KR102301985B1 - Method for modulating and demodulating and apparatus thereof - Google Patents

Abstract

A method and apparatus for modulating and demodulating a signal in a communication system are disclosed. A reception node according to an embodiment of the present invention includes a processor, a first camera for photographing a blinking state of a first LED array (Light Emitting Diode Array) included in a transmission node under the control of the processor, and the processor. A second camera for photographing a blinking state of a second LED array included in a transmission node according to control, and one or more instructions executed by the processor are stored in a memory (memory) in which the one or more instructions are, the first Obtaining a first image through a camera, performing demodulation on the first image to obtain control information, obtaining a region of interest of the second camera based on the first image, and obtaining the region of interest of the second camera based on the region of interest acquiring a second image by using the second camera, and performing demodulation on the second image to acquire user data. Accordingly, the performance of the communication system may be improved.

Description

Signal modulation and demodulation method and apparatus

The present invention relates to a signal modulation and demodulation method and apparatus, and more particularly, to a signal modulation and demodulation method and apparatus using an optical camera communication technology.

With the development of information and communication technology, various wireless communication technologies are being developed. Visible Light Communication (VLC) may be performed using a Light Emitting Diode (LED). Visible light communication technology is standardized by Institute of Electrical and Electronics Engineers (IEEE) 802.15.7, and IEEE 802.15.7 specifies technologies of a PHY (physical) layer and a MAC (medium access control) layer. In particular, IEEE 802.15.7 specifies technologies for high-speed data transmission and reception in a Line of Sight (LoS) environment, and the technologies specified in IEEE 802.15.7 are difficult to apply to an actual communication environment.

IEEE 802.15.7m was standardized according to the need for improvement of IEEE 802.15.7. IEEE 802.15.7m defines OWC (Optical Wireless Communication) technology, OWC technology may include LiFi (Light Fidelity) technology, OCC (Optical Camera Communication) technology, and LED-ID (LED Identification) technology, etc. .

In a communication system supporting OCC (hereinafter referred to as "OCC communication system"), a transmitter may perform communication using a DSM-PSK modulation scheme, and a receiver may perform DSM-PSK modulation using a matched filter based on the circuit principle. In this way, the modulated signal can be demodulated. On the other hand, when communication is performed using the DSM-PSK modulation method, communication can be performed using only a single-color LED array, and in this case, a problem of a low data transmission/reception speed of the communication system may occur.

An object of the present invention to solve the above problems is to provide a signal modulation and demodulation method and apparatus using a CDS8-PSK (Color-based Dimmable Spatial 8-phase Shift Keying) modulation scheme.

According to an embodiment of the present invention for achieving the above object, the receiving node detects the blinking state of the first LED array (Light Emitting Diode Array) included in the transmitting node according to the control of the processor and the processor. A first camera for photographing, a second camera for photographing a blinking state of a second LED array included in a transmission node under the control of the processor, and a memory in which one or more instructions executed by the processor are stored wherein the one or more instructions include: acquiring a first image through the first camera, performing demodulation on the first image to obtain control information, and based on the first image, a region of interest of the second camera , acquiring a second image using the second camera based on the region of interest, and performing demodulation on the second image to acquire user data.

Here, the second LED array may include one or more RGB LEDs (Red Green Blue Light Emitting Diodes).

Here, the control information includes at least one of an ID (Identifier) of the transmitting node, an ID of the receiving node, an arrangement form of LEDs included in the first LED array, and an arrangement form of LEDs included in the second LED array. may include.

Here, when obtaining the control information, the one or more commands may be executed to obtain the control information by performing demodulation on the first image using a Spatial 2-Phase Shift Keying (S2-PSK) demodulation method.

Here, when acquiring the user data, the one or more commands perform demodulation on the second image using a CDS8-PSK (Color-based Dimmable Spatial 8-phase Shift Keying) demodulation scheme to acquire the user data. can be executed

According to another embodiment of the present invention for achieving the above object, a method of operating a receiving node uses a first camera to capture a blinking state of a first LED array (Light Emitting Diode array) included in a transmitting node and remove it. acquiring a first image, acquiring control information by performing demodulation on the first image, acquiring a region of interest of the second camera based on the first image, and the second camera based on the region of interest 2 It may include acquiring a second image by photographing a blinking state of a second LED array included in the transmission node using a camera, and acquiring user data by demodulating the second image.

Here, the second LED array may include one or more RGB LEDs (Red Green Blue Light Emitting Diodes).

Here, the control information includes at least one of an ID (Identifier) of the transmitting node, an ID of the receiving node, an arrangement form of LEDs included in the first LED array, and an arrangement form of LEDs included in the second LED array. may include.

Here, the acquiring of the control information may include acquiring the control information by demodulating the first image using a Spatial 2-Phase Shift Keying (S2-PSK) demodulation method.

Here, the acquiring of the user data may include acquiring the user data by demodulating the second image using a CDS8-PSK (Color-based Dimmable Spatial 8-phase Shift Keying) demodulation method. have.

According to the present invention, since communication is performed using a color LED, data transmission/reception speed between the transmitting node and the receiving node may be improved.

In addition, according to the present invention, since communication is performed using a color LED, demodulation efficiency of a receiving node can be improved.

1 is a conceptual diagram of a communication system according to an embodiment of the present invention.
2 is a block diagram of a communication node according to an embodiment of the present invention.
3 is a block diagram of a transmission module according to an embodiment of the present invention.
4 is a conceptual diagram of a second LED array according to an embodiment of the present invention.
5 is a block diagram of a receiving module according to an embodiment of the present invention.
6 is a flowchart of a data transmission/reception method according to an embodiment of the present invention.
7 and 8 are conceptual views of a second LED array blinking state according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, a communication system may be used in the same sense as a communication network (network).

1 is a conceptual diagram illustrating a first embodiment of a communication system.

Referring to FIG. 1 , a communication system may include a plurality of communication nodes 110 and 120 . The plurality of communication nodes 110 and 120 may perform communication using communication methods defined in Institute of Electrical and Electronics Engineers (IEEE) 802.15.7 (eg, IEEE 802.15.7m). For example, each of the plurality of communication nodes 110 and 120 may include a Light Emitting Diode (LED) and a camera, and may transmit a signal by blinking the LED, based on the blinking state of the LED photographed by the camera. to obtain a signal. Each of the plurality of communication nodes 110 and 120 may be a sensor node, an Internet of Things (IoT) node, a smart phone, or the like. Each of the plurality of communication nodes 110 and 120 may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may be one of the plurality of communication nodes 110 and 120 of FIG. 1 . The communication node 200 may include a processor 210 , a memory 220 , a transmission module 230 , and a reception module 240 . In addition, the communication node 200 may further include a storage device 250 and the like. Each of the components included in the communication node 200 may be connected by a bus to communicate with each other.

However, each component included in the communication node 200 may not be connected to the common bus 260 but to the processor 210 through an individual interface or an individual bus. For example, the processor 210 may be connected to at least one of the memory 220 , the transmission module 230 , the reception module 240 , and the storage device 250 through a dedicated interface.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 250 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 250 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

The transmission module 230 may include an LED array and may operate under the control of the processor 210 . The receiving module 240 may include a camera and may operate under the control of the processor 210 . The transmission module 230 may be configured as follows.

3 is a block diagram of a transmission module according to an embodiment of the present invention.

Referring to FIG. 3 , the transmission module 300 may be configured the same as or similarly to the transmission module 230 of FIG. 2 . The transmission module 300 may include a first transmission processing unit 310 , a second transmission processing unit 320 , a dimming control unit 330 , and a first LED array 340 and a second LED array 350 . have. The first transmission processing unit 310 may generate a low-speed data packet by processing the control information. The first transmission processing unit 320 may process the control information using the first modulation method. The first modulation method may be a Spatial 2-Phase Shift Keying (S2-PSK) modulation method, but this is only an example and is not limited thereto. The first transmission processing unit 310 may transmit the low-speed data packet to the dimming processing unit 330 .

The second transmission processing unit 320 may generate high-speed data by processing user data. The second transmission processing unit 320 may process user data using the second modulation method. It may be a second modulation c modulation scheme. The second transmission processing unit 320 may transmit the processed user data to the dimming processing unit 330 .

The dimming control unit 330 may receive the low-speed data packet from the first transmission processing unit 310 . The dimming controller 330 may control the first LED array 340 based on the low-speed data packet. The dimming control unit 330 may transmit control information to a receiving node (eg, the receiving node 120 of FIG. 1 ) in a manner of flickering the first LED array 340 .

The dimming control unit 330 may receive high-speed data from the second transmission processing unit 320 . The dimming controller 330 may control the second LED array 350 based on high-speed data. The dimming control unit 330 may transmit the user data to the receiving node in a manner of blinking the second LED array 350 . Meanwhile, the second LED array 350 may be configured as follows.

4 is a conceptual diagram of a second LED array according to an embodiment of the present invention.

The second LED array 400 of FIG. 4 may be configured the same as or similar to the second LED array 350 of FIG. 3 . The second LED array 400 may include a plurality of LED groups 410 and 420 , wherein the LED group includes a reference LED group 411 and a data LED group 421 , 422 , 423 , 424 , 425 . , 426, 427). That is, the second LED array 400 may include one reference LED group 411 and a plurality of data LED groups 421 , 422 , 423 , 424 , 425 , 426 , and 427 . Here, the reference LED group 411 may be an LED group to which a reference signal is transmitted, and the plurality of data LED groups 421, 422, 423, 424, 425, 426, 427 is an LED group to which a user data signal is transmitted. can be

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,

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형태로 배치될 수 있다. 한편, 수신 모듈(예를 들어, 도 2의 수신 모듈(240)은 다음과 같이 구성될 수 있다.Each of the plurality of LED groups 410 and 420 may include K LEDs. The LEDs may be Red Green Blue (RGB) LEDs, and K may be a natural number. For example, K may be 8. In the LED group, the LEDs may be arranged in an A×B shape. A may indicate the number of rows in the LED group, and B may indicate the number of columns in the LED group. For example, in a group of LEDs, the LEDs are

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can be placed in the form. Meanwhile, the receiving module (eg, the receiving module 240 of FIG. 2 ) may be configured as follows.

5 is a block diagram of a receiving module according to an embodiment of the present invention.

Referring to FIG. 5 , the reception module 500 receives a first camera 510 , a region of interest update unit 520 , a first reception processing unit 530 , a second camera 540 , and a second reception processing unit 550 . may include The first camera 510 may acquire a first image by photographing a blinking state of the first LED array (eg, the first LED array 340 of FIG. 3 ). That is, the first camera 510 may transmit the first flashing image to the ROI update unit 520 and the first reception processing unit 530 .

The region of interest updating unit 520 may receive the first blinking image from the first camera 510 . The region of interest update unit 520 may detect the region of interest of the second camera 540 based on the first blinking image. The region of interest update unit 520 may activate the second camera 540 based on the region of interest. When the second camera 540 is activated, a communication link between the transmission node (eg, the transmission node 110 of FIG. 1 ) and the reception node 120 may be activated.

The first reception processing unit 530 may receive the first image from the first camera 510 . The first reception processing unit 530 may obtain control information by processing the first image. For example, the first reception processing unit 530 may process the first image in the S2-PSK demodulation method, but this is only an example and is not limited thereto.

The second camera 540 may acquire a second image by photographing a blinking state of the second LED array (eg, the second LED array 350 of FIG. 3 ). The second camera 540 may acquire a second image by photographing the second LED array included in the ROI. The second camera 540 may transmit the second image to the second reception processing unit 550 .

The second reception processing unit 550 may receive the second image from the second camera 540 . The second reception processing unit 550 may obtain user data by processing the second image. For example, the second reception processing unit 550 may perform processing on the second image using the CDS8-PSK demodulation method, but this is only an example and is not limited thereto.

6 is a flowchart of a data transmission/reception method according to an embodiment of the present invention.

Referring to FIG. 6 , the transmitting node (eg, the transmitting node 110 of FIG. 1 ) may generate a low-speed data packet including control information ( S610 ), where the control information is described in Table 1 below. It may include one or more information elements among the information elements.

The ID may indicate the ID of the transmitting node. In addition, the ID may indicate not only the ID of the transmitting node, but also the ID of the receiving node (eg, the receiving node 120 of FIG. 1 ), which is the reception target of the low-speed data packet. The hybrid modulation indicator may be set to 1. The phase mapping table may be set as shown in Table 1.

The transmitting node may transmit the low-speed data packet to the receiving node (S620). The transmitting node may transmit the low-speed data packet to the receiving node by blinking the first LED array (eg, the first LED array 340 of FIG. 3 ). On the other hand, the receiving node may take a first image (eg, the blinking state of the first LED array) using the first camera (eg, the first camera 610 of FIG. 6 ).

The receiving node may obtain control information from the first image (S630). Here, the control information obtained by the receiving node may be control information included in the low-speed data packet or information included in Table 1. The receiving node may acquire control information by demodulating the first image. The receiving node may demodulate the first image using the S8-PSK demodulation method. The receiving node may determine whether to perform communication with the transmitting node based on the control information. That is, the receiving node detects the region of interest using the region of interest update unit (eg, the region of interest update unit 520 of FIG. 5 ), and based on the result, a second camera (eg, the second camera of FIG. 6 ) (640)) can be activated.

When the second camera is activated, a communication link between the transmitting node and the receiving node may be established ( S640 ). In this case, the receiving node may transmit a response packet including the ID and capability information of the receiving node to the transmitting node. The response data is transmitted by the first transmission processing unit (eg, the first transmission processing unit 310 of FIG. 3 ) or the second transmission processing unit (eg, the second transmission processing unit 320 of FIG. 3 ) included in the receiving node. may be transmitted to the sending node. That is, the response packet may be transmitted in the S8-PSK scheme or the CDS8-PSK scheme. The receiving node may perform an operation for photographing the blinking state of the second LED array of the transmitting node.

When the setting of the communication link between the transmitting node and the receiving node is completed, the transmitting node may generate a high-speed data packet (S650). The second transmission processing unit may receive user data. The second transmission processing unit may perform modulation on the user data to generate a high-speed data packet. The second transmission processing unit may perform modulation on the user data using the second modulation method. The second modulation scheme may be a CDS8-PSK modulation scheme. The transmitting node may transmit the high-speed data packet to the receiving node by blinking the LEDs belonging to the second LED array (ie, the reference LED group and the data LED groups) based on the methods described above ( S660 ). The transmitting node may blink the second LED array in the following way.

7 and 8 are conceptual views of a second LED array blinking state according to an embodiment of the present invention.

7 and 8 , the second LED arrays 700 and 800 may be configured the same as or similar to the second LED array 350 of FIG. 3 . The second LED arrays 700 and 800 may include a plurality of Red Green Blue (RGB) LEDs. The RGB LEDs of the second LED arrays 700 and 800 may be flickered by a command from a dimming controller (eg, the dimming controller 330 of FIG. 3 ). That is, as the RGB LEDs of the second LED arrays 700 and 800 flicker, a high-speed data packet may be transmitted to a receiving node (eg, the receiving node 120 of FIG. 1 ). When the second LED arrays 700 and 800 include RGB LEDs, a data transmission rate may be increased three times or more, and demodulation efficiency of a receiving node may be improved as compared to a case where a monochromatic ELD is included.

Referring back to FIG. 6 , the receiving node may take a second image (eg, a blinking state of the second LED array) using the second camera. The receiving node may acquire user data from the second image (S670). The receiving node may acquire user data by demodulating the second image. The receiving node may demodulate the second image by using the CDS8-PSK demodulation method.

The methods according to the invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (10)

As a receiving node in a communication system,
processor;
a first camera for photographing a blinking state of a first LED array (Light Emitting Diode Array) included in a transmitting node under the control of the processor;
a second camera for photographing a blinking state of a second LED array included in the transmitting node under the control of the processor;
and a memory in which one or more instructions executed by the processor are stored,
the one or more instructions,
acquiring a first image through the first camera;
performing demodulation on the first image to obtain control information;
acquiring a region of interest of the second camera based on the first image;
acquiring a second image using the second camera based on the region of interest; and,
Executed to obtain user data by performing demodulation on the second image,
When acquiring the user data,
The one or more instructions include:
The receiving node is executed to obtain the user data by performing demodulation on the second image using a Color-based Dimmable Spatial 8-phase Shift Keying (CDS8-PSK) demodulation scheme. The method according to claim 1,
The second LED array comprises one or more RGB LEDs (Red Green Blue Light Emitting Diodes). The method according to claim 1,
The control information includes at least one of an ID (Identifier) of the transmitting node, an ID of the receiving node, an arrangement form of LEDs included in the first LED array, and an arrangement form of LEDs included in the second LED array which, the receiving node. The method according to claim 1,
When obtaining the control information,
the one or more instructions,
and performing demodulation on the first image using a Spatial 2-Phase Shift Keying (S2-PSK) demodulation scheme to obtain the control information. delete A method of operation of a receiving node in a communication system, comprising:
obtaining a first image by photographing a blinking state of a first LED array (Light Emitting Diode array) included in a transmitting node using a first camera;
acquiring control information by demodulating the first image;
acquiring a region of interest of a second camera based on the first image;
acquiring a second image by photographing a blinking state of a second LED array included in a transmission node using the second camera based on the region of interest; and
performing demodulation on the second image to obtain user data,
The step of obtaining the user data includes:
and obtaining the user data by demodulating the second image using a color-based Dimmable Spatial 8-phase Shift Keying (CDS8-PSK) demodulation method. 7. The method of claim 6,
The second LED array includes one or more RGB LEDs (Red Green Blue Light Emitting Diodes). 7. The method of claim 6,
The control information includes at least one of an ID (Identifier) of the transmitting node, an ID of the receiving node, an arrangement form of LEDs included in the first LED array, and an arrangement form of LEDs included in the second LED array A method of operation of a receiving node. 7. The method of claim 6,
The step of obtaining the control information
and acquiring the control information by demodulating the first image using a Spatial 2-Phase Shift Keying (S2-PSK) demodulation method. delete

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