Intelligent metasurface relay method and device for electric power scene

Abstract

The embodiment of the invention provides an intelligent metasurface relay method and device for an electric power scene. The method comprises the steps of active intelligent metasurface relay scheme design, user service algorithm design and intelligent reflector beam scanning process design. A signal of a control end of the unmanned aerial vehicle is received through the array antenna, after being amplified by the multi-stage power amplifier, the signal is transmitted to the intelligent metasurface through the feed source antenna, and then the intelligent metasurface carries out dynamic beam scanning, so that mobile beam tracking of the unmanned aerial vehicle is realized. According to the embodiment of the invention, the problem of how to expand the communication range of the unmanned aerial vehicle through the intelligent metasurface in the communication process of the unmanned aerial vehicle is solved, and the instant messaging of the unmanned aerial vehicle in tasks in wide plain areas and mountain areas is ensured.

Description

Technical Field

[0001] The present invention relates to the field of communication technology for electric power inspection drones, and in particular to a relay method and device based on intelligent metasurface technology when existing electric power inspection drones are at a long distance or are blocked. Background Art

[0002] In the current field of power inspection, drones, as an important inspection tool, can effectively improve inspection efficiency and coverage. Controlling drones for inspections through existing ground wireless infrastructure is an important research direction. However, during inspections in vast plains, mountains and other areas, there are problems of insufficient transmission distance and blocked transmission paths, which limits the operating range and data transmission efficiency of drones and affects the overall effectiveness of inspection tasks.

[0003] As an emerging communication enhancement technology, smart metasurface technology can improve signal coverage and transmission quality by adjusting the propagation characteristics of surface electromagnetic waves, thus achieving more stable and efficient communication. Therefore, considering how to use smart metasurface technology to assist in extending the communication distance of drones is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide an intelligent metasurface relay method and device for power scenarios to solve the problems of insufficient transmission distance and blocked transmission paths during power inspections by drones in vast plains, mountains and other areas.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] The invention relates to an intelligent metasurface relay method and device for power scenarios, comprising a receiving antenna for receiving a UAV control signal, the signal containing the UAV's predetermined route information, status information and task instructions; a multi-stage power amplifier for amplifying the control signal to increase the signal transmission distance; a feed antenna for providing gain while covering the signal to the intelligent metasurface; an intelligent metasurface for changing the propagation characteristics of electromagnetic waves by adjusting the surface voltage to perform beamforming; and a core board, as the intelligent metasurface control end, for controlling and realizing intelligent beam tracking.

[0007] Optionally, based on the initial setting of the UAV power inspection area, set the initial beam scan as follows:

[0008] The core board configures the bias voltage of the smart metasurface by calling the pre-stored code book, so that each unit of the smart metasurface produces a different phase distribution, so that the incident angle of the drone control signal sent by the feed antenna to the smart metasurface side is reflected by the smart metasurface, and the reflection angle is ω i of reflected waves.

[0009] The intelligent metasurface traverses the pre-stored codebook to scan the initial power inspection line area of ​​the drone. If, at a certain moment t, the drone detects that the received signal strength exceeds the threshold ε, the drone continuously sends back signals to report to the intelligent metasurface control end and stops scanning.

[0010] The drone sends back signals to report its own location and speed information, and then performs dynamic beamforming to achieve mobile tracking.

[0011] Optionally, based on the spatial position of the drone user, the spatial position of the smart metasurface, and the spatial position of the drone control station, the additional loss and attenuation coefficient of the drone link in the drone power inspection area are calculated, and the link characteristics from the drone to the smart metasurface and from the drone control terminal to the smart metasurface are modeled, specifically including:

[0012] Construct a three-dimensional Cartesian coordinate system. Assuming that the UAV control station actively provides its position to the UAV, the coordinates of the UAV control terminal and the intelligent metasurface can be expressed as p k =[x k ,y k ] T and p r =[x r ,y r ] T .

[0013] Set the drone to a height of H U Divide the total flight period T of the drone into N time slots of equal length, that is, T = Nδ, where δ represents the length of a time slot, and the approximate trajectory of the drone can be obtained as p[n] = [x U [n],y U [n]] T , n∈Ν={1,...,N}.

[0014] The communication link between the UAV and the smart metasurface relay is a relatively open airspace, so the link from the UAV to the smart reflective surface can be assumed to be a line-of-sight channel. The channel gain h of the link from the UAV to the smart reflective surface in the nth time slot is UR [n]∈C K×1 Given by:

[0015]

[0016] in, is the distance between the UAV and the smart reflector in the nth time slot, and the rightmost term is the array response of the uniform linear array of K elements. represents the cosine of the signal arrival angle from the UAV to the uniform linear array at the smart reflector at the nth time slot, d is the antenna spacing, and λ is the carrier wavelength.

[0017] Similarly, the channel gain h of the link from the smart reflector to the UAV control station in the nth time slot is RG ∈C M×1 It can be expressed as:

[0018]

[0019] in is the distance between the smart reflector and the ground user in the nth time slot, where represents the cosine of the signal deviation angle from the smart reflection surface to the ground user in the nth time slot, β is the Rice factor, and α is the path loss index of the link from the smart reflection surface to the UAV control station.

[0020] Optionally, the smart metasurface used in this embodiment is composed of K phases θ k [n]∈[0,2π) reflection units, and use

[0021]

[0022] As the diagonal phase offset matrix of the smart reflection surface in the nth time slot.

[0023] Optionally, according to the channel gains of the two channels in the system, the diagonal phase offset matrix of the intelligent metasurface, and the relay system gain G, the signal-to-noise ratio of the received signal of the drone in time slot n is calculated:

[0024]

[0025] in,(·) H The Hermitian matrix representation of this matrix or vector is: P is the fixed transmission power of the UAV control station, σ 2 is the noise variance.

[0026] Optionally, the receiving rate (in bits per second per Hertz, bps / Hz) of the drone user in the nth time slot is given by:

[0027] R GU [n] = log2(1 + γ GU [n])

[0028] Then the average receiving rate of the total N time slots of the drone user can be expressed as:

[0029]

[0030] Optionally, by regulating the voltage of each unit of the smart metasurface, the control signals reaching each smart metasurface unit are coherently combined, thereby maximizing the power of the received signal and thus maximizing the achievable rate. Therefore, by superimposing the signals in phase, we have:

[0031]

[0032] The channel gain from the UAV control end to the smart metasurface is expressed as:

[0033]

[0034] Furthermore, according to the above received signal noise ratio and channel gain in time slot n, the maximum value of the drone receiving signal rate can be obtained as:

[0035]

[0036] Beneficial Effects

[0037] From the above, it can be seen that the intelligent metasurface relay method and device for assisting UAV communication proposed in the present invention, based on the existing power amplifier amplifying the signal, uses intelligent reflection surfaces to intelligently shape the signal beam, which can effectively improve the communication quality and stability of the UAV during the power inspection process, expand the operating range of the UAV, improve efficiency, and ensure the reliability of data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a broad plain system model diagram of the reflector-assisted power inspection drone control signal transmission method of the present invention;

[0039] Figure 2 It is a mountain system model diagram of the control signal transmission method of the reflector-assisted power inspection UAV of the present invention;

[0040] Figure 3 It is an implementation flow chart of the present invention;

[0041] Figure 4 It is a flow chart of the intelligent metasurface beamforming algorithm of the present invention. DETAILED DESCRIPTION

[0042] In order to clarify the purpose, implementation scheme and technical advantages of the present invention, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0043] Figure 1 The intelligent metasurface relay method and device for assisting power inspection UAV communication of the present invention is applied in the actual application scenario of the vast plain area. The UAV control end link is too long and the attenuation is serious, making it difficult for the UAV to communicate. The present invention aims to improve the communication quality and stability of the UAV during the process, expand the operating range of the UAV, and improve the task efficiency.

[0044] Figure 2The present invention is an actual application scenario of the intelligent metasurface relay method and device for assisting power inspection drone communication in mountainous areas. The communication link of the power inspection drone is blocked by mountains and is severely attenuated, making it difficult for drones to communicate. The present invention uses an intelligent metasurface to control the reflection direction of the drone control signal, so that the control signal bypasses the mountain blockage, expands the operating range of the drone, and improves the mission efficiency.

[0045] Figure 1 , 2 As shown in , the relay device includes: a receiving antenna, a power amplifier, a feed antenna, and an intelligent metasurface.

[0046] Figure 3 The figure is a flowchart of the intelligent metasurface relay method and device for assisting UAV communication of the present invention, including:

[0047] Step 201: The array antenna receives the control signal sent by the drone control terminal, transmits it to the feed antenna via the power amplifier, and the feed antenna transmits the signal to the smart metasurface.

[0048] Step 202: The intelligent metasurface control end performs intelligent codebook control to form the signal into a high-gain narrow beam.

[0049] Step 203: The drone device receives the control signal.

[0050] Figure 4 It is a flow chart of the implementation process of the intelligent metasurface beamforming algorithm of the present invention, including:

[0051] Step 301: The intelligent metasurface receives a drone control signal via a feed antenna, starts traversing a pre-stored codebook, and performs random beam scanning.

[0052] Step 302: The drone detects the strength of its received signal. When it exceeds a predetermined threshold ε, the drone starts to continuously report its position and speed information, and notifies the intelligent metasurface to stop random wave scanning.

[0053] Step 303: the intelligent metasurface stops scanning and then uses the information reported by the drone to calculate the reflection angle to achieve the drone mobile beam tracking.

[0054] In step 301, the smart metasurface may be tested indoors in advance to obtain a codebook for the smart reflective surface to control the beam to various angles.

[0055] In step 302, the drone position information is represented as p[n]=[x U [n],y U [n]] T , n∈Ν={1,...,N}.

[0056] In step 303, based on the spatial position of the drone user p[n]=[x U [n],y U [n]] T 、Smart metasurface spatial position p r =[x r ,y r ] T and the spatial position of the UAV control station p k =[x k ,y k ] T , calculate the additional loss and attenuation coefficient of the UAV link within the UAV mission area, and model the link characteristics from the UAV to the smart metasurface and from the UAV control end to the smart metasurface.

[0057] The communication link between the UAV and the smart metasurface relay is a relatively open airspace, so the link from the UAV to the smart reflective surface can be assumed to be a line-of-sight channel. The channel gain h of the link from the UAV to the smart reflective surface in the nth time slot is UR [n]∈C K×1 Given by:

[0058]

[0059] in, is the distance between the UAV and the smart reflector in the nth time slot, and the rightmost term is the array response of the uniform linear array of K elements. represents the cosine of the signal arrival angle from the UAV to the uniform linear array at the smart reflector at the nth time slot, d is the antenna spacing, and λ is the carrier wavelength.

[0060] Similarly, the channel gain h of the link from the smart reflector to the UAV control station in the nth time slot is RG ∈C M×1 It can be expressed as:

[0061]

[0062] in is the distance between the smart reflector and the ground user in the nth time slot, where represents the cosine of the signal deviation angle from the smart reflection surface to the ground user in the nth time slot, β is the Rice factor, and α is the path loss index of the link from the smart reflection surface to the UAV control station.

[0063] In step 303, by regulating the voltage of each unit of the smart metasurface, the control signals reaching each smart metasurface unit are coherently combined, thereby maximizing the power of the received signal and thus maximizing the achievable rate.

[0064] Therefore, the reflection angle is calculated according to the following formula.

[0065]

[0066] Optionally, according to the above received signal noise ratio and channel gain in time slot n, the maximum value of the drone receiving signal rate can be obtained as:

[0067] .

Claims

1. A smart metasurface relay method and device for power scenarios, characterized in that include: Design of intelligent metasurface relay device, including power amplifier, feed antenna, intelligent metasurface, and core board; Design beamforming algorithms to achieve mobile beam tracking of UAVs; Design of intelligent metasurface-assisted UAV communication beam scanning process.

2. The method according to claim 1, characterized in that In each time slot, the beam direction is adjusted in real time according to the movement trajectory and speed information of the power inspection drone to optimize signal coverage and ensure that the drone receives the maximum signal rate during flight.

3. The method according to claim 1, according to the formula: Calculate the phase of each reflection unit of the smart metasurface, where: θ k [n] represents the phase of each reflective unit of the smart metasurface, ω i is the reflection angle of the reflected wave, represents the cosine of the signal arrival angle from the UAV to the uniform linear array at the smart reflector at the nth time slot, d is the antenna spacing, and λ is the carrier wavelength.

4. The method according to claim 1, according to the formula: The maximum value of the drone receiving signal rate is calculated, where: P is the fixed transmission power of the UAV control station, σ 2 is the noise variance, G is the relay system gain, h RG,i is the channel gain of the link from the smart reflector to the UAV control station in the nth time slot, d UG [n] is the distance from the drone control terminal to the drone in the nth time slot.

5. The device according to claim 1, an intelligent metasurface relay device for assisting UAV communication, characterized in that: include: Receiving antenna, used to receive information from the drone control end; A feed antenna is used to overlay the information amplified by the power amplifier onto the smart metasurface; Smart metasurface arrays for beam scanning; The power amplifier is used to amplify the signal; the core board is used to control the intelligent metasurface to perform beam scanning.

6. The device according to claim 5, characterized in that The phase adjustment unit of the smart metasurface array can adjust the propagation characteristics of electromagnetic waves. Specifically, the smart metasurface forms a desired beam shape by adjusting the phase difference of each unit, thereby controlling the propagation direction and intensity of the signal.

7. The method according to claim 2, characterized in that The moving trajectory of the UAV is divided into a plurality of time slots of equal length to facilitate dynamic adjustment of the beam.

8. The device according to claim 5, characterized in that The core board integrates signal processing and control algorithms to achieve dynamic adjustment and optimization of the beam.

9. The method according to claim 1, characterized in that: The intelligent metasurface beam scanning process includes: configuring the initial random beam scanning according to the pre-stored code book; after the UAV signal strength reaches the standard, adjusting the beam direction in real time according to the UAV's real-time position and speed information.

Images