Method and device for cooperatively enhancing communication capacity by multiple unmanned aerial vehicles in emergency scene

Abstract

The invention discloses a method and device for cooperatively enhancing communication capacity by multiple unmanned aerial vehicles in an emergency scene, and the method comprises the steps: obtaining the position information of a virtual non-uniform transmission linear array and a ground receiving antenna linear array according to a preset coordinate system; the virtual non-uniform emission linear array comprises a plurality of unmanned aerial vehicles; a far-field line-of-sight transmission condition is met between the virtual non-uniform transmitting linear array and the ground receiving antenna linear array; according to the position information, constructing a high order-rank sight distance MIMO channel matrix; determining the position of the unmanned aerial vehicle and a precoding matrix when the channel capacity is maximized according to the high-order-rank sight distance MIMO channel matrix; and configuring a virtual non-uniform transmission linear array according to the position of the unmanned aerial vehicle and the pre-coding matrix, so that the configured virtual non-uniform transmission linear array communicates with equipment where the ground receiving antenna linear array is located. According to the invention, the problems of limited airborne energy and limited transmitting power during auxiliary communication of the unmanned aerial vehicle are solved.

Description

Technical Field

[0001] The present invention belongs to the field of unmanned aerial vehicle communication technology, and specifically relates to a method and device for collaboratively enhancing communication capacity of multiple unmanned aerial vehicles in an emergency scenario. Background Art

[0002] In recent years, UAVs have received extensive attention in assisting wireless communications. UAV-assisted communications do not rely on fixed ground facilities and can be used as airspace-assisted communication platforms based on their own advantages such as multi-function, high mobility, easy deployment, and low cost.

[0003] However, drones are small and cannot carry large-scale antenna arrays, so their communication capacity is limited. In addition, drone transmission power depends on the battery carried by the drone itself, so it also faces challenges such as limited onboard energy and limited transmission power. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a method and device for collaboratively enhancing communication capacity of multiple UAVs in an emergency scenario.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] A method for enhancing communication capacity by coordinating multiple unmanned aerial vehicles in an emergency scenario, comprising:

[0007] According to a preset coordinate system, position information of a virtual non-uniform transmitting linear array and a ground receiving antenna array is obtained; wherein the virtual non-uniform transmitting linear array includes a plurality of drones; the virtual non-uniform transmitting linear array and the ground receiving antenna array satisfy a far-field line-of-sight transmission condition; the coordinate system takes the center of the virtual non-uniform transmitting linear array as the coordinate origin; the xy plane of the coordinate system is parallel to the ground plane, the x-axis is parallel to the ground receiving antenna array, and the z-axis points to the ground plane;

[0008] Constructing a high-order-rank line-of-sight MIMO channel matrix according to the position information;

[0009] Determining a UAV position and a precoding matrix when channel capacity is maximized based on the high-order-rank line-of-sight MIMO channel matrix;

[0010] The virtual non-uniform transmission linear array is configured according to the position of the UAV and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with the device where the ground receiving antenna array is located.

[0011] Optionally, obtaining position information of a virtual non-uniform transmitting linear array and a ground receiving antenna linear array according to a preset coordinate system includes:

[0012] According to the position of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, the coordinates (x T,n ,y T,n ,z T,n ), and the coordinates (x r,m ,y r,m ,z r,m );

[0013]

[0014] Wherein, L is the length of the virtual non-uniform transmission linear array; η n ∈[-1,1] is the normalized position of the nth UAV relative to the coordinate origin, n=1,2,…,N; φ is the angle between the virtual non-uniform transmitting linear array and the x-axis, is the azimuth angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array; θ is the elevation angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, d is the array element spacing of the ground receiving antenna array; m=1,2,…,M, M is the number of receiving antennas of the ground receiving antenna array; represents the ground receiving antenna array; R is the distance between the coordinate origin and the ground receiving antenna array.

[0015] Optionally, constructing a high-order-rank line-of-sight MIMO channel matrix according to the position information includes:

[0016] Based on the position information, the transmission distance between the drone and the receiving antenna is calculated:

[0017]

[0018] Among them, τ m,n represents the transmission distance between the mth receiving antenna and the nth UAV;

[0019] According to the transmission distance, a high-order-rank line-of-sight MIMO channel matrix is ​​constructed:

[0020]

[0021] Among them, e is the natural base, π is the ratio of pi, j is the symbol of the imaginary part, and f c is the carrier frequency of the virtual non-uniform transmitting linear array, t represents time, and c represents the propagation speed of electromagnetic waves in vacuum; H is the high-order-rank line-of-sight MIMO channel matrix;

[0022] P R=diag(p R,1 ,p R,2 ,...,p R,M );

[0023]

[0024] P T =diag(p T,1 ,p T,2 ,...,p T,N );

[0025]

[0026] diag(·) is a function for constructing a diagonal matrix. Represents a set of M×N complex numbers.

[0027] Optionally, determining the position of the UAV and the precoding matrix when the channel capacity is maximized according to the high-order-rank MIMO channel matrix includes:

[0028] According to the high-order-rank MIMO channel matrix, a maximum channel capacity problem is constructed; wherein the maximum channel capacity problem uses the position of the UAV and the precoding matrix as solution parameters, and takes maximizing the channel capacity as the optimization goal;

[0029] Decomposing the maximum channel capacity problem into a first optimization subproblem of maximizing the product of channel eigenvalues ​​and a second optimization subproblem of maximizing the minimum received signal-to-noise ratio;

[0030] Solve the first optimization sub-problem to obtain the optimal solution for the position of the UAV;

[0031] The second optimization subproblem is solved according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix.

[0032] Optionally, the maximum channel capacity problem is:

[0033]

[0034] Wherein, M is the number of receiving antennas of the ground receiving antenna array, m=1, 2, ..., M; represents the ground receiving antenna array; N is the number of UAVs of the virtual non-uniform transmitting linear array, n=1,2,…,N; is the signal-to-noise ratio of the signal received by the receiving antenna, w is a precoding vector used to adjust the amplitude and phase of the transmitted signal of the virtual non-uniform transmitting linear array; h m is the channel vector of the mth receiving antenna of the ground receiving antenna array, σ 2 represents the noise variance; λ mThe gain matrix G = HH H The mth eigenvalue of H is the precoding matrix, and the superscript H represents the matrix conjugate transpose; The superscript T indicates the matrix transpose; η=η1,η2,…,η N , η n ∈[-1,1] is the normalized position of the nth UAV relative to the coordinate origin; C is the channel capacity.

[0035] Optionally, the first optimization sub-problem is:

[0036] The second optimization sub-problem is:

[0037] Among them, P n Indicates the transmission power limit of the nth UAV; [WW H ] n,n Indicates taking the matrix WW H The element at the nth row and nth column of .

[0038] Optionally, solving the first optimization subproblem includes: converting the first optimization subproblem into a solvable first optimization subproblem and solving it;

[0039] The first solvable optimization subproblem is:

[0040] Among them, η k represents the normalized position of the kth UAV relative to the coordinate origin, k = 2, 3, ..., M, η l Represents the normalized position of the lth UAV relative to the coordinate origin.

[0041] Optionally, solving the second optimization subproblem according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix includes:

[0042] converting the second optimization subproblem into a solvable second optimization subproblem;

[0043] Solving the solvable second optimization sub-problem according to the optimal solution for the position of the UAV;

[0044] The solvable second optimization sub-problem is:

[0045]

[0046] Among them, q and s m are all auxiliary variables introduced, vec(·) is a function that rearranges the matrix into a vector, h mAccording to the optimal solution of the drone position,

[0047] Optionally, the method is applied to a control terminal of multiple UAVs.

[0048] The present invention also provides a device for enhancing communication capacity of multiple UAVs in an emergency scenario, comprising:

[0049] An acquisition module is used to acquire position information of a virtual non-uniform transmitting linear array and a ground receiving antenna array according to a preset coordinate system; wherein the virtual non-uniform transmitting linear array includes a plurality of drones; the virtual non-uniform transmitting linear array and the ground receiving antenna array satisfy a far-field line-of-sight transmission condition; the coordinate system takes the center of the virtual non-uniform transmitting linear array as the coordinate origin; the xy plane of the coordinate system is parallel to the ground plane, the x-axis is parallel to the ground receiving antenna array, and the z-axis points to the ground plane;

[0050] A construction module, configured to construct a high-order-rank line-of-sight MIMO channel matrix according to the location information;

[0051] A determination module, configured to determine a UAV position and a precoding matrix when the channel capacity is maximized according to the high-order-rank line-of-sight MIMO channel matrix;

[0052] A configuration module is used to configure the virtual non-uniform transmission linear array according to the position of the UAV and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with the device where the ground receiving antenna array is located.

[0053] The method for multi-UAV collaborative enhancement of communication capacity in emergency scenarios provided by the present invention has the following beneficial effects:

[0054] The present invention jointly designs the position of the drone and the precoding matrix, uses a virtual non-uniform transmitting linear array to communicate with the equipment where the ground receiving antenna array is located, and uses independent and identically distributed sub-channels to improve the channel gain and maximize the channel capacity, thus overcoming the defects of a single drone with limited volume and airborne energy, which cannot carry a large-scale antenna array and meet the requirements of high-power transmission signals. Therefore, based on the collaborative transmission of signals by multiple drones to form a virtual non-uniform transmitting linear array, it is possible to achieve large-capacity reliable communication in complex emergency scenarios, and improve the efficiency and interconnection of communication.

[0055] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1is a flow chart of a method for multi-UAV collaborative enhancement of communication capacity in an emergency scenario provided by an embodiment of the present invention;

[0057] Figure 2 Schematic diagram of a multi-UAV cooperative communication scenario in an emergency scenario in an embodiment of the present invention;

[0058] Figure 3 It is a UAV location distribution map designed using the method of an embodiment of the present invention;

[0059] Figure 4 FIG. 4 shows a comparison result of the channel capacity variation trend of the virtual non-uniform transmitting array in the embodiment of the present invention and the traditional virtual uniform transmitting antenna array with the signal-to-noise ratio;

[0060] Figure 5 It is a structural schematic diagram of a device for collaboratively enhancing communication capacity of multiple UAVs in an emergency scenario provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0062] In order to solve the problems of limited airborne energy and limited transmission power in UAV-assisted communication, an embodiment of the present invention provides a method for enhancing communication capacity through multi-UAV collaboration in an emergency scenario. The method adopts multi-UAV collaboration, uses multiple UAVs to form a virtual non-uniform transmission array, and obtains good transmission performance through multi-UAV collaborative beamforming. Figure 1 As shown, the method comprises the following steps:

[0063] S10. Acquire position information of a virtual non-uniform transmitting linear array and a ground receiving antenna linear array according to a preset coordinate system.

[0064] Among them, see Figure 2 As shown, the coordinate system takes the center of the virtual non-uniform transmission linear array as the origin O; the xy plane of the coordinate system is parallel to the ground plane, the x axis is parallel to the ground receiving antenna array, and the z axis points to the ground plane; the virtual non-uniform transmission linear array includes multiple drones, defined as The length of the virtual non-uniform transmitting linear array is L, and N is the number of UAVs; the ground receiving antenna array is defined as The ground receiving antenna array is a uniform linear array with an array element spacing of d; the virtual non-uniform transmitting linear array and the ground receiving antenna array meet the far-field line-of-sight transmission condition.

[0065] Hence, see Figure 2, the angle between the virtual non-uniform transmission linear array and the x-axis of the coordinate system is φ, the direction from the origin of the coordinate perpendicular to the xy plane to the earth is the z-axis direction, and the distance between the center of the virtual non-uniform transmission linear array and the ground receiving antenna array is R. Considering the target far-field signal transmission model, parallel wave and line-of-sight transmission are established at the same time, the azimuth angle of the ground receiving antenna array relative to the virtual non-uniform transmission linear array is recorded as The elevation angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array is denoted as θ.

[0066] Accordingly, according to the preset coordinate system, the position information of the virtual non-uniform transmitting linear array and the ground receiving antenna linear array is obtained, including: according to the position of the ground receiving antenna linear array relative to the virtual non-uniform transmitting linear array, the coordinates (x T,n ,y T,n ,z T,n ), and the coordinates (x r,m ,y r,m ,z r,m ), n=1,2,…,N, m=1,2,…,M.

[0067] Among them, the coordinates of the drone (x T,n ,y T,n ,z T,n )for:

[0068]

[0069] In the above formula, the coordinate (x T,n ,y T,n ,z T,n ) in the subscript of the three components represents transmission; L is the length of the virtual non-uniform transmission linear array, that is, the aperture of the virtual non-uniform transmission linear array; η n ∈[-1,1] is the normalized position of the nth UAV relative to the coordinate origin; φ is the angle between the virtual non-uniform transmitting linear array and the x-axis.

[0070] The coordinates of the receiving antenna (x r,m ,y r,m ,z r,m )for:

[0071]

[0072] in, is the azimuth angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, θ is the elevation angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, d is the element spacing of the ground receiving antenna array; m = 1, 2, ..., M, M is the number of receiving antennas of the ground receiving antenna array; R is the spacing between the coordinate origin and the ground receiving antenna array. In addition, the coordinate (x r,m ,y r,m ,z r,m ) in the subscripts of the three components represents reception.

[0073] S20. Construct a high-order-rank line-of-sight MIMO channel matrix according to the position information of the virtual non-uniform transmitting linear array and the ground receiving antenna linear array.

[0074] Specifically, based on the location information, a high-order-rank line-of-sight MIMO channel matrix is ​​constructed, including:

[0075] (1) Calculate the transmission distance between the drone and the receiving antenna based on the location information:

[0076]

[0077] Among them, τ m,n Represents the transmission distance between the mth receiving antenna and the nth UAV.

[0078] (2) According to the transmission distance τ m,n , construct a high-order-rank line-of-sight MIMO channel matrix:

[0079] H={h m,n};

[0080] in, represents the channel gain between the mth receiving antenna and the nth UAV, represents the radio path loss, c represents the propagation speed of electromagnetic waves in a vacuum, and f c is the carrier frequency of the virtual non-uniform transmitting linear array, t represents time, and R is the distance between the coordinate origin and the ground receiving antenna array.

[0081] The above formula is expanded by Taylor to further decompose the high-order-rank line-of-sight MIMO channel matrix into:

[0082]

[0083] Among them, e is the natural base, π is the ratio of pi, j is the imaginary part symbol, and the meanings of other symbols are as mentioned above.

[0084] P R =diag(p R,1 ,p R,2 ,...,pR,M );

[0085]

[0086] Here, diag(·) is a function that constructs a diagonal matrix.

[0087] P T =diag(p T,1 ,p T,2 ,...,p T,N );

[0088]

[0089] Represents a set of M×N complex numbers.

[0090] S30. Determine the UAV position and precoding matrix when the channel capacity is maximized based on the high-order-rank line-of-sight MIMO channel matrix.

[0091] Specifically, according to the high-order-rank MIMO channel matrix, the drone position and precoding matrix when the channel capacity is maximized are determined, including: constructing a maximum channel capacity problem according to the high-order-rank MIMO channel matrix; wherein the maximum channel capacity problem uses the drone position and precoding matrix as solution parameters, and takes maximizing the channel capacity as the optimization goal. Then, by solving the maximum channel capacity problem, the optimal solution for the drone position and precoding matrix can be obtained.

[0092] Among them, the maximum channel capacity problem is:

[0093]

[0094] In the maximum channel capacity problem, M is the number of receiving antennas of the ground receiving antenna array, m = 1, 2, ..., M; represents the ground receiving antenna array; N is the number of UAVs in the virtual non-uniform transmitting linear array, n = 1, 2, ..., N; W = ww H is the precoding matrix; the superscript H represents the matrix conjugate transpose; w is the precoding vector, which is used to adjust the amplitude and phase of the transmitted signal of the virtual non-uniform transmitting linear array; let x represent the transmitted symbol stream vector of the virtual non-uniform transmitting linear array, then the transmitted signal of the virtual non-uniform transmitting linear array is s=Wx, and correspondingly, the received signal of the ground receiving antenna array is expressed as: y=Hs+n. is the signal-to-noise ratio of the signal received by the receiving antenna, h m is the channel vector of the mth receiving antenna of the ground receiving antenna array, h m =[h m1 ,h m2,...,h mN ],σ 2 represents the noise variance; λ m The gain matrix G = HH H The mth eigenvalue of ; The superscript T indicates the matrix transpose; η=η1,η2,…,η N , C is the channel capacity.

[0095] In one implementation, determining a UAV position and a precoding matrix when channel capacity is maximized according to a high-order-rank MIMO channel matrix includes:

[0096] (1) Based on the high-order-rank MIMO channel matrix, construct the above maximum channel capacity problem;

[0097] (2) decomposing the maximum channel capacity problem into a first optimization subproblem of maximizing the product of channel eigenvalues ​​and a second optimization subproblem of maximizing the minimum received signal-to-noise ratio;

[0098] (3) Solve the first optimization subproblem and obtain the optimal solution for the UAV position;

[0099] (4) Solve the second optimization subproblem based on the optimal solution of the drone position and obtain the optimal solution of the precoding matrix.

[0100] In this implementation, by maximizing the product of channel eigenvalues, independent and identically distributed sub-channels can be used to maximize channel gain and increase channel capacity; by maximizing the minimum received signal-to-noise ratio, the minimum received signal-to-noise ratio of all received symbol streams can be maximized while meeting the transmission power limit of a single UAV, ensuring efficient reception.

[0101] Among them, the first optimization sub-problem is:

[0102]

[0103] Solving the first optimization subproblem includes: converting the first optimization subproblem into a solvable first optimization subproblem and solving it; here, the solvable first optimization subproblem is:

[0104]

[0105] Among them, η k represents the normalized position of the kth UAV relative to the coordinate origin, k = 2, 3, ..., M, η l Represents the normalized position of the lth UAV relative to the coordinate origin.

[0106] In the embodiment of the present invention, the optimal solution for the position of the UAV can be obtained by solving the Fechter node of the above-mentioned solvable first optimization subproblem.

[0107] The second optimization sub-problem is:

[0108]

[0109] Among them, P n Indicates the transmission power limit of the nth UAV; [WW H ] n,n Indicates taking the matrix WW H The element at the nth row and nth column of .

[0110] Accordingly, the second optimization subproblem is solved according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix, including: converting the second optimization subproblem into a solvable second optimization subproblem; solving the solvable second optimization subproblem according to the optimal solution of the drone position; here, the solvable second optimization subproblem is:

[0111]

[0112] Among them, q and s m are all auxiliary variables introduced, vec(·) is a function that rearranges the matrix into a vector, h m According to the optimal solution of the drone position,

[0113] In the embodiment of the present invention, the second optimization sub-problem to be solved may be solved with the help of a convex optimization tool, thereby obtaining an optimal solution of the precoding matrix.

[0114] S40, configuring a virtual non-uniform transmission linear array according to the determined position of the UAV and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with a device where a ground receiving antenna array is located.

[0115] Specifically, the distribution position of each drone in the virtual non-uniform transmission linear array is configured according to the determined drone position, and each drone adjusts the transmission symbol stream vector according to the precoding vector in the determined precoding matrix, and then transmits the signal to the device where the ground receiving antenna array is located.

[0116] The method for enhancing communication capacity by cooperating with multiple UAVs in emergency scenarios provided by the embodiment of the present invention, by jointly designing the UAV position and precoding matrix, using a virtual non-uniform transmitting linear array to communicate with the equipment where the ground receiving antenna array is located, and using independent and identically distributed sub-channels to improve the channel gain, maximizes the channel capacity, and overcomes the defects of a single UAV with limited volume and airborne energy, which cannot carry a large-scale antenna array and meet the requirements of high-power transmission signals. Therefore, based on the collaborative transmission of signals by multiple UAVs to form a virtual non-uniform transmitting linear array, it is possible to achieve large-capacity reliable communication in complex emergency scenarios, and improve the efficiency of communication and interoperability.

[0117] The method for collaboratively enhancing communication capacity of multiple UAVs in an emergency scenario provided by an embodiment of the present invention can be applied to the control end of multiple UAVs.

[0118] The following is a simulation experiment to further illustrate the embodiment of the present invention. The carrier frequency is set to f c =1GHz, N=24 drones form a virtual non-uniform transmission linear array, R=200m, on this basis, Figure 3 The figure shows a distribution diagram of the position of the UAV designed by the method of the embodiment of the present invention, wherein the value of the horizontal axis is the normalized position of the UAV relative to the coordinate origin; Figure 4 Shows Figure 3 The relationship between the signal-to-noise ratio (SNR) and channel capacity of the virtual non-uniform transmitting linear array and the traditional virtual uniform transmitting antenna array in the figure, where the "non-uniform virtual linear array" is also Figure 3 The virtual non-uniform transmitting linear array in the , "uniform virtual linear array" is also the traditional virtual uniform transmitting antenna array. Figure 4 It can be seen from the figure that the channel capacity of the virtual non-uniform transmission linear array configured by the method of the embodiment of the present invention is higher than that of the traditional uniform virtual linear array.

[0119] Corresponding to the above-mentioned method for multi-UAV collaboratively enhancing communication capacity in emergency scenarios, an embodiment of the present invention further provides a device for multi-UAV collaboratively enhancing communication capacity in emergency scenarios, see Figure 5 ,include:

[0120] The acquisition module 501 is used to acquire the position information of the virtual non-uniform transmission linear array and the ground receiving antenna array according to a preset coordinate system; wherein the virtual non-uniform transmission linear array includes a plurality of drones; the virtual non-uniform transmission linear array and the ground receiving antenna array meet the far-field line-of-sight transmission condition; the coordinate system takes the center of the virtual non-uniform transmission linear array as the coordinate origin; the xy plane of the coordinate system is parallel to the ground plane, the x axis is parallel to the ground receiving antenna array, and the z axis points to the ground plane;

[0121] A construction module 502 is used to construct a high-order-rank line-of-sight MIMO channel matrix according to the above position information;

[0122] A determination module 503 is used to determine the position of the UAV and the precoding matrix when the channel capacity is maximized according to the high-order-rank line-of-sight MIMO channel matrix;

[0123] The configuration module 504 is used to configure the virtual non-uniform transmission linear array according to the determined UAV position and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with the device where the ground receiving antenna array is located.

[0124] Optionally, the acquisition module 501 is specifically configured to:

[0125] According to the position of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, the coordinates (x T,n ,y T,n ,z T,n ), and the coordinates (x r,m ,y r,m ,z r,m );

[0126]

[0127]

[0128] Wherein, L is the length of the virtual non-uniform transmission linear array; η n ∈[-1,1] is the normalized position of the nth UAV relative to the coordinate origin, n=1,2,…,N, N is the number of UAVs; φ is the angle between the virtual non-uniform transmitting linear array and the x-axis, is the azimuth angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array; θ is the pitch angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, d is the array element spacing of the ground receiving antenna array; m=1,2,…,M, M is the number of receiving antennas of the ground receiving antenna array; R is the spacing between the coordinate origin and the ground receiving antenna array.

[0129] Optionally, the construction module 502 is specifically configured to:

[0130] Based on the position information, the transmission distance between the drone and the receiving antenna is calculated:

[0131]

[0132] Among them, τ m,nrepresents the transmission distance between the mth receiving antenna and the nth UAV;

[0133] According to the transmission distance, a high-order-rank line-of-sight MIMO channel matrix is ​​constructed:

[0134]

[0135] Among them, e is the natural base, π is the ratio of pi, j is the symbol of the imaginary part, and f c is the carrier frequency of the virtual non-uniform transmitting linear array, t represents time, and c represents the propagation speed of electromagnetic waves in a vacuum; H is the high-order-rank line-of-sight MIMO channel matrix;

[0136] P R =diag(p R,1 ,p R,2 ,...,p R,M );

[0137]

[0138] P T =diag(p T,1 ,p T,2 ,...,p T,N );

[0139]

[0140] diag(·) is a function for constructing a diagonal matrix. Represents a set of M×N complex numbers.

[0141] Optionally, the determination module 503 is specifically configured to:

[0142] According to the high-order-rank MIMO channel matrix, a maximum channel capacity problem is constructed; wherein the maximum channel capacity problem uses the position of the UAV and the precoding matrix as solution parameters, and takes maximizing the channel capacity as the optimization goal;

[0143] Decomposing the maximum channel capacity problem into a first optimization subproblem of maximizing the product of channel eigenvalues ​​and a second optimization subproblem of maximizing the minimum received signal-to-noise ratio;

[0144] Solve the first optimization sub-problem to obtain the optimal solution for the position of the UAV;

[0145] The second optimization subproblem is solved according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix.

[0146] Optionally,

[0147]

[0148] Wherein, M is the number of receiving antennas of the ground receiving antenna array, m=1, 2, ..., M; represents the ground receiving antenna array; N is the number of UAVs of the virtual non-uniform transmitting linear array, n=1,2,…,N; is the signal-to-noise ratio of the signal received by the receiving antenna, w is a precoding vector used to adjust the amplitude and phase of the transmitted signal of the virtual non-uniform transmitting linear array; h m is the channel vector of the mth receiving antenna of the ground receiving antenna array, σ 2 represents the noise variance; λ m The gain matrix G = HH H The mth eigenvalue of H is the precoding matrix, and the superscript H represents the matrix conjugate transpose; The superscript T indicates the matrix transpose; η=η1,η2,…,η N , η n ∈[-1,1] is the normalized position of the nth UAV in the virtual non-uniform transmission linear array; C is the channel capacity.

[0149] Optionally,

[0150] The first optimization sub-problem is:

[0151]

[0152] The second optimization sub-problem is:

[0153]

[0154] Among them, P n Indicates the transmission power limit of the nth UAV; [WW H ] n,n Indicates taking the matrix WW H The element at the nth row and nth column of .

[0155] Optionally, solving the first optimization sub-problem includes:

[0156] Converting the first optimization subproblem into a solvable first optimization subproblem and solving it;

[0157] The first solvable optimization subproblem is:

[0158]

[0159] Among them, η k represents the normalized position of the kth UAV relative to the coordinate origin, k = 2, 3, ..., M, η lRepresents the normalized position of the lth UAV relative to the coordinate origin.

[0160] Optionally, solving the second optimization sub-problem according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix includes:

[0161] converting the second optimization subproblem into a solvable second optimization subproblem;

[0162] Solving the solvable second optimization sub-problem according to the optimal solution for the position of the UAV;

[0163] The solvable second optimization sub-problem is:

[0164]

[0165] Among them, q and s m are all auxiliary variables introduced, vec(·) is a function that rearranges the matrix into a vector, h m According to the optimal solution of the drone position,

[0166] Optionally, the above device is applied to the control end of multiple drones.

[0167] It should be noted that, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0168] It should be noted that the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure.

[0169] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0170] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art can understand and implement other changes to the disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the term "comprising" does not exclude other components or steps, "one" or "an" does not exclude multiple situations, and the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0171] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for enhancing communication capacity of multiple UAVs in an emergency scenario, characterized in that: include: According to a preset coordinate system, position information of a virtual non-uniform transmitting linear array and a ground receiving antenna array is obtained; wherein the virtual non-uniform transmitting linear array includes a plurality of drones; the virtual non-uniform transmitting linear array and the ground receiving antenna array satisfy a far-field line-of-sight transmission condition; the coordinate system takes the center of the virtual non-uniform transmitting linear array as the coordinate origin; the xy plane of the coordinate system is parallel to the ground plane, the x-axis is parallel to the ground receiving antenna array, and the z-axis points to the ground plane; Constructing a high-order-rank line-of-sight MIMO channel matrix according to the position information; Determining a UAV position and a precoding matrix when channel capacity is maximized based on the high-order-rank line-of-sight MIMO channel matrix; The virtual non-uniform transmission linear array is configured according to the position of the UAV and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with the device where the ground receiving antenna array is located.

2. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 1 is characterized in that: According to a preset coordinate system, the position information of the virtual non-uniform transmitting linear array and the ground receiving antenna linear array is obtained, including: According to the position of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, the coordinates (xT,n,yT,n,zT,n) of each UAV in the virtual non-uniform transmitting linear array and the coordinates (xr,m,yr,m,zr,m) of each receiving antenna in the ground receiving antenna array are obtained; Wherein, L is the length of the virtual non-uniform transmitting linear array; ηn∈[-1,1] is the normalized position of the nth UAV relative to the coordinate origin, n=1,2,…,N, N is the number of UAVs; φ is the angle between the virtual non-uniform transmitting linear array and the x-axis, is the azimuth angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array; θ is the pitch angle of the ground receiving antenna array relative to the virtual non-uniform transmitting linear array, d is the array element spacing of the ground receiving antenna array; m=1,2,…,M, M is the number of receiving antennas of the ground receiving antenna array; R is the spacing between the coordinate origin and the ground receiving antenna array.

3. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 2 is characterized in that: According to the position information, a high-order-rank line-of-sight MIMO channel matrix is ​​constructed, including: Based on the location information, calculate the transmission distance between the drone and the receiving antenna: Among them, τm,n represents the transmission distance between the mth receiving antenna and the nth UAV; According to the transmission distance, a high-order-rank line-of-sight MIMO channel matrix is ​​constructed: Wherein, e is a natural base, π is pi, j is the symbol of the imaginary part, fc is the carrier frequency of the virtual non-uniform transmission linear array, t represents time, and c represents the propagation speed of electromagnetic waves in a vacuum; H is the high-order-rank line-of-sight MIMO channel matrix; PR=diag(pR,1,pR,2,...,pR,M); PT=diag(pT,1,pT,2,...,pT,N); diag(·) is a function for constructing a diagonal matrix. Represents a set of M×N complex numbers.

4. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 1 is characterized in that: Determining the position of the UAV and the precoding matrix when the channel capacity is maximized according to the high-order-rank MIMO channel matrix includes: According to the high-order-rank MIMO channel matrix, a maximum channel capacity problem is constructed; wherein the maximum channel capacity problem uses the position of the UAV and the precoding matrix as solution parameters, and takes maximizing the channel capacity as the optimization goal; Decomposing the maximum channel capacity problem into a first optimization subproblem of maximizing the product of channel eigenvalues ​​and a second optimization subproblem of maximizing the minimum received signal-to-noise ratio; Solve the first optimization sub-problem to obtain the optimal solution for the position of the UAV; The second optimization subproblem is solved according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix.

5. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 4 is characterized in that: The maximum channel capacity problem is: Wherein, M is the number of receiving antennas of the ground receiving antenna array, m=1, 2, ..., M; represents the ground receiving antenna array; N is the number of UAVs of the virtual non-uniform transmitting linear array, n=1,2,…,N; is the signal-to-noise ratio of the signal received by the receiving antenna, w is the precoding vector used to adjust the amplitude and phase of the transmitted signal of the virtual non-uniform transmitting linear array; hm is the channel vector of the mth receiving antenna of the ground receiving antenna array, σ2 represents the noise variance; λm is the mth eigenvalue of the gain matrix G=HHH; W=wwH is defined as the precoding matrix, and the superscript H represents the matrix conjugate transpose; The superscript T represents matrix transpose; η = η1, η2, …, ηN, ηn∈[-1, 1] is the normalized position of the nth UAV relative to the coordinate origin; C is the channel capacity.

6. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 5, characterized in that: The first optimization sub-problem is: The second optimization sub-problem is: Among them, Pn represents the transmission power limit of the nth UAV; [WWH]n,n means taking the element of the nth row and nth column of the matrix WWH.

7. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 6, characterized in that: Solving the first optimization subproblem includes: converting the first optimization subproblem into a solvable first optimization subproblem and solving it; The first solvable optimization subproblem is: Wherein, ηk represents the normalized position of the kth UAV relative to the coordinate origin, k=2,3,…,M, and ηl represents the normalized position of the lth UAV relative to the coordinate origin.

8. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to claim 6, characterized in that: Solving the second optimization sub-problem according to the optimal solution of the drone position to obtain the optimal solution of the precoding matrix includes: converting the second optimization subproblem into a solvable second optimization subproblem; Solving the solvable second optimization sub-problem according to the optimal solution for the position of the UAV; The solvable second optimization sub-problem is: Among them, q and sm are introduced auxiliary variables, vec(·) is a function that rearranges the matrix into a vector, hm is determined based on the optimal solution of the drone’s position.

9. The method for enhancing communication capacity of multiple UAVs in an emergency scenario according to any one of claims 1 to 8, characterized in that: Applied to the control end of multiple drones.

10. A device for enhancing communication capacity of multiple UAVs in an emergency scenario, characterized in that: include: An acquisition module is used to acquire position information of a virtual non-uniform transmitting linear array and a ground receiving antenna array according to a preset coordinate system; wherein the virtual non-uniform transmitting linear array includes a plurality of drones; the virtual non-uniform transmitting linear array and the ground receiving antenna array satisfy a far-field line-of-sight transmission condition; the coordinate system takes the center of the virtual non-uniform transmitting linear array as the coordinate origin; the xy plane of the coordinate system is parallel to the ground plane, the x-axis is parallel to the ground receiving antenna array, and the z-axis points to the ground plane; A construction module, configured to construct a high-order-rank line-of-sight MIMO channel matrix according to the location information; A determination module, configured to determine a UAV position and a precoding matrix when the channel capacity is maximized according to the high-order-rank line-of-sight MIMO channel matrix; A configuration module is used to configure the virtual non-uniform transmission linear array according to the position of the UAV and the precoding matrix, so that the configured virtual non-uniform transmission linear array communicates with the device where the ground receiving antenna array is located.

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