KR20100131615A - System and method for advancing data reliability in buried type wireless network - Google Patents

Abstract

PURPOSE: A method and a system of wireless networking for underground laying, capable of improving data reliability, are provided to improve reliability of data through effective routing and retransmission mechanism in wireless network for collecting data in underground environment. CONSTITUTION: Each neighbor node, which did not receives a first ACK message operates a timer according to a pre-stored priority table(S51). The neighbor nodes starts retransmission by generating the timer(S53). The neighbor nodes receives a second ACK message form a sync node(S55). If the second ACK message is not receives, the last priority neighbor node restarts retransmission from a specific sensor node to the sync node(S57).

Description

System and method for advancing data reliability in buried type wireless network for underground laying

The present invention relates to sensor network routing in an underground environment. More specifically, in the event of a sensor node failing to transmit data to a sink node, the nodes around each sensor node are overheared. Accordingly, when retransmitting the sensing data from the sensor node to the sink node, the overhearing peripheral node having the highest data success rate with the sink node among the neighboring nodes other than the source node retransmits, thereby improving reliability of data transmission. And underground wireless networking system and method for undergrounding.

The sensor network is a network configured to collect information collected from various sensors wirelessly, and has been actively researched as an important technology for realizing ubiquitous computing. However, this is limited only to the ground, and research on sensor networks in the underground environment is insufficient.

In modern times, agriculture and military facilities have entered the modernization, and much progress has been made. As a result, people need to monitor not only the ground but also the underground. However, the current underground environmental sensor network is wired or sensor only system underground and the communication module is installed on the ground.

Although various protocols have been proposed for implementing routing methods in the sensor network, these are methods for transmitting and receiving data in the air. In the underground environment, radio signal attenuation is severe and fading occurs a lot. In addition, since the underground sensor node uses a limited power because the battery is limited, packet loss also occurs because the RF range of each sensor node is narrow.

Therefore, in the technical field, there is a demand for technology development that can increase the reliability of data transmission and increase the throughput according to the underground characteristics.

The technical problem of the present invention devised to improve the above problems is to provide a wireless networking system and method for laying underground for improving data reliability for efficient routing and retransmission mechanism in a wireless sensor network for data collection in the underground environment. The purpose.

Another technical problem of the present invention is to provide a wireless networking system and method for underground embedding for improving data reliability for increasing reliability and increasing throughput in an underground embedding sensor network in an underground environment where wireless communication is restricted. do.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In accordance with another aspect of the present invention, there is provided a method of undergrounding wireless networking for improving data reliability, comprising: a first step of a plurality of sensor nodes receiving a beacon message from a sink node and initializing a cost value to zero; Generating a priority table by measuring a cost value through the beacon message exchange between the plurality of sensor nodes and the plurality of sensor nodes and the sink node; A third step of wirelessly transmitting sensing data generated by detecting a situation at predetermined time intervals among the plurality of sensor nodes to the sink node; A fourth step of overhearing and storing the sensing data of a peripheral node of the specific sensor node among the plurality of sensor nodes; A fifth step of receiving a first response message indicating that the specific sensor node has received the sensing data from the sink node; And a sixth step in which each of the peripheral nodes retransmits the stored sensing data to the sink node by operating a retransmission timer according to the generated priority table when the first node fails to overhear the first response message. It may be characterized in that it comprises a.

Deleting the stored sensing data when the neighboring node, performed in the sixth step, overhears the first response message; It may be characterized in that it further comprises.

If the peripheral node, which is performed after the sixth step, does not receive the second response message according to the retransmission of the sensing data from the sink node to the neighbor node of the last priority, the specific sensor node for the sink node to the specific sensor node; Requesting retransmission of sensing data; It may be characterized in that it further comprises.

The requesting of retransmission of the sensing data for the sink node to the specific sensor node may be characterized in that the peripheral node of the last priority requests the retransmission.

In the underground embedding wireless networking system for improving data reliability according to an embodiment of the present invention, in the underground embedding wireless networking system including a plurality of sensor nodes and sink nodes, a beacon message is received from the sink node, and thus a cost value is obtained. Initializes the value to 0, generates a priority table by measuring a cost value by exchanging beacon messages between the plurality of sensor nodes, and between the plurality of sensor nodes and the sink node, and recognizes a situation every predetermined time. The plurality of sensor nodes for wirelessly transmitting the generated sensing data to the sink node; And a first response message indicating that the sensing data is received by receiving the sensing data from a specific sensor node among the plurality of sensor nodes, wherein a peripheral node of a specific sensor node among the plurality of sensor nodes receives the first response message. A sink node configured to receive the retransmitted sensing data and to transmit a second response message when retransmitting the stored sensing data because the overhearing is not performed; It may be characterized in that it comprises a.

The peripheral node may delete the stored sensing data when the first response message is overheared.

If the peripheral node has not received the second response message according to the retransmission of the sensing data from the sink node to the peripheral node of the last priority, requesting the specific sensor node to retransmit the sensing data for the sink node; It can be characterized.

The peripheral node requesting retransmission of the sensing data for the sink node to the specific sensor node may be a peripheral node of a last priority in the list of the priority table.

Underground buried wireless networking system and method for improving data reliability according to the present invention provides an effect that can improve the data reliability through the efficient routing and retransmission mechanism in the wireless sensor network for data collection in the underground environment.

In addition, the present invention provides an effect of improving data reliability for increasing reliability and increasing throughput in an underground buried sensor network in an underground environment where wireless communication is restricted.

In addition, according to the present invention, by reducing the number of retransmissions in the underground wireless sensor network provides an effect that can also build a system for low power.

In addition, according to the present invention, it is possible to monitor a wide and deep underground environment for a long time, bringing the performance improvement of the sensor node and the wireless sensor network as a whole, and contribute to the development of the underground wireless sensor network which is very important in ubiquitous computing. To provide.

Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted when it is deemed that they may unnecessarily obscure the subject matter of the present invention.

In the present specification, when one component 'transmits' data or a signal to another component, any one component may directly transmit data or a signal to another component, and at least one other component. This means that data or signals can be transmitted to other components through.

1 is a view showing a wireless networking system for laying underground for improving data reliability according to an embodiment of the present invention. Referring to FIG. 1, the underground networking wireless networking system for improving data reliability includes a plurality of sensor nodes 10 and sink nodes 20. On the other hand, the underground networking wireless networking system for improving data reliability uses a so-called Underground Opportunistic Routing (UnOR) method for effective routing in the buried underground environment.

First, each of the sensor nodes 10 distributed in the basement basically enters their respective operating states, senses the underground environment, and transmits the state of the sensing area to the sink node 20 through the communication network at a predetermined time. The data transmitted in this way can be delivered to other extended networks through the expansion gateway.

The plurality of sensor nodes 10 (A, B, C, and D) initialize the cost value Cost to 0 according to the beacon message broadcast from the sink node 20.

Each of the plurality of sensor nodes 10 (A, B, C, D) and the sink node 20 having received the initial beacon message measures the cost value through the exchange of beacon messages, and the measured Each priority table is created based on the cost data.

Among the plurality of sensor nodes 10, a specific sensor node 10 (C) recognizes a situation every predetermined time and wirelessly transmits sensing data to the sink node 20.

At this time, the peripheral nodes (eg, 10: B, D) of the specific sensor node 10 (C) overhear the sensing data in the wireless communication and store the overheard sensing data in a buffer.

Thereafter, each of the peripheral nodes 10 (B, D) of the specific sensor node 10 (C) may also have a first response message (1st ACK Message) transmitted from the sink node 20 to the specific sensor node 10 (C). When overhearing, the overhearing sensing data stored in the buffer is deleted.

Accordingly, when the peripheral nodes 10 (B, D) of the specific sensor node 10 (C) do not overhear the first response message (1st ACK Messgae), a retransmission mechanism is generated.

That is, when overhearing the first response message (1st ACK Messgae), the peripheral nodes 10 (B, D) of the specific sensor node (10: C) are priorities generated according to the cost value (Cost) measurement. Start the retransmission timer according to the table. For example, a retransmission timer of 10 ms when the priority is 1, 20 ms when the priority is 2, 30 ms when the priority is 3, and 40 ms when the priority is 4 may be preset.

Accordingly, the sensing data stored in the buffers of the peripheral nodes 10 (B, D) are sink nodes in order of the higher priority among the peripheral nodes 10 (B, D) of the specific sensor node 10 (C). Retransmission proceeds to (20).

Each peripheral node 10 (B, D) receives a second response message (2nd ACK Message) from the sink node 20.

If each of the neighbor nodes 10, B and D has retransmitted to the last priority node, but the second response message (2nd ACK message) is not received, the neighbor node as the last priority sink node first sensing data. By requesting retransmission to the specific sensor node 10 (C) transmitted to (20), the retransmission is resumed from the sink node 20 which is a conventional scheme.

2 is a flowchart illustrating a process of measuring a cost value through a beacon message in a wireless networking method for improving data reliability according to an embodiment of the present invention. 3 is a view showing a beacon message formation according to an embodiment of the present invention. 4 is a diagram illustrating a cost value Cost measured according to an exemplary embodiment of the present invention. FIG. 5 is a diagram illustrating the cost value of FIG. 4 as an ETX value.

1 to 5, a plurality of sensor nodes 10 (A, B, C, and D) receive a beacon message from the sink node 20 (S31). That is, the sink node 20 broadcasts 203 every predetermined time period by initializing the cost value Cost to 0 in the beacon message. That is, step S31 is a step in which the sink node 20 initializes the cost value Cost by flooding the beacon message.

In one embodiment of the present invention, the cost value may be formed of an ETX, LQI, RSSI value. Meanwhile, sensor nodes that do not receive the first beacon message from the sink node 20 are also initialized (eg, 0xFFFF).

After step S31, the plurality of sensor nodes 10, A, B, C, and D and the sink node 20 measure a cost value Cost through exchange of beacon messages with each other (S33). Referring to FIG. 3 in more detail, the sensor nodes 10 A, B, C, and D that have received the beacon message 203 from the sink node 20 are link cost values between the sink node 20 and themselves. The value of Cost is measured and broadcasted to its neighboring nodes again by including the cost value Cost measured in the beacon message.

After step S33, the plurality of sensor nodes 10: A, B, C, and D generate a priority table at step S35. That is, each of the sensor nodes 10 A, B, C, and D receives a beacon message from the sink node 20, and includes a plurality of sensor nodes 10 A, B, including the sink node 20 and itself. After measuring the link cost value (Cost) value with C, D) and adding the cost value (Cost) value included in the beacon message, the priority table (see 301, 302 in the sensor node (C) of FIG. 5) is added. Save it. That is, each sensor node 10 (A, B, C, D) makes a priority table (301, 302) by comparing cost values (Cost) values of links (eg, 303, 304 in FIG. 5) passing through surrounding nodes. Will be. Referring to FIG. 4, a more detailed example is taken from the perspective of sensor node C, where the routing paths of <0-B-C> have a lower cost value than the routing paths of <0-D-C> and thus have a higher priority. high. Therefore, the sensor node B among the peripheral nodes of the sensor node 10 (C) becomes a priority in the priority table compared to the sensor node D.

6 is a flowchart illustrating a process of overhearing by neighboring nodes in a wireless networking method for improving data reliability according to an embodiment of the present invention. 1 to 5, the specific sensor node 10 (C) recognizes a situation at each predetermined time to the sink node 201 and wirelessly transmits sensing data (S41).

According to the transmission of step S41, other sensor nodes 10 (A, C, D) around the wireless communication characteristic overhear the corresponding sensing data and store (S43).

After step S43, when the sink node 20 wirelessly transmits a first response message (1st ACK message) indicating that the sensing data has been received, the specific sensor node 10 (C), the specific sensor node 10 (C). Receives a first response message (1st ACK Message) (S45).

At this time, the peripheral nodes 10 (A, B, D) of the specific sensor node 10 (C) are the first response message (ACK Message) of the sensing data transmitted from the sink node 20 to the specific sensor node 10 (C). ) Is also overheared to delete the sensing data stored in the buffer (S47).

Referring to FIG. 3, the sensor node 10 (C), which is the source node, transfers data to the sink node 20, and the sensor nodes 10 (B, D) around the sensing data are overhearing ( Overhearing) to save.

In this case, each node 10 (B, D) stores the sensing data of the sensor node 10 (C) in a buffer, and is transmitted from the sink node 20 to the sensor node 10 (C) as the source node. It waits for a 1st ACK message. When the first response message (1st ACK message) is normally delivered, the sensor nodes 10 (B, D) are overheared and the specific sensor node 10 (C), which is a source node, is transmitted to the sink node 20. Delete one sensing data from the buffer.

7 is a flowchart illustrating a process of retransmission by neighboring nodes in a wireless networking method for improving data reliability according to an embodiment of the present invention. That is, when the sensing data sensed from the sensor node 10 (C) that is the source node in FIG. 6 is not transmitted to the sink node 20, the retransmission mechanism is generated by the peripheral nodes 10 (B, D). It is a figure for demonstrating.

1 to 7, as in step S47 of FIG. 5, peripheral nodes 10 (B and D) of a specific sensor node C, which is a source node, may overhear the sensing data to buffer the buffer. Store, and when the sink node 20 fails to overhear due to a loss of the first response message (1st ACK message) transmitted to the source node 10 (C), the source node 10 (C). The peripheral nodes 10 of B and D retransmit the sensing data to the sink node 20 according to their retransmission priority list through the priority table generated by measuring the sensing data in the buffer in advance.

Therefore, when the specific sensor node 10 (C) does not receive the first response message (1st ACK message) from the sink node 20, the peripheral nodes (10, B, D) overhearing it are previously stored. The retransmission timer according to the priority is operated using the retransmission timer according to the priority table (S51).

After step S51, the peripheral nodes 10 (C, D) start retransmission due to the generation of an activated timer (S53).

After step S53, each of the peripheral nodes 10 (C and D) receives a second response message (2st ACK Message) for step S53 from the sink node 20 (S55).

If each of the peripheral nodes 10 (C, D) has retransmitted to the last priority node, but the second response message (2nd ACK Message) is not received, the peripheral node (10: D) of the last priority is the source By requesting retransmission to the specific sensor node 10 which is a node, retransmission is resumed from the specific sensor node 10 which is a source node to the sink node 20 (S57).

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (eg, transmission over the Internet). It also includes.

The computer readable recording medium can also be injected onto a networked computer system so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

Although the contents of the present invention have been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art may realize various modifications and other equivalent embodiments therefrom. I will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Underground wireless networking system and method for improving data reliability of the present invention, to improve the data reliability for efficient routing and retransmission mechanism in the wireless sensor network for data collection in the underground environment, and to increase the data throughput Technology can be provided.

1 is a view showing a wireless networking system for laying underground for improving data reliability according to an embodiment of the present invention.

2 is a flowchart illustrating a process of measuring a cost value through a beacon message in a wireless networking method for improving data reliability according to an embodiment of the present invention.

3 is a view showing a beacon message formation according to an embodiment of the present invention.

4 is a view showing a cost value measured according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating the cost value of FIG. 4 as an ETX value.

6 is a flowchart illustrating a process of overhearing by neighboring nodes in a wireless networking method for improving data reliability according to an embodiment of the present invention.

7 is a flowchart illustrating a process of retransmission by neighboring nodes in a wireless networking method for improving data reliability according to an embodiment of the present invention.

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

10: sensor node

20: sink node

Claims (8)

A first step of a plurality of sensor nodes receiving a beacon message from the sink node and initializing the cost value to zero; Generating a priority table by measuring a cost value through the beacon message exchange between the plurality of sensor nodes and the plurality of sensor nodes and the sink node; A third step of wirelessly transmitting sensing data generated by detecting a situation at predetermined time intervals among the plurality of sensor nodes to the sink node; A fourth step of overhearing and storing the sensing data of a peripheral node of the specific sensor node among the plurality of sensor nodes; A fifth step of receiving a first response message indicating that the specific sensor node has received the sensing data from the sink node; And A sixth step in which each of the peripheral nodes retransmits the stored sensing data to the sink node by operating a retransmission timer according to the generated priority table when the first node fails to overhear the first response message; Underground embedding wireless networking method for improving the data reliability comprising a. The method according to claim 1, which is carried out in the sixth step, Deleting the stored sensing data when the peripheral node overhears the first response message; Underground buried wireless networking method for improving data reliability further comprising a.  The method of claim 2, wherein the step is performed after the sixth step, Requesting retransmission of the sensing data for the sink node to the specific sensor node when the peripheral node has not received the second response message according to the retransmission of the sensing data from the sink node to the peripheral node of the last priority; Underground buried wireless networking method for improving data reliability further comprising a. The method of claim 3, wherein requesting retransmission of the sensing data for the sink node to the specific sensor node comprises: And the neighbor node of the last priority requesting the retransmission. In the underground embedding wireless networking system composed of a plurality of sensor nodes and sink nodes, Receiving a beacon message from the sink node, initializes the cost value to 0, measures the cost value by exchanging beacon messages between the plurality of sensor nodes, the plurality of sensor nodes and the sink node, and sets a priority table. A plurality of sensor nodes which generate and wirelessly transmit sensing data generated by sensing a situation at predetermined time intervals to the sink node; And Receiving the sensing data from a specific sensor node of the plurality of sensor nodes and transmits a first response message indicating that the sensing data has been received, the peripheral node of a specific sensor node of the plurality of sensor nodes to the first response message A sink node configured to receive the retransmitted sensing data and to transmit a second response message when the stored sensing data is retransmitted due to overhearing; Underground buried wireless networking system for improving the data reliability, comprising a. The method of claim 5, wherein the peripheral node, Underground wireless networking system for improving the data reliability, characterized in that for overhearing the first response message, the stored sensing data is deleted. The method of claim 6, wherein the peripheral node, If the second response message according to the retransmission of the sensing data from the sink node has not received until the neighboring node of the last priority, the specific sensor node to request the retransmission of the sensing data for the sink node, characterized in that the data Underground buried wireless networking system for improved reliability. The method of claim 7, wherein the peripheral node for requesting retransmission of the sensing data for the sink node to the specific sensor node, And a neighboring node having a last priority among the list of the priority table.

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