KR102226408B1 - Apparatus for Wireless Communication in Underwater and Driving Method Thereof - Google Patents

Abstract

The present invention relates to an underwater wireless communication device which promotes communication stability, and a driving method of the device. According to an embodiment of the present invention, the underwater wireless communication device comprises: a first encoder linearly encoding a received information bit; a demultiplexer dividing the linearly encoded information bit to generate soft information bits of a specified length with a short code length so as to output the same to multiple channels; and a second encoder performing learning on the soft information bits provided through the multiple channels, respectively, and transmitting the same to an external communication device in the water.

Description

Underwater wireless communication device and its driving method {Apparatus for Wireless Communication in Underwater and Driving Method Thereof}

The present invention relates to an underwater wireless communication device and a method of driving the device, and more particularly, in a situation where channel information is insufficient or through a learning base and linear coding in underwater communication, an underwater wireless communication device and device thereof are intended to promote stability of communication. It relates to the driving method of.

Since the sea is a treasure trove of natural resources and an unexplored field of humanity, research on marine development has been conducted for a long time. Underwater exploration robots have been researched and developed to collect deep-sea mineral resources, and underwater wireless communication has been researched to control them efficiently. In addition, as interest in marine development and disaster prevention systems has recently increased, studies related to underwater sensor networks are actively underway, and the need for a high-speed, low-cost, low-power underwater ultrasonic communication modem to efficiently manage multiple nodes is increasing. .

In general, an underwater radio channel has a property of scattering and absorbing radio waves, so it cannot communicate using radio frequencies that are widely used on the ground, and must communicate using ultrasonic waves. However, ultrasound has a feature of a low data transmission rate due to a large time delay due to a low transmission speed and a narrow bandwidth.

For the above reasons, there is an urgent need for a method capable of stably performing communication in an underwater environment, for example.

Korean Patent Publication No. 10-2007-0007462 (2007.01.16) Korean Patent Publication No. 10-2012-0062587 (2012.06.14) Korean Patent Application Publication No. 10-2019-0062920 (2019.06.07) Korean Registered Patent Publication No. 10-0885265 (2009.02.17) Korean Registered Patent Publication No. 10-1004364 (2010.12.21) Korean Registered Patent Publication No. 10-1000972 (2010.12.07) Korean Registered Patent Publication No. 10-1377205 (2014.03.17) Korean Registered Patent Publication No. 10-1497805 (2015.02.24)

An object of the present invention is to provide an underwater wireless communication device and a driving method of the device to achieve stability of communication through learning-based and linear coding in a situation where channel information is insufficient or underwater communication.

In an underwater wireless communication device according to an embodiment of the present invention, a first encoding unit that linearly encodes a received information bit, divides the linearly encoded information bit, and generates soft information bits of a designated length having a short code length. And a demultiplexer that outputs each of a plurality of channels, and a second encoding unit that performs learning on each soft information bit provided through the plurality of channels and then transmits each of them underwater to an external communication device.

The second encoder may modulate each soft information bit of the plurality of channels and transmit it underwater.

The underwater wireless communication apparatus may further include a decoder for decoding the linearly encoded information bits based on the soft information bits.

The decoder includes a first decoding unit that decodes each soft information bit after demodulating the modulated soft information bit, a multiplexer that muxes each of the decoded soft information bits, and linearly decodes the muxed soft information bit. Thus, it may include a second decoding unit for restoring the information bit.

In addition, the driving method of an underwater wireless communication device according to an embodiment of the present invention includes the steps of linearly encoding received information bits in a first encoding unit, and a demultiplexer divides the linearly encoded information bits to designate a short code length. The step of generating soft information bits of length and outputting them to a plurality of channels, and the second encoding unit learns each of the soft information bits provided through the plurality of channels, and then transmits them to an external communication device from underwater. It includes the step of.

The transmitting may include modulating each soft information bit of the plurality of channels and transmitting it underwater.

The driving method may further include decoding, by a decoder, the linearly encoded information bits based on the soft information bits.

The driving method includes the steps of: decoding each soft information bit after demodulating the modulated soft information bit by a first decoding unit of the decoder, and muxing each decoded soft information bit by a multiplexer of the decoder. And restoring the information bits by linearly decoding the muxed soft information bits by a second decoding unit of the decoder.

According to an embodiment of the present invention, for example, in a learning-based communication system, an autoencoder may cause a problem in which channel information is inaccurate or a code length is short in underwater communication. You will be able to perform stable communication.

1 is an exemplary diagram of an underwater wireless communication network system according to an embodiment of the present invention;
2 is a block diagram illustrating a detailed structure of an underwater wireless communication device according to an embodiment of the present invention;
3 is a diagram showing the main functions of the encoder and decoder of FIG. 2, and
4 is a flowchart illustrating a driving process of an underwater wireless communication device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is an exemplary diagram of an underwater wireless communication network system according to an embodiment of the present invention.

1, the underwater wireless communication network system 90 according to the embodiment of the present invention is an underwater wireless communication sensor network system, for example, a first communication device 100, a plurality of underwater sensors 105, the first It includes a part or all of the 2 communication device 110, the third communication device 120, and the control device 130, and may further include a satellite navigation system (GPS).

Here, "including some or all" means that some components such as the underwater sensor 105 or GPS are omitted so that the underwater wireless communication network system 90 is configured, or a partial configuration such as the first communication device 100 It means that the element is integrated and configured with other components such as the second communication device 110 to perform direct (eg, P2P) communication with the underwater sensor 105, and helps a sufficient understanding of the invention. It will be described as including all for this purpose.

The first communication device 100 may include a data sink (or data sink node) provided in water such as a sea according to an embodiment of the present invention. Of course, the first communication device 100 may include an underwater robot for underwater exploration. The first communication device 100 of FIG. 1 performs communication (eg, ultrasonic communication) with a plurality of underwater sensors 105 located at a specified distance (eg, within a communication radius) around it to perform various sensing related to ocean conditions. The data may be collected and the collected data may be transmitted to the second communication device 110.

In addition, the first communication device 100 may communicate with the second communication device 110 and operate according to a control command from the second communication device 110. Of course, it can be seen that the second communication device 110 performs an operation of transmitting a control command of the control device 130. When the second communication device 110 is provided on the ship, it will be able to provide a control command by itself. For example, the first communication device 100 operates in accordance with a control command of the control device 130 to collect various information required by the control device 130 from a plurality of underwater sensors 105 located nearby. Can provide.

The second communication device 110 may be installed on a buoy or a ship, and operates as a gateway. The second communication device 110 operates as a kind of relay device. The second communication device 110 transmits the sensing data of the underwater sensors 105 provided by the first communication device 100 to the third communication device 120. The second communication device 110 performs underwater wireless communication (eg, ultrasonic communication) or wired communication with the first communication device 100, but the third communication device 120 performs general radio frequency (RF) communication. I can.

The third communication device 120 includes a communication device such as a radar that relays the second communication device 110 and the control device 130. The third communication device 120 receives data transmitted from the second communication device 110, that is, an information bit, and provides it to the control device 130. In addition, the third communication device 120 receives the control command from the control device 130 and transmits it to the second communication device 110. Of course, the corresponding control command is a signal for providing to the first communication device 100. In general, communication includes data in a packet and transmits packet data, and it can be considered that all data is composed of binary bit information. Accordingly, bit information or information bits may mean data.

The GPS may perform communication with the second communication device 110 or the third communication device 120. When communication between the second communication device 110 and the third communication device 120 is not smooth, a satellite navigation device may be utilized. In addition, the satellite navigation device may be utilized to acquire location information of the second communication device 110. When there is a movement of a buoy or a ship, it may be possible to accurately measure the location of the second communication device 110 through triangulation, typically.

In practice, the underwater wireless communication network system 90 of FIG. 1 is linked to a plurality of second communication devices 110, a plurality of first communication devices 100, and the plurality of first communication devices 100, respectively. It consists of a number of underwater sensors 105 that operate. Through this, it can be seen that monitoring related to the underwater environment becomes possible.

FIG. 2 is a block diagram illustrating a detailed structure of an underwater wireless communication device according to an embodiment of the present invention, and FIG. 3 is a view showing main functions of the encoder and decoder of FIG. 2.

2 and 3, the underwater wireless communication device 190 according to the embodiment of the present invention is, for example, an underwater wireless communication modem, and includes a first transmission/reception device and a second transmission/reception device, where the first transmission/reception The device may include the encoder 200 of FIG. 2, and the second transmission/reception device may include the decoder 210 of FIG. 2. Of course, since all communication devices perform both encoding, that is, encoding and decoding, that is, decoding in one device, it is desirable to consider that an encoder and a decoder are provided together.

For convenience of explanation, in FIGS. 2 and 3, it is assumed that a transmitting device including an encoder 200 and a receiving device including the decoder 210 perform communication with an underwater fading channel interposed therebetween. In practice, as can be seen in FIG. 1, many communication devices 100, 110, and 120 transmit signals and perform an operation of receiving signals together, and are sometimes referred to as transceivers in this sense. . In the embodiments of the present invention, there will be no particular limitation on the use of such terms.

In addition, most of the communication devices 100, 110, and 120 tend to include both an encoder and a decoder in one device. In addition, in order to check whether encoding is properly performed during encoding, that is, encoding is performed, a decoder having the same specificity as that of the decoder of the receiving device is provided in the encoding device to determine whether or not there is an abnormality in encoding. Accordingly, in Figs. 2 and 3, since an underwater channel is interposed, it is assumed that an encoder and a decoder are provided in communication devices located in different places. For example, as shown in FIG. 1, when the first communication device 100 and the second communication device 110 perform underwater wireless communication, the encoder 200 is connected to the first communication device 100 and the decoder 210 ) Can be seen as being provided in the second communication device 110.

The encoder 200 of FIG. 2 is, for example, a learning-based autoencoder and may include some or all of the first encoder 201, the demultiplexer 203, and the second encoder 205. Here, "including some or all" may be considered to mean something that is configured by hardware and software, and a combination thereof, but may be configured by integrating some or all of them. For example, as the demultiplexer 203, an IC device in which a logic circuit is integrated, that is, hardware may be used.

For example, the encoder 200 according to an embodiment of the present invention constituting a magnetic encoder may have a configuration of machine learning (eg, DNN) and power normalization by receiving transmission bits, and may be applied to a wireless fading channel. have. The decoding end receives fading information and a received signal, and the decoding end of the magnetic encoder is configured with DNN, and the output executes (or outputs) a bitwise softmax. Here, "bitwise" refers to an operation processing in units of bits, and "softmax" may be a kind of program. Argmax may correspond to an encoding method in which only one value is true and all others are false. The soft Argmax function representing machine learning, that is, Softmax, is also called a Normalized Exponential Function, and standardization is performed through the ratio of relative values. However, the effect is amplified by expanding the maximum value to the maximum.

More specifically, the magnetic encoder divides the communication structure into an outer code and an inner code according to an embodiment of the present invention. For the outer code, a long linear code (eg LDPC, Turbo, polar code) is used. In addition, the inner code performs a short code by considering the outer code as an information bit, and modulation may be performed together with it. Based on this, the encoder may include a modulator. The output of the internal code becomes soft information. Here, "soft information" may mean information in a unit of dividing a long linear code into a plurality of channels. In addition, for example, a decoder or a decoder of an encoder may perform external code decoding based on soft information of the internal code.

The first encoder 201 of FIG. 2 includes a linear coder such as Turbo, Low Density Parity Check Code (LDPC), or Polar. The input information bits are linearly encoded and output. Since encoding is a process of compressing data, a linear code means a tissue code in which a checkpoint is determined as a linear function of an information point. It forms a subspace of the vector space of the finite field. Linear signs form a bunch of vector additions. Codes that form a group in this way are called group codes, and codes other than linear codes are called nonlinear codes. The first encoder 201 is a learning-based communication system and may compensate for a situation in which channel information is inaccurate or a shortcoming of a short code length in underwater communication.

The demultiplexer 203 separates bit information linearly encoded by the first encoder 201 into a plurality of channels. That is, it splits. According to an embodiment of the present invention, the demultiplexer 203 may divide one input channel into 4 to n channels. Here, n may mean an integer greater than 4. Of course, the demultiplexer 203 may be composed of an IC integrated device, but is composed of a combination of logic circuits.

The second encoder 205 performs machine learning (eg, DNN)-based encoding. For example, after collecting input encoding information, forming big data in a separate memory or registry, etc., it can be used for learning. The second encoder 205 may be referred to as an inner code in an embodiment of the present invention to distinguish it from the first encoder 201, and may be used as a short code and a modulator by considering the outer code as an information bit. Here, modulation means a signal processing operation for carrying a short code, that is, an information bit, on a carrier wave and transmitting it underwater, that is, a fading channel.

Meanwhile, the decoder 210 of FIG. 2 includes some or all of the first decoder 211, the multiplexer 213, and the second decoder 215, where "including some or all" means It is the same as the previous meaning.

The first decoder 211 receives bit information from a transmission device including, for example, the decoder 200 of FIG. 2 via an underwater channel. More precisely, it receives modulated bit information (or information bits). The first decoder 211 may execute a program for outputting soft information, for example, as shown in FIG. 3. For example, the second encoder 205 of FIG. 2 performs an inverse operation or an inverse function operation for machine learning, and of course, for this purpose, the first decoder 211 may execute a softmax. Each of the soft information (LLR) is output.

The multiplexer 213 merges soft information input through a plurality of channels, forms a single channel, and outputs it. The multiplexer 213 performs the reverse operation of the demultiplexer 203.

In addition, the second decoder 215 performs an inverse function, that is, an inverse operation, with respect to the operation of the first encoder 201, and accordingly, all information bits of the form input to the first encoder 201 of the encoder 200 are stored. It can be restored.

As a result of the above configuration, the embodiment of the present invention performs learning-based communication in order to increase the accuracy of the encoding. However, due to the nature of underwater communication, the learning-based communication system may cause a problem that the code length is shortened. It will be possible to perform stable underwater wireless communication by complementing it.

4 is a flowchart illustrating a driving process of an underwater wireless communication device according to an embodiment of the present invention.

For convenience of explanation, referring to FIG. 4 together with FIGS. 1 and 2, the underwater wireless communication apparatus 190 according to an embodiment of the present invention linearly encodes information bits received from the outside (S400). Here, the information bits include various types of data. For example, the sensing data is one of various types of data according to an embodiment of the present invention. In addition, when there is underwater photographing, the photographed image may be image data. Since such data is processed as binary bit information, for example, the information bit can be considered to mean this.

In addition, the underwater wireless communication apparatus 190 generates the linearly encoded information bits as soft information bits of a designated length having a short code length through the demultiplexer 203 and outputs them through a plurality of channels (S410). Here, the soft information bit may mean a state in which the linearly coded information bit is divided into a predetermined length, which may be determined according to fading information of an underwater fading channel. That is, it can be determined according to the underwater environment.

Further, the underwater wireless communication device 190 learns each soft information bit provided through a plurality of channels, and then transmits each (divided soft information bit) to an external communication device underwater (S420). In this process, a modulation operation may be further performed. The transmit power can be kept constant.

In an embodiment of the present invention, if the underwater wireless communication device 190 is, for example, the first communication device 100 of FIG. 1, the external communication device may be the second communication device 110, and the underwater wireless communication device 190 is If the second communication device 110 of FIG. 1, the external communication device may be the first communication device 100.

Furthermore, the underwater wireless communication device 190 according to an embodiment of the present invention may further perform a decoding operation in addition to the encoding operation described so far. Of course, due to the nature of the communication device, the underwater wireless communication device 190 may only perform a decoding operation. It is well known to those skilled in the field of codec that most devices may have an encoder and a decoder together.

Except for these details, the details related to the underwater wireless communication device 190 of FIG. 4 have been sufficiently described above, and thus, the contents will be substituted.

On the other hand, even if all components constituting an embodiment of the present invention are described as being combined into one or operating in combination, the present invention is not necessarily limited to this embodiment. That is, within the scope of the object of the present invention, all the constituent elements may be selectively combined and operated in one or more. In addition, although all of the components may be implemented as one independent hardware, a program module that performs some or all functions combined in one or more hardware by selectively combining some or all of the components. It may be implemented as a computer program having Codes and code segments constituting the computer program may be easily inferred by those skilled in the art of the present invention. Such a computer program is stored in a non-transitory computer readable media that can be read by a computer and is read and executed by a computer, thereby implementing an embodiment of the present invention.

Here, the non-transitory readable recording medium is not a medium that stores data for a short moment, such as a register, cache, memory, etc., but a medium that stores data semi-permanently and can be read by a device. . Specifically, the above-described programs may be provided by being stored in a non-transitory readable recording medium such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, or the like.

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and is generally used in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications may be made by those skilled in the art, and these modifications should not be understood individually from the technical idea or perspective of the present invention.

100: first communication device 105: underwater sensor
110: second communication device 120: third communication device
130: control device 200: encoder
201: first encoder (or external encoder) 203: demultiplexer
205: second encoder (or internal encoder) 210: decoder
211: first decoder (or internal decoder) 213: multiplexer
215: second decoder (or external decoder)

Claims (8)

A first communication device provided underwater and performing communication with a plurality of underwater sensors located within a communication radius to collect various sensing data related to an ocean condition;
A second communication device for receiving data collected by the first communication device and transmitting the data to a third communication device; And
And a control device for providing a control command to the first, second, and third communication devices,
The first communication device,
A first encoder that linearly encodes the received information bits;
A demultiplexer for dividing the linearly encoded information bits, generating soft information bits having a short code length, and outputting them to a plurality of channels, respectively; And
A second encoding unit that performs learning on each soft information bit provided through the plurality of channels and transmits each of the soft information bits underwater to the second communication device, and modulates and transmits each soft information bit of the plurality of channels; Including,
The second communication device,
Includes; a decoder for decoding the linearly coded information bit based on the soft information bit,
The decoder,
A first decoding unit for decoding each soft information bit after demodulating the modulated soft information bit;
A multiplexer for muxing each of the decoded soft information bits; And
And a second decoding unit that linearly decodes the muxed soft information bits to restore the information bits. delete delete delete Linearly encoding the received information bits by a first encoder;
Generating, by a demultiplexer, the linearly encoded information bits, generating soft information bits having a short code length and outputting them to a plurality of channels, respectively; And
A second encoding unit, after learning the soft information bits each provided through the plurality of channels, transmits them respectively to an external communication device underwater, and modulates each soft information bit of the plurality of channels and transmits them underwater ;
Including, by a decoder, decoding the linearly coded information bit based on the soft information bit,
Demodulating the modulated soft information bit and then decoding each soft information bit by a first decoding unit of the decoder;
Muxing, by the multiplexer of the decoder, each of the decoded soft information bits; And
Restoring the information bits by linearly decoding the muxed soft information bits by a second decoding unit of the decoder;
Driving method of an underwater wireless communication device comprising. delete delete delete

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