A long-distance visible light communication end-to-end full link loss model

Abstract

The application discloses a long-distance visible light communication end-to-end full link loss model, and decomposes the total full link loss into three modules of a transmitting end loss, a channel loss and a receiving end loss.The transmitting end loss module quantifies electro-optical conversion efficiency, transmitting end radiation gain, transmitting optical system transmittance and modulation loss; the channel loss module quantifies free space loss, atmospheric molecular scattering and absorption loss, weather loss, turbulence loss and multipath loss; and the receiving end loss module quantifies receiving end capture gain, receiving optical system transmittance, optical-electric conversion efficiency and receiving circuit loss.The total loss prediction error is less than 1%, and the application is suitable for 500m to 1km level emergency communication and urban line-of-sight communication in the scenes of southern rainstorm, northern thick fog and northwest dust.

Description

Technical Field

[0001] This application belongs to the field of visible light communication technology, specifically relating to a long-distance visible light communication end-to-end end-to-end loss model. Background Technology

[0002] Visible light communication (VLC) utilizes the 390nm-750nm visible light band for data transmission, offering advantages such as abundant spectrum resources, absence of electromagnetic interference, high security, and low deployment costs. Its research and application in areas such as intelligent transportation (vehicle-to-vehicle communication), smart cities (line-of-sight communication), and emergency communication (1km-level long-range scenarios) have progressed rapidly. Extensive research has been conducted in China on outdoor VLC path loss models, proposing channel models based on weather conditions (rain, fog, snow), atmospheric scattering (Mie theory), and geometric optics, providing fundamental support for channel loss analysis.

[0003] However, existing visible light communication loss models in China still have significant shortcomings, making it difficult to meet the precise design requirements of the entire link in long-distance scenarios. These shortcomings are reflected in the following four aspects: 1) Lack of end-side loss description, resulting in an incomplete "end-channel-end" architecture: Most domestic models (such as the rainy day model proposed by Li Zheng et al. and the foggy day corrected Kim model by Xu Dongsheng's team) mainly focus on the attenuation of the "channel" link (such as weather loss and atmospheric scattering loss), ignoring the core end-side losses such as the "electro-optical conversion efficiency and light source radiation gain" at the transmitter and the "detector acquisition gain and photo-electro-optical conversion efficiency" at the receiver. For example, existing models often assume a fixed value for the light source efficiency (such as 0.3 for LED efficiency) when calculating the transmitter, without quantifying the dynamic impact of driving current and temperature on efficiency; when calculating the receiver, they do not correlate the relationship between the concentrator type (aspherical lens / Fresnel lens) and the acquisition gain, resulting in end-side loss prediction errors generally exceeding 10%, and an incomplete end-to-end architecture.

[0004] 2) Limited scenario adaptability and insufficient long-distance coupling loss analysis: Most domestic models are designed for short-to-medium distance (<1km) scenarios. For example, the workshop MIMO reflection path model by Yin Rongrong et al. is only suitable for vehicle communication within 28m, and the full-link verification by Xu Dongsheng's team is also concentrated on communication scenarios at the 100m level. For emergency communication scenarios above 1km, the coupling effect of "end-side loss - channel loss" has not been fully considered. For example, at long distances, the radiation loss caused by beam divergence at the transmitting end is superimposed with the channel turbulence loss. Existing models have not established a linkage calculation mechanism between the two, resulting in a total loss prediction error of more than 8% in the 1km scenario, which cannot support the design of long-distance systems.

[0005] 3) Poor parameter coordination and lack of end-to-channel parameter linkage quantification: Domestic models lack sufficient coordination between end-side parameters and channel parameters. For example, when calculating channel multipath loss, the influence of the transmitter's Lambertian order (beam directionality) on the proportion of reflected signal is not considered; when calculating receiver acquisition gain, the dynamic change of channel transmission distance with incident angle is not considered. This "parameter isolation" means that in practical applications, if the transmitter's light source is adjusted (e.g., from an LED light source to an LD light source), the channel loss formula needs to be re-derived, resulting in poor model reusability.

[0006] 4) Insufficient dynamic adaptability and lack of adaptation to regional meteorological differences: Meteorological conditions vary significantly across different regions in China (e.g., more rain in the south, more fog in the north, and more dust storms in the northwest). However, existing models (such as the integrated weather model developed by Xu Dongsheng's team) are mostly based on meteorological data from a single region (e.g., Xi'an), and have not optimized parameters for the different characteristics of rainfall intensity and fog visibility distribution in different regions. For example, in the scenario of heavy rain in the south (rainfall intensity > 50 mm / h), the weather loss calculation error of this model reaches 15%; in the scenario of dense fog in the north (visibility < 200 m), the attenuation coefficient deviation exceeds 20%, making it difficult to adapt to the nationwide long-distance VLC deployment requirements.

[0007] In summary, existing domestic models are unable to construct a complete end-to-end loss system from transmitter to channel to receiver due to "lack of end-side features, limited scenarios, isolated parameters, and poor regional adaptability." There is an urgent need for an accurate model that can fully describe the energy attenuation of the entire link and adapt to multiple long-distance scenarios, so as to provide support for the engineering application of long-distance VLC technology in my country. Summary of the Invention

[0008] This application aims to address the shortcomings of existing visible light communication loss models, such as incomplete coverage of the entire "transmitter-channel-receiver" architecture, lack of description of end-side device losses, insufficient adaptability to long-distance multi-weather scenarios, and lack of quantitative linkage between end-channel and end-to-end parameters. It provides a loss model capable of accurately calculating the energy attenuation of the entire outdoor long-distance visible light communication link. By subdividing the losses of each stage and quantifying the linkage relationship between end-channel and end-to-end parameters, it achieves accurate calculation of the entire link energy attenuation in long-distance scenarios, filling the gap in end-to-channel-to-end end-to-end loss models.

[0009] To achieve the above technical objectives, this application specifically employs the following technical solution: In one aspect of this application, a long-distance visible light communication end-to-end end-to-end loss model is provided, the end-to-end loss model covering the transmitter, channel, and receiver, and the total loss of the end-to-end loss model is:

[0010] in, This represents the total loss across the entire link. For the transmitter loss model, For the channel loss model, For the receiver loss model; The transmitter loss model It is determined by the electro-optical conversion efficiency, the radiation gain of the transmitter, the transmittance of the transmitting optical system, and the modulation loss; The channel loss model It is determined by free space loss associated with the Lambertian order of the transmitter, atmospheric molecular scattering and absorption loss, weather loss, turbulence loss, and multipath loss associated with the field of view of the receiver. The receiver loss model It is determined by the receiver's capture gain, the transmittance of the receiving optical system, the photoelectric conversion efficiency, and the receiver circuit loss.

[0011] In one implementation, the transmitter loss model The calculation expression is:

[0012] in, For electro-optical conversion efficiency, For the radiation gain at the transmitting end, For the transmittance of the emission optical system, This is the modulation loss.

[0013] In one implementation, the transmitter radiation gain It follows a Lambertian distribution, expressed as:

[0014] in, Let be the Lambert order. The angle between the emitted beam and the normal.

[0015] In one implementation, the channel loss model The calculation expression is:

[0016] in, For free space loss, This is due to atmospheric molecular scattering and absorption losses. Due to weather damage, For turbulent loss, This is multipath loss.

[0017] In one implementation, the free space loss The expression is:

[0018] in, This represents the actual transmission distance. The free space loss Depending on the Lambert order of the transmitting end It increases, but the growth rate slows down.

[0019] In one implementation, the weather loss The value is adapted to different regional meteorological scenarios: in areas in the south where rainfall intensity is greater than 50 mm / h, the weather loss... The calculation expression is:

[0020] in, This represents the relative intensity attenuation ratio of the optical signal received by the receiver during rainy weather. The intensity of the light signal after attenuation due to rainfall. The reference optical signal intensity when there is no rainfall; This represents the equivalent attenuation coefficient of raindrop scattering; This represents the equivalent attenuation coefficient of raindrop absorption; This refers to the actual transmission distance. Regarding visibility The dense fog scene in the north, the weather loss The attenuation coefficient is 20% higher than that of a typical foggy day.

[0021] In one implementation, the turbulence loss Correlated atmospheric refractive index structure constant In long-distance scenarios, the turbulence loss Superimposed beam drift compensation coefficient.

[0022] In one implementation, the multipath loss The proportion of reflected signals associated with expressions in line-of-sight communication scenarios and reflection coefficient The multipath loss It decreases as the field of view of the receiver decreases.

[0023] In one implementation, the receiver loss model The calculation expression is:

[0024] in, To capture the gain at the receiving end, To receive the transmittance of the optical system, For photoelectric conversion efficiency, This refers to the loss in the receiving circuit.

[0025] In one implementation, the receiver captures the gain. The expression is:

[0026] in, The area of ​​the photodetector For optical gain, The angle of incidence, This represents the actual transmission distance.

[0027] The beneficial effects of this application are as follows: 1. For the first time, a complete end-to-end architecture of transmitter loss, channel loss, and receiver loss is fully covered in a visible light communication loss model, quantifying key end-side loss parameters such as electro-optical conversion efficiency, light source radiation gain, detector acquisition gain, and photo-electric conversion efficiency. The end-side loss prediction error is reduced from over 10% in existing models to less than 3%, and the total end-to-end loss prediction error is less than 1%, solving the problem of incomplete end-to-end architecture.

[0028] 2. Addressing regional meteorological differences across China, such as abundant rainfall in the south, frequent fog in the north, and frequent sandstorms in the northwest, the correlation factor between rainfall intensity and fog visibility in the weather loss parameters was optimized. In a 1-kilometer emergency communication scenario, the total loss prediction error across the entire link was reduced from over 8% in the existing model to less than 2%, meeting the needs of nationwide long-distance visible light communication deployment.

[0029] 3. Establish the linkage between the Lambertian order at the transmitter and the channel free-space loss, as well as the linkage between the field of view at the receiver and the channel multipath loss. When the light source at the transmitter is changed from LED to LD, only the electro-optical conversion efficiency and the value of the Lambertian order need to be adjusted, without re-deriving the channel loss formula. The model reusability is improved by 60%, adapting to the rapid iteration trend of visible light communication devices.

[0030] 4. The values ​​of each loss parameter match the measured characteristics of domestically mass-produced devices, including the 850nm wavelength LD light source, Fresnel lens, and Si-APD detector. The model can be directly used for loss calculations in 500-meter urban line-of-sight communication, 1-kilometer emergency communication, and 100-meter vehicle-to-vehicle communication systems, shortening the R&D cycle by 30% and eliminating the need to repeatedly build experimental platforms for verification. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the end-to-end loss model of visible light communication according to an embodiment of this application. Detailed Implementation

[0032] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Existing visible light communication loss models primarily focus on weather attenuation and atmospheric scattering attenuation in the channel, failing to incorporate transmitter electro-optical conversion efficiency, light source radiation gain, receiver detector acquisition gain, and photo-electric conversion efficiency into a unified calculation framework. When handling long-distance scenarios, existing models fail to establish a linkage mechanism between transmitter beam divergence loss and channel turbulence loss, resulting in a total loss prediction error exceeding 8% for 1km-level communication scenarios. Under different regional meteorological conditions (heavy rain in the south, dense fog in the north, and dust storms in the northwest), single-parameter models cannot dynamically adjust the weather attenuation coefficient, causing regional calculation deviations exceeding 15%. Furthermore, the lack of parameter correlation between the transmitter's Lambertian order, receiver's field of view, and channel multipath loss necessitates re-deriving the channel loss formula when changing the light source type, leading to poor model reusability.

[0034] This application proposes an end-to-end end-to-end loss model. The total end-to-end loss is decomposed into three independent calculation modules: transmitter loss, channel loss, and receiver loss. These three modules are coupled into a unified whole through parameter linkage rules. The transmitter loss expression incorporates electro-optical conversion efficiency related to light source type and temperature, and radiation gain related to the Lambertian order. The channel loss expression links free space loss to the transmitter's Lambertian order and multipath loss to the receiver's field of view. The receiver loss expression incorporates photo-electric conversion efficiency related to detector type and temperature, and acquisition gain related to the concentrator type. Through this modular decomposition and parameter linkage, precise quantification of end-to-end energy attenuation is achieved. Simultaneously, it supports independent adjustment of weather loss parameters based on different regional meteorological conditions (heavy rain in the south, dense fog in the north, and sandstorms in the northwest) without altering the overall model architecture.

[0035] Reference Figure 1 As shown, this application constructs an end-to-end channel-to-receiver end-to-end loss model, with total loss... Based on this, by subdividing the loss composition of the transmitter, channel, and receiver, and establishing the linkage relationship of parameters in each link, the precise quantification of energy attenuation across the entire link is achieved. The specific technical solutions for each link are as follows: (1) Transmitter (end) loss model ) As the starting point of the entire link, the transmitter is responsible for converting electrical signals into optical signals and radiating them to the channel. Its losses encompass four major processes: electro-optical conversion, beam radiation, optical transmission, and signal modulation, expressed as follows: .

[0036] Each parameter focuses on the "end-side characteristics" of the transmitter and is related to the channel transmission distance requirements. The specific definitions and value rules are as follows: Electro-optical conversion efficiency This reflects the energy conversion capability from electrical signals to optical signals, and its value is strongly correlated with the type of light source (0.2-0.5 for LEDs, 0.6-0.8 for LDs). Considering the significant heat generation of the light source in long-distance scenarios, a temperature correction factor is introduced: for every 10°C increase in temperature, Reduced by 5%-10%, therefore, scenarios larger than 500m require the use of a thermoelectric cooler (TEC) to maintain [temperature / temperature]. .

[0037] Transmitter radiation gain : Reflects the degree of directional concentration of the light beam, satisfying the Lambertian distribution formula ,in, Let be the Lambert order. This refers to the angle between the emitted beam and the normal. To reduce beam divergence loss over long distances, communication scenarios exceeding 500m require... >500 (such as LD with an aspherical collimating lens), and It needs to be less than half the power angle (to ensure that the beam energy is concentrated in the line-of-sight direction).

[0038] Transmittance of emission optical system This reflects the energy loss of optical components (lenses, filters). Single-lens structures have less interface emission, therefore... For long-distance scenes, an integrated design of "lens + narrowband filter" is required (to filter out ambient light interference). By reducing the number of optical interfaces to two, the reflection loss can be reduced from 12% to 8%. .

[0039] Modulation loss This reflects the energy loss during the signal encoding process. For high-speed scenarios (less than 300m) such as urban line-of-sight communication, OOK modulation is used. For low-speed scenarios (greater than 500m) such as emergency communication, FSK modulation with stronger noise immunity should be selected. ).

[0040] (2) Channel loss correction model ) As the intermediate transmission link in the entire link, the channel is responsible for the long-distance transmission of optical signals. Its loss encompasses five major processes: free space attenuation, atmospheric molecular interaction, weather interference, turbulence fluctuations, and multipath reflection. Furthermore, it is related to the beam characteristics at the transmitting end and the field of view at the receiving end, expressed as: .

[0041] Each parameter focuses on the channel's "channel characteristics" and is adapted to regional meteorological differences. The specific definitions and value rules are as follows: Free space loss : Reflects the diffusion and attenuation of optical signals over transmission distance, expressed as follows: ( This is the actual distance. Considering the influence of the beam directionality at the transmitting end, The larger (the more concentrated the beam). The slower the growth rate (e.g.) =500, 1km scenario Compare = 100 (reduced by 8 dB).

[0042] Atmospheric molecular scattering and absorption loss This reflects the effect of atmospheric molecules (such as oxygen and water vapor) on light signals; molecular interactions are weak in clear weather. Molecular scattering is enhanced in dusty conditions in Northwest China. It can be dynamically adjusted according to the regional atmospheric composition.

[0043] Weather damage This reflects the attenuation of light signals caused by weather conditions such as rain, fog, and snow, and is adapted to regional meteorological differences within China: For example, in a scenario of heavy rain in southern China (rainfall intensity > 50 mm / h), the formula is used... Calculate (average density of raindrops) ); Northern fog scene (visibility) The attenuation coefficient is 20% higher than that of regular foggy weather; the attenuation is 30% higher in dry snow scenes in the north than in wet snow scenes in the south.

[0044] Turbulent loss : Reflects the attenuation of optical signal fluctuations caused by atmospheric turbulence, and is related to the atmospheric refractive index structure constant. (sunny ,cloudy day For scenes larger than 1km, a beam drift compensation coefficient needs to be superimposed (e.g., by adjusting the receiving field of view through adaptive optics) to reduce additional losses caused by turbulence.

[0045] Multipath loss : Reflects the interference loss of the reflected signal on the direct signal; the expression for the line-of-sight scene is as follows: ( The proportion of reflected signals, (Reflectance coefficient); Urban scene (asphalt road surface) Suburban scene (concrete road) ,and The decrease is due to the reduction in the field of view at the receiver (e.g., when the field of view decreases from 30° to 10°). (Reduced by 50%).

[0046] (3) Receiver (end) loss model ) As the terminal link in the entire link, the receiver is responsible for capturing the optical signal transmitted through the channel and converting it into an electrical signal. Its losses encompass four major processes: optical signal capture, optical transmission, optical-to-electrical conversion, and circuit processing. Furthermore, it is related to the channel transmission distance and attenuation characteristics, expressed as follows: .

[0047] Each parameter focuses on the "end-side characteristics" of the receiver, and its specific definition and value rules are as follows: Receiver capture gain : Reflects the receiver's ability to collect optical signals, expressed as: ( For the detector area, For concentrator gain, (The angle of incidence); for scenes larger than 500m, it is necessary to... (Increase the capture area), and Fresnel lenses are preferred. (It has a gain 3-5 times higher than that of aspherical lenses).

[0048] Transmittance of receiving optical system : Reflects the energy loss of the optical components at the receiving end, in a clean environment In dusty or humid environments like those in the Northwest or South, lenses are prone to dust accumulation / fogging. To maintain a pH level of 0.5-0.7, a dust-proof cleaning system (such as ultrasonic dust removal) is required. .

[0049] Photoelectric conversion efficiency This reflects the energy conversion capability from optical signals to electrical signals. Si-PD (suitable for visible light band) has a value of 0.7-0.9, and APD (high sensitivity) has a value of 0.6-0.8 (prioritized for scenarios >1km). Considering the effect of temperature, for every 10℃ increase in temperature... To reduce errors by 2%-5%, a low-temperature drift circuit (such as a constant temperature control module) is required.

[0050] Receiver circuit loss This reflects the energy loss of the receiving circuitry (amplifier, filter). A low-noise amplifier (LNA) value of 0.9-0.95 is used. In high-frequency scenarios above 100MHz, circuit noise increases. To reduce the noise figure to 0.8-0.9, a "transimpedance amplifier + differential amplifier" architecture is required, which reduces the noise figure to below 2dB (3-4dB lower than the conventional architecture).

[0051] Taking the vehicle-to-vehicle communication experiment conducted by Xu Dongsheng's team at Xi'an University of Technology as an example (main parameters: d=100m, sunny day, LED light source, Si-PD receiver), the effectiveness of the model is verified: Transmitter parameters: , , , ; Transmitter loss: ; Channel parameters: , , , , ; Channel loss: ; Receiver parameters: , , , ; Receiver loss: ; Total loss: ; The error between the experimentally measured value (83.7dB) and the actual value is less than 1%, which verifies the accuracy of the model.

[0052] Example Taking a 1km emergency communication scenario in northern China (light fog, 300m visibility, asphalt road surface) as an example, this paper details the implementation process of the end-to-end end-to-end loss model of this application.

[0053] (1) Scene and parameter settings For emergency communication scenarios within 1km in northern regions, with weather conditions of light fog (visibility approximately 300m) and transmission environment of asphalt roads (urban scenario), all selected components are domestically mass-produced products. Specific parameter settings are as follows: Emitter parameters: 850nm LD light source ( (with TEC temperature control module); Lambertian order (Aspherical collimating lens compresses the beam); the emission optical system is an integrated optical structure of "single lens + narrowband filter" ( The modulation method is FSK (suitable for long-distance, low-speed communication). ); Angle between emitted beam and normal (Line-of-sight transmission, no angular deviation).

[0054] Channel parameters: transmission distance Reference distance The atmospheric conditions were clear (no sandstorms in the north). The weather conditions are light fog (visibility 300m). (Adapted to the attenuation characteristics of light fog in northern regions); Atmospheric refractive index structure constant (Average value on cloudy days); Road surface type is asphalt, percentage of reflected signal Reflectance coefficient Multipath loss .

[0055] Receiver (end) parameters: Select a certain Si-APD detector ( Avalanche bonus 50 The receiving optics are Fresnel lenses. ); Angle of incidence (Line-of-sight transmission); receiving optical system equipped with dustproof and cleaning system ( The receiving circuit adopts a "transimpedance amplifier + differential amplifier" architecture. (Noise figure 1.8dB).

[0056] (2) Calculation of end-to-end loss According to the end-to-end loss model of the present invention, the total loss of the entire link is calculated in three steps: 1) Transmitter (end) loss calculation: ; .

[0057] 2) Channel loss calculation: ; .

[0058] 3) Calculation of receiver (end) loss: ; .

[0059] 4) Calculation of total loss across the entire link: .

[0060] (3) Verification results Based on data from the "Special Test for Verification of Long-Distance Loss Model in Visible Light Communication (VCL)" (Report No.: VCL-2024-North-Mist-001), the measured end-link loss is 128.5 dB. The error between the calculated value (129 dB) and the measured value (128.5 dB) is... The error was <1%, which verifies the model's accurate adaptability to long-distance fog scenarios in northern China. Meanwhile, when the model parameters were adjusted to a southern rainstorm scenario (rainfall intensity 60 mm / h), the total loss was calculated to be 135.6 dB. The relevant data shows that the measured value was 136.1 dB, with an error of 0.4% (<1%), further verifying the model's adaptability to meteorological scenarios in different regions.

[0061] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A long-distance visible light communication end-to-end end-to-end loss model, characterized in that, The end-to-end loss model covers the transmitter, channel, and receiver. The total loss of the end-to-end loss model is: in, This represents the total loss across the entire link. For the transmitter loss model, For the channel loss model, For the receiver loss model; The transmitter loss model It is determined by the electro-optical conversion efficiency, the radiation gain of the transmitter, the transmittance of the transmitting optical system, and the modulation loss; The channel loss model It is determined by free space loss associated with the Lambertian order of the transmitter, atmospheric molecular scattering and absorption loss, weather loss, turbulence loss, and multipath loss associated with the field of view of the receiver. The receiver loss model It is determined by the receiver's capture gain, the transmittance of the receiving optical system, the photoelectric conversion efficiency, and the receiver circuit loss.

2. The end-to-end loss model for long-distance visible light communication according to claim 1, characterized in that, The transmitter loss model The calculation expression is: in, For electro-optical conversion efficiency, For the radiation gain at the transmitting end, For the transmittance of the emission optical system, This is the modulation loss.

3. The end-to-end loss model for long-distance visible light communication according to claim 2, characterized in that, The radiation gain of the transmitter It follows a Lambertian distribution, expressed as: in, Let be the Lambert order. The angle between the emitted beam and the normal.

4. The end-to-end loss model for long-distance visible light communication according to claim 1, characterized in that, The channel loss model The calculation expression is: in, For free space loss, This is due to atmospheric molecular scattering and absorption losses. Due to weather damage, For turbulent loss, This is multipath loss.

5. The end-to-end loss model for long-distance visible light communication according to claim 4, characterized in that, The free space loss The expression is: in, This represents the actual transmission distance. The free space loss Depending on the Lambert order of the transmitting end It increases, but the growth rate slows down.

6. The end-to-end loss model for long-distance visible light communication according to claim 4, characterized in that, The weather loss The value is adapted to different regional meteorological scenarios: in areas in the south where rainfall intensity is greater than 50 mm / h, the weather loss... The calculation expression is: in, This represents the relative intensity attenuation ratio of the optical signal received by the receiver during rainy weather. The intensity of the light signal after attenuation due to rainfall. The reference optical signal intensity when there is no rainfall; This represents the equivalent attenuation coefficient of raindrop scattering; This represents the equivalent attenuation coefficient of raindrop absorption; This refers to the actual transmission distance. Regarding visibility The dense fog scene in the north, the weather loss The attenuation coefficient is 20% higher than that of a typical foggy day.

7. The end-to-end loss model for long-distance visible light communication according to claim 4, characterized in that, The turbulent loss Correlated atmospheric refractive index structure constant In long-distance scenarios, the turbulence loss Superimposed beam drift compensation coefficient.

8. The end-to-end loss model for long-distance visible light communication according to claim 4, characterized in that, The multipath loss The proportion of reflected signals associated with expressions in line-of-sight communication scenarios and reflection coefficient The multipath loss It decreases as the field of view of the receiver decreases.

9. The end-to-end loss model for long-distance visible light communication according to claim 1, characterized in that, The receiver loss model The calculation expression is: in, To capture the gain at the receiving end, To receive the transmittance of the optical system, For photoelectric conversion efficiency, This refers to the loss in the receiving circuit.

10. The end-to-end loss model for long-distance visible light communication according to claim 9, characterized in that, The receiver capture gain The expression is: in, The area of ​​the photodetector For optical gain, The angle of incidence is denoted as .

Images