KR20130007391A - Visible light communication apparatus capable of minute dimming control and method using the same - Google Patents

Abstract

PURPOSE: A visible light wireless communication apparatus and a visible light wireless communication method are provided to combine VPPM(Variable Pulse Position Modulation) dimming signals which controls brightness and to perform dimming control. CONSTITUTION: A dimming level determining unit(410) determines dimming level variable for controlling minute brightness. A brightness symbol selecting unit(420) selects a high brightness symbol and low brightness symbol between VPPM symbols based on the dimming level variable. A transmission frequency calculation unit(430) determines transmission frequency based on a high brightness symbol and a low brightness symbol. A signal generator(440) assembles the high brightness symbol and the low brightness symbol based on the number of transmission. [Reference numerals] (410) Dimming level determining unit; (420) Brightness symbol selecting unit; (430) Transmission frequency calculation unit; (440) Signal generator

Description

Visible light communication apparatus supporting fine brightness control and visible light wireless communication method using the same {Visible light communication apparatus capable of minute dimming control and method using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visible light wireless communication device and a brightness control technology thereof, and more particularly, to a visible light wireless communication device that can be finely adjusted by applying brightness to a variable pulse position modulation (VPMPM) modulation mode and using the same. A visible light wireless communication method.

Visible light is a light ray having a wavelength in the visible range among the electromagnetic waves and corresponds to a wavelength of 380 nm to 780 nm.

In visible light, the change of the properties according to the wavelength is shown in color, and the wavelength becomes shorter from red to purple. Light with a longer wavelength than red is called infrared, and light with a shorter wavelength than purple is called ultraviolet. For monochromatic light, 700-610nm is red, 610-590nm is orange, 590-570nm is yellow, 570-500nm is green, 500-450nm is blue, and 450-400nm is purple. Various colors can be expressed by mixing colors of each wavelength.

Visible light, unlike ultraviolet or infrared light, is visible to humans, and the light emitted must satisfy various requirements such as accurate color representation. One of the requirements is that there should be fewer blinks.

Since humans cannot recognize more than 200 flashes per second, lighting using LED (Light Emitting Diode), which has fast flashing performance, controls flashing using PWM (Pulse Width Modulation) to prolong the life of the lighting and save energy. have.

Visible light communication is a wireless communication technology using a wavelength between 380nm and 780nm, and standardization is underway in IEEE 802.15 Wireless Personal Area Network (WPAN) Working Group, and in Korea, Telecommunications Technology Association (TTA) ) Is operating a visible light wireless communication working group.

Several modulation schemes have been discussed in visible light wireless communication, one of which is On-Off Keying (OOK). On-off keying indicates '1' when the signal level is high, '0' when low, or '1' when the signal level is low and '0' when high. Modulation method. This on-off keying method is also widely used in optical communication because the modulated signal can be directly switched to flashing light.

In addition to on-off keying, Pulse Position Modulation (PPM), Pulse Amplitude Modulation (PAM), and sub-carrier 4PPM (SC-4PPM) incorporating carriers in pulse position modulated signals are available for visible light wireless communications. It is considered as a modulation method.

The method of adjusting the brightness (brightness) of LED lighting is to change the amount of current flowing through the LED by changing the voltage applied to the resistor by using a simple variable resistor, and the time that the LED is turned on by changing the pulse width of the voltage applied to the LED. There are many ways to control the amount of.

In lighting equipment using LEDs, the brightness of the lighting is controlled using pulse width modulation (PWM), which provides the highest efficiency and the finest current control. Pulse-width modulation modulates the brightness of light by adjusting the on / off ratio of the signal. In other words, the longer the time the LED light is turned on per unit time is the result that the LED light emits bright light, the shorter the time the LED light is turned on per unit time can be seen as a dark LED light.

Visible light wireless communication technology includes VPPM (Variable PPM) technology that enables communication and dimming at the same time. This technique enables both communication and dimming at the same time by varying the length of the light-on period within a symbol of the PPM.

However, adjusting the brightness very finely with only the pulse width is very difficult to implement, and even if possible, there is a problem in that it takes a lot of cost and time. Furthermore, if the pulse width of the transmission signal is finely adjusted and transmitted, it is difficult for the receiver to decode it.

Thus, there is an urgent need for a new brightness control technique that can more simply and effectively control brightness in visible light communications.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to combine a VPPM dimming signal whose rough brightness is adjusted to enable finer dimming control.

It is also an object of the present invention to produce a transmission sequence corresponding to the desired brightness by combining the VPPM dimming signals as appropriate.

In accordance with another aspect of the present invention, there is provided a wireless light communication method comprising: determining a dimming level parameter for adjusting fine brightness; Based on the dimming level variable, selecting a higher brightness symbol and a lower brightness symbol, each of one of the VPPM symbols; Determining a number of transmissions of at least one of the upper and lower brightness symbols based on the dimming level variable; And generating a transmission sequence corresponding to the dimming level variable by combining the higher brightness symbol and the lower brightness symbol based on the number of transmissions.

In this case, the VPPM symbols correspond to a VPPM symbol corresponding to a state in which the light source is completely turned off, a VPPM symbol corresponding to a state in which the light source is completely turned on, and nine VPPM duty cycles varying from 0.1 to 0.9, respectively, from 1 to 9 It may include nine VPPM symbols having a VPPM symbol index that is a natural number of.

In this case, the upper brightness symbol may be the darkest VPPM symbol among the VPPM symbols corresponding to the brightness higher than the dimming level corresponding to the dimming level variable. In this case, the higher brightness symbol may correspond to a symbol index calculated by rounding the dimming level variable by 1000 to the next higher integer.

In this case, the lower brightness symbol may be the brightest VPPM symbol among the VPPM symbols corresponding to the brightness lower than the dimming level corresponding to the dimming level variable. In this case, the lower brightness symbol may correspond to a symbol index calculated by rounding the dimming level variable by 1000 to the next lower integer.

In this case, the determining of the number of transmission may include calculating the number of transmission of the higher brightness symbol using a dimming level variable, and calculating the number of transmission of the lower brightness symbol using the number of transmission of the higher brightness symbol. Can be. In this case, the number of transmission of the upper brightness symbol may be calculated by subtracting a value obtained by multiplying the symbol index of the lower brightness symbol by 100 from the dimming level variable. In this case, the number of transmission of the lower brightness symbol may be calculated by subtracting the number of transmission of the upper brightness symbol from 100.

In this case, the generating of the transmission sequence may include allocating a data symbol to the lower brightness symbol by the number of transmission of the lower brightness symbol, allocating the data symbol to the higher brightness symbol by the number of transmission of the higher brightness symbol, and If the data symbols are not divided by 100, the method may include assigning a VPPM idle pattern symbol to a lower brightness symbol or a higher brightness symbol so that the transmission sequence is divided by 100.

In addition, the visible light wireless communication device according to an embodiment of the present invention, the dimming level determination unit for determining a dimming level variable for fine brightness control; A brightness symbol selector configured to select an upper brightness symbol and a lower brightness symbol, each of which is one of VPPM symbols, based on the dimming level variable; A transmission count calculator configured to determine the number of transmissions of at least one of the upper brightness symbol and the lower brightness symbol based on the dimming level variable; And a signal generator that combines the higher brightness symbol and the lower brightness symbol based on the number of transmissions to generate a transmission sequence corresponding to the dimming level variable.

According to the present invention, finer dimming control is possible with data communication by combining a roughly adjusted VPPM dimming signal.

In addition, the present invention can generate a transmission sequence corresponding to the desired brightness by properly combining the VPPM dimming signal.

1 is a diagram illustrating an example of a VPPM signal.
2 is a flowchart illustrating a visible light wireless communication method according to an embodiment of the present invention.
3 is a flowchart illustrating an example of generating a transmission sequence shown in FIG. 2.
Figure 4 is a block diagram showing a visible light wireless communication device according to an embodiment of the present invention.
5 is a block diagram illustrating an example of a transmission count calculator of FIG. 4.
6 is a block diagram illustrating an example of the signal generator illustrated in FIG. 4.
7 and 8 illustrate examples in which an idle pattern is inserted into a transmission sequence.
FIG. 9 is a waveform diagram illustrating a case where brightness corresponding to a dimming level variable is implemented by a combination of VPPM symbols.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity.

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

1 is a diagram illustrating an example of a VPPM signal.

Referring to FIG. 1, it can be seen that dimming and communication can be simultaneously performed using the VPPM signal.

The longer the light source such as an LED (Light Emitting Diode) is turned on, that is, the longer the signal level is high in the unit symbol, the brighter the LED light is. In addition, when the section in which the signal level is high is located in the front of the unit symbol, the data '0' may be shown, and in the rear, the data '1' may be represented. Of course, according to the exemplary embodiment, the data '1' may be represented when the signal level is high in the unit symbol and the data '0' is located in the rear.

The example shown in FIG. 1 shows the case where the brightness is 0%, 12.5%, 25%, 37.5%, 50%, 52%, 54% and 55%. .

2 is a flowchart illustrating a visible light wireless communication method according to an embodiment of the present invention.

Referring to FIG. 2, in the visible light wireless communication method according to an embodiment of the present invention, a dimming level variable macDim is first determined (S210).

In this case, the dimming level variable macDim may be determined based on a user's selection, or may be determined by an automatic adjustment algorithm.

In addition, the visible light wireless communication method according to an embodiment of the present invention, based on the dimming level variable (macDim), respectively, one of the VPPM symbols, the higher brightness symbol VS _k2 and lower brightness symbol VS _k1 Select (S220). That is, when the dimming level variable is determined, the visible light wireless communication method according to an embodiment of the present invention determines two types of VPPM dimming symbols to be combined to create a desired dimming level.

In this case, the VPPM symbols may be VPPM dimming symbols in units of 10%. That is, the VPPM dimming symbol is defined as 11 of VS ₀ , VS ₁ , VS ₂ , VS ₃ , VS ₄ , VS ₅ , VS ₆ , VS ₇ , VS ₈ , VS ₉ , VS ₁₀ , and VS ₀ is fully illuminated In the off state, the VS ₁₀ may correspond to the fully lit state. In addition, VS ₁ may correspond to a dimming state of 10% and VS ₂ .

In other words, the VPPM symbols are the VPPM symbol VS ₀ corresponding to the state in which the light source is completely turned off, the VPPM symbol VS ₁₀ corresponding to the state in which the light source is completely turned on, and nine VPPM duty cycles varying from 0.1 to 0.9 each by 0.1. 9 VPPM symbols (VS ₁ , VS ₂ , VS ₃ , VS ₄ , VS ₅ , VS ₆ , VS ₇ , VS ₈ , corresponding to the duty cycles and having a VPPM symbol index that is a natural number from 1 to 9 VS ₉ ).

As a result, the present invention can be seen to implement a finer dimming by combining the dimming symbols of 10% units.

When using VPPM which can simultaneously communicate and dimm, dimming by 10% may be advantageous in terms of reception.

In this case, the upper brightness symbol may be the darkest VPPM symbol among the VPPM symbols corresponding to the brightness higher than the dimming level corresponding to the dimming level variable.

In this case, the lower brightness symbol may be the brightest VPPM symbol among the VPPM symbols corresponding to the brightness lower than the dimming level corresponding to the dimming level variable.

For example, if a dimming level of 33% is selected, then the brightest of the dimming symbols corresponding to darker than 33% and VS ₄ at 40% of the dimming symbols that are brighter than 33%. VS ₃ with 30% brightness is selected.

In this case, the higher brightness symbol may correspond to a symbol index k ₂ calculated by rounding the dimming level variable macDim by 1000 to rounding to the next higher integer. In this case, the lower brightness symbol may correspond to a symbol index k ₁ calculated by rounding the dimming level variable macDim by 1000 to the next lower integer.

The determination of the higher brightness symbol and the lower brightness symbol may be represented by Equations 1 and 2 below.

은 다음 높은 정수로 반올림, k₂는 상위 밝기 심볼의 심볼 인덱스, macDim은 디밍 수준 변수)(

Is rounded up to the next higher integer, k ₂ is the symbol index of the higher brightness symbol, and macDim is the dimming level variable)

은 다음 낮은 정수로 반올림, k₁은 하위 밝기 심볼의 심볼 인덱스, macDim은 디밍 수준 변수)
(

Rounded up to the next lower integer, k ₁ is the symbol index of the lower brightness symbol, and macDim is the dimming level variable)

For example, if the dimming level variable (macDim) is determined to be 330 for a dimming level of 33% (0≤macDim≤1000), then the symbol index (k ₂ ) of the higher brightness symbol is 4, rounding 3.3 to the next higher integer. The symbol index k ₁ of the lower brightness symbol is 3, rounding 3.3 to the next lower integer.

In addition, the visible light wireless communication method according to an embodiment of the present invention determines the number of transmission of the upper brightness symbol VS _k2 based on the dimming level variable macDim (S230).

In this case, the number of transmission of the upper brightness symbol VS _k2 may be calculated by subtracting a value obtained by multiplying the symbol index k ₁ of the lower brightness symbol by the dimming level variable macDim by 100.

That is, the number of transmissions of the higher brightness symbol VS _k2 may be calculated by Equation 3 below.

(rep_2 is the number of transmission of the high brightness symbol, macDim is the dimming level variable, k ₁ is the low brightness symbol index)

For example, if the dimming level variable (macDim) is determined to be 330 for a dimming level of 33%, the symbol index k ₂ of the high brightness symbol is 4 and the symbol index k ₁ of the low brightness symbol is 3, The number of transmissions of the higher brightness symbol is 30 minus 300 minus 300.

In addition, the visible light wireless communication method according to an embodiment of the present invention determines the number of transmission of the lower brightness symbol VS _k1 based on the number of transmissions rep_2 of the upper brightness symbol VS _k2 (S240).

In this case, the number of transmissions of the lower brightness symbol VS _k1 may be calculated by subtracting the number of transmissions rep_2 of the upper brightness symbol VS _k2 from 100.

That is, the number of transmissions of the lower brightness symbol VS _k1 may be calculated by Equation 4 below.

(rep_1 is the number of transmission of the lower brightness symbol, rep_2 is the number of transmission of the higher brightness symbol)

For example, for a dimming level of 33%, the dimming level variable (macDim) is determined to be 330, the symbol index (k ₂ ) of the high brightness symbol is 4, the symbol index (k ₁ ) of the low brightness symbol is 3, and the high When the number of transmission of the brightness symbol is 30, the number of transmission of the lower brightness symbol is 70 minus 30 minus 30.

That is, if 100 data symbols are transmitted, 70 data symbols are transmitted by using the lower brightness symbol and 30 data symbols are transmitted by using the higher brightness symbol to obtain a desired dimming level of 33%. have.

In addition, the visible light wireless communication method according to an embodiment of the present invention is a transmission sequence corresponding to the dimming level variable (macDim) by combining the upper brightness symbol VS _k2 and the lower brightness symbol VS _k1 based on the determined number of transmissions. To generate (S250).

In this case, step S250 may include assigning data symbols to the lower brightness symbols by the number of transmission of the lower brightness symbols, allocating data symbols to the higher brightness symbols by the number of transmission of the higher brightness symbols, and transmitting. If the data symbols to be divided are not divided by 100, the method may include assigning a VPPM idle pattern symbol to the lower brightness symbol or the higher brightness symbol to divide the transmission sequence by 100.

That is, the desired dimming level can be obtained by rep_2 times the upper brightness symbol VS _k2 and rep_1 the lower brightness symbol VS _k1 . In general, since the number of VPPM data symbols is not an integer multiple of 100, idle pattern symbols may be used to implement a desired dimming level.

For example, if the number of VPPM data symbols to be transmitted is 80, first assign data to 70 lower brightness symbols and transmit data to 10 high brightness symbols for a dimming level of 33%. An idle pattern symbol may be allocated to a higher brightness symbol and transmitted.

For example, if the number of VPPM data symbols to be transmitted is 50, the data is first allocated to the 50 lower brightness symbols for the dimming level of 33%, and the idle pattern symbols are assigned to the 20 lower brightness symbols. In addition, the idle pattern symbols may be allocated to 30 higher brightness symbols and transmitted.

3 is a flowchart illustrating an example of generating a transmission sequence shown in FIG. 2.

Referring to FIG. 3, the transmission sequence generation step S250 illustrated in FIG. 2 first starts to transmit the lower brightness symbol VS _k1 (S310).

In addition, the step of generating the transmission sequence determines whether the lower brightness symbol VS _k1 has been transmitted as many times as the lower brightness symbol rep_1 (S320).

As a result of the determination in step S320, if the lower brightness symbol VS _k1 has not been transmitted as many times as the lower brightness symbol rep_1, the transmission sequence generation step determines whether data transmission is completed (S360).

If it is determined in step S360 that the data transmission is not completed, the transmission sequence generation step returns to step S310 to allocate data to the lower brightness symbol and transmit the data.

As a result of the determination in step S360, when the data transmission is completed, the transmission sequence generating step allocates the idle pattern to the lower brightness symbols as many times as the remaining number of the lower brightness symbol transmission times rep_1 (S370) and transmits the higher brightness symbol. An idle pattern is allocated to a higher brightness symbol by as much as (rep_2) (S390).

As a result of the determination of step S320, if the lower brightness symbol VS _k1 has been transmitted as many times as the lower brightness symbol rep_1, the transmission sequence generation step starts transmitting the higher brightness symbol VS _k2 (S330).

In operation S340, the transmitting sequence generation step may determine whether the higher brightness symbol VS _k2 has been transmitted as many times as the higher brightness symbol rep_2.

As a result of the determination in step S340, if the higher brightness symbol VS _k2 is not transmitted as many times as the higher brightness symbol rep_2, the transmission sequence generation step determines whether data transmission is completed (S380).

As a result of the determination in step S380, if the data transmission is not completed, the transmission sequence generation step returns to step S330 again and allocates data to the higher brightness symbol and transmits it.

As a result of the determination in step S380, when data transmission is completed, the transmission sequence generation step allocates an idle pattern to the higher brightness symbol by the remaining number of times of the higher brightness symbol transmission rep_2 (S390).

As a result of the determination in step S340, if the higher brightness symbol VS _k2 has been transmitted by the higher brightness symbol transmission number rep_2, the transmission sequence generation step determines whether all data transmission is completed (S350).

As a result of the determination in step S350, if all data transmissions are not completed, the transmission sequence generation step returns to step S310 and allocates data to the lower brightness symbols and transmits the data.

As a result of the determination of step S350, if all data transmission is completed, the transmission sequence generation step is completed.

Figure 4 is a block diagram showing a visible light wireless communication device according to an embodiment of the present invention.

Referring to FIG. 4, a visible light wireless communication device according to an embodiment of the present invention includes a dimming level determiner 410, a brightness symbol selector 420, a transmission count calculator 430, and a signal generator 440. do.

The dimming level determiner 410 determines a dimming level variable for fine brightness control.

The brightness symbol selector 420 selects an upper brightness symbol and a lower brightness symbol, which are one of the VPPM symbols, respectively, based on the dimming level variable.

In this case, the VPPM symbols correspond to a VPPM symbol corresponding to a state in which the light source is completely turned off, a VPPM symbol corresponding to a state in which the light source is completely turned on, and nine VPPM duty cycles varying from 0.1 to 0.9, respectively, from 1 to 9 It may include nine VPPM symbols having a VPPM symbol index that is a natural number of.

In this case, the upper brightness symbol may be the darkest VPPM symbol among the VPPM symbols corresponding to the brightness higher than the dimming level corresponding to the dimming level variable. In this case, the higher brightness symbol may correspond to a symbol index calculated by rounding the dimming level variable by 1000 to the next higher integer.

In this case, the lower brightness symbol may be the brightest VPPM symbol among the VPPM symbols corresponding to the brightness lower than the dimming level corresponding to the dimming level variable. In this case, the lower brightness symbol may correspond to a symbol index calculated by rounding the dimming level variable by 1000 to the next lower integer.

The transmission count calculator 430 determines the transmission count of at least one of the upper and lower brightness symbols based on the dimming level variable.

The signal generator 440 combines the high brightness symbol and the low brightness symbol based on the determined number of transmissions to generate a transmission sequence corresponding to the dimming level variable.

At this time, the signal generator 440 allocates a data symbol to the lower brightness symbol by the number of transmission of the lower brightness symbol, allocates a data symbol to the higher brightness symbol by the number of transmission of the higher brightness symbol, and the data symbols to be transmitted are 100. If not divided, the VPPM idle pattern symbol may be assigned to the lower or higher brightness symbol so that the transmission sequence is divided by 100.

5 is a block diagram illustrating an example of a transmission count calculator of FIG. 4.

Referring to FIG. 5, the transmission count calculator includes a higher brightness symbol transmission count calculator 510 and a lower brightness symbol transmission count calculator 520.

The higher brightness symbol transmission count calculator 510 calculates the transmission frequency of the higher brightness symbol by using a dimming level variable. At this time, the higher brightness symbol transmission count calculator 510 may calculate the number of transmission of the higher brightness symbol by Equation 3 above.

The lower brightness symbol transmission count calculator 520 calculates the number of transmission of the lower brightness symbol by using the number of transmission of the higher brightness symbol. At this time, the lower brightness symbol transmission count calculator 520 may calculate the number of transmission of the lower brightness symbol by Equation (4).

6 is a block diagram illustrating an example of the signal generator illustrated in FIG. 4.

Referring to FIG. 6, the signal generator includes a transmission data buffer 610, a signal counter 620, an idle-pattern generator 630, an upper brightness signal generator 640, a lower brightness signal generator 650, and a VPPM. And a signal generator 660.

The transmit data buffer 610 stores the data to be transmitted, transferred from the upper layer.

The signal counter 620 receives the number of high brightness symbol transmissions and the number of low brightness symbol transmissions. The signal counter 620 reads the data to be transmitted from the transmission data buffer 610 and counts the number of transmissions of the high brightness symbol and the low brightness symbol, and transmits the data to be transmitted to the high brightness signal generator 640 and the low brightness signal generator ( 650).

In addition, the signal counter 620 receives the idle pattern from the idle-pattern generator 630 if there is no data to be transmitted even though the number of transmissions of the high brightness symbol or the low brightness symbol remains, the high brightness signal generator 640 or the low brightness. The signal generator 650 transmits the signal.

The VPPM signal generator 660 combines the signals generated by the upper brightness signal generator 640 and the lower brightness signal generator 650 to generate a VPPM signal that finally provides a desired brightness.

7 and 8 illustrate examples in which an idle pattern is inserted into a transmission sequence.

Referring to FIG. 7, it can be seen that an idle pattern is assigned to a lower brightness symbol VS _K1 and an upper brightness symbol VS _K2 to generate a transmission sequence.

That is, in order to finally obtain the desired dimming level, the low brightness symbol VS _K1 is rep_1 times and the high brightness symbol VS _K2 is rep_2 times. Send an idle pattern to a symbol.

Referring to FIG. 8, it can be seen that an idle pattern is assigned only to a higher brightness symbol VS _K2 to generate a transmission sequence.

That is, in order to finally obtain the desired dimming level, the low brightness symbol VS _K1 is rep_1 times and the high brightness symbol VS _K2 is rep_2 times. Send by sending.

In this manner, brightness can be adjusted with 0.1% accuracy by using a VPPM symbol having a 10% resolution.

FIG. 9 is a waveform diagram illustrating a case where brightness corresponding to a dimming level variable is implemented by a combination of VPPM symbols.

Referring to FIG. 9, while the 18-bit data “001001011110110010” is transmitted, a lower brightness symbol VS _K1 and a higher brightness symbol VS _K2 are combined 2: 1 to realize brightness corresponding to the dimming level variable macDim. It can be seen that.

As described above, the visible light wireless communication method and the visible light wireless communication apparatus according to the present invention are not limited to the configuration and method of the embodiments described as described above, but the embodiments may be modified in various ways. All or some of the embodiments may be optionally combined.

410: dimming level determination unit
420: brightness symbol selection unit
430: transmission count calculation unit
440: signal generator

Claims (20)

Determining a dimming level variable for fine brightness control;
Based on the dimming level variable, selecting a higher brightness symbol and a lower brightness symbol, each of one of the VPPM symbols;
Determining a number of transmissions of at least one of the upper and lower brightness symbols based on the dimming level variable; And
Generating a transmission sequence corresponding to the dimming level variable by combining the higher brightness symbol and the lower brightness symbol based on the number of transmissions
Visible light wireless communication method comprising a. The method according to claim 1,
The VPPM symbols
A VPPM symbol corresponding to the state in which the light source is completely turned off;
A VPPM symbol corresponding to a state in which the light source is completely turned on; And
And 9 VPPM symbols each corresponding to 9 VPPM duty cycles varying from 0.1 to 0.9 by 0.1 and having a VPPM symbol index that is a natural number from 1 to 9. The method according to claim 2,
The higher brightness symbol is
And the darkest VPPM symbol among the VPPM symbols corresponding to the brightness that is brighter than the dimming level corresponding to the dimming level variable. The method according to claim 3,
The higher brightness symbol is
And dividing the dimming level variable by 1000 to a symbol index calculated by rounding to the next higher integer. The method of claim 4,
The lower brightness symbol is
And the brightest VPPM symbol among the VPPM symbols corresponding to the brightness lower than the dimming level corresponding to the dimming level variable. The method according to claim 5,
The lower brightness symbol is
And dividing the dimming level variable by 1000 to a symbol index calculated by rounding to the next lower integer. The method according to claim 2,
Determining the number of transmissions
Calculating the number of transmissions of the higher brightness symbol using the dimming level variable; And
Calculating the number of transmission of the lower brightness symbol by using the number of transmission of the higher brightness symbol
Visible light wireless communication method comprising a. The method of claim 7,
The number of transmission of the higher brightness symbol is
And calculating a value obtained by subtracting a symbol index of the lower brightness symbol by 100 from the dimming level variable. The method according to claim 8,
The number of transmission of the lower brightness symbol is
And calculating the number of transmissions of the higher brightness symbol by 100. The method according to claim 2,
Generating the transmission sequence
Allocating a data symbol to the lower brightness symbol by the number of times of transmission of the lower brightness symbol;
Allocating a data symbol to the higher brightness symbol by the number of transmissions of the higher brightness symbol; And
If the data symbols to be transmitted are not divided by 100, assigning a VPPM idle pattern symbol to the lower or higher brightness symbol so that the transmission sequence is divided by 100
Visible light wireless communication method comprising a. A dimming level determiner configured to determine a dimming level variable for adjusting fine brightness;
A brightness symbol selector configured to select an upper brightness symbol and a lower brightness symbol, each of which is one of VPPM symbols, based on the dimming level variable;
A transmission count calculator configured to determine the number of transmissions of at least one of the upper brightness symbol and the lower brightness symbol based on the dimming level variable; And
A signal generator that generates a transmission sequence corresponding to the dimming level variable by combining the high brightness symbol and the low brightness symbol based on the number of transmissions
Visible light wireless communication device comprising a. The method of claim 11,
The VPPM symbols
A VPPM symbol corresponding to the state in which the light source is completely turned off;
A VPPM symbol corresponding to a state in which the light source is completely turned on; And
And nine VPPM symbols each corresponding to nine VPPM duty cycles varying from 0.1 to 0.9 by 0.1 and having a VPPM symbol index that is a natural number from 1 to 9. The method of claim 12,
The higher brightness symbol is
And the darkest VPPM symbol among the VPPM symbols corresponding to the brightness that is brighter than the dimming level corresponding to the dimming level variable. The method according to claim 13,
The higher brightness symbol is
And a symbol index calculated by rounding the dimming level variable by 1000 to a next higher integer. The method according to claim 14,
The lower brightness symbol is
And the brightest VPPM symbol among the VPPM symbols corresponding to the brightness lower than the dimming level corresponding to the dimming level variable. The method according to claim 15,
The lower brightness symbol is
And a symbol index calculated by rounding the dimming level variable by 1000 to a next lower integer. The method of claim 12,
The transmission count calculator
A higher brightness symbol transmission count calculator for calculating the number of transmission of the higher brightness symbol using the dimming level variable; And
A lower brightness symbol transmission count calculator for calculating the number of transmission of the lower brightness symbol using the number of transmission of the higher brightness symbol
Visible light wireless communication device comprising a. 18. The method of claim 17,
The number of transmission of the higher brightness symbol is
And calculating a value obtained by subtracting a symbol index of the lower brightness symbol by 100 from the dimming level variable. 19. The method of claim 18,
The number of transmission of the lower brightness symbol is
And calculating the number of transmission of the higher brightness symbol by 100. The method of claim 12,
The signal generator
Assigns a data symbol to the lower brightness symbol by the number of transmissions of the lower brightness symbol,
Assigns a data symbol to the high brightness symbol by the number of transmissions of the high brightness symbol,
And when the data symbols to be transmitted are not divided by 100, assigning a VPPM idle pattern symbol to the lower or higher brightness symbol so that the transmission sequence is divided by 100.

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