Simulation visible light communication method and related equipment

Abstract

The invention provides a visible light communication simulation method and related equipment. The method comprises the following steps: constructing an optical communication channel response model; in the optical communication channel response model, modulating a received first signal by using M-bit pulse amplitude to obtain a second signal; performing direct current bias processing on the second signal to obtain a third signal; in response to the third signal passing through an optical channel in the optical communication channel response model, performing DC bias removal and demodulation processing on the third signal to obtain a fourth signal; and receiving the fourth signal to complete simulated visible light communication. According to the embodiment of the invention, the signal is modulated and demodulated by using the M-bit pulse amplitude, the low-order harmonic component contained in the output voltage of the inverter is effectively reduced, and the output frequency and the output voltage can be adjusted.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to a method for simulating visible light communication and related equipment. Background Art

[0002] With the development of wireless communication technology, the demand for spectrum resources is increasing. The visible light spectrum, an underutilized resource, has become a new research hotspot. Indoor visible light communication (VLC) uses LED lighting devices as data transmitters and receivers, not only providing illumination but also enabling high-speed data transmission. VLC is a green technology with low power consumption and low carbon emissions, offering excellent sustainability and promising development prospects. VLC technology is safe and healthy for the human body and poses no electromagnetic radiation hazards. Its data transmission is localized, secure, and accurate. VLC offers several significant advantages over traditional radio frequency communication and can be applied in scenarios where traditional radio frequency communication is insufficient, such as underwater communications, hazardous environments, hospitals, and airports.

[0003] However, at high data rates, signal bandwidth increases significantly, potentially leading to spectral overlap and interference between adjacent channels. Complex signal processing algorithms increase system cost and power consumption. The high peak-to-average power of OFDM signals can cause nonlinear distortion in the LED (Light Emitting Diode) drive current, necessitating precise frequency synchronization and phase compensation mechanisms. Summary of the Invention

[0004] In view of this, the purpose of this application is to propose a simulated visible light communication method and related equipment.

[0005] Based on the above objectives, the present application provides a method for simulating visible light communication, comprising:

[0006] Construct an optical communication channel response model;

[0007] In the optical communication channel response model, a received first signal is modulated using an M-bit pulse amplitude to obtain a second signal; the second signal is subjected to DC bias processing to obtain a third signal; and in response to the third signal passing through an optical channel in the optical communication channel response model, the third signal is subjected to DC bias removal and demodulation processing to obtain a fourth signal;

[0008] The fourth signal is received to complete the simulated visible light communication.

[0009] In a possible implementation, after obtaining the second signal, the method further includes:

[0010] adding a cyclic prefix to the second signal to obtain a fifth signal;

[0011] The performing DC bias processing on the second signal to obtain a third signal includes:

[0012] Performing DC bias processing on the fifth signal to obtain the third signal.

[0013] In a possible implementation manner, after obtaining the third signal, the method further includes:

[0014] performing shearing processing on the third signal to obtain a sixth signal;

[0015] The step of removing a DC bias and performing demodulation processing on the third signal in response to the third signal passing through the optical channel in the optical communication channel response model to obtain a fourth signal includes:

[0016] In response to the sixth signal passing through the optical channel in the optical communication channel response model, the sixth signal is subjected to DC bias removal and demodulation processing to obtain a fourth signal.

[0017] In a possible implementation, removing a DC bias and performing demodulation processing on the third signal to obtain a fourth signal includes:

[0018] removing a DC bias from the third signal to obtain a seventh signal;

[0019] The seventh signal is demodulated using M-bit pulse amplitude modulation to obtain the fourth signal.

[0020] In a possible implementation, after obtaining the seventh signal, the method further includes:

[0021] Perform zero-force balancing processing on the seventh signal to obtain an eighth signal.

[0022] In a possible implementation, after obtaining the eighth signal, the method further includes:

[0023] removing a cyclic prefix from the eighth signal to obtain a ninth signal;

[0024] The demodulating the seventh signal by using M-bit pulse amplitude modulation to obtain the fourth signal includes:

[0025] The ninth signal is demodulated using M-bit pulse amplitude modulation to obtain the fourth signal.

[0026] Based on the same inventive concept, an embodiment of the present application further provides a simulated visible light communication device, comprising:

[0027] A building module configured to build an optical communication channel response model;

[0028] The transmission module is configured to modulate the received first signal using an M-bit pulse amplitude in the optical communication channel response model to obtain a second signal; perform DC bias processing on the second signal to obtain a third signal; and remove the DC bias and demodulate the third signal in response to the third signal passing through the optical channel in the optical communication channel response model to obtain a fourth signal;

[0029] The receiving module is configured to receive the fourth signal to complete the simulated visible light communication.

[0030] In one possible implementation,

[0031] Based on the same inventive concept, an embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein when the processor executes the program, the simulated visible light communication method as described in any one of the above items is implemented.

[0032] Based on the same inventive concept, an embodiment of the present application further provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable the computer to execute any of the above-mentioned simulated visible light communication methods.

[0033] Based on the same inventive concept, an embodiment of the present application further provides a computer program product, which includes computer program instructions, and the computer instructions are used to enable the computer program product to execute any of the above-mentioned simulated visible light communication methods.

[0034] From the above, it can be seen that the present application provides a method and related equipment for simulating visible light communication, by constructing an optical communication channel response model; in the optical communication channel response model, the received first signal is modulated with an M-bit pulse amplitude to obtain a second signal; the second signal is subjected to DC bias processing to obtain a third signal; in response to the third signal passing through the optical channel in the optical communication channel response model, the third signal is subjected to DC bias removal and demodulation processing to obtain a fourth signal; the fourth signal is received to complete the simulation of visible light communication. The embodiment of the present application simulates the indoor light reflection model to study and calculate the multi-channel response of the optical signal, selects the appropriate signal coding modulation method, reduces inter-cell interference and white noise interference in the transmission process, and ensures accurate signal transmission. At the same time, signal interference between cells is introduced to simulate the indoor multi-cell scenario. By introducing a precise channel response algorithm and a new signal modulation method, the impact on the signal transmission efficiency, throughput and anti-interference ability of indoor optical communication is studied. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 This is a flow chart of a method for simulating visible light according to an embodiment of the present application;

[0037] Figure 2 This is a schematic diagram of an indoor optical communication channel model according to an embodiment of the present application;

[0038] Figure 3 This is a schematic diagram of indoor visible light transmission through a hybrid link according to an embodiment of the present application;

[0039] Figure 4 Schematic diagram of the reflection path loss iterative algorithm according to an embodiment of the present application;

[0040] Figure 5 This is a schematic diagram of a system channel model according to an embodiment of the present application;

[0041] Figure 6 This is a schematic diagram of the structure of a vector coding system according to an embodiment of the present application;

[0042] Figure 7 Schematic diagram of simulation results of each channel reflection pulse response according to an embodiment of the present application;

[0043] Figure 8 Schematic diagram of discrete-time channel response of each channel after filtering according to an embodiment of the present application;

[0044] Figure 9 This is a schematic structural diagram of a simulated visible light communication device according to an embodiment of the present application;

[0045] Figure 10 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0047] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0048] It is understandable that before using the technical solutions of each embodiment of the present disclosure, the type, scope of use, usage scenarios, etc. of the personal information involved will be informed to the user in an appropriate manner, and the user's authorization will be obtained.

[0049] For example, in response to a user's active request, a prompt message is sent to the user to clearly inform the user that the requested operation will require the acquisition and use of the user's personal information. This allows the user to independently choose whether to provide personal information to the electronic device, application, server, storage medium, or other software or hardware that performs the operation of the disclosed technical solution based on the prompt message.

[0050] As an optional but non-limiting implementation, in response to a user's active request, the prompt information may be sent to the user in the form of a pop-up window, in which the prompt information may be presented in text form. Furthermore, the pop-up window may also contain a selection control for the user to select "agree" or "disagree" to provide personal information to the electronic device.

[0051] It is understandable that the above notification and user authorization process are merely illustrative and do not constitute a limitation on the implementation of the present disclosure. Other methods that comply with relevant laws and regulations may also be applied to the implementation of the present disclosure.

[0052] As mentioned in the background technology section, with the development of wireless communication technology, the demand for spectrum resources is increasing. The visible light spectrum, an underutilized resource, has become a new research hotspot. Indoor visible light communication uses light-emitting diode lighting devices as data transmitters and receivers, not only providing lighting functions but also enabling high-speed data transmission. Visible light communication is a green technology with low power consumption and low carbon emissions, offering good sustainability and promising development prospects. Visible light communication technology is safe and healthy for the human body and poses no electromagnetic radiation hazards. Its data transmission is localized, secure, and accurate. Compared with traditional radio frequency communication, visible light communication technology has several significant advantages and can be applied in scenarios where traditional radio frequency communication is insufficient, such as underwater communications, hazardous environments, hospitals, and airports.

[0053] However, at high data rates, signal bandwidth increases significantly, potentially leading to spectral overlap and interference between adjacent channels. Complex signal processing algorithms increase system cost and power consumption. The high peak-to-average power of OFDM signals can cause nonlinear distortion of the LED drive current, requiring precise frequency synchronization and phase compensation mechanisms.

[0054] Taking the above into consideration, the embodiment of the present application proposes a method for simulating visible light communication, by constructing an optical communication channel response model; in the optical communication channel response model, the received first signal is modulated with an M-bit pulse amplitude to obtain a second signal; the second signal is subjected to DC bias processing to obtain a third signal; in response to the third signal passing through the optical channel in the optical communication channel response model, the third signal is subjected to DC bias removal and demodulation processing to obtain a fourth signal; the fourth signal is received to complete the simulation of visible light communication. The embodiment of the present application simulates the indoor light reflection model to study and calculate the multi-channel response of the optical signal, selects the appropriate signal coding modulation method, reduces inter-cell interference and white noise interference in the transmission process, and ensures accurate signal transmission. At the same time, signal interference between cells is introduced to simulate the indoor multi-cell scenario. By introducing a precise channel response algorithm and a new signal modulation method, its impact on the signal transmission efficiency, throughput and anti-interference ability of indoor optical communication is studied.

[0055] The technical solutions of the embodiments of the present application are described in detail below through specific examples.

[0056] refer to Figure 1 The method for simulating visible light communication in an embodiment of the present application includes the following steps:

[0057] Step S101, constructing an optical communication channel response model;

[0058] Step S102: In the optical communication channel response model, modulate the received first signal using an M-bit pulse amplitude to obtain a second signal; perform DC bias processing on the second signal to obtain a third signal; and in response to the third signal passing through the optical channel in the optical communication channel response model, remove the DC bias and demodulate the third signal to obtain a fourth signal.

[0059] Step S103: receiving the fourth signal to complete the simulated visible light communication.

[0060] For step S101, it is first necessary to construct an optical communication channel response model.

[0061] First, let's introduce the visible light communication (VLC) system. A VLC system consists of an LED transmitter, an optical channel, and a photon detector (PD). The LED is powered by a pre-processed and modulated input electrical signal, generating a light signal. This light is transmitted through the optical channel and detected by a photodetector at the receiving end, generating an electrical signal with added noise.

[0062] refer to Figure 2 , which is a schematic diagram of the indoor optical communication channel model of an embodiment of the present application.

[0063] In this embodiment, if Figure 2 As shown in the VLC optical channel model, the room size is set to 5 meters long, 5 meters wide, and 3 meters high. Two transmitting sources are set symmetrically at the roof of the room. Two receivers are set on a table 0.7 meters high. The radiated power of the white light emitting diode is widely distributed across the visible spectrum (from 380nm to 780nm). The power spectral distribution (PSD) is denoted as Indicates white LED light source [8] The radiant power per unit wavelength. Spectral reflectance, ρ(λ), is a function of how reflectance varies with wavelength. Different reflective surfaces have different spectral reflectances depending on their material, color, texture, and other physical characteristics. The reflectance varies from 0.1 to 0.8 with wavelength.

[0064] refer to Figure 3 , which is a schematic diagram of indoor visible light transmission through a hybrid link in an embodiment of the present application.

[0065] In indoor environments, the received light signal experiences time dispersion due to reflections from walls and other objects. Most reflections are usually diffuse and generally conform to the Lambertian radiation pattern. We assume that the indoor materials or indoor devices are completely scattered. The impulse response calculation of the diffuse reflection light channel model is based on a recursive algorithm. Figure 3As shown in the figure, Light of Sight (LOS) is the direct path of the light signal transmitted directly from the light source to the receiver, and the diffuse reflection path is the reflection path of the light reflected by the wall or object to the receiver.

[0066] In this application, the direct path and the reflected light propagate through the kth reflecting surface to the photoelectric receiver through multiple paths as shown in FIG. Figure 3 As shown, the irradiance angle is defined as The incident angle is θ, and the viewing angle of the LED is 120°. FOV (Field of View) is the field of view of the receiver, which determines whether the incident light can be received. The rectangular function is shown in formula (1):

[0067]

[0068] The impulse response of LOS can be defined by formula (2):

[0069]

[0070] In formula (2), t is the time variable, p l is the power of the LED lamp. θ0 is the incident angle of the direct light. d0 is the light propagation distance from the light source to the PD, c is the speed of light, and δ(t-d0 / c) is the light propagation delay. L0 is the path loss of the LOS, which can be obtained according to Equation (3).

[0071]

[0072] Where m is the directivity of light, A PD is the area of ​​the photon detector.

[0073] The intensity of reflected light is related to the reflectivity of the walls and objects of different materials in the room. It is defined as Pn=(ρ1ρ2…ρ k )P, where ρ (*) is the spectral reflectance of the reflecting surface.

[0074] The impulse response of the diffuse reflection channel is calculated by formula (4):

[0075]

[0076] In formula (4), δ(*) is the time delay of light propagation, θ k+1 is the incident angle of the kth reflection. L1,L K+1 is the path loss, as shown in Equation (5) and Equation (6):

[0077]

[0078] Theoretically, there are infinite reflections in the indoor VLC system, so the time-varying channel impulse response of the multipath channel can be expressed as Equation (7):

[0079]

[0080] However, due to dispersion, the power of light decreases significantly during propagation. The optical power amplitude after multiple reflections is very limited, and its impact on the overall channel response is almost negligible. Therefore, this study only calculated the channel response for straight-line propagation and the first five reflections. An iterative algorithm was used in the MATLAB modeling to simulate the channel response for multipath propagation.

[0081] According to equations (5) and (6), the channel response of the line-of-sight signal is simulated, and the responses of five kinds of reflected signals are simulated using loops. Assuming that there are N reflection points in the room, and the light passes through each reflection surface at each reflection, then there are N k computing elements.

[0082] refer to Figure 4 , which is a schematic diagram of the reflection path loss iterative algorithm of an embodiment of the present application.

[0083] The channel response value is as follows Figure 4 The results are obtained by iterative accumulation algorithm in MATLAB.

[0084] The time-discrete channel is modeled by the time-varying channel response h(t) at a symbol rate of Rs = 1 / Ts. High-speed LEDs can achieve a modulation bandwidth of Bw = 50 MHz. According to the Nyquist equation, the symbol duration Ts = 1 / (2Bw) = 10 ns. To eliminate intersymbol interference (ISI) at the transmitter, a rectangular pulse shaping waveform P is applied to H(t). t , match the corresponding filter P at the receiving end r The final channel response h can be calculated from this, as shown in Equation (8) and Equation (9):

[0085]

[0086] h=P t ×H(t)×P r (9)

[0087] refer to Figure 5 , which is a schematic diagram of the system channel model of an embodiment of the present application.

[0088] like Figure 5As shown in Figure 1, there are four optical signal transmission channels between the transmitter and receiver, defined as h11, h12, h21, and h22. In the channel model, each receiver receives signals from two transmitters via two channels. Tx1's signal is transmitted to Rx1 via h11, and Tx2's signal is transmitted to Rx2 via h22. Therefore, the signals transmitted via h21 and h12 represent the intercellular interference between Rx1 and Rx2, respectively.

[0089] The signal x1 is input to the transmitter Tx1, the signal X2 is input to Tx2, and additive white Gaussian noise (AWGN) is introduced. The output signal Y of the receiver Rx1 is calculated by equation (10):

[0090] Y=R(x1*h11+x2*h21)+n (10)

[0091] Where * represents convolution, R is the receiver response rate, n is Gaussian white noise, and the power spectral density is σ 2 =N0 / 2.

[0092] For step S102, in the optical communication channel response model, the received first signal is modulated using an M-bit pulse amplitude to obtain a second signal; the second signal is DC biased to obtain a third signal; in response to the third signal passing through the optical channel in the optical communication channel response model, the third signal is DC biased and demodulated to obtain a fourth signal.

[0093] In this embodiment, DC bias vector coding (DCO-VC) is an optimized channel division technology. Channel State Information (CSI) needs to be obtained before transmitting the signal. [6-7] Since the Doppler effect is not strong in a relatively stable indoor environment, the CSI of the channel is not difficult to estimate. The M-bit pulse amplitude modulation (M-PAM) method is an effective method to reduce the low-order harmonic components contained in the inverter output voltage, while also having the function of adjusting the output frequency and output voltage. It is used for the modulation and demodulation of the signal in this application. [8] .

[0094] The mechanism of vector coding is to apply singular value decomposition (SVD) to the circulant channel matrix H. H is an N×(N+μ) prefix circulant matrix of the discrete-time channel response h, as shown in Equation (11):

[0095]

[0096] Where N is the number of subchannels and μ is the cyclic prefix (CP) length. The singular value decomposition of H is as follows:

[0097] H=USV H (12)

[0098] U is a unitary matrix of rank N×N, V is a unitary matrix of rank (N+μ)×(N+μ), and S is a diagonal matrix of rank N×(N+μ) consisting of the singular values ​​of h. H is the conjugate transpose of the matrix V.

[0099] refer to Figure 6 , is a schematic diagram of the structure of a vector coding system according to an embodiment of the present application,

[0100] The signal modulation process uses M-bit pulse amplitude modulation. Pulse amplitude modulation does not generate complex signals during the modulation process and uses discrete time pulse waves as carriers. Unlike the currently used quadrature amplitude modulation (QAM), the pulse amplitude modulation method is single-dimensional, that is, it has no orthogonal components. [9] Typically, a QAM modulation scheme can be decomposed into two orthogonal PAM modulation schemes. For example, 16-QAM modulation is equivalent to two orthogonal 4-PAM modulation schemes, and 64-QAM modulation is equivalent to two orthogonal 8-PAM modulation schemes. PAM uses a discrete-time baseband model as a modulator to transmit information symbols, and the demodulation process is the inverse of the modulation process.

[0101] The input data is grouped into symbols X = [X0, X1, ..., X N-1 ] T , inserting a CP of length μ at the end of each symbol, which can be expressed as: X=[X0,X1,…,X N+μ-1 ] T Applying the matrix V to the precoded symbols at the transmitter, the precoded signal x can be described as equation (13):

[0102] x=VX (13)

[0103] Applying a DC bias to the signal x generates a true unipolar signal, which is then transmitted to the receiver through an optical channel. At the receiving end, the received signal after removing the DC bias can be expressed as Equation (14):

[0104] y=Hx+n (14)

[0105] Considering the introduction of inter-cell interference in the channel model, the receiver Rx1 receives the signal x1 from the transmitter Tx1 and receives the inter-cell interference signal x2 from Tx2. Since the signal X1 is to be transmitted to Rx1, the calculation method of the precoding vector x1 is: 11 =U1S1V1H ,x1=V1X1. Similarly, the signal X2 is expected to be transmitted to the receiver Rx2, and its precoding vector x2 is obtained by H 22 =U2S2V2 H , x2=V2X2 is calculated.

[0106] Therefore, the signal received at Rx1 is expressed as follows:

[0107] y1=H 11 x1+H 21 x2+n (15)

[0108] Where n is additive white Gaussian noise. The receiver applies a matched filter U1:

[0109]

[0110] Formula (16) can be rewritten as:

[0111]

[0112] In some embodiments, after obtaining the second signal, the method further includes: adding a cyclic prefix to the second signal to obtain a fifth signal; performing DC bias processing on the second signal to obtain the third signal includes: performing DC bias processing on the fifth signal to obtain the third signal.

[0113] In the embodiment of the present application, in order to eliminate the interference between the transmission signal and the symbol, the present study applies the cyclic prefix (CP) to the VC system. The CP provides a protection interval for the symbol to avoid the interference between the symbols.

[10] CP provides a guard interval for symbols to avoid interference between symbols. The length of CP is related to the channel impulse response (CIR). Let L I is the length of the input signal, L H is the length of the channel response, then the length of the linear convolution of the signal and the channel response is L I +L H -1. In order to ensure that the size of the circular convolution is the same as that of the linear convolution, it is necessary to insert a length of L into the signal. H A cyclic prefix of -1.

[0114] In some embodiments, after obtaining the third signal, the method further includes: performing shearing processing on the third signal to obtain a sixth signal; in response to the third signal passing through the optical channel in the optical communication channel response model, removing the DC bias and demodulating the third signal to obtain a fourth signal, including: in response to the sixth signal passing through the optical channel in the optical communication channel response model, removing the DC bias and demodulating the sixth signal to obtain a fourth signal.

[0115] In this embodiment, intensity modulation and direct detection (IM / DD) technology is used in indoor visible light communication applications. To eliminate inter-symbol interference (ISI) caused by multipath fading in the optical channel, the system introduces multi-channel modulation (MCM) technology based on vector coding (VC). Because IM / DD systems only transmit true unipolar positive signals, traditional multi-channel modulation schemes require a direct current (DC) bias before transmission. When using IM / DD technology, transmission must ensure that all signals are positive real numbers. Therefore, a DC bias is added to the signal before transmission to convert negative signals to positive values. If any signal value is still less than 0, it is defaulted to 0 and transmitted. This method is called clipping. This eliminates negative values ​​in the signal during transmission. The clipping process generates interference that can be seen as signal distortion noise, which can be eliminated by increasing the DC bias.

[0116] However, since the power consumption of the system increases with the increase of DC bias, the value of DC bias cannot increase indefinitely. The clipping distortion should be suppressed within a reasonable range by referencing an appropriate DC bias. The unipolar signal after clipping can be expressed as Equation (21):

[0117] X u (t) = x b (t)+B dc +n clipping (twenty one)

[0118] B DC represents the bias voltage that needs to be added to the signal and can be calculated by equation (22):

[0119]

[0120] In formula (22) is the average power of the bipolar signal, and K is an adjustable proportional coefficient.

[0121] In some embodiments, removing the DC bias and demodulating the third signal to obtain the fourth signal includes: removing the DC bias of the third signal to obtain a seventh signal; and demodulating the seventh signal using M-bit pulse amplitude modulation to obtain the fourth signal.

[0122] In some embodiments, after obtaining the seventh signal, the method further includes: performing zero-force balancing processing on the seventh signal to obtain an eighth signal.

[0123] In the embodiment of the present application, the zero-forcing equalizer SI can be generated in MATLAB simulation by the following code:

[0124] SI = pinv(S'*S)*S';

[0125] After applying zero force equilibrium to y1, the signal becomes:

[0126]

[0127] Formula (18) can be rearranged into formula (19):

[0128]

[0129] The throughput of the DCO-VC system can be calculated by formula (20):

[0130]

[0131] In formula (20), B is the number of bits in the M-PAM symbol, P e is the message error rate. Rs = 1 / Ts is the symbol rate, and Nc / NT is the ratio of the subchannel carrying data to the total number of subchannels.

[0132] In some embodiments, after obtaining the eighth signal, the method further includes: removing the cyclic prefix of the eighth signal to obtain a ninth signal; and demodulating the seventh signal using M-bit pulse amplitude modulation to obtain the fourth signal includes: demodulating the ninth signal using M-bit pulse amplitude modulation to obtain the fourth signal.

[0133] In another feasible embodiment, the VLC system is set up in a room measuring 5m x 5m x 3m. The receiver is located at a height of 0.7m. The lower left corner of the room is set as the origin of the three-dimensional rectangular coordinate system. The coordinate unit is meters. The coordinates of the two LEDs are (1, 2.5, 3) and (4, 2.5, 3), and the two receivers are located at (2.5, 2.5, 0.7) and (4.5, 2.5, 0.7). The parameters of the simulation reflection model are shown in Table 1.

[0134] Table 1 Reflection model parameters

[0135]

[0136] In the channel response model, to simulate real-world conditions, we assume that the room's reflective surfaces are made of plaster and plastic. The reflectivity of each reflective surface is shown in Table 2.

[0137] Table 2 Surface reflectivity parameters

[0138] reflective surface South north East West desktop ceiling Material plaster plaster plastic plastic plastic plaster Reflectivity ρ 0.81 0.81 0.12 0.12 0.63 0.4

[0139] Channel delay spread is a characteristic of multipath optical channels, usually expressed as the root mean square delay τ rms and the average excess delay, as quantified in Equation (23).

[0140]

[0141] In formula (23),

[0142]

[0143] Where the channel response at time t=i is a time variable. The RMS delay is related to the multipath inter-symbol interference. When τ rms When the delay is less than 10% of the signal symbol duration, the probability of inter-symbol interference is extremely small. The channel delay spread is related to the room size and the location of the transmitter and receiver.

[13] Table 3 lists the channel delay distribution of each channel in the simulation room.

[0144] Table 3 Channel delay distribution of each channel

[0145]

[0146] The channel impulse response after pulse shaping is discrete in time, with a symbol duration of Ts = 10 ns. Table 3 shows that the RMS delay between each transmitter and its corresponding receiver is small, indicating a high probability of no severe intersymbol interference.

[0147] refer to Figure 7 , which is a schematic diagram of the simulation results of each channel reflection pulse response of an embodiment of the present application.

[0148] refer to Figure 8 , is a schematic diagram of the discrete-time channel response of each channel after filtering in an embodiment of the present application.

[0149] The results show that the direct path response signal power is the strongest, and the reflected path signal gradually decreases until it can be ignored. To reduce inter-symbol interference during the modulation process, a square filter is added to the multipath channel response.

[0150] It can be seen from the above embodiments that the method for simulating visible light communication described in the embodiments of the present application is to construct an optical communication channel response model; in the optical communication channel response model, the received first signal is modulated with an M-bit pulse amplitude to obtain a second signal; the second signal is subjected to DC bias processing to obtain a third signal; in response to the third signal passing through the optical channel in the optical communication channel response model, the third signal is subjected to DC bias removal and demodulation processing to obtain a fourth signal; and the fourth signal is received to complete the simulation of visible light communication. The embodiment of the present application simulates the indoor light reflection model to study and calculate the multi-channel response of the optical signal, selects the appropriate signal coding modulation method, reduces inter-cell interference and white noise interference in the transmission process, and ensures accurate signal transmission. At the same time, signal interference between cells is introduced to simulate the indoor multi-cell scenario. By introducing a precise channel response algorithm and a new signal modulation method, its impact on the signal transmission efficiency, throughput and anti-interference ability of indoor optical communication is studied.

[0151] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied in a distributed scenario and performed by multiple devices working together. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the method.

[0152] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0153] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a simulated visible light communication device.

[0154] refer to Figure 9 , the simulated visible light communication device comprises:

[0155] A construction module 91 is configured to construct an optical communication channel response model;

[0156] The transmission module 92 is configured to modulate the received first signal using an M-bit pulse amplitude in the optical communication channel response model to obtain a second signal; perform DC bias processing on the second signal to obtain a third signal; and remove the DC bias and demodulate the third signal in response to the third signal passing through the optical channel in the optical communication channel response model to obtain a fourth signal.

[0157] The receiving module 93 is configured to receive the fourth signal to complete the simulated visible light communication.

[0158] For the convenience of description, the above device is described as being divided into various modules according to their functions. Of course, when implementing this application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0159] The device of the above embodiment is used to implement the corresponding simulated visible light communication method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0160] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein when the processor executes the program, the simulated visible light communication method described in any of the above embodiments is implemented.

[0161] Figure 10 10 is a schematic diagram showing a more specific hardware structure of an electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other within the device via the bus 1050.

[0162] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0163] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage devices, dynamic storage devices, etc. The memory 1020 can store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0164] The input / output interface 1030 is used to connect input / output modules to implement information input and output. The input / output modules can be configured as components within the device (not shown in the figure) or can be externally connected to the device to provide corresponding functions. Input devices may include a keyboard, mouse, touch screen, microphone, various sensors, etc., and output devices may include a display, speaker, vibrator, indicator light, etc.

[0165] The communication interface 1040 is used to connect to a communication module (not shown) to enable communication between the device and other devices. The communication module can communicate via a wired method (such as USB, network cable, etc.) or a wireless method (such as mobile network, WiFi, Bluetooth, etc.).

[0166] The bus 1050 comprises a path for transmitting information between the various components of the device (eg, the processor 1010 , the memory 1020 , the input / output interface 1030 , and the communication interface 1040 ).

[0167] It should be noted that although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050, in a specific implementation, the device may also include other components necessary for normal operation. In addition, it will be understood by those skilled in the art that the above device may only include the components necessary to implement the embodiments of this specification, and does not necessarily include all the components shown in the figure.

[0168] The electronic device of the above embodiment is used to implement the corresponding simulated visible light communication method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0169] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the simulated visible light communication method described in any of the above embodiments.

[0170] The computer-readable media of this embodiment include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0171] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the method for simulating visible light communication as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0172] Based on the same inventive concept, corresponding to the method for simulating visible light communication described in any of the above embodiments, the present disclosure further provides a computer program product comprising computer program instructions. In some embodiments, the computer program instructions can be executed by one or more processors of a computer to cause the computer and / or the processor to perform the method for simulating visible light communication. For the execution entities corresponding to the steps in each embodiment of the method for simulating visible light communication, the processors that execute the corresponding steps can belong to the corresponding execution entities.

[0173] The computer program product of the above embodiment is used to enable the computer and / or the processor to execute the method for simulating visible light communication as described in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0174] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0175] In addition, for simplicity of description and discussion, and in order not to make the embodiment of the application difficult to understand, the known power supply / ground connection with integrated circuit (IC) chip and other components may or may not be shown in the accompanying drawings provided. In addition, the device can be shown in the form of a block diagram to avoid making the embodiment of the application difficult to understand, and this also takes into account the following fact, that is, the details of the embodiment of these block diagram devices are highly dependent on the platform to be implemented in the embodiment of the application (that is, these details should be fully within the scope of understanding of those skilled in the art). When specific details (for example, circuit) are set forth to describe exemplary embodiments of the application, it will be apparent to those skilled in the art that the embodiment of the application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0176] Although the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those skilled in the art based on the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may utilize the embodiments discussed.

[0177] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of this application.

Claims

1. A method for simulating visible light communication, characterized in that: include: Constructing optical communication channel response models; In the optical communication channel response model, the received first signal is modulated using an M-bit pulse amplitude to obtain a second signal; Performing direct current bias processing on the second signal to obtain a third signal; In response to the third signal passing through the optical channel in the optical communication channel response model, removing the DC bias and demodulating the third signal to obtain a fourth signal; The fourth signal is received to complete the simulated visible light communication.

2. The method according to claim 1, characterized in that After obtaining the second signal, the method further includes: adding a cyclic prefix to the second signal to obtain a fifth signal; The performing DC bias processing on the second signal to obtain a third signal includes: Performing direct current bias processing on the fifth signal to obtain the third signal.

3. The method according to claim 2, characterized in that After obtaining the third signal, the method further includes: Performing shearing processing on the third signal to obtain a sixth signal; The step of removing a DC bias and performing demodulation processing on the third signal in response to the third signal passing through an optical channel in the optical communication channel response model to obtain a fourth signal comprises: In response to the sixth signal passing through the optical channel in the optical communication channel response model, the sixth signal is subjected to direct current bias removal and demodulation processing to obtain a fourth signal.

4. The method according to claim 3, characterized in that The removing DC bias and demodulating the third signal to obtain the fourth signal comprises: removing a DC bias from the third signal to obtain a seventh signal; The seventh signal is demodulated using M-bit pulse amplitude modulation to obtain the fourth signal.

5. The method according to claim 4, characterized in that After obtaining the seventh signal, the method further includes: The seventh signal is subjected to zero-force balancing processing to obtain an eighth signal.

6. The method according to claim 5, characterized in that After obtaining the eighth signal, the method further includes: removing a cyclic prefix from the eighth signal to obtain a ninth signal; The demodulating the seventh signal by using M-bit pulse amplitude modulation to obtain the fourth signal includes: The ninth signal is demodulated using M-bit pulse amplitude modulation to obtain the fourth signal.

7. A simulated visible light communication device, characterized in that: include: A building module configured to build an optical communication channel response model; A transmission module, configured to modulate the received first signal using an M-bit pulse amplitude in the optical communication channel response model to obtain a second signal; Performing direct current bias processing on the second signal to obtain a third signal; In response to the third signal passing through the optical channel in the optical communication channel response model, removing the DC bias and demodulating the third signal to obtain a fourth signal; The receiving module is configured to receive the fourth signal to complete the simulated visible light communication.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium storing computer instructions, characterized in that: The computer instructions are used to enable a computer to execute the method according to any one of claims 1 to 6.

10. A computer program product, comprising computer program instructions, which, when executed on a computer, cause the computer to execute the method according to any one of claims 1 to 6.

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