in FIG. 5 (b). Accordingly, the smaller the measured link quality value, the better the link quality.

As described above, each sensor node can calculate a weight value of a sensor node usable in a cluster header selection competition through a combination of the energy remaining amount and the link quality information of the sensor node itself (S300). At this time, as shown in Equation (2), the weight value (sensor node weight value) of the sensor node can be determined by combining the residual energy information of each sensor node and the link quality information to select the best cluster header node among all the sensor nodes .

In this case, w is an application weight of residual energy and link quality, it is important to set an appropriate application weight (w) value for selecting an excellent cluster header node, and the application weight value may vary depending on the characteristics of the sensor node have. Therefore, in the present invention, as the round progresses, the application weight w is set to a lower value. That is, as the round progresses, the link quality is set to be higher than the energy remaining energy. This is because, at the beginning of the round, selecting a sensor node having a large amount of residual energy as a cluster header node is effective for efficient energy management. However, as the round progresses, a sensor node having a higher link quality than remaining energy is selected as a cluster header node This is because reliable transmission of data and unnecessary retransmission can be reduced.

Then, the sensor node having the highest weight value is selected through comparison between the sensor nodes based on the weight value of the sensor node calculated by the weight calculating unit 300 through the cluster header node selecting unit 400, (S400).

Meanwhile, in order for the sensor nodes to be selected as the cluster header node, a series of processes shown in FIG. 4 is required and iteratively proceeds until the best cluster header is selected. In this case, the process of selecting the sensor nodes as the cluster header node is performed for one round. As shown in FIG. 6, the cluster header selection competition and the result are known as the setup phase and the information is collected and transmitted It can be divided into a steady process. At this time, the setup process includes a competition and an announcement, and the fixed process includes a connection and a report.

Referring to FIG. 4, when a round is started as a setup process, as shown in FIG. 7, a weight value of each sensor node calculated through a weighting calculation unit 300 in a competition period is used to calculate the weight Node A (Node B) (Node C) (S410). At this time, when the sensor nodes compare with the sensor node having a higher weight value than the sensor node, the sensor node stops the competition and maintains the sensor node state, and changes its state to the cluster header node when compared with the sensor node having the lower weight value. This is repeated until the end of the competition.

When the competition header is determined and the cluster header node (Node B) is determined, the determined cluster header node (Node B) transmits a notification operation indicating that the cluster header node is a cluster header node to the announcement section And transmits a notification message to the sensor nodes Node A (Node C) (S420). If the sensor node (Node A) receives all the notification messages from the cluster header node (Node B), the setup phase ends (S430).

As shown in FIG. 7, the sensor nodes (Node A) in the cluster may transmit a connection message including information to be transmitted by itself to its own cluster header node To the Node B (S440).

Then, the cluster header node (Node B) collects the information of the sensor nodes (Node A) (Node C) during the connection and transmits the collected information to the base station in the report period as shown in FIG. 7 And the steady process is terminated (S450).

After completion of the reporting period, the sensor node (Node B) serving as a cluster header node in this round transmits information on the number of times that the sensor node (Node B) is selected as a cluster header and information on the number of retransmissions that occurs when information is transmitted to the base station, (500), so that the link quality information measuring unit 200 can be utilized to measure the link quality in the next round (S460).

When the above-described series of processes are repeatedly performed, the same result as shown in FIG. 8 can be obtained.

8 shows an example for showing different link quality information generated when the cluster header node 20 selected for each cluster in this round transfers information to the base station 30. In this embodiment, In the case of the selected sensor nodes A and B, the result of poor link quality when transmitting information to the base station 30 in this round is shown, while at the same time, an expected sensor And a predestinator 40 are respectively present.

Accordingly, the predicted sensor node 40 has a better weight value than the cluster header node 20 selected in this round, and the likelihood of being selected as the cluster header node in the next round increases.

FIG. 9 shows an example of a phenomenon occurring in the next round when the situation shown in FIG. 8 occurs. After the sensor node A (B) having low link quality is selected as a cluster header node in FIG. 8 In the next round, the expected sensor node 40 of FIG. 8 having a good link quality through competition is selected as the cluster header node 20 to form a network as shown in FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (11)

An energy remaining amount estimating unit estimating remaining energy of each sensor node included in the wireless sensor network,
A link quality information measurement unit for measuring link quality of each sensor node;
A weight calculation unit for collecting remaining energy information and link quality information of each estimated sensor node and calculating a weight value for each sensor node through a combination of remaining energy information and link quality information of each sensor node;
A cluster header node selection unit for selecting a sensor node having the highest weight value as a cluster header node through comparison among the sensor nodes based on the calculated weight value,
And a link quality information updating unit for updating the link quality measurement result measured by the link quality information measuring unit by updating the number of times that the selected cluster header node is selected as the cluster header and the number of retransmission times when the information is transmitted to the base station And transmitting the information to the wireless sensor network. The method according to claim 1,
The energy remaining amount estimating unit estimates remaining energy of each sensor node using an operation voltage value measured using an ADC (Analog-to-Digital Converter) provided by an MCU (Micro Controller Unit) of a sensor node Device for energy saving and reliable information transmission in wireless sensor network. 3. The method of claim 2,
The estimation of the remaining energy of the sensor node

Wherein the wireless sensor network is connected to the wireless sensor network. The method according to claim 1,
Wherein the link quality information measurement unit measures link quality information using the number of times that the sensor node is selected as the cluster header and the number of retransmission times when the information is transmitted to the base station. Lt; / RTI > (A) estimating the residual energy of each sensor node included in the wireless sensor network,
(B) measuring link quality information of the sensor nodes,
(C) collecting remaining energy information and link quality information of each estimated sensor node, calculating a weight value for each sensor node through a combination of remaining energy information and link quality information of each sensor node collected,
(D) selecting a sensor node having the highest weight value as a cluster header node by comparing the sensor nodes based on the calculated weight value,
In this case, in step (B), the link quality information is obtained using the number of times that the sensor node is selected as the cluster header and the number of retransmission times when the information is transmitted to the base station. Method for delivery. delete 6. The method of claim 5,
In step (C), the weight value of the sensor node (sensor node weight value)

, ≪ / RTI >
Wherein the w is an applied weight of residual energy and link quality. ≪ Desc / Clms Page number 20 > 8. The method of claim 7,
Wherein the application weight w is set to be lower as the round progresses so that the link weight is set to be higher than the residual energy as the round progresses. Way. 6. The method of claim 5,
Wherein the step (D) is performed for one round. 10. The method of claim 9, wherein step (D)
(D1) comparing (competing) the sensor nodes with each other using the calculated weight values of the sensor nodes,
(D2) If the cluster header node is determined as a sensor node having the highest weight value in the comparison, the determined cluster header node transmits a notification message to the sensor nodes in the cluster, Wow,
(D3) receiving a connection message including information to be transmitted from sensor nodes in the cluster,
(D4) collecting information of the transmitted sensor nodes and transferring the collected information to a base station,
(D5) the number of times it is selected as the cluster header and the number of retransmission times generated when the information is transmitted to the base station, and providing the information so as to be utilized for measuring the link quality in the next round in the step (B) Wherein the wireless sensor network is a wireless sensor network. 11. The method of claim 10, wherein step (D1)
Stopping the competition and maintaining the state of the sensor node when the sensor nodes are compared with the sensor node having a weight value higher than the sensor node and changing the state of the sensor node to the cluster header node when compared with the sensor node having a weight value lower than the sensor node, A method for energy saving and reliable information transmission in a wireless sensor network.

Images