Single-hop FSO communication method and device based on unmanned aerial vehicle relay, and storage medium

Abstract

The invention relates to a single-hop FSO communication method and device based on unmanned aerial vehicle relay and a storage medium, and belongs to the technical field of wireless optical communication. Comprising the following steps: constructing an atmospheric turbulence loss model, a path fading loss model and an alignment loss model; acquiring information of a transmitting end, a receiving end and an obstacle, and establishing a single-hop FSO communication system model under the optimal elevation angle of the unmanned aerial vehicle; obtaining a function relationship between the relay position of the unmanned aerial vehicle and the overall channel signal-to-noise ratio under the optimal elevation angle; and solving the function relationship to obtain the position with the maximum signal-to-noise ratio of the overall channel as the optimal relay position of the unmanned aerial vehicle. The method focuses on the phenomenon that the overall channel signal-to-noise ratio is different due to the hovering position difference of the unmanned aerial vehicle in the single-hop FSO communication process of the unmanned aerial vehicle relay, the optimal unmanned aerial vehicle relay position is accurately calculated through deep analysis and research on the overall channel signal-to-noise ratio, the influence of a shielding object can be avoided, the system performance can be optimized and improved, and the system performance is improved. And a solid foundation is laid for efficient and stable communication.

Description

Technical Field

[0001] The present invention relates to a single-hop FSO communication method, device and storage medium based on an unmanned aerial vehicle (UAV) relay, belonging to the technical field of wireless optical communication. Background Art

[0002] Free space optical (FSO) communication, as a broadband wireless optical communication technology that uses lasers to transmit data, exhibits many significant technical advantages compared with traditional radio frequency communication. Its optical bandwidth is extremely wide, and with wavelength division multiplexing technology, a high transmission rate of 100 Gbps or more can be achieved, which can meet the requirements of rapid transmission of big data. It also has excellent anti-electromagnetic interference ability, especially suitable for areas where wireless radio frequency communication is strictly prohibited and places with strong electromagnetic environments. At the same time, its spectrum resources do not require special application, and the laser beam is narrow, with good directivity and excellent confidentiality, which can effectively ensure the security and privacy of communication content.

[0003] However, the light beam emitted by FSO communication is extremely vulnerable to interference and influence from the climate and external environment, and the transmission distance is greatly limited. At present, a relay method is mostly used to overcome this problem. However, most of them use a fixed relay method, resulting in their inability to flexibly explore the optimal communication position according to the channel environment. Moreover, FSO communication is line-of-sight communication, and various obstacles will inevitably exist in the transmission channel, severely restricting the application scenarios.

[0004] Some scholars have proposed using UAVs as communication relays to achieve mobile relaying. However, during the process of using UAVs as communication relay nodes, due to the change in their positions, the path fading loss will change accordingly, which has a greater impact on the communication performance of the entire system. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a single-hop FSO communication method based on a UAV relay, which solves the problem of poor communication performance in UAV relay communication under non-line-of-sight conditions.

[0006] To achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In a first aspect, the present invention provides a single-hop FSO communication method based on a UAV relay, including:

[0008] S1: Construct a channel loss model, including: an atmospheric turbulence loss model, a path fading loss model, and an alignment loss model; wherein, the atmospheric turbulence loss and alignment loss are independent of the communication path distance, while the path fading loss is related to the communication path distance;

[0009] S2: Obtain information of the transmitter, receiver, and obstacles, and establish a single-hop FSO communication system model at the optimal elevation angle of the UAV;

[0010] S3: Based on the single-hop FSO communication system model and the channel loss model, obtain the functional relationship between the UAV relay position and the overall channel signal-to-noise ratio at the optimal elevation angle;

[0011] S4: Solve the functional relationship to obtain the position with the maximum overall channel signal-to-noise ratio as the optimal UAV relay position.

[0012] Furthermore, both the transmitter and the receiver are equipped with bidirectional photodetectors for converting the received optical signal into an electrical signal; the UAV is equipped with a bidirectional photodetector with an amplification function for first amplifying the optical signal and then converting it into an electrical signal; the transmitter, the UAV, and the receiver are all equipped with acquisition, tracking, and pointing devices to achieve alignment between the two ends.

[0013] Furthermore, the path fading loss model is: ; wherein, is the path fading loss, is the communication path distance.

[0014] Furthermore, establish a single-hop FSO communication system model at the optimal elevation angle of the UAV, including:

[0015] S21: Construct the physical architecture of the communication system, including: the transmitter as the source node for information transmission, denoted as A; the receiver as the destination node, denoted as B; the UAV as the relay node, denoted as C; wherein, A and B are fixed nodes, and C is a mobile node; the horizontal distance between the transmitter A and the receiver B is , the height difference between the transmitter A and the receiver B is ; the elevation angle of the highest point of the obstacle with respect to the transmitter A is ;

[0016] S22: Determine the elevation angle as the optimal elevation angle to minimize the path fading loss; and denote the horizontal distance between the transmitter A and the UAV C as ;

[0017] S23: Establish a single-hop FSO communication system model, wherein the communication path of the single-hop FSO communication system includes: the first path from the transmitter A to the UAV C and the second path from the UAV C to the receiver B;

[0018] The communication path distances of the first path and the second path are: ; ;

[0019] The signal received by the UAV relay is: ;

[0020] The signal at the receiving end is: ; Among them, ; ; In the formula, is the transmitted signal, is the signal received by the UAV relay, is the signal received by the receiving end, is the responsivity of the bi-directional photodetector on the UAV, is the total loss of the first path, is the noise of the first path; is the responsivity of the bi-directional photodetector at the receiving end, is the total loss of the second path, is the amplification gain, is the noise of the second path; is the atmospheric turbulence loss of the first path, is the alignment loss of the first path, is the atmospheric turbulence loss of the second path, is the alignment loss of the second path.

[0021] Furthermore, obtain the functional relationship between the UAV relay position and the overall channel signal-to-noise ratio at the optimal elevation angle, including:

[0022] Obtain the signal-to-noise ratio of the first path and the signal-to-noise ratio of the second path , and the expression is: ; ; In the formula, is the average power of the first path, is the noise power of the first path; is the average power of the second path; is the noise power of the second path;

[0023] Obtain the overall channel signal-to-noise ratio with respect to the signal-to-noise ratio of the first path and the signal-to-noise ratio of the second path : ;

[0024] Obtain the overall channel signal-to-noise ratio Expression for the horizontal distance between the transmitter and the drone is as follows: ;

[0025] Furthermore, the atmospheric turbulence loss model is characterized by the turbulence model or the Gamma-Gamma distribution.

[0026] Furthermore, the noise of the first path and the second path is both additive white Gaussian noise;

[0027] When using the turbulence model to characterize the atmospheric turbulence loss model, the probability density function of the signal-to-noise ratio of the path is represented by the Meyer function; ; wherein, ; ; ; ; ; In the formula, , is the standard deviation of the additive white Gaussian noise, is related to the effective number of large-scale scattering units, is the off-axis received scattering component, is the scattering power coupled to the line-of-sight transmission component, is the average power of the total scattering amount, is the number of fades, is the average power of the coherent signal, is the Bessel function of the second kind order gamma function, is the first intermediate quantity, is the second intermediate quantity, is the third intermediate quantity.

[0028] Furthermore, in the alignment loss model, the probability density function of the alignment loss is: ; In the formula, is the incident angle received by the bi-directional photodetector on the drone, is the distance from the transmission center to the beam center, is the variance of, is the distance The beam width at is the radius of the circular receiving area on the bi-directional photodetector.

[0029] In a second aspect, the present invention provides an electronic device, comprising: a processor and a memory; computer-readable instructions are stored on the memory, and when the computer-readable instructions are executed by the processor, the single-hop FSO communication method based on UAV relay described in the first aspect is implemented.

[0030] In a third aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the single-hop FSO communication method based on UAV relay described in the first aspect is implemented.

[0031] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) Through in-depth analysis and research on the overall channel signal-to-noise ratio, the present invention accurately calculates the optimal UAV relay position, which can avoid the influence of obstacles and can also optimize and improve the system performance, laying a solid foundation for the efficient and stable progress of communication; (2) By installing an optical amplifier to amplify the transmitted optical signal, the present invention helps to achieve long-distance communication, can effectively solve the problem of line-of-sight communication, and greatly extends the application range of FSO; (3) When the optical cable is blocked between important nodes and it is urgent to construct a communication link, the present invention relies on UAVs to quickly construct an end-to-end communication network and adjusts the channel transmission performance to the best state. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flowchart of the single-hop FSO communication method based on UAV relay provided in Embodiment 1 of the present invention;

[0033] Figure 2 is a schematic diagram of the single-hop FSO communication system model provided in Embodiment 1 of the present invention;

[0034] Figure 3 is a schematic diagram of two-way communication of the single-hop FSO communication system provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] In the description and claims of this application and the above-mentioned drawings, 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 that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments.

[0036] Free space optical communication (FSO) has the advantages of high bandwidth, easy deployment, high security and cost-effectiveness, and is an effective solution for terrestrial, airborne and satellite networks. However, the transmission performance of FSO will be limited by impairments such as geometric loss, pointing error, atmospheric attenuation and turbulence effects.

[0037] Embodiment 1

[0038] This embodiment provides a single-hop FSO communication method based on UAV relay. As Figure 1 shown, this method includes the following steps:

[0039] Step 1: Construct a channel loss model, including: an atmospheric turbulence loss model, a path fading loss model and an alignment loss model.

[0040] As is well known, the atmospheric turbulence effect refers to the random change of the local temperature and pressure of the atmosphere, resulting in the random fluctuation of the refractive index of the atmosphere, causing the light intensity and phase to change in space and time during the light transmission process, generating phase distortion, light intensity scintillation, etc. It mainly occurs at the junction of several air flow layers moving at different speeds. Thus, it can be seen that the magnitude of the atmospheric turbulence loss is affected by the atmospheric state.

[0041] The atmospheric environment is by no means an ideal vacuum state, filled with various complex media and changing meteorological conditions. These factors are intertwined and become an "energy trap" on the way of optical signal transmission. And the atmosphere itself also has certain absorption characteristics, which will convert part of the energy of the optical signal into heat energy and dissipate it invisibly. Therefore, the path fading loss is introduced to describe the loss amount in the propagation environment between the transmitter and the receiver. The path fading loss is only related to the propagation path. The longer the path, the greater the path loss.

[0042] During the operation of an optical communication system, the alignment loss is also a factor that cannot be ignored. One of the main reasons for its generation is the offset of the photodetector. As a key component for receiving optical signals, the slightest change in the position of the photodetector will affect the accurate reception of optical signals. The hovering and shaking of the UAV will also bring troubles in terms of alignment loss to optical communication.

[0043] Therefore, in the present invention, three models are established to describe the atmospheric turbulence loss, path fading loss, and alignment loss in a single-hop FSO communication transmission system. Among them, the models of atmospheric turbulence loss and alignment loss are independent of the communication path distance variable, while the model of path fading loss is related to the communication path distance variable.

[0044] In the prior art, a common path fading loss model is: ; In the formula, is the path fading loss, is the communication path distance, is the fading coefficient.

[0045] For the above common path fading loss model, when the weather is clear, is taken as 1. Therefore, in this embodiment, the path fading loss model is: ;

[0046] In some specific embodiments, the atmospheric turbulence loss model is characterized by using turbulence model or Gamma-Gamma distribution.

[0047] Step 2: Obtain the information of the transmitter, receiver, and obstacle, and establish a single-hop FSO communication system model at the optimal elevation angle of the UAV.

[0048] As Figure 2 shown, the positions and heights of the FSO transmitter and receiver are fixed, there is a height difference, and there is an obstacle in the middle, so line-of-sight communication cannot be achieved; the UAV is deployed as a relay between the two to construct a single-hop FSO communication system model of transmission-relay-reception under non-line-of-sight conditions.

[0049] It should be noted that the present invention is applicable to the case where the distance between the transmitter and the receiver satisfies normal single-hop FSO communication and does not require the use of a UAV for multi-hop relay.

[0050] Specifically, first construct the physical architecture of the communication system. As Figure 2 shown, the transmitter is used as the source node for information transmission, denoted as A; the receiver is used as the destination node, denoted as B; the UAV is used as the relay node, denoted as C; among them, A and B are fixed nodes, and C is a mobile node; the horizontal distance between the transmitter A and the receiver B is , and the height difference between the transmitter A and the receiver B is ; the elevation angle of the highest point of the obstacle with respect to the transmitter A is .

[0051] To minimize the path fading loss, the elevation angle Determine the optimal elevation angle for the deployment of the UAV. And set the horizontal distance between the transmitting end A and the UAV C as the independent variable.

[0052] In addition, both the transmitting end and the receiving end are equipped with bidirectional photodetectors for converting the received optical signal into an electrical signal, and the UAV for relaying is a hoverable UAV equipped with a bidirectional photodetector with an amplification function for first amplifying the optical signal and then converting it into an electrical signal.

[0053] The transmitting end, the UAV, and the receiving end are all equipped with acquisition, tracking, and pointing (ATP) devices to achieve 360° horizontal and 90° vertical rotation, facilitating alignment between the two ends.

[0054] The optical amplifier of the relaying UAV adopts the amplify-and-forward mode, the bidirectional photodetector uses intensity detection / direct detection, and the modulation method uses on-off keying.

[0055] Bidirectional communication exists between the transmitting end, the UAV, and the receiving end.

[0056] Specifically, as Figure 3 shown, when the transmitting end A sends an optical signal to the receiving end B, the wavelength is , the optical signal is sent through the FSO channel to the relaying UAV C. The photodetector at the C end converts the received optical signal into an electrical signal and amplifies the signal, and then converts it into an optical signal with a wavelength of , and is sent to the receiving end B through the FSO channel.

[0057] When the receiving end B sends an optical signal to the transmitting end A, the wavelength is , the optical signal is sent through the FSO channel to the relaying UAV C. The photodetector at the C end converts the received optical signal into an electrical signal and amplifies the signal, and then converts it into an optical signal with a wavelength of , and is sent to the transmitting end A through the FSO channel.

[0058] Establish a single-hop FSO communication model. Among them, the communication path of the single-hop FSO communication model includes: the first path from the transmitting end A to the UAV C and the second path from the UAV C to the receiving end B.

[0059] According to Figure 2 the single-hop FSO communication system model shown, the communication path distances of the first path and the second path are: ; ;

[0060] The signal received by the UAV relay is: ;

[0061] The signal at the receiving end is: ; Wherein, ; ; In the formula, is the transmitted signal, is the signal received by the UAV relay, is the signal received by the receiving end, is the responsivity of the bi-directional photodetector on the UAV, is the total loss of the first path, is the noise of the first path; is the responsivity of the bi-directional photodetector at the receiving end, is the total loss of the second path, is the amplification gain, is the noise of the second path; is the atmospheric turbulence loss of the first path, is the alignment loss of the first path, is the atmospheric turbulence loss of the second path, is the alignment loss of the second path.

[0062] It can be seen from the above single-hop FSO communication system model that when the position of the UAV changes, the path fading loss will change accordingly, affecting the performance of the entire FSO communication system.

[0063] Step 3: Based on the single-hop FSO communication system model and the channel loss model, obtain the functional relationship between the UAV relay position and the overall channel signal-to-noise ratio at the optimal elevation angle, including:

[0064] Step 31: Obtain the signal-to-noise ratio of the first path and the signal-to-noise ratio of the second path , and the expression is: ; ; In the formula, is the average power of the first path, is the noise power of the first path; is the average power of the second path; is the noise power of the second path.

[0065] Step 32: Obtain the expression of the overall channel signal-to-noise ratio with respect to the signal-to-noise ratio of the first path and the signal-to-noise ratio of the second path : ;

[0066] Specifically, the overall channel signal-to-noise ratio with respect to the signal-to-noise ratio of the first path and the signal-to-noise ratio of the second path is obtained as follows:

[0067] From the calculation formula of the instantaneous signal-to-noise ratio of the entire system, we have: ; where: ;

[0068] Combining and we can deduce the general expression for with respect to and : ;

[0069] In the case of high signal-to-noise ratio, the number 1 can be omitted, thus obtaining the above expression for and .

[0070] Step 33: Obtain the overall channel signal-to-noise ratio with respect to the horizontal distance between the transmitter and the UAV : ;

[0071] So far, the functional relationship between the overall channel signal-to-noise ratio and the independent variable, the horizontal distance between the transmitter and the UAV, at the optimal elevation angle is obtained. By solving the functional relationship, the value when the overall channel signal-to-noise ratio is maximized at the optimal elevation angle can be obtained, which is the optimal relay position of the UAV.

[0072] In this embodiment, based on the FSO transmission channel model, the internal relationships among the deployment position of the UAV, the position of the obstacle, the elevation angle of the UAV, the characteristics of the transmission channel, and the transmitter and the receiver are comprehensively analyzed. Taking the signal-to-noise ratio of the entire communication system as the evaluation criterion, the mathematical relationship between the deployment position of the UAV and the signal-to-noise ratio of the entire communication system is obtained. By analyzing the mathematical relationship, the deployment position of the UAV at the optimal signal-to-noise ratio is determined, providing strong support and guarantee for the technical development in related fields.

[0073] Embodiment 2

[0074] ​Based on Embodiment 1, this embodiment provides the construction of an atmospheric turbulence loss model and an alignment loss model.

[0075] When studying the impact of atmospheric turbulence on an optical communication system, the distribution has extremely excellent universality. Whether facing a weak turbulence environment with relatively stable airflows and fewer interference factors, or a strong turbulence situation with violently churning airflows and a complex and changeable optical transmission environment, the distribution model can accurately depict the optical signal fading characteristics caused by atmospheric turbulence, fitting the actual transmission situation.

[0076] When focusing on the observation field at the receiver, three key components can be clearly deconstructed: the line-of-sight transmission component, the energy component scattered to the receiver, and the scattering component on the signal transmission axis, and they are coupled with the line-of-sight transmission.

[0077] It should be noted that the noise of the first path and the second path in this embodiment is additive white Gaussian noise.

[0078] In some specific embodiments, a turbulence model is used to characterize the atmospheric turbulence loss model, and the signal-to-noise ratio probability density functions of the first path and the second path are represented by the Meyer function; ; wherein, ; ; ; ; ; In the formula, , describes the signal-to-noise ratio probability density function of the first path when describes the signal-to-noise ratio probability density function of the second path when is the standard deviation of the additive white Gaussian noise, is related to the effective number of large-scale scattering units, is the off-axis received scattering component, is the scattering power coupled to the line-of-sight transmission component, is the average power of the total scattering amount, is the number of fades, is the average power of the coherent signal, is the Bessel function is of the second kind order gamma function, is the first intermediate quantity, is the second intermediate quantity, is the third intermediate quantity.

[0079] In some specific embodiments, the alignment loss has a probability density function as follows: ; In the formula, is the incident angle received by the bidirectional photodetector on the UAV, is the distance from the transmission center to the beam center, is the variance of, is the distance at which the beam width is, is the radius of the circular receiving area on the bidirectional photodetector.

[0080] Embodiment 3

[0081] This embodiment provides an electronic device, including: a processor, a communication interface, a communication bus, and a memory; wherein, the processor, the communication interface, and the memory complete communication with each other through the communication bus, and computer-readable instructions are stored on the memory. The processor can call the computer-readable instructions in the memory to execute the single-hop FSO communication method based on UAV relay described in Embodiment 1 or Embodiment 2.

[0082] In addition, when the computer-readable instructions in the above-mentioned memory are implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing 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.

[0083] Embodiment 4

[0084] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the single-hop FSO communication method based on UAV relay described in Embodiment 1 or Embodiment 2. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0085] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A single-hop FSO communication method based on drone relay, characterized in that: include: S1: constructing a channel loss model, including: an atmospheric turbulence loss model, a path fading loss model and an alignment loss model; wherein the atmospheric turbulence loss and the alignment loss are independent of the communication path distance, while the path fading loss is related to the communication path distance; S2: Obtain information about the transmitter, receiver, and obstacles, and establish a single-hop FSO communication system model at the optimal elevation angle of the UAV; S3: Based on the single-hop FSO communication system model and the channel loss model, the functional relationship between the drone relay position and the overall channel signal-to-noise ratio at the optimal elevation angle is obtained; S4: Solve the functional relationship to obtain the position with the maximum overall channel signal-to-noise ratio as the optimal relay position for the UAV.

2. The single-hop FSO communication method based on drone relay according to claim 1 is characterized in that: The transmitting end and the receiving end are both equipped with a bidirectional photoelectric detector for converting the received optical signal into an electrical signal; the drone is equipped with a bidirectional photoelectric detector with an amplification function for first amplifying the optical signal and then converting it into an electrical signal; The transmitting end, the UAV and the receiving end are all equipped with acquisition, tracking and pointing equipment to achieve alignment between the two ends.

3. The single-hop FSO communication method based on drone relay according to claim 2 is characterized in that: The path fading loss model is: ； In the formula, is the path fading loss, is the communication path distance.

4. The single-hop FSO communication method based on drone relay according to claim 3 is characterized in that: The single-hop FSO communication system model at the optimal elevation angle of the UAV is established, including: S21: Construct the physical architecture of the communication system, including: the sender as the source node of information transmission, denoted by A; the receiver as the destination node, denoted by B; the drone as the relay node, denoted by C; A and B are fixed nodes, C is a mobile node; the horizontal distance between the sender A and the receiver B is , the height difference between the transmitter A and the receiver B is ; The elevation angle of the highest point of the obstacle to the transmitter A is ; S22: Elevation Determine the optimal elevation angle to minimize the path fading loss; and record the horizontal distance between the transmitter A and the drone C as ; S23: establishing a single-hop FSO communication system model, wherein the communication path of the single-hop FSO communication system model includes: a first path from the transmitter A to the drone C and a second path from the drone C to the receiver B; The communication path distance between the first path and the second path is: ； ； The signal received by the drone relay is: ； The signal at the receiving end is: ； in, ； ； In the formula, To transmit the signal, Relays received signals for drones, is the signal received by the receiving end, is the responsivity of the bidirectional photodetector on the drone, is the total loss of the first path, is the first path noise; is the responsivity of the bidirectional photodetector at the receiving end, is the total loss of the second path, is the amplification gain, is the second path noise; is the atmospheric turbulence loss of the first path, is the alignment loss of the first path, is the atmospheric turbulence loss of the second path, is the alignment loss of the second path.

5. The single-hop FSO communication method based on drone relay according to claim 4 is characterized in that: The functional relationship between the drone relay position and the overall channel signal-to-noise ratio at the optimal elevation angle is obtained, including: Get the first path signal-to-noise ratio and the signal-to-noise ratio of the second path , the expression is: ； ； In the formula, is the average power of the first path, is the noise power of the first path; is the average power of the second path; is the noise power of the second path; Get the overall channel signal-to-noise ratio About the First Path Signal-to-Noise Ratio and the second path SNR The expression is: ； Get the overall channel signal-to-noise ratio About the horizontal distance between the transmitter and the drone The expression is: 。 6. The single-hop FSO communication method based on drone relay according to claim 4 is characterized in that: The atmospheric turbulence loss model adopts Turbulence model or Gamma-Gamma distribution representation.

7. The single-hop FSO communication method based on drone relay according to claim 6 is characterized in that: The noises of the first path and the second path are both additive Gaussian white noise; use When the turbulence model represents the atmospheric turbulence loss model, the Meier function is used to represent the first Probability density function of path signal-to-noise ratio; ； in, ; ； ； ； ； In the formula, , is the standard deviation of additive white Gaussian noise, is related to the effective number of large-scale scattering units, is the scattered component received off-axis, is the scattered power coupled to the line-of-sight transmission component, is the average power of the total scattered energy, is the number of declines, is the average power of the coherent signal, is the Bessel function For the second category The gamma function of order, is the first intermediate quantity, is the second intermediate quantity, The third intermediate quantity.

8. The single-hop FSO communication method based on drone relay according to claim 7 is characterized in that: In the alignment loss model, the alignment loss The probability density function of is: ； In the formula, is the receiving incident angle of the bidirectional photodetector on the drone, is the distance from the transmission center to the beam center, for The variance of For distance The beam width at is the radius of the circular receiving area on the bidirectional photodetector.

9. An electronic device, characterized in that: include: Processor and memory; The memory stores computer-readable instructions, which, when executed by the processor, implement the single-hop FSO communication method based on drone relay according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the single-hop FSO communication method based on drone relay is implemented as described in any one of claims 1 to 8.

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