CN114726438A - Visible light modulation method, demodulation method and device - Google Patents

Abstract

A visible light modulation method, demodulation method and device, the visible light modulation method comprising: performing color modulation on a first data stream to obtain the light intensity of each color light path in multiple color light paths; For the data stream, the modulation mode of orthogonal frequency division multiplexing OFDM is used to modulate the data stream on the optical path of each color on the modulation bandwidth corresponding to the optical path of each color, so as to obtain the OFDM signal of the optical path of each color; The light intensity of the color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and transmit the signal on the optical channel corresponding to the color optical path by means of wavelength division multiplexing. The invention makes full use of the physical properties of the visible light polychromatic light path, and can improve the data transmission efficiency by utilizing the freedom degree of complex space in the frequency domain.

Description

Visible light modulation method, demodulation method and device

technical field

The present invention relates to the technical field of visible light communication (Visible Light Communication, VLC), in particular to a visible light modulation method, a demodulation method and equipment.

Background technique

VLC technology is a communication technology that can realize high-speed information transmission under the premise of ensuring the lighting function of Light-emitting Diode (LED). It mainly uses intensity modulation (Intensity Modulation, IM) and direct detection (Direct Detection, DD) technology, using the rapid changes in light intensity imperceptible to the human eye to achieve information transmission, so as to support lighting and communication at the same time. It has the characteristics of high speed, wide spectrum and no license, high security, low cost and no electromagnetic interference.

Visible light communication modulation technologies include single-carrier modulation, multi-carrier modulation and color modulation, among which multi-carrier modulation and color modulation are the most commonly used modulation methods.

Among them, in single-carrier modulation, pulse amplitude modulation (Pulse Amplitude Modulation, PAM) and pulse position modulation (Pulse Position Modulation, PPM) carry information through the amplitude and position changes of the pulse carrier, respectively.

In multi-carrier modulation, Orthogonal Frequency Division Multiplexing (OFDM), as a representative technology of multi-carrier modulation, can be effectively applied to visible light communication to realize broadband high-speed data transmission. It is converted into multiple relatively low-speed parallel data modulated to each sub-channel for transmission.

Color modulation mainly uses light of different wavelengths of multi-color light sources to carry multiple sets of data streams at the same time to improve the system data rate. , Blue, RGB) three-color LED light source, the modulation mode of information transmission is realized by controlling the light intensity on the three color bandwidths and the combination ratio of the three color light components. change to avoid light flickering effects that affect the lighting experience. In addition, CSK modulation uses RGB-LED as the emission light source, which has a higher modulation bandwidth than the traditional phosphor LED light source used in the VLC system, and can realize the change of light intensity at a higher frequency. Due to the optical power constraints of CSK, the constellation points of CSK are limited to a three-dimensional plane. In CSK modulation, data bits are first mapped to chromaticity values, and then the intensities of the corresponding three-color light are calculated according to the chromaticity values, and then data is transmitted through a multi-color light source. The color shift keying modulation technology can also ensure that the lighting needs are taken into account at the same time, and the effective color band and intensity combination can be used for signal modulation.

The single-carrier modulation method is simple, and the most common modulation method is On-Off Keying (OOK) technology, which has the disadvantage of low bandwidth efficiency and can only be used as a candidate for low-speed VLC. Multi-carrier modulation is similar to traditional wireless communication modulation methods, but it does not take full advantage of the physical properties of visible light polychromatic light paths, and other technologies need to be considered to take into account lighting needs. Color modulation can only modulate the intensity of each light color, so that the degree of freedom of the complex space is not fully utilized.

SUMMARY OF THE INVENTION

At least one embodiment of the present invention provides a visible light modulation method, a demodulation method, a terminal, and a network device, which make full use of the physical characteristics of the visible light polychromatic optical path, and can improve the data transmission efficiency by utilizing the degree of freedom of the complex space in the frequency domain .

According to one aspect of the present invention, at least one embodiment provides a visible light modulation method, comprising:

Perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths;

For the data streams on the optical paths of the various colors, the modulation mode of orthogonal frequency division multiplexing (OFDM) is used to modulate the data streams on the optical paths of each color in the modulation bandwidth corresponding to the optical paths of each color, to obtain the optical paths of each color. OFDM signal;

The light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and transmits on the optical channel corresponding to the color optical path by means of wavelength division multiplexing.

In addition, according to at least one embodiment of the present invention, performing color modulation on the first data stream includes:

performing color shift keying CSK processing on the data of the first data stream to obtain corresponding chrominance values;

According to the chromaticity value, the light intensity of each color light path is calculated.

In addition, according to at least one embodiment of the present invention, for the data streams on the multiple color optical paths, an orthogonal frequency division multiplexing (OFDM) modulation method is used, and the color optical paths are respectively on the modulation bandwidth corresponding to each color optical path. Data stream modulation on the road, including:

On the modulation bandwidth corresponding to each color optical path, frequency domain mapping processing and inverse fast Fourier transform processing are respectively performed on the data stream on each color optical path.

In addition, according to at least one embodiment of the present invention, between the frequency domain mapping processing and the inverse fast Fourier transform processing, the method further includes: performing serial-to-parallel conversion processing on the signal obtained by the frequency domain mapping processing;

After the inverse fast Fourier transform processing, the method further includes: adding a cyclic prefix CP to the signal obtained by the inverse fast Fourier transform processing and performing parallel-serial conversion processing.

In addition, according to at least one embodiment of the present invention, the modulation of the OFDM is DC-biased light DCO-OFDM multi-carrier modulation, and the light intensity of each color light path is superimposed on the OFDM signal of the corresponding color light path, Include any of the following stacking methods:

The first superposition method: calculate the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and add the first product and the predetermined DC component to obtain the to-be-sent signal on each color optical path ;

The second superposition method: the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component are added to obtain the to-be-sent signal on each color optical path;

The third superposition method: separately add the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, calculate the product of the sum value and the light intensity of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path ;

The fourth superposition method: respectively calculate the second product of the light intensity of each color optical path and the predetermined DC component, and add the second product to the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path .

In addition, according to at least one embodiment of the present invention, the modulation of the OFDM is asymmetric sliced optical ACO-OFDM multi-carrier modulation or flip-Flip-OFDM multi-carrier modulation, and the light intensity of each color optical path is superimposed to the OFDM signal of the corresponding color optical path, including any one of the following superposition methods:

Fifth superposition method: separately calculate the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path;

Sixth superposition method: respectively adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path.

In addition, according to at least one embodiment of the present invention, the first sampling frequency of the first data stream when the color is modulated is the same as the second sampling frequency when the data stream on the optical path of each color is subjected to OFDM modulation, or , the first sampling frequency is N times the second sampling frequency, or the second sampling frequency is N times the first sampling frequency, and N is an integer greater than 1.

According to another aspect of the present invention, at least one embodiment provides a visible light demodulation method, applied to a second device, including:

receiving a signal sent by the first device on each color optical path among the multiple color optical paths;

demodulating the second data stream from the signals of the multiple color optical paths through color demodulation;

On the modulation bandwidth corresponding to each color optical path, OFDM demodulates the data stream on the color optical path respectively to obtain the data stream on each color optical path;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color through wavelength division multiplexing, and the transmission signal on each optical channel is in the corresponding It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the color light path. The OFDM signal of each color light path is for the data streams on the multiple color light paths, using the OFDM modulation method, and the modulation method corresponding to each color light path is used. It is obtained by modulating the data stream on the optical path of the color respectively in terms of bandwidth.

In addition, according to at least one embodiment of the present invention, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is a first superposition mode; The second data stream is demodulated from the signal of the optical path, including:

Detecting the variance value of the power of the transmitted signal on each color optical path, and performing color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the power, to obtain the second data stream;

or,

Detect the variance value of the DC component intensity of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the DC component intensity to obtain the second data stream ;

The first superposition method is: calculating the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and adding the first product and a predetermined DC component.

In addition, according to at least one embodiment of the present invention, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the second superposition mode, the third superposition mode or the fourth superposition mode; or, the The modulation of the OFDM is ACO-OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, and the preset superposition mode is the fifth superposition mode or the sixth superposition mode; The second data stream is demodulated from the signal of the optical path, including:

Detect the power or signal strength of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation diagram corresponding to the ratio of the power or the CSK constellation diagram corresponding to the ratio of the signal strength to obtain the second data flow;

Wherein, the second superposition method is: adding the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component respectively;

The third superposition method is: separately adding the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, and calculating the product of the sum value and the light intensity of the corresponding color optical path;

The fourth superposition method is: separately calculating the second product of the light intensity of each color optical path and the predetermined DC component, and adding the second product to the OFDM signal of the corresponding color optical path;

The fifth superposition method is: separately calculating the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path;

The sixth superposition manner is: adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path respectively.

In addition, according to at least one embodiment of the present invention, the demodulation of the second data stream from the signals of the multiple-color optical paths through color demodulation further includes:

The signal sampling of the color demodulation is performed according to the first sampling frequency when the first device performs color modulation on the first data stream, wherein:

When the first sampling frequency is the same as the second sampling frequency when the first device performs OFDM modulation on the data stream on the optical path of each color, perform signal detection on each OFDM symbol on the optical path of each color and demodulation;

When the first sampling frequency is N times the second sampling frequency, signal detection is performed on N OFDM symbols on the optical path of each color, and the average value of the detection results of the N OFDM symbols is calculated. The average value is demodulated;

When the second sampling frequency is N times the first sampling frequency, signal detection and demodulation are performed on 1/N OFDM symbols on the optical path of each color;

The N is an integer greater than 1.

In addition, according to at least one embodiment of the present invention, when the preset superposition method adds a DC component to the transmitted signal, before performing the OFDM demodulation on the data stream on the optical path of each color, the method further includes: The DC component in the transmission signal is removed.

According to another aspect of the present invention, at least one embodiment provides a first device, comprising:

a first modulation module, configured to perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths;

The second modulation module is configured to perform orthogonal frequency division multiplexing (OFDM) modulation on the data stream on the color optical path on the modulation bandwidth corresponding to each color optical path, to obtain the OFDM signal of each color optical path;

The superposition module is used to superimpose the light intensity of each color optical path on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and use wavelength division multiplexing on the light corresponding to the color optical path. send on the channel.

According to another aspect of the present invention, at least one embodiment provides a first device including a transceiver and a processor, wherein,

The transceiver is used to perform color modulation on the first data stream to obtain the light intensity of each color optical path in the multiple color optical paths; on the modulation bandwidth corresponding to each color optical path, the data streams on the color optical path are respectively Orthogonal frequency division multiplexing OFDM modulation is performed to obtain the OFDM signal of each color optical path; the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path.

The processor is configured to transmit signals on each color optical path on the optical channel corresponding to the color optical path by means of wavelength division multiplexing.

According to another aspect of the present invention, at least one embodiment provides a first device comprising: a processor, a memory, and a program stored on the memory and executable on the processor, the program being The processor implements the steps of the method described above when executed.

According to another aspect of the present invention, at least one embodiment provides a second device, comprising:

a receiving module, configured to receive a signal sent by the first device on each color optical path among the multiple color optical paths;

a first demodulation module, configured to demodulate a second data stream from the signals of the multiple-color optical paths through color demodulation;

The second demodulation module is used for respectively performing OFDM demodulation on the data stream on the color optical path on the modulation bandwidth corresponding to each color optical path to obtain the data stream on each color optical path;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color by the wavelength division multiplexing method, and the transmission signal on the optical channel of each color is according to the preset superposition method, It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the corresponding color light path. The OFDM signal of each color light path is obtained by OFDM modulation of the data stream on the color light path. The light intensity of each color light path is The first data stream is obtained by performing color modulation.

According to another aspect of the present invention, at least one embodiment provides a second device including a transceiver and a processor, wherein,

The transceiver is used to receive a signal sent by the first device on each color optical path among the multiple color optical paths;

The processor is used for demodulating the second data stream from the signals of the multiple color optical paths through color demodulation; on the modulation bandwidth corresponding to each color optical path, the data streams on the color optical path are respectively Perform OFDM demodulation to obtain the data stream on the optical path of each color;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color by the wavelength division multiplexing method, and the transmission signal on the optical channel of each color is according to the preset superposition method, It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the corresponding color light path. The OFDM signal of each color light path is obtained by OFDM modulation of the data stream on the color light path. The light intensity of each color light path is The first data stream is obtained by performing color modulation.

According to another aspect of the present invention, at least one embodiment provides a second device comprising: a processor, a memory, and a program stored on the memory and executable on the processor, the program being The processor implements the steps of the method described above when executed.

According to another aspect of the present invention, at least one embodiment provides a computer-readable storage medium, where a program is stored on the computer-readable storage medium, and when the program is executed by a processor, the above-mentioned method is implemented. step.

Compared with the prior art, in the visible light modulation method, demodulation method and device provided by the embodiments of the present invention, two sets of independent data streams (the first data stream and the data stream on the optical path of each color) are respectively used at the transmitting end. The modulation method of the color dimension and the frequency domain dimension (multi-carrier) is modulated and then superimposed and transmitted, realizing a dual modulation method, which can not only make full use of the frequency domain resources of visible light, but also take into account the lighting needs, using light with multi-color wavelengths. Strong transmission of extra information flow.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the invention. Also, the same components are denoted by the same reference numerals throughout the drawings. In the attached image:

1 is a schematic flowchart of a visible light modulation method according to an embodiment of the present invention;

FIG. 2 is an exemplary diagram of a visible light modulation method according to an embodiment of the present invention;

3 is a schematic flowchart of a visible light demodulation method according to an embodiment of the present invention;

4 is an exemplary diagram of a visible light demodulation method according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a first device according to an embodiment of the present invention;

FIG. 6 is another schematic structural diagram of a first device provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a second device according to an embodiment of the present invention;

FIG. 8 is another schematic structural diagram of a second device according to an embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be more thoroughly understood, and will fully convey the scope of the present invention to those skilled in the art.

The terms "first", "second" and the like in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the application described herein can, for example, be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices. In the description and the claims, "and/or" means at least one of the connected objects.

The following description provides examples and does not limit the scope, applicability, or configuration set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the spirit and scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to some examples may be combined in other examples.

As described in the background art, the VLC modulation technologies in the prior art have their own shortcomings. The embodiments of the present invention provide a visible light modulation method and a demodulation method, which not only fully utilize the physical characteristics of the visible light polychromatic optical path, but also provide a visible light modulation method and a demodulation method. The degree of freedom of the complex space can be used in the frequency domain to improve the data transmission efficiency. A visible light modulation method provided by an embodiment of the present invention is applied to a first device side, where the first device is a sending end device and sends a modulated visible light signal to a second device. The second device is a receiver device, which receives the modulated visible light signal sent by the first device and demodulates a data stream therefrom. It should be noted that the identities of the first device and the second device are not fixed, and the transmitting end device may also receive the modulated visible light signal sent by the opposite end device. That is, the visible light modulation method on the first device side can also be applied to the second device side, and the visible light demodulation method on the second device side can also be applied to the first device side.

Please refer to FIG. 1 , which is a flowchart when the visible light modulation method provided by the embodiment of the present invention is applied to the side of the first device. Assuming that the visible light communication adopted by the first device includes N light paths of colors, in the embodiment of the present invention, the first device can simultaneously A maximum of N+1 data streams are sent. Generally, the N color light paths include red light paths, green light paths and blue light paths. In addition to sending one data stream on each color optical path, the embodiment of the present invention can also send another color-modulated data stream. Of course, according to different color divisions, the N color light paths may also include more or less than three color light paths. This embodiment of the present invention does not specifically limit this. FIG. 2 is an example diagram of a modulation flow provided by taking the red optical path, the green optical path and the blue optical path as an example of three color optical paths.

The visible light modulation method of the embodiment of the present invention makes full use of the physical characteristics of the visible light polychromatic optical path, and can improve the data transmission efficiency by utilizing the degree of freedom of the complex space in the frequency domain. As shown in FIG. 1 , the visible light modulation method according to the embodiment of the present invention includes:

Step 11: Perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths.

Here, the number of multi-color light paths is the number of color light paths used by the first device to perform visible light communication. Generally, the multi-color light paths include three types, namely, red light paths, green light paths, and blue light paths. Of course, according to different color divisions, the number of the multiple color light paths may also be more than three or less than three.

In step 11, the embodiment of the present invention performs color modulation on the first data stream to obtain the light intensity of each color optical path. Specifically, the color modulation includes: performing CSK processing on the data of the first data stream to obtain a corresponding chromaticity value; and then calculating the light intensity of each color optical path according to the chromaticity value. For example, as shown in FIG. 2 , the light intensities P_i, P_j, and P_k of the red light path, the green light path, and the blue light path are respectively obtained by processing color mapping and coordinate conversion for the first data stream.

Step 12: For the data streams on the multiple color optical paths, use the OFDM modulation method to modulate the data streams on the color optical paths in the modulation bandwidth corresponding to each color optical path, to obtain the OFDM signal of each color optical path. .

Here, the embodiment of the present invention uses the OFDM modulation technology to modulate the data streams to be sent on the optical paths of multiple colors, wherein the data streams on the optical paths of each color are modulated on the modulation bandwidth corresponding to the optical path. That is, the modulation bandwidth of each color optical path is relative to one carrier in the multi-carrier modulation. As shown in FIG. 2 , the OFDM modulation methods that can be used in this embodiment of the present invention include but are not limited to the following methods: Direct Current Biased Optical OFDM (DCO-OFDM) multi-carrier modulation, Asymmetrically Clipped Optical (Asymmetrically Clipped Optical OFDM) OFDM, ACO-OFDM multi-carrier modulation and flip-OFDM (Flip-OFDM) multi-carrier modulation, etc. Mapping methods include but are not limited to Quadrature Amplitude Modulation (QAM), Amplitude Phase Shift Keying (Amplitude Phase Shift Keying, APSK), etc., to obtain a set of data signals.

Specifically, when performing OFDM modulation, the embodiment of the present invention can perform frequency domain mapping processing and inverse fast Fourier transform on the data stream on each color optical path on the modulation bandwidth corresponding to each color optical path. (Invert Fast Fourier Transformation, IFFT) processing, so as to obtain the OFDM signal of each color optical path. Optionally, as shown in FIG. 2 , between the frequency domain mapping processing and the inverse fast Fourier transform processing, the embodiment of the present invention may further perform serial-parallel conversion processing on the signal obtained by the frequency domain mapping processing. , and then perform IFFT transformation after obtaining the parallel data of the corresponding number of bits. After the inverse fast Fourier transform processing, a cyclic prefix (Cyclic prefix, CP) may also be added to the signal obtained by the inverse fast Fourier transform processing, and parallel-serial conversion processing may be performed.

Step 13: Superimpose the light intensity of each color optical path on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and use wavelength division multiplexing on the optical channel corresponding to the color optical path. to send.

Here, the light intensity of each color optical path obtained in step 11 is superimposed on the OFDM signal of the corresponding color optical path in step 12, so as to obtain the transmitted signal on each color optical path, and then, through digital-to-analog conversion, converted into The analog signal is sent to the transmitter of the corresponding color for transmission, so that the data stream on the optical path of each color is sent to the optical channel of the corresponding optical path through wavelength division multiplexing. As shown in Figure 2, the light intensity modulated by the first data stream is superimposed on the multi-channel signal obtained by the data stream of each color optical path, and the wavelength division multiplexing technology is used to perform independent signal transmission in each optical channel, These signals are sent out through red/green/blue light emitters, respectively.

It can be seen from the above that in the embodiment of the present invention, two sets of independent data streams (the first data stream and the data stream on the optical path of each color) are respectively used at the transmitting end in the color dimension and the frequency domain dimension (multi-carrier). The modulation method is modulated and then superimposed and transmitted, thereby realizing a dual modulation method, which can not only make full use of the frequency domain resources of visible light, but also take into account the lighting requirements and transmit additional information flow by using the light intensity of multi-color wavelengths.

For example, considering the aspect of networking transmission, the embodiment of the present invention can perform aliasing transmission of the broadcast channel (as the first data stream) and the data channel (as the data stream on each color optical path) to further improve the transmission efficiency during networking. Specifically, the data stream of the data channel can be loaded on the time-frequency domain resources of visible light by using multi-carrier modulation, and the broadcast channel can be modulated to the light intensity of multi-color wavelengths. In this way, the user only needs to detect the average power or DC component intensity of the multi-color light source when demodulating the broadcast channel, and the broadcast channel can be obtained according to the color demodulation, which can reduce the complexity of demodulation and the power consumption of the device. Therefore, optionally, the first data stream is a data stream of a broadcast channel, and the data streams of the multi-color optical paths are service data streams for different user equipments or service data streams for different services.

In step 12, the embodiment of the present invention may adopt a variety of multi-carrier modulation techniques, such as DCO-OFDM multi-carrier modulation, ACO-OFDM multi-carrier modulation and Flip-OFDM multi-carrier modulation, etc. The following provides for different multi-carrier modulation techniques , the signal superposition method that can be used in step 13.

For example, in the case where the modulation of the OFDM is DCO-OFDM multi-carrier modulation, in step 13, the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path, and the following superposition method can be used Either of:

The first superposition method: calculate the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and add the first product and the predetermined DC component to obtain the to-be-sent signal on each color optical path .

Here, the first superposition method can be expressed as: OFDM signal of the color optical path*light intensity of the color optical path (ie, CSK modulated light intensity)+DC component, wherein the OFDM signal is a signal with 0 mean value. The multiplication of the OFDM signal by the light intensity means that the signal intensity of each OFDM symbol is multiplied by the light intensity.

The second superposition method: the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component are respectively added to obtain the to-be-sent signal on each color optical path.

Here, the second superposition mode can be expressed as: OFDM signal of color optical path+DC component+CSK modulated light intensity. Wherein, the OFDM signal is a signal with 0 mean value.

The third superposition method: separately add the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, calculate the product of the sum value and the light intensity of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path .

Here, the third superposition method can be expressed as: (OFDM signal of color optical path+DC component)*CSK modulated light intensity, where the OFDM signal is a signal with 0 mean value.

The fourth superposition method: respectively calculate the second product of the light intensity of each color optical path and the predetermined DC component, and add the second product to the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path .

Here, the fourth superposition mode can be expressed by a formula as: OFDM signal of the color optical path+DC component*CSK modulated light intensity, where the OFDM signal is a signal with 0 mean value.

In the case where the modulation of the OFDM is ACO-OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, that is, when no additional direct current (DC) component is required to ensure a non-negative signal, in step 13, the The light intensity of each color light path is superimposed on the OFDM signal of the corresponding color light path, and any of the following superposition methods can be used:

Fifth superposition method: separately calculate the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path;

Here, the fifth superposition mode can be expressed as: OFDM signal (positive mean value)*CSK modulated light intensity, wherein the OFDM signal is a signal with a positive mean value.

Sixth superposition method: respectively adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path.

Here, the sixth superposition mode can be expressed as: OFDM signal (positive mean value)+CSK modulated light intensity. Wherein, the OFDM signal is a signal with a positive average value.

In addition, in the embodiment of the present invention, considering the sampling frequency matching, it is assumed that the sampling frequency of the first data stream during the color modulation in step 11 is the first sampling frequency, and when the data stream on the optical path of each color is subjected to OFDM modulation both use the second sampling frequency, then the first sampling frequency is the same as the second sampling frequency, or the first sampling frequency is N times the second sampling frequency, or the second sampling frequency is the N times the sampling frequency, where N is an integer greater than 1. That is to say, when the first device synthesizes the signal by multiplying the light intensity signal modulated by the first data stream and the multi-channel data signals obtained by various color optical paths, the sampling frequency of the signal here should be consistent, or all The sampling frequency of the light intensity signal is N times or 1/N times the sampling frequency of the multi-channel data signals obtained by the light paths of various colors, where N is a positive integer.

The following describes the visible light demodulation method according to the embodiment of the present invention from the receiving end.

Referring to FIG. 3 , a schematic flowchart of the visible light demodulation method on the second device side according to the embodiment of the present invention is given. FIG. 4 is an example diagram of a demodulation process provided by taking the red light path, the green light path and the blue light path as an example of three color light paths. In this example, the multiple color light paths include red light paths, green light paths and blue light paths. In the visible light demodulation method, the embodiment of the present invention demodulates the visible light signal sent by the first device, and recovers multiple data streams therefrom. Specifically, as shown in FIG. 3 , the visible light demodulation method provided by the embodiment of the present invention includes:

Step 31: Receive a signal sent by the first device on each color optical path among the multiple color optical paths.

Here, as mentioned above, the transmitted signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color through wavelength division multiplexing, and the transmitted signal on each optical channel is based on the pre- Assuming the superposition method, it is obtained by superimposing the light intensity of the corresponding color optical path on the OFDM signal of the corresponding color optical path. The OFDM signal of each color optical path is for the data streams on the multiple color optical paths, using the OFDM modulation method. It is obtained by modulating the data stream on the optical path of each color respectively on the modulation bandwidth corresponding to the optical path of the color.

As shown in FIG. 4 , the second device can receive the transmitted signal on the light path of each color through the photodetector. The photodetector includes a filter corresponding to the color light path, and can extract the signal corresponding to the color light path from the visible light signal and perform subsequent processing.

Step 32 , demodulate a second data stream from the signals of the multiple-color optical paths through color demodulation.

Step 33 , respectively perform OFDM demodulation on the data streams on the optical paths of each color on the modulation bandwidth corresponding to the optical paths of each color, to obtain the data streams on the optical paths of each color.

Here, in the case where the preset superposition method adopted by the transmitting end adds a DC component to the transmitted signal, in step 33, before performing OFDM demodulation on the data stream on the optical path of each color, it is also necessary to remove the DC component. The DC component in the transmitted signal is described, and then demodulated.

A specific example of OFDM demodulation is given in FIG. 4 , for example, it includes steps such as serial-to-parallel conversion, CP removal, FFT transformation, parallel-serial conversion, and data demodulation, so as to obtain data streams on each color optical path.

Through the above steps, the embodiment of the present invention demodulates multiple data streams from the visible light signal, thereby realizing the demodulation of the modulated signal at the transmitting end.

Specifically, in the above steps, the second device can first use the color demodulation technology to demodulate a data signal (herein referred to as the second data stream) according to the different superposition methods adopted by the transmitting end (the first device), and then The signal after removing the DC component is demodulated in the frequency domain dimension.

For example, in the case where the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the first superposition mode; in step 32, the second superposition mode is demodulated from the signals of the multiple color optical paths. Data flow, including:

1) detecting the variance value of the power of the transmitted signal on each color optical path, and performing demodulation of the color domain according to the CSK constellation diagram corresponding to the ratio of the variance value of the power to obtain the second data stream;

or,

2) Detecting the variance value of the DC component intensity of the transmitted signal on the optical path of each color, and performing demodulation of the color domain according to the CSK constellation map corresponding to the ratio of the variance value of the DC component intensity to obtain the second data flow;

The first superposition method is: calculating the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and adding the first product and a predetermined DC component.

Specifically, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the second superposition mode, the third superposition mode or the fourth superposition mode; or, the modulation of the OFDM is ACO- In the case of OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, and the preset superposition mode is the fifth superposition mode or the sixth superposition mode, in step 32, the solution is obtained from the signals of the multi-color optical paths. Calling out the second data stream, which specifically includes:

Detect the power or signal strength of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation diagram corresponding to the ratio of the power or the CSK constellation diagram corresponding to the ratio of the signal strength to obtain the second data flow.

Wherein, the second superposition method is: adding the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component respectively;

The third superposition method is: separately adding the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, and calculating the product of the sum value and the light intensity of the corresponding color optical path;

The fourth superposition method is: separately calculating the second product of the light intensity of each color optical path and the predetermined DC component, and adding the second product to the OFDM signal of the corresponding color optical path;

The fifth superposition method is: separately calculating the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path;

The sixth superposition manner is: adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path respectively.

Considering that the receiving end needs to sample the color demodulated signal according to the sampling frequency used by the transmitting end, if the sampling frequency of the color modulation at the transmitting end is the same as that of OFDM multi-carrier modulation, the receiving end needs to perform signal variance or Detection and demodulation of signal power and intensity; if the sampling frequency of color modulation is N times that of OFDM multi-carrier modulation, it is necessary to detect signal variance or signal power and intensity on N OFDMs, and then demodulate after averaging; If the sampling frequency of color modulation is 1/N times that of OFDM multi-carrier modulation, it is necessary to perform detection and demodulation of signal variance or signal power and intensity on 1/N OFDMs.

In this way, in the above step 32, the second device also performs the color demodulation signal sampling according to the first sampling frequency when the first device performs color modulation on the first data stream, wherein:

When the first sampling frequency is the same as the second sampling frequency when the first device performs OFDM modulation on the data stream on the optical path of each color, perform signal detection on each OFDM symbol on the optical path of each color and demodulation;

When the first sampling frequency is N times the second sampling frequency, signal detection is performed on N OFDM symbols on the optical path of each color, and the average value of the detection results of the N OFDM symbols is calculated. The average value is demodulated;

When the second sampling frequency is N times the first sampling frequency, signal detection and demodulation are performed on 1/N OFDM symbols on the optical path of each color;

The N is an integer greater than 1.

Various methods of the embodiments of the present invention have been described above. Apparatus for carrying out the above method will be further provided below.

An embodiment of the present invention provides a first device shown in FIG. 5, including:

The first modulation module 51 is configured to perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths;

The second modulation module 52 is configured to perform orthogonal frequency division multiplexing (OFDM) modulation on the data stream on the optical path of each color on the modulation bandwidth corresponding to the optical path of each color, to obtain the OFDM signal of the optical path of each color;

The superimposing module 53 is used to superimpose the light intensity of each color optical path on the OFDM signal of the corresponding color optical path, obtain the transmission signal on each color optical path, and use wavelength division multiplexing on the corresponding color optical path. transmitted on the optical channel.

Based on the above modules, the embodiments of the present invention make full use of the physical characteristics of the visible light polychromatic optical path, and can improve the data transmission efficiency by utilizing the degree of freedom of the complex space in the frequency domain.

Optionally, the multiple color light paths include red light paths, green light paths and blue light paths.

Optionally, the first modulation module is further configured to perform color shift keying CSK processing on the data of the first data stream to obtain corresponding chromaticity values; according to the chromaticity values, calculate each color The light intensity of the light path.

Optionally, the second modulation module is further configured to perform frequency domain mapping processing and inverse fast Fourier transform processing on the data streams on the optical paths of each color on the modulation bandwidth corresponding to the optical paths of each color.

Optionally, the second modulation module is further configured to further include between the frequency domain mapping processing and the inverse fast Fourier transform processing: performing serial-parallel conversion processing on the signal obtained by the frequency domain mapping processing. ;

After the inverse fast Fourier transform processing, the method further includes: adding a cyclic prefix CP to the signal obtained by the inverse fast Fourier transform processing and performing parallel-serial conversion processing.

Optionally, the modulation of the OFDM is DC-biased light DCO-OFDM multi-carrier modulation, and the superposition module is further configured to superimpose the light intensity of each color optical path according to any one of the following superposition methods To the OFDM signal corresponding to the color optical path:

The first superposition method: calculate the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and add the first product and the predetermined DC component to obtain the to-be-sent signal on each color optical path ;

The second superposition method: the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component are added to obtain the to-be-sent signal on each color optical path;

The third superposition method: separately add the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, calculate the product of the sum value and the light intensity of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path ;

The fourth superposition method: respectively calculate the second product of the light intensity of each color optical path and the predetermined DC component, and add the second product to the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path .

optional,

The modulation of the OFDM is asymmetric limiting optical ACO-OFDM multi-carrier modulation or flip-Flip-OFDM multi-carrier modulation. The light intensity of the light path is superimposed on the OFDM signal of the corresponding color light path:

Fifth superposition method: separately calculate the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path;

Sixth superposition method: respectively adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path.

Optionally, the first sampling frequency of the first data stream when the color is modulated is the same as the second sampling frequency when the data stream on each color optical path is modulated by OFDM, or the first sampling frequency is N times the second sampling frequency, or the second sampling frequency is N times the first sampling frequency, where N is an integer greater than 1.

It should be noted that the apparatus in this embodiment is a device corresponding to the method shown in FIG. 1 above, and the implementation manners in the above embodiments are all applicable to the embodiments of the device, and the same technical effect can also be achieved. It should be noted here that the above-mentioned device provided by the embodiment of the present invention can realize all the method steps realized by the above-mentioned method embodiment, and can achieve the same technical effect, and the same as the method embodiment in this embodiment is not repeated here. The parts and beneficial effects will be described in detail.

Referring to FIG. 6, an embodiment of the present invention provides a schematic structural diagram of a first device, including: a processor 601, a transceiver 602, a memory 603, and a bus interface, wherein:

In this embodiment of the present invention, the first device further includes: a program stored on the memory 603 and executable on the processor 601, and the program implements the following steps when executed by the processor 601:

Perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths;

For the data streams on the optical paths of the various colors, the modulation mode of orthogonal frequency division multiplexing (OFDM) is used to modulate the data streams on the optical paths of each color in the modulation bandwidth corresponding to the optical paths of each color, to obtain the optical paths of each color. OFDM signal;

The light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and transmits on the optical channel corresponding to the color optical path by means of wavelength division multiplexing.

Optionally, the multiple color light paths include red light paths, green light paths and blue light paths.

Optionally, the processor further implements the following steps when executing the program:

performing color shift keying CSK processing on the data of the first data stream to obtain corresponding chrominance values;

According to the chromaticity value, the light intensity of each color light path is calculated.

Optionally, when the processor executes the program, the following steps are also implemented: on the modulation bandwidth corresponding to each color optical path, respectively perform frequency domain mapping processing and inverse fast Fourier on the data stream on each color optical path. Leaf transform processing.

Optionally, the processor further implements the following steps when executing the program:

Between the frequency domain mapping processing and the inverse fast Fourier transform processing, the method further includes: performing serial-to-parallel conversion processing on the signal obtained by the frequency domain mapping processing;

After the inverse fast Fourier transform processing, the method further includes: adding a cyclic prefix CP to the signal obtained by the inverse fast Fourier transform processing and performing parallel-serial conversion processing.

Optionally, the modulation of the OFDM is DC bias light DCO-OFDM multi-carrier modulation, and the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path, including any of the following superposition methods. A sort of:

The first superposition method: calculate the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and add the first product and the predetermined DC component to obtain the to-be-sent signal on each color optical path ;

The second superposition method: the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component are added to obtain the to-be-sent signal on each color optical path;

The third superposition method: separately add the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, calculate the product of the sum value and the light intensity of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path ;

The fourth superposition method: respectively calculate the second product of the light intensity of each color optical path and the predetermined DC component, and add the second product to the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path .

Optionally, the modulation of the OFDM is asymmetric amplitude limiting optical ACO-OFDM multi-carrier modulation or flip-Flip-OFDM multi-carrier modulation, and the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path. , including any of the following stacking methods:

Fifth superposition method: separately calculate the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path;

Sixth superposition method: respectively adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path.

Optionally, the first sampling frequency of the first data stream when the color is modulated is the same as the second sampling frequency when the data stream on each color optical path is modulated by OFDM, or the first sampling frequency is N times the second sampling frequency, or the second sampling frequency is N times the first sampling frequency, where N is an integer greater than 1.

It is understandable that in this embodiment of the present invention, when the computer program is executed by the processor 601, each process of the method embodiment shown in FIG. 1 can be implemented, and the same technical effect can be achieved. Repeat.

In FIG. 6, the bus architecture may include any number of interconnected buses and bridges, in particular one or more processors represented by processor 601 and various circuits of memory represented by memory 603 linked together. The bus architecture may also link together various other circuits, such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be described further herein. The bus interface provides the interface. Transceiver 602 may be a number of elements, including a transmitter and a receiver, that provide a means for communicating with various other devices over a transmission medium.

The processor 601 is responsible for managing the bus architecture and general processing, and the memory 603 may store data used by the processor 601 in performing operations.

It should be noted that the terminal in this embodiment is a device corresponding to the method shown in FIG. 1 above, and the implementation manners in the above embodiments are all applicable to the embodiments of the terminal, and the same technical effect can also be achieved. In this device, the transceiver 602 and the memory 603, as well as the transceiver 602 and the processor 601 can be communicated and connected through a bus interface, the function of the processor 601 can also be realized by the transceiver 602, and the function of the transceiver 602 can also be realized by the processor 601 realized. It should be noted here that the above-mentioned device provided by the embodiment of the present invention can realize all the method steps realized by the above-mentioned method embodiment, and can achieve the same technical effect, and the same as the method embodiment in this embodiment is not repeated here. The parts and beneficial effects will be described in detail.

In some embodiments of the present invention, a computer-readable storage medium is also provided, on which a program is stored, and when the program is executed by a processor, the following steps are implemented:

Perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths;

For the data streams on the optical paths of the various colors, the modulation mode of orthogonal frequency division multiplexing (OFDM) is used to modulate the data streams on the optical paths of each color in the modulation bandwidth corresponding to the optical paths of each color, to obtain the optical paths of each color. OFDM signal;

The light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and transmits on the optical channel corresponding to the color optical path by means of wavelength division multiplexing.

When the program is executed by the processor, all the above-mentioned implementation modes of the visible light modulation method and the demodulation method applied to the first device can be realized, and the same technical effect can be achieved. To avoid repetition, details are not described here.

Referring to FIG. 7 , an embodiment of the present invention provides a second device, including:

a receiving module 71, configured to receive a signal sent by the first device on each color optical path among the multiple color optical paths;

a first demodulation module 72, configured to demodulate a second data stream from the signals of the multiple-color optical paths through color demodulation;

The second demodulation module 73 is configured to perform OFDM demodulation on the modulation bandwidth corresponding to each color optical path, respectively, on the data stream on the color optical path, to obtain the data stream on each color optical path;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color by the wavelength division multiplexing method, and the transmission signal on the optical channel of each color is according to the preset superposition method, It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the corresponding color light path. The OFDM signal of each color light path is obtained by OFDM modulation of the data stream on the color light path. The light intensity of each color light path is The first data stream is obtained by performing color modulation.

Optionally, the multiple color light paths include red light paths, green light paths and blue light paths.

Optionally, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is a first superposition mode; optionally, the first demodulation module is further configured to:

Detecting the variance value of the power of the transmitted signal on each color optical path, and performing color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the power, to obtain the second data stream;

or,

Detect the variance value of the DC component intensity of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the DC component intensity to obtain the second data stream ;

The first superposition method is: calculating the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and adding the first product and a predetermined DC component.

Optionally, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the second superposition mode, the third superposition mode or the fourth superposition mode; or, the modulation of the OFDM is ACO- OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, and the preset superposition mode is the fifth superposition mode or the sixth superposition mode;

The first demodulation module is also used for:

Detect the power or signal strength of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation diagram corresponding to the ratio of the power or the CSK constellation diagram corresponding to the ratio of the signal strength to obtain the second data flow;

Wherein, the second superposition method is: adding the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component respectively;

The third superposition method is: separately adding the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, and calculating the product of the sum value and the light intensity of the corresponding color optical path;

The fourth superposition method is: separately calculating the second product of the light intensity of each color optical path and the predetermined DC component, and adding the second product to the OFDM signal of the corresponding color optical path;

The fifth superposition method is: separately calculating the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path;

The sixth superposition manner is: adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path respectively.

Optionally, the first demodulation module is further configured to:

The signal sampling of the color demodulation is performed according to the first sampling frequency when the first device performs color modulation on the first data stream, wherein:

When the first sampling frequency is the same as the second sampling frequency when the first device performs OFDM modulation on the data stream on the optical path of each color, perform signal detection on each OFDM symbol on the optical path of each color and demodulation;

When the first sampling frequency is N times the second sampling frequency, signal detection is performed on N OFDM symbols on the optical path of each color, and the average value of the detection results of the N OFDM symbols is calculated. The average value is demodulated;

When the second sampling frequency is N times the first sampling frequency, signal detection and demodulation are performed on 1/N OFDM symbols on the optical path of each color;

The N is an integer greater than 1.

Optionally, the second demodulation module is further configured to perform OFDM demodulation on the data stream on the optical path of each color before the OFDM demodulation is performed when the preset superposition mode adds a DC component to the transmitted signal. , remove the DC component in the transmission signal.

It should be noted that the device in this embodiment is a device corresponding to the method shown in FIG. 3 above, and the implementation manners in each of the above embodiments are applicable to the embodiments of the device, and the same technical effect can also be achieved. The above-mentioned device provided in the embodiment of the present invention can realize all the method steps realized by the above-mentioned method embodiment, and can achieve the same technical effect, and the parts and beneficial effects that are the same as the method embodiment in this embodiment will not be described in detail here. Repeat.

Please refer to FIG. 8 , which is a schematic structural diagram of a terminal provided by an embodiment of the present invention. The terminal includes: a processor 801 , a transceiver 802 , a memory 803 , a user interface 804 , and a bus interface.

In this embodiment of the present invention, the terminal further includes: a program stored on the memory 803 and executable on the processor 801 .

When the processor 801 executes the program, the following steps are implemented: '

receiving a signal sent by the first device on each color optical path among the multiple color optical paths;

demodulating the second data stream from the signals of the multiple color optical paths through color demodulation;

On the modulation bandwidth corresponding to each color optical path, OFDM demodulates the data stream on the color optical path respectively to obtain the data stream on each color optical path;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color through wavelength division multiplexing, and the transmission signal on the optical channel of each color is based on the preset superposition method, in the corresponding It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the color light path. The OFDM signal of each color light path is for the data streams on the multiple color light paths, using the OFDM modulation method, and the modulation method corresponding to each color light path It is obtained by modulating the data stream on the optical path of the color respectively in terms of bandwidth.

Optionally, the multiple color light paths include red light paths, green light paths and blue light paths.

Optionally, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the first superposition mode; when the processor executes the program, the following steps are further implemented:

Detecting the variance value of the power of the transmitted signal on each color optical path, and performing color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the power, to obtain the second data stream;

or,

Detect the variance value of the DC component intensity of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the DC component intensity to obtain the second data stream ;

The first superposition method is: calculating the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and adding the first product and a predetermined DC component.

Optionally, the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the second superposition mode, the third superposition mode or the fourth superposition mode; or, the modulation of the OFDM is ACO- OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, and the preset superposition mode is the fifth superposition mode or the sixth superposition mode;

The processor also implements the following steps when executing the program:

Detect the power or signal strength of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation diagram corresponding to the ratio of the power or the CSK constellation diagram corresponding to the ratio of the signal strength to obtain the second data flow;

Wherein, the second superposition method is: adding the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component respectively;

The third superposition method is: separately adding the OFDM signal of each color optical path and a predetermined DC component to obtain a sum value, and calculating the product of the sum value and the light intensity of the corresponding color optical path;

The fourth superposition method is: separately calculating the second product of the light intensity of each color optical path and the predetermined DC component, and adding the second product to the OFDM signal of the corresponding color optical path;

The fifth superposition method is: separately calculating the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path;

The sixth superposition manner is: adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path respectively.

Optionally, the processor further implements the following steps when executing the program:

The signal sampling of the color demodulation is performed according to the first sampling frequency when the first device performs color modulation on the first data stream, wherein:

When the first sampling frequency is the same as the second sampling frequency when the first device performs OFDM modulation on the data stream on the optical path of each color, perform signal detection on each OFDM symbol on the optical path of each color and demodulation;

When the first sampling frequency is N times the second sampling frequency, signal detection is performed on N OFDM symbols on the optical path of each color, and the average value of the detection results of the N OFDM symbols is calculated. The average value is demodulated;

When the second sampling frequency is N times the first sampling frequency, signal detection and demodulation are performed on 1/N OFDM symbols on the optical path of each color;

The N is an integer greater than 1.

Optionally, optionally, the processor further implements the following steps when executing the program: in the case where the preset superposition mode adds a DC component to the transmitted signal, compare the data on the optical path of each color. Before the stream is subjected to OFDM demodulation, the DC component in the transmitted signal is removed.

Understandably, in this embodiment of the present invention, when the computer program is executed by the processor 801, each process of the method embodiment shown in FIG. 3 can be implemented, and the same technical effect can be achieved. Repeat.

In FIG. 8, the bus architecture may include any number of interconnected buses and bridges, in particular one or more processors represented by processor 801 and various circuits of memory represented by memory 803 linked together. The bus architecture may also link together various other circuits, such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be described further herein. The bus interface provides the interface. Transceiver 802 may be a number of elements, including a transmitter and a receiver, that provide a means for communicating with various other devices over a transmission medium. For different user equipments, the user interface 804 may also be an interface capable of externally connecting the required equipment, and the connected equipment includes but is not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

The processor 801 is responsible for managing the bus architecture and general processing, and the memory 803 may store data used by the processor 801 in performing operations.

It should be noted that the device in this embodiment is a device corresponding to the method shown in FIG. 3 above, and the implementation manners in each of the above embodiments are applicable to the embodiments of the device, and the same technical effect can also be achieved. In this device, the transceiver 802 and the memory 803, as well as the transceiver 802 and the processor 801 can be communicated and connected through a bus interface, the function of the processor 801 can also be realized by the transceiver 802, and the function of the transceiver 802 can also be realized by the processor 801 implementation. It should be noted here that the above-mentioned device provided by the embodiment of the present invention can realize all the method steps realized by the above-mentioned method embodiment, and can achieve the same technical effect, and the same as the method embodiment in this embodiment is not repeated here. The parts and beneficial effects will be described in detail.

In some embodiments of the present invention, a computer-readable storage medium is also provided, on which a program is stored, and when the program is executed by a processor, the following steps are implemented:

receiving a signal sent by the first device on each color optical path among the multiple color optical paths;

demodulating the second data stream from the signals of the multiple color optical paths through color demodulation;

On the modulation bandwidth corresponding to each color optical path, OFDM demodulates the data stream on the color optical path respectively to obtain the data stream on each color optical path;

Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color through wavelength division multiplexing, and the transmission signal on each optical channel is in the corresponding It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the color light path. The OFDM signal of each color light path is for the data streams on the multiple color light paths, using the OFDM modulation method, and the modulation method corresponding to each color light path is used. It is obtained by modulating the data stream on the optical path of the color respectively in terms of bandwidth.

When the program is executed by the processor, all the above-mentioned implementation modes of the visible light modulation method and the demodulation method applied to the second device side can be realized, and the same technical effect can be achieved. To avoid repetition, details are not described here.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solutions in the embodiments of the present invention.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present invention can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: a U disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk, and other media that can store program codes.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (19)

1. a visible light modulation method, is characterized in that, comprises: Perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths; For the data streams on the optical paths of the various colors, the modulation mode of orthogonal frequency division multiplexing (OFDM) is used to modulate the data streams on the optical paths of each color in the modulation bandwidth corresponding to the optical paths of each color, to obtain the optical paths of each color. OFDM signal; The light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and transmits on the optical channel corresponding to the color optical path by means of wavelength division multiplexing. 2. The method according to claim 1, wherein the performing color modulation on the first data stream comprises: performing color shift keying CSK processing on the data of the first data stream to obtain corresponding chrominance values; According to the chromaticity value, the light intensity of each color light path is calculated. 3. The method according to claim 1, wherein, for the data streams on the optical paths of the multiple colors, an orthogonal frequency division multiplexing (OFDM) modulation method is used, and the modulation bandwidths corresponding to the optical paths of each color are respectively Modulation of the data stream on the optical path of this color, including: On the modulation bandwidth corresponding to each color optical path, frequency domain mapping processing and inverse fast Fourier transform processing are respectively performed on the data stream on each color optical path. 4. The method of claim 3, wherein Between the frequency domain mapping processing and the inverse fast Fourier transform processing, the method further includes: performing serial-to-parallel conversion processing on the signal obtained by the frequency domain mapping processing; After the inverse fast Fourier transform processing, the method further includes: adding a cyclic prefix CP to the signal obtained by the inverse fast Fourier transform processing and performing parallel-serial conversion processing. 5. The method of claim 3, wherein The modulation of the OFDM is DC-biased light DCO-OFDM multi-carrier modulation, and the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path, including any one of the following superposition methods: The first superposition method: calculate the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and add the first product and the predetermined DC component to obtain the to-be-sent signal on each color optical path ; The second superposition method: the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component are added to obtain the to-be-sent signal on each color optical path; The third superposition method: separately add the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, calculate the product of the sum value and the light intensity of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path ; The fourth superposition method: calculate the second product of the light intensity of each color optical path and the predetermined DC component, and add the second product to the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path . 6. The method of claim 3, wherein The modulation of the OFDM is asymmetric limiting optical ACO-OFDM multi-carrier modulation or flip-Flip-OFDM multi-carrier modulation, and the light intensity of each color optical path is superimposed on the OFDM signal of the corresponding color optical path, including the following: Any of the stacking methods: Fifth superposition method: separately calculate the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and obtain the to-be-sent signal on each color optical path; Sixth superposition method: respectively adding the light intensity of each color optical path and the OFDM signal of the corresponding color optical path to obtain the to-be-sent signal on each color optical path. 7. The method of claim 1, wherein, The first sampling frequency of the first data stream during the color modulation is the same as the second sampling frequency when the data streams on each color optical path are subjected to OFDM modulation, or the first sampling frequency is the second sampling frequency N times the frequency, or the second sampling frequency is N times the first sampling frequency, where N is an integer greater than 1. 8. A visible light demodulation method, applied to the second device, is characterized in that, comprising: receiving a signal sent by the first device on each color optical path among the multiple color optical paths; demodulating the second data stream from the signals of the multiple color optical paths through color demodulation; On the modulation bandwidth corresponding to each color optical path, OFDM demodulates the data stream on the color optical path respectively to obtain the data stream on each color optical path; Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color through wavelength division multiplexing, and the transmission signal on each optical channel is in the corresponding It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the color light path. The OFDM signal of each color light path is for the data streams on the multiple color light paths, using the OFDM modulation method, and the modulation method corresponding to each color light path is used. It is obtained by modulating the data stream on the optical path of the color respectively in terms of bandwidth. 9. The method according to claim 8, wherein the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the first superposition mode; The second data stream is demodulated from the signals of the multi-color optical paths, including: Detecting the variance value of the power of the transmitted signal on each color optical path, and performing color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the power, to obtain the second data stream; or, Detect the variance value of the DC component intensity of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation map corresponding to the ratio of the variance value of the DC component intensity to obtain the second data stream ; The first superposition method is: calculating the first product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path, and adding the first product and a predetermined DC component. 10 . The method according to claim 8 , wherein the modulation of the OFDM is DCO-OFDM multi-carrier modulation, and the preset superposition mode is the second superposition mode, the third superposition mode or the fourth superposition mode. 11 . Or, the modulation of the OFDM is ACO-OFDM multi-carrier modulation or Flip-OFDM multi-carrier modulation, and the preset superposition mode is the fifth superposition mode or the sixth superposition mode; The second data stream is demodulated from the signals of the multi-color optical paths, including: Detect the power or signal strength of the transmitted signal on the optical path of each color, and perform color domain demodulation according to the CSK constellation diagram corresponding to the ratio of the power or the CSK constellation diagram corresponding to the ratio of the signal strength to obtain the second data flow; Wherein, the second superposition method is: adding the light intensity of each color optical path, the OFDM signal corresponding to the color optical path, and the predetermined DC component respectively; The third superposition method is: separately adding the OFDM signal of each color optical path and the predetermined DC component to obtain a sum value, and calculating the product of the sum value and the light intensity of the corresponding color optical path; The fourth superposition method is: separately calculating the second product of the light intensity of each color optical path and the predetermined DC component, and adding the second product to the OFDM signal of the corresponding color optical path; The fifth superposition method is: separately calculating the third product of the light intensity of each color optical path and the OFDM signal of the corresponding color optical path; The sixth superposition manner is: adding the light intensity of each color light path and the OFDM signal of the corresponding color light path respectively. 11. The method according to claim 9 or 10, wherein the demodulating the second data stream from the signals of the multiple-color optical paths through color demodulation, further comprising: The signal sampling of the color demodulation is performed according to the first sampling frequency when the first device performs color modulation on the first data stream, wherein: When the first sampling frequency is the same as the second sampling frequency when the first device performs OFDM modulation on the data stream on the optical path of each color, perform signal detection on each OFDM symbol on the optical path of each color and demodulation; When the first sampling frequency is N times the second sampling frequency, signal detection is performed on N OFDM symbols on the optical path of each color, and the average value of the detection results of the N OFDM symbols is calculated. The average value is demodulated; When the second sampling frequency is N times the first sampling frequency, signal detection and demodulation are performed on 1/N OFDM symbols on the optical path of each color; The N is an integer greater than 1. 12 . The method according to claim 8 , wherein, in the case that a DC component is added to the transmitted signal in the preset superposition manner, before performing OFDM demodulation on the data stream on the optical path of each color , and further comprising: removing the DC component in the transmission signal. 13. A first device, characterized in that, comprising: a first modulation module, configured to perform color modulation on the first data stream to obtain the light intensity of each color light path in the multiple color light paths; The second modulation module is configured to perform orthogonal frequency division multiplexing (OFDM) modulation on the data stream on the color optical path on the modulation bandwidth corresponding to each color optical path, so as to obtain the OFDM signal of each color optical path; The superposition module is used to superimpose the light intensity of each color optical path on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path, and use wavelength division multiplexing on the light corresponding to the color optical path. send on the channel. 14. A first device, comprising a transceiver and a processor, wherein, The transceiver is used to perform color modulation on the first data stream to obtain the light intensity of each color optical path in the multiple color optical paths; on the modulation bandwidth corresponding to each color optical path, the data streams on the color optical path are respectively Perform orthogonal frequency division multiplexing OFDM modulation to obtain the OFDM signal of each color optical path; superimpose the light intensity of each color optical path on the OFDM signal of the corresponding color optical path to obtain the transmitted signal on each color optical path; The processor is configured to transmit signals on each color optical path on the optical channel corresponding to the color optical path by means of wavelength division multiplexing. 15. A first device, comprising: a processor, a memory, and a program stored on the memory and executable on the processor, the program being executed by the processor to achieve the right The steps of the method of any one of claims 1 to 7. 16. A second device, comprising: a receiving module, configured to receive a signal sent by the first device on each color optical path among the multiple color optical paths; a first demodulation module, configured to demodulate a second data stream from the signals of the multiple-color optical paths through color demodulation; The second demodulation module is used for respectively performing OFDM demodulation on the data stream on the color optical path on the modulation bandwidth corresponding to each color optical path to obtain the data stream on each color optical path; Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color by the wavelength division multiplexing method, and the transmission signal on the optical channel of each color is according to the preset superposition method, It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the corresponding color light path. The OFDM signal of each color light path is obtained by OFDM modulation of the data stream on the color light path. The light intensity of each color light path is The first data stream is obtained by performing color modulation. 17. A second device comprising a transceiver and a processor, wherein, The transceiver is used to receive a signal sent by the first device on each color optical path among the multiple color optical paths; The processor is used for demodulating the second data stream from the signals of the multiple color optical paths through color demodulation; on the modulation bandwidth corresponding to each color optical path, the data streams on the color optical path are respectively Perform OFDM demodulation to obtain the data stream on the optical path of each color; Wherein, the transmission signal on the optical path of each color is sent by the first device on the optical channel corresponding to the optical path of each color by the wavelength division multiplexing method, and the transmission signal on the optical channel of each color is according to the preset superposition method, It is obtained by superimposing the light intensity of the corresponding color light path on the OFDM signal of the corresponding color light path. The OFDM signal of each color light path is obtained by OFDM modulation of the data stream on the color light path. The light intensity of each color light path is The first data stream is obtained by performing color modulation. 18. A second device, comprising: a processor, a memory, and a program stored on the memory and executable on the processor, the program being executed by the processor to achieve the right The steps of any one of claims 8 to 12. 19. A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method according to any one of claims 1 to 12 is implemented A step of.

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