WO2018199455A1 - Underwater networking method using magnetic-field communications system - Google Patents

Abstract

The present invention relates to an underwater networking method using a magnetic-field communications system. The underwater networking method using a magnetic-field communications system comprising a plurality of mobile relay nodes and a magnetic-field communications server comprises: a step in which the magnetic-field communications server obtains location information on a transmission node, a reception node, and the plurality of mobile relay nodes; a step for selecting N (a natural number greater than or equal to 1) mobile relay nodes required for relay by using information on the distance between the transmission node and the reception node; a step for configuring the locations of the N mobile relay nodes, moving the N mobile relay nodes to the configured locations, and aligning the coil axes of the transmission node, the reception node, and the plurality of mobile relay nodes; and a step in which the transmission node transmits data to the reception node via the selected mobile relay nodes. According to the present invention, long-distance and high-speed transmission can be stably provided by adopting a waveguide transmission scheme in magnetic-field communications advantageously reducing propagation delay time and enabling the establishment of a network at lost costs. In addition, the performance of the magnetic-field communications can be improved as a result of effectively utilizing mobile relay nodes by merging location information obtained by means of a magnetic-field positioning technique and the waveguide transmission scheme.

Description

Underwater network method using magnetic field communication system

The present invention relates to an underwater network method using a magnetic field communication system, and more particularly, to an underwater network method using a magnetic field communication system that forms an underwater network through a mobile relay node in an underwater environment and provides a long-distance high-speed transmission technology. will be.

Magnetic field communication technology is a wireless communication system using a magnetic field region is a technology for transmitting information using a magnetic field generated over time in extreme environments, such as metal, underwater, underground, building collapse obstacles. Magnetic field communication technology monitors ground conditions such as ground subsidence, ground movement monitoring, leaks and damage of underground facilities such as water pipes, sewer pipes, power pipes, communication pipes, gas pipes, oil pipelines, etc. It can monitor the condition of cracks and vibrations and is suitable for next generation wireless communication system.

In particular, the magnetic field communication technology is the most suitable communication technology among the data transmission methods for the underwater network, compared with the data transmission method using optical, electromagnetic and acoustic, which are general underwater networks.

The magnetic field communication technology in the underwater environment has the advantage that the propagation speed of the magnetic field communication is faster than the propagation speed of the sound, and the propagation delay time is shortened.The magnetic field signal is not visible to the eyes like the optical signal or the ear like the acoustic signal. Because of the same characteristics, it can be used underwater for security and military purposes. In addition, magnetic induction coils can be probed into small underwater robots or submersibles that are easy to move, and are much cheaper than antennas of other underwater communication technologies, making it possible to economically construct large scale underwater sensor networks.

Underwater magnetic field communication, on the other hand, is more affected by propagation path loss than multipath fading and channel distortion. The path loss of the magnetic field communication is caused by insufficient energy from the transmitting end to the receiving end.

In other words, in order to accurately detect the phenomenon occurring in the underwater magnetic field system and to transmit a large amount of information to the control station on the ground quickly and accurately, a technique for improving the reliability of data transmission while extending the transmission distance from the transmitting end to the receiving end is required. do.

The background technology of the present invention is disclosed in Korean Patent Registration No. 10-1192414 (2012.10.17 announcement).

SUMMARY OF THE INVENTION The present invention provides an underwater network method using a magnetic field communication system that forms an underwater network through a mobile underwater sensor in an underwater environment and provides a long-distance high speed transmission technology.

According to an embodiment of the present invention for achieving the above technical problem, in the underwater network method using a magnetic field communication system including a plurality of mobile relay nodes and magnetic field communication server, the magnetic field communication server is a transmitting node, a receiving node and a plurality of Obtaining location information of a mobile relay node, selecting N mobile relay nodes (N is a natural number of 1 or more) required for relaying using distance information between the transmitting node and the receiving node, and the N mobile relay nodes Setting a position of the, moving the N mobile relay nodes to the set position, aligning coil axes of the transmitting node, the receiving node and the plurality of the mobile relay nodes, and the transmitting node through the selected mobile relay node. Transmitting data to the receiving node.

The acquiring of the position information may include positions of the plurality of mobile relay nodes using absolute position coordinates of the receiving node and the transmitting node and coil X-axis, coil Y-axis, and coil Z-axis values of the receiving node and the transmitting node. Can be obtained.

When the transmitting node performs the magnetic field communication, the magnetic field communication server receives feedback information on the strength and magnetic field distortion of the received signal between each adjacent node, and each node corrects the coil axis in consideration of the feedback information. It further comprises the step.

In the correcting of the coil axis, the coil axis of each node may be corrected using the acceleration and the rotation direction of the coil according to the flow velocity of the water in which the nodes are located.

The plurality of mobile relay nodes move to the derived position or correct the axis of the coil of each node, and then, when the current of the coil antenna is induced through the magnetic field generated from the adjacent nodes, the plurality of mobile relay nodes perform a search process on the induced current. Selects the largest signal and passes the selected largest signal to another selected mobile relay node or receiving node.

According to the present invention, it is possible to stably provide long-distance and high-speed transmission by acquiring a waveguide transmission scheme in magnetic field communication, which has an advantage of shortening propagation delay time and can build a network at low cost.

In addition, it is possible to improve the performance of the magnetic field communication by fusing the position information obtained by the waveguide transmission method and the magnetic field positioning technique to effectively use the mobile relay node.

1 is a diagram showing an underwater network structure including a mobile relay node according to an embodiment of the present invention.

2 is a view for explaining a magnetic field communication system using a mobile relay node according to an embodiment of the present invention.

3 is a flowchart illustrating an underwater network method using a magnetic field communication system according to an exemplary embodiment of the present invention.

4 is a view for explaining a three-dimensional magnetic field positioning technique according to an embodiment of the present invention.

5 is a view for explaining a magnetic field transmission method using a mobile relay node according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a coil rotation and a magnetic waveguide transmission technique of a node in a magnetic interference environment according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

Hereinafter, an underwater network of a magnetic field communication system using a mobile relay node proposed in an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

1 is a view showing an underwater network structure including a mobile relay node according to an embodiment of the present invention, Figure 2 is a view for explaining a magnetic field communication system using a mobile relay node according to an embodiment of the present invention.

As shown in FIG. 1, when underwater information is collected through a sensor in an underwater environment, the information is transmitted to a control station through a magnetic vertical link. And surface stations can share underwater information through communications with surface sinks, onshore sinks, and satellites.

That is, the magnetic field communication system according to an embodiment of the present invention accurately captures and collects information on phenomena occurring in the water, and accurately stores a large amount of data from the sensor to a surface station on the ground. In order to transmit fast and fast, it performs magnetic field communication using relay node.

In addition, in the magnetic field communication system according to an embodiment of the present invention, in selecting and arranging a mobile relay node corresponding to a distance between a transmitting node and a receiving node, in order to transmit data, the position of the mobile relay node in the water is accurately determined. High precision magnetic field positioning technology.

As shown in FIG. 2, the magnetic field communication system according to an exemplary embodiment of the present invention obtains each position of the plurality of mobile relay nodes using magnetic field positioning technology, and arranges the plurality of mobile relay nodes using the obtained position information. It performs magnetic field communication between the transmitting node, the plurality of mobile relay nodes and the receiving node.

Since the nodes in the aquatic environment are affected by water currents and changes in water temperature and water pressure, the magnetic field communication system according to the embodiment of the present invention has a strong magnetic induction in the aquatic environment in order to obtain the position information of the plurality of mobile relay nodes. A method based high precision location estimation technique is used.

That is, in the embodiment of the present invention, the magnetic field communication technology using a plurality of mobile relay nodes and the high-precision magnetic field positioning technology are organically and complementarily integrated with each other to enable long-distance high-speed transmission based on location information. We propose an underwater network method using a system.

Hereinafter, an underwater network method of a magnetic field communication system including a mobile relay node and a magnetic field communication server according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 to 5.

3 is a flowchart illustrating an underwater network method using a magnetic field communication system according to an embodiment of the present invention, and FIG. 4 is a view for explaining a 3D magnetic field positioning technique according to an embodiment of the present invention. 5 is a view for explaining a magnetic field transmission method using a mobile relay node according to an embodiment of the present invention.

First, hereinafter, the magnetic field communication server communicates with a transmitting node, a receiving node, and a mobile relay node, and each node has an ID which can be individually identified.

Here, the transmitting node and the receiving node are nodes that know absolute position information, and the mobile relay node may be attached to a mobile robot or submersible that can move, and may be represented as a separate sensor node that is free to move.

As shown in FIG. 3, the magnetic field communication server acquires location information of the transmitting node 100, the receiving node 300, and the plurality of mobile relay nodes 200 (S310).

Here, since the transmitting node 100 and the receiving node 300 are nodes having absolute position information, the magnetic field communication server uses the absolute position coordinates of the transmitting node 100 and the receiving node 300 to position the three-dimensional magnetic field. The location information of the plurality of mobile relay nodes 200 may be obtained through the technique.

That is, the magnetic field communication server acquires the positions of the plurality of mobile relay nodes using absolute position coordinates of the receiving node and the transmitting node and coil X-axis, coil Y-axis, and coil Z-axis values of the receiving node and the transmitting node.

As shown in Figure 4, the magnetic field communication server is a mobile relay through the α value of the coil X axis (Coil X), the β of the coil Y axis (Coil Y), the Y value of the coil Z axis (Coil Z) based on the absolute position coordinates. The position of the node (X _r , Y _r , Z _r ) can be obtained, and the distance d from the absolute position coordinate can be estimated.

Next, the magnetic field communication server selects N mobile relay nodes (N is one or more natural numbers) required for relaying using distance information between the transmitting node 100 and the receiving node 300 (S320).

The magnetic field communication server estimates the distance using the absolute position coordinates of the transmitting node 100 and the receiving node 300, and the number of mobile relay nodes (N) capable of performing the most efficient magnetic field communication corresponding to the estimated distance. Select. The magnetic field communication server may select N mobile relay nodes that are located closest to the transmitting node 100 and the receiving node 300 and do not perform magnetic field communication using the position information of the mobile relay node.

Next, the magnetic field communication server sets the positions of the N mobile relay nodes 200, moves the N mobile relay nodes 200 to the set position, the transmitting node 100, the receiving node 100, and the plurality of mobile nodes. Align the axes of the relay node 200 (S330).

The magnetic field communication server may set a position of the mobile relay node 200 for performing waveguide transmission (relay transmission) and move each selected mobile relay node 200 to a non-overlapping position. In this case, the magnetic field communication server may derive the positions of the N mobile relay nodes and set the derived positions so as not to cause mutual interference with other communication lines performing direct field communication.

The magnetic field communication server may align the coil axes of the transmitting node 100 and the receiving node 300 with the coil axis of the mobile relay node 200 when the mobile relay node 200 moves to the set position.

Next, the transmitting node 100 transmits data to the receiving node 300 through the selected N mobile relay nodes 200 (S340).

In this case, the transmitting node 100 converts the underwater information collected from the mounted sensors into a digital signal suitable for transmission, and modulates the converted digital signal using a technique selected according to the channel environment.

The transmitting node 100 generates a magnetic field while passing the coil antenna of the transmitting node 100 by carrying the modulated signal on an alternating current. At this time, a current is induced to the coil antenna of the mobile relay node 200 in the magnetic field region of the transmitting node 100 to transmit a modulated signal.

In addition, the plurality of mobile relay nodes 200 move to the derived position or correct the axis of the coil of each node, and when the current of the coil antenna is induced through the magnetic field generated from the adjacent nodes, the search process is performed in the induced current. The signal with the largest intensity is selected. In addition, the plurality of mobile relay nodes 200 may transmit the selected largest signal to another selected mobile relay node 200 or the receiving node 300.

Meanwhile, the magnetic field communication system may perform direct communication without selecting the mobile relay node according to the distance information between the receiving node 100 and the transmitting node 300.

That is, as shown in (a) of FIG. 5, the magnetic field communication system performs direct communication between a sensor node with a MI transceiver 100 or a root node with a MI transceiver and a connection to the above ground. 5, the magnetic field communication system uses a plurality of mobile relay nodes MI relay 200 between the transmitting node 100 and the receiving node 300 as shown in FIG. Communication can be performed.

In addition to the distance information between the transmitting node 100 and the receiving node 300, the magnetic field communication system performs direct communication between the transmitting node 100 and the receiving node 300 in consideration of a condition of the underwater environment or the mobile relay node 200. It is possible to change and set to perform the waveguide communication using.

Meanwhile, when the transmitting node 100 performs magnetic field communication, the magnetic field communication server may receive feedback information about the strength of the received signal and the magnetic field distortion between each adjacent node. In consideration of the feedback information, the transmitting node 100, the plurality of mobile relay nodes 200, and the receiving node 300 may correct the respective coil axes.

In this case, the transmitting node 100, the plurality of mobile relay nodes 200, and the receiving node 300 may correct the coil axis of each node by using the acceleration and the rotation direction of the coil according to the flow velocity of the water in which the nodes are located. have.

Hereinafter, the change in the coil axis of the node in the magnetic field interference environment will be described with reference to FIG. 6.

FIG. 6 is a diagram illustrating a coil rotation and a magnetic waveguide transmission technique of a node in a magnetic interference environment according to an exemplary embodiment of the present invention.

6 (a) is an exemplary view showing the rotation and polarization angle of the coil of the node, Figure 6 (b) is an exemplary view showing a situation in which interference caused by the change of the axis of the mobile relay node in the magnetic field interference environment.

In the underwater environment, each node of the magnetic field communication system is continuously moved and rotated by the flow of water, unlike on the ground. The rotational acceleration is proportional to the flow velocity and the direction of rotation is influenced by the flow velocity direction. When the coil antenna moves and rotates underwater, the coaxial property of the coil antenna is destroyed, and the path loss varies greatly depending on the direction of the antenna, and thus the magnetic field communication performance is severely affected.

Referring to the left figure of (a) of FIG. 6, the magnetic field direction of the transmitter node is connected to the magnetic field direction of the receiver node, so that the magnetic field communication is performed smoothly. The coil axes of the transmitter node and the receiver node are rotated so that the magnetic field direction is shifted.

FIG. 6 (b) shows a situation in which the performance of the magnetic field communication system is degraded by rotating the shaft of the coil as shown in FIG. 6 (a) in the waveguide transmission using the mobile relay node 200 (relay coil) proposed by the present invention. It is shown. Referring to FIG. 6 (b), while transmitting data from a transmitting node 100 (TX Coil) to a receiving node 300 (RX Coil) via a plurality of mobile relay nodes 200 (Relay Coil), the second and third It can be seen that the interference occurred due to the rotation of the coil axis of the mobile relay node 200 (relay coil).

In order to overcome such a situation, the magnetic field communication system according to an embodiment of the present invention performs normal magnetic field communication by correcting the coil axis of a corresponding node when the strength of a received signal decreases above a threshold or detects a situation about magnetic field distortion. Feedback information can be used to make this possible.

Thus, according to the embodiment of the present invention, it is possible to stably provide long-distance and high-speed transmission by acquiring a waveguide transmission scheme in magnetic field communication that has an advantage of shortening propagation delay time and can build a network at low cost.

In addition, it is possible to improve the performance of the magnetic field communication by fusing the position information obtained by the waveguide transmission method and the magnetic field positioning technique to effectively use the mobile relay node.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

In the underwater network method using a magnetic field communication system comprising a plurality of mobile relay nodes and a magnetic field communication server, The magnetic field communication server acquiring position information of a transmitting node, a receiving node, and a plurality of mobile relay nodes; Selecting N mobile relay nodes (N is a natural number of 1 or more) required for relaying using distance information between the transmitting node and the receiving node; Setting positions of the N mobile relay nodes, moving the N mobile relay nodes to the set positions, aligning coil axes of the transmitting node, the receiving node, and the plurality of mobile relay nodes; and Said transmitting node transmitting data to said receiving node via said selected mobile relay node. The method of claim 1, Acquiring the location information, And obtaining positions of the plurality of mobile relay nodes using absolute position coordinates of the receiving node and the transmitting node and coil X-axis, coil Y-axis, and coil Z-axis values of the receiving node and the transmitting node. The method of claim 2, When the transmitting node performs magnetic field communication, the magnetic field communication server receives feedback information on strength and magnetic field distortion of a received signal between each adjacent node, and Considering the feedback information, each node further comprises the step of correcting the coil axis. The method of claim 3, Compensating the coil axis, Underwater network method for correcting the coil axis of each node by using the acceleration and rotation direction of the coil according to the flow velocity of the water where each node is located. The method of claim 4, wherein The plurality of mobile relay nodes, After moving to the derived position or correcting the axis of the coil of each node, if the current of the coil antenna is induced through the magnetic field generated from the adjacent node, the signal with the highest intensity is selected through the search process from the induced current, An underwater network method for delivering the largest signal selected to other selected mobile relay nodes or receiving nodes.

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