A Wide-Area Coverage Star-Sky Fusion Wireless Transmission Method for Sharing Millimeter-Wave Frequency Bands

Abstract

The present invention discloses a wide-area coverage star-sky fusion wireless transmission method for sharing millimeter-wave frequency bands, which includes the following steps: obtaining channel state information; based on the channel state information, grouping satellite users within the coverage range of the satellite communication system and using multi-group multicast technology for signal transmission, and the unmanned aerial vehicle (UAV) communication system using layer division multiplexing technology to serve multiple UAV users, constructing an optimization problem; based on a method combining semi-definite programming and penalty function method, solving the optimization problem to obtain the beamforming weight vectors of the satellite and the UAV, and realizing wide-area coverage star-sky fusion wireless transmission for sharing millimeter-wave frequency bands. While the present invention adopts multi-group multicast and layer division multiplexing technologies for the star-sky fusion network to provide heterogeneous services for various users within the wide-area coverage range, it also enables the satellite communication system and the UAV communication system to share millimeter-wave spectrum resources, thereby improving the spectrum utilization rate.

Description

Technical Field

[0001] The present invention relates to a wide-area coverage star-sky fusion wireless transmission method for sharing millimeter-wave frequency bands, belonging to the technical field of wireless communication. Background Art

[0002] Future mobile communication needs to achieve wide-area coverage and ubiquitous access. The star-sky fusion network combines the advantages of satellite communication, which is not restricted by geographical conditions and has a wide coverage range, and the advantages of drone communication, which has flexible coverage and low latency, through the organic integration of satellite communication systems and drone communication systems. It is considered an essential part of the new generation of information and communication infrastructure. However, with the rapid growth of various multimedia services and wireless terminal devices, the existing spectrum resources below 6 GHz have become extremely scarce. Therefore, it is of great significance to fully develop and utilize the electromagnetic spectrum in the millimeter-wave frequency band between 30 GHz and 300 GHz. At the same time, adopting multi-antenna and beamforming technologies to enhance the received signal power while effectively suppressing inter-network interference to achieve spectrum sharing is also an effective way to improve spectrum utilization. For these reasons, the wireless transmission technology of the star-sky fusion network operating in the millimeter-wave frequency band has received extensive attention from the academic and industrial communities.

[0003] Traditional wireless communication systems usually use orthogonal multiple access technologies such as frequency-division multiple access, time-division multiple access, and space-division multiple access for signal transmission. However, it should be noted that orthogonal multiple access technologies require the transmitted signals to meet the orthogonality requirements in the corresponding dimensions. For example, frequency-division multiple access needs to achieve orthogonality among users in the frequency domain, while time-division multiple access serves users through different time slots, and neither can effectively improve the spectrum efficiency of the system. Space-division multiple access serves different users within the same time-frequency resources and differentiates different users through the spatial domain. It requires the transmitting end to be equipped with multiple antennas to provide sufficient antenna degrees of freedom and is suitable for lightly loaded network scenarios where the number of antennas at the transmitting end is sufficient and the interference between groups is mostly weak interference. However, in the scenario of large-scale device connection, the degrees of freedom are limited by the number of antennas at the transmitter, resulting in difficulty in effectively suppressing the interference between multicast groups and inability to achieve reliable communication.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies in the prior art and provide a wide-area coverage star-sky fusion wireless transmission method for sharing millimeter-wave frequency bands. When the present invention adopts multi-group multicast and layer division multiplexing technologies for the star-sky fusion network to provide heterogeneous services for various users within the wide-area coverage, it also designs the beamforming weight vector by optimizing the problem to suppress various interferences within and between networks, enabling the satellite communication system and the unmanned aerial vehicle communication system to share millimeter-wave spectrum resources and further improving the spectrum utilization rate of the system.

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

[0007] In the first aspect, the present invention discloses a wide-area coverage star-sky fusion wireless transmission method for sharing millimeter-wave frequency bands, including the following steps:

[0008] Obtain channel state information;

[0009] According to the channel state information, group the satellite users within the coverage of the satellite communication system and use multi-group multicast technology for signal transmission, and the unmanned aerial vehicle communication system uses layer division multiplexing technology to serve multiple unmanned aerial vehicle users to construct an optimization problem;

[0010] Based on a method combining semi-definite programming and penalty function method, solve the optimization problem to obtain the beamforming weight vectors of the satellite and the unmanned aerial vehicle, and realize wide-area coverage star-sky fusion wireless transmission for sharing millimeter-wave frequency bands;

[0011] Among them, the objective function of the optimization problem is to minimize the sum of the transmission powers of the satellite and the unmanned aerial vehicle, and the constraint conditions of the optimization problem are that the quality of service of the satellite and unmanned aerial vehicle users meets their respective requirements.

[0012] Further, the channel state information includes the channel vector g i from the satellite to the i-th user, and i the channel vector h from the unmanned aerial vehicle to the i-th user.

[0013] Further, according to the channel state information, the satellite communication system groups the satellite users within its coverage, including:

[0014] Adopt a user grouping algorithm and define the correlation between two user groups as a cost function;

[0015] In the initial state, regard each user as an independent user group, and in each loop, pair the user group that minimizes the cost function to form a larger user group until all satellite users within the satellite coverage are grouped.

[0016] Further, using multi-group multicast technology for signal transmission includes:

[0017] The expression of the output signal-to-interference-plus-noise ratio (SINR) of the satellite users is as follows:

[0018]

[0019] where, γ l,m is the output SINR of the m-th satellite user in the l-th group, g l,m is the channel vector from the satellite to the m-th earth station in the l-th group; h l,m is the channel vector from the unmanned aerial vehicle (UAV) to the m-th earth station in the l-th group; is the beamforming weight vector of the l-th beam of the satellite; is the beamforming weight vector for the UAV to transmit the multicast signal; is the beamforming weight vector for the UAV to transmit the k-th unicast signal; is the noise power of the m-th earth station in the l-th group.

[0020] Furthermore, according to the channel state information, the UAV communication system uses the layer division multiplexing technology to serve multiple UAV users, including:

[0021] The output SINRs of the multicast signal and the unicast signal of the k-th UAV user can be respectively expressed as:

[0022]

[0023]

[0024] where, is the output SINR of the multicast signal of the k-th UAV user, γ u,k is the output SINR of the unicast signal of the k-th UAV user; h u,k is the channel vector from the UAV to the k-th UAV user; v0 is the weight vector for the UAV to transmit the multicast signal; v k is the weight vector for the UAV to transmit the k-th unicast signal; K is the number of UAV users; is the noise power of the k-th UAV user.

[0025] Furthermore, the expression of the optimization problem is as follows:

[0026]

[0027]

[0028]

[0029]

[0030] where, Γs,l is the minimum signal-to-interference-plus-noise ratio (SINR) threshold for the \(l\)-th satellite user group; is the minimum SINR threshold for the \(k\)-th UAV user to decode the multicast signal, and \(\Gamma\) u,k is the minimum SINR threshold for the \(k\)-th UAV user to decode the unicast signal.

[0031] Furthermore, based on the method combining semidefinite programming and penalty function method, the optimization problem is solved, including:

[0032] Using the method combining semidefinite programming and penalty function method, the optimization problem is transformed into a convex optimization problem and then solved. The expression of the convex optimization problem is as follows:

[0033]

[0034]

[0035]

[0036]

[0037] where is the matrix composed of the beamforming weight vectors of the \(l\)-th beam of the satellite; is the matrix composed of the beamforming weight vectors for the \(k\)-th UAV to send the unicast signal; is the channel matrix from the satellite to the \(m\)-th earth station in the \(l\)-th group; is the channel matrix from the UAV to the \(m\)-th earth station in the \(l\)-th group; is the channel matrix from the UAV to the \(k\)-th UAV user; \(\lambda\) max (·) represents the maximum eigenvalue of the matrix; is the optimal solution of the beamforming weight matrix of the \(l\)-th beam of the satellite at the \(t\)-th iteration; is the optimal solution of the beamforming weight matrix for the \(k\)-th UAV to send the unicast signal at the \(t\)-th iteration; is the eigenvector corresponding to the maximum eigenvalue; is the eigenvector corresponding to the maximum eigenvalue; \(\delta\) l is the penalty function coefficient corresponding to; \(\rho\) k is the penalty function coefficient corresponding to; is the noise variance of the \(m\)-th satellite user in the \(l\)-th group, is the noise variance of the \(k\)-th UAV user.

[0038] Second aspect, the present invention discloses a wide-area coverage star-sky fusion wireless transmission device sharing a millimeter-wave frequency band, including a processor and a storage medium;

[0039] The storage medium is used for storing instructions;

[0040] The processor is used to operate according to the instructions to execute the steps of the method according to the first aspect.

[0041] Third aspect, the present invention discloses a storage medium, on which a computer program is stored, characterized in that the steps of the method according to the second aspect are realized when the computer program is executed by a processor.

[0042] Compared with the prior art, the beneficial effects achieved by the present invention:

[0043] For the wide-area coverage star-sky fusion wireless transmission method sharing a millimeter-wave frequency band of the present invention, the satellite communication system groups the satellite users within its coverage area and uses multi-group multicast technology for signal transmission, and the unmanned aerial vehicle communication system uses layer division multiplexing technology to serve multiple unmanned aerial vehicle users. While improving the spectral efficiency of the system, it can effectively meet the heterogeneous needs of various users; secondly, by establishing an optimization problem of spectrum coexistence, the beamforming weight vector is optimized and designed to suppress various interferences within and between networks.

[0044] The present invention also adopts a method combining semi-definite programming and penalty function to transform the complex and difficult-to-solve optimization problem into an easy-to-solve convex optimization problem, so as to obtain the beamforming weight vectors of satellites and unmanned aerial vehicles with high efficiency, and realize wide-area coverage star-sky fusion wireless transmission sharing a millimeter-wave frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flowchart of a wide-area coverage star-sky fusion wireless transmission method sharing a millimeter-wave frequency band;

[0046] Figure 2 is a schematic diagram of a star-sky fusion network communication system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0048] Embodiment 1

[0049] Embodiment 1 of the present invention discloses a wide-area coverage star-sky fusion wireless transmission method sharing a millimeter-wave frequency band, including the following steps:

[0050] Obtain channel state information;

[0051] Based on the channel state information, group the satellite users within the coverage of the satellite communication system and use the multi-group multicast technology for signal transmission. The unmanned aerial vehicle (UAV) communication system uses the layer division multiplexing technology to serve multiple UAV users, and construct an optimization problem.

[0052] Based on the method combining semidefinite programming and penalty function method, solve the optimization problem to obtain the beamforming weight vectors of the satellite and the UAV, and achieve wide-area coverage star-sky fusion wireless transmission sharing the millimeter wave band.

[0053] Among them, the objective function of the optimization problem is to minimize the sum of the transmission powers of the satellite and the UAV, and the constraint conditions of the optimization problem are that the quality of service of the satellite and UAV users meets their respective requirements.

[0054] The technical concept of the present invention is that the satellite communication system and the UAV communication system in the star-sky fusion network respectively use the multi-group multicast and layer division multiplexing technologies to serve various users within their coverage, and suppress various interferences inside and between the networks through beamforming technology, so that the two systems share the millimeter wave spectrum resources, thereby improving the spectrum utilization rate.

[0055] As Figure 2 shown, the satellite communication system uses the multi-group multicast technology to serve L satellite user groups. It is assumed that the satellite is equipped with a reflector antenna with N s (N s > L) feed sources, and the satellite users are equipped with parabolic antennas with a single feed source. The UAV service uses the layer division multiplexing technology to serve K UAV users. It is assumed that the UAV is equipped with a uniform planar array with N u (N u > K) array elements, and the UAV users are equipped with single antennas. Considering the large path loss of the satellite link and the small receiving gain of the UAV users, the interference of the satellite communication system to the UAV users is ignored.

[0056] As Figure 1 shown, this method first obtains the channel state information of the satellite users and the UAV users at the central control unit by means of millimeter wave channel estimation technology; using the obtained channel state information, the satellite communication system groups the users within its coverage and further uses the multi-group multicast technology for signal transmission, while the UAV communication system uses the layer division multiplexing technology to serve multiple users within its coverage; under the condition that the satellite communication system and the UAV communication system share the millimeter wave spectrum resources, with the sum of the transmission powers of the satellite and the UAV minimized as the objective function and the quality of service of the satellite and UAV users meeting their respective requirements as the constraint conditions, establish the corresponding star-sky fusion wireless transmission optimization problem; solve the optimization problem by the method combining semidefinite programming and penalty function method to obtain the beamforming weight vectors of the satellite and UAV platforms, and complete the design of the entire system transmission scheme. The detailed steps are as follows:

[0057] (1) The central control unit obtains the channel state information of satellite users and UAV users within the wide-area coverage by means of millimeter-wave channel estimation technology, including: the channel vector g from the satellite to the i-th satellite user i , which can be expressed as:

[0058]

[0059] where ⊙ is the Hadamard product; G i,r is the receiving gain of the parabolic antenna of the i-th earth station; is the rain attenuation coefficient vector, the elements of which in dB form follow a lognormal random distribution, N s is the number of satellite antenna feeds; is the satellite beam gain; is the satellite steering vector; b i and The specific elements in can be expressed as:

[0060]

[0061]

[0062]

[0063] where b i,n is the n-th element of the beam gain vector b i , b i,max is the maximum beam gain; J1(·) and J3(·) are the first-kind Bessel functions of the first and third orders respectively; is the angle between the i-th earth station and the center of the n-th beam; θ 3dB is the satellite unilateral half-power beam width; c is the speed of light; d i,n is the distance between the i-th earth station and the n-th feed; f c is the carrier frequency.

[0064] The channel vector h from the UAV to the i-th user i , which can be expressed as:

[0065]

[0066] where, is the Kronecker product; φ i is the elevation angle of the direct path of the i-th user; ψ i is the azimuth angle of the direct path of the i-th user; φ i,j is the elevation angle of the j-th non-direct path of the i-th user; ψ i,j is the azimuth angle of the j-th non-direct path of the i-th user; L nis the number of non-direct paths; ρ0 is the propagation loss of the direct path; ρ i is the propagation loss of the i-th non-direct path; a x (φ i , ψ i ) is the steering vector of the direct path of the i-th user along the X-axis; a y (φ i , ψ i ) is the steering vector of the direct path of the i-th user along the Y-axis; a x (φ i,j , ψ i,j ) is the steering vector of the j-th non-direct path of the i-th user along the X-axis; a y (φ i,j , ψ i,j ) are respectively the steering vectors of the j-th non-direct path of the i-th user along the Y-axis; g c (φ i,j , ψ i,j ) is the radiation pattern of the j-th non-direct path of the i-th user; g c (φ i , ψ i ) is the radiation pattern of the direct path of the i-th user, in dB form The expression is:

[0067]

[0068]

[0069]

[0070] where, G max is the maximum transmission gain of the UAV; S g is the sidelobe gain; g x (φ i , ψ i ) is the relative radiation pattern along the X-axis; g y (φ i , ψ i ) is the relative radiation pattern along the Y-axis; is the 3dB beamwidth in the X-axis direction; is the 3dB beamwidth in the Y-axis direction.

[0071] (2) Using the obtained channel state information, the satellite communication system needs to group the satellite users within its coverage area. The user grouping algorithm can be described as follows: Define the following cost function to measure the correlation between user groups:

[0072]

[0073] where, U pis the p-th user group; U q is the q-th user group; g k is the channel vector from the satellite to the k-th satellite user; g l is the channel vector from the satellite to the l-th satellite user; is the correlation between the k-th satellite user and the l-th satellite user; |·| is the cardinality of a set, (·) H is the conjugate transpose, ||·|| is the 2-norm of a vector.

[0074] In the initial state, each user is regarded as an independent user group. In each loop, a pair of user groups that minimize the cost function are formed or merged into a larger user group until all satellite users within the satellite service area are grouped.

[0075] (3) If the satellite communication system uses a user grouping algorithm to divide M users within its coverage area into L groups and uses multi-group multicast technology for signal transmission, then the output signal-to-interference-plus-noise ratio (SINR) of the m-th satellite user in the l-th group can be expressed as:

[0076]

[0077] where, γ l,m is the output SINR of the m-th satellite user in the l-th group, g l,m is the channel vector from the satellite to the m-th earth station in the l-th group; h l,m is the channel vector from the UAV to the m-th earth station in the l-th group; is the beamforming weight vector of the l-th beam of the satellite; is the beamforming weight vector for the UAV to send multicast signals; is the beamforming weight vector for the UAV to send the k-th unicast signal; is the noise power of the m-th earth station in the l-th group; (·) H represents the operation of conjugate transposing a vector.

[0078] (4) The UAV communication system uses layer division multiplexing technology to serve UAV users. The process includes: the UAV sends multicast signals to K UAV users and simultaneously sends a unicast signal to the k-th UAV user. The UAV user first treats the unicast signal as noise, decodes the multicast signal, and then uses successive interference cancellation technology to cancel the decoded multicast signal and then decodes the unicast signal. Therefore, the output SINRs of the multicast signal and the unicast signal of the k-th UAV user can be expressed as:

[0079]

[0080]

[0081] wherein, is the output signal-to-interference-plus-noise ratio of the multicast signal for the k-th UAV user, and γ u,k is the output signal-to-interference-plus-noise ratio of the unicast signal for the k-th UAV user; h u,k is the channel vector from the UAV to the k-th UAV user; v0 is the weight vector for the UAV to transmit the multicast signal; v k is the weight vector for the UAV to transmit the k-th unicast signal; K is the number of UAV users; is the noise power of the k-th UAV user.

[0082] (5) Under the condition that the satellite communication system and the UAV communication system share the millimeter-wave spectrum resources, with the minimization of the sum of the transmission powers of the satellite and the UAV as the objective function and the service quality of the satellite and UAV users meeting their respective requirements as the constraint conditions, a corresponding space-air integrated wireless transmission optimization problem is constructed, which can be expressed as:

[0083]

[0084] wherein, Γ s,l is the minimum signal-to-interference-plus-noise ratio threshold for the l-th satellite user group; is the minimum signal-to-interference-plus-noise ratio threshold for the k-th UAV user to decode the multicast signal, and Γ u,k is the minimum signal-to-interference-plus-noise ratio threshold for the k-th UAV user to decode the unicast signal.

[0085] (6) Substitute formulas (10)-(12) into problem (13), and use the semidefinite programming method for equivalent transformation, and the following can be obtained:

[0086]

[0087] wherein, is the matrix composed of the beamforming weight vectors of the l-th beam of the satellite; is the matrix composed of the beamforming weight vectors for the UAV to transmit the k-th unicast signal; is the channel matrix from the satellite to the m-th earth station in the l-th group; is the channel matrix from the UAV to the m-th earth station in the l-th group; is the channel matrix from the UAV to the k-th UAV user; rank(·) is the matrix rank.

[0088] (6) There is a rank-one constraint problem for W l and V k . By using the penalty function to rewrite the optimization objective function and eliminate the rank-one constraint, problem (14) can be converted into a convex optimization problem, which can be expressed as:

[0089]

[0090] Among them, λ max (·) represents the maximum eigenvalue of the matrix; is the optimal solution of the beamforming weight matrix of the l-th beam of the satellite at the t-th iteration; is the optimal solution of the beamforming weight matrix for the drone to send the k-th unicast signal at the t-th iteration; is the eigenvector corresponding to the maximum eigenvalue; is the eigenvector corresponding to the maximum eigenvalue; δ l is the penalty function coefficient corresponding to; ρ k is the penalty function coefficient corresponding to; is the noise variance of the m-th satellite user in the l-th group, is the noise variance of the k-th drone user.

[0091] (7) Iteratively solve the convex optimization problem (15) to obtain the satellite and drone beamforming weight vectors, and complete the wide-area coverage starry sky fusion wireless transmission of the shared millimeter-wave band. The process includes:

[0092] 1) Initialize the penalty factors δ l and ρ k , the calculation accuracy ε, and the iteration number t = 0;

[0093] 2) Solve the optimization problem (14) ignoring the rank-one constraint, and denote the optimal solution as and

[0094] 3) Calculate and obtain and the maximum eigenvalues and as well as the corresponding eigenvectors and

[0095] 4) Solve the convex optimization problem (15) to obtain the optimal solution denoted as and

[0096] 5) If then δ l = 2δ l ; if then ρ l = 2ρ l ;

[0097] 6) Update the iteration number t = t + 1;

[0098] 7) If the convergence condition is satisfied

[0099]

[0100] The iteration ends, and the satellite beamforming weight vector and the UAV transmission beamforming weight vector are output; otherwise, return to 3).

[0101] Embodiment 2

[0102] Embodiment 2 of the present invention provides a wide-area coverage star-sky fusion wireless transmission device sharing a millimeter wave band, including a processor and a storage medium;

[0103] The storage medium is used to store instructions;

[0104] The processor is used to operate according to the instructions to execute the steps of the method described in Embodiment 1.

[0105] Embodiment 3

[0106] Embodiment 3 of the present invention provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Embodiment 1 are implemented.

[0107] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0108] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0109] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions in the process Figure 1one or more processes and / or blocks Figure 1 the functions specified in one or more blocks.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more processes and / or blocks Figure 1 the one or more blocks.

[0111] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A wide-area coverage star-sky fusion wireless transmission method for sharing millimeter-wave frequency bands, characterized in that, It includes the following steps: Obtain channel state information; Based on the channel state information, group satellite users within the coverage of the satellite communication system and use multi-group multicast technology for signal transmission, and the unmanned aerial vehicle (UAV) communication system uses layer division multiplexing technology to serve multiple UAV users, and construct an optimization problem; Based on a method combining semidefinite programming and penalty function method, solve the optimization problem to obtain the beamforming weight vectors of the satellite and the UAV, and achieve wide-area coverage starry sky fusion wireless transmission sharing the millimeter wave band; Among them, the objective function of the optimization problem is to minimize the sum of the transmission powers of the satellite and the UAV, and the constraint conditions of the optimization problem are that the quality of service of satellite and UAV users meets their respective requirements; Using multi-group multicast technology for signal transmission includes: The expression of the output signal-to-interference-plus-noise ratio (SINR) of satellite users is as follows: ； wherein, is the output signal-to-interference-plus-noise ratio of the m-th satellite user in the l-th group; is the channel vector from the satellite to the m-th earth station in the l-th group; is the channel vector from the UAV to the m-th earth station in the l-th group; is the beamforming weight vector of the l-th beam of the satellite; is the beamforming weight vector for the UAV to transmit the multicast signal; is the beamforming weight vector for the UAV to transmit the k-th unicast signal; is the noise power of the m-th earth station in the l-th group; Based on the channel state information, the UAV communication system uses layer division multiplexing technology to serve multiple UAV users, including: The output SINRs of the multicast signal and the unicast signal of the k-th UAV user can be respectively expressed as: ； ； Among them, is the output signal-to-interference-plus-noise ratio (SINR) of the multicast signal for the k-th UAV user, is the output SINR of the unicast signal for the k-th UAV user; is the channel vector from the UAV to the k-th UAV user; is the weight vector for the UAV to transmit the multicast signal; is the weight vector for the UAV to transmit the k-th unicast signal; K is the number of UAV users; is the noise power of the k-th UAV user. The expression of the optimization problem is as follows: ； wherein, is the minimum signal-to-interference-plus-noise ratio threshold of the l-th satellite user group; is the minimum signal-to-interference-plus-noise ratio threshold for the k-th UAV user to decode the multicast signal, is the minimum signal-to-interference-plus-noise ratio threshold for the k-th UAV user to decode the unicast signal; Based on a method combining semidefinite programming and penalty function method, solving the optimization problem includes: Using a method combining semidefinite programming and penalty function method, transform the optimization problem into a convex optimization problem and then solve it. The expression of the convex optimization problem is as follows: ； wherein, is the matrix formed by the beamforming weight vectors of the l-th beam of the satellite; is the matrix formed by the beamforming weight vectors for the satellite to send the k-th unicast signal; is the channel matrix from the satellite to the m-th earth station in the l-th group; is the channel matrix from the UAV to the m-th earth station in the l-th group; is the channel matrix from the UAV to the k-th UAV user; represents the maximum eigenvalue of the matrix; is the optimal solution of the beamforming weight matrix of the l-th beam of the satellite at the t-th iteration; is the optimal solution of the beamforming weight matrix for the UAV to send the k-th unicast signal at the t-th iteration; is the eigenvector corresponding to the maximum eigenvalue; is the eigenvector corresponding to the maximum eigenvalue; is the penalty function coefficient corresponding to; is the penalty function coefficient corresponding to; is the noise variance of the m-th satellite user in the l-th group, is the noise variance of the k-th UAV user.

2. The method for wide-area coverage star-sky integrated wireless transmission sharing a millimeter wave band according to claim 1, wherein The said channel state information includes the channel vector from the satellite to the i-th user , and the channel vector from the UAV to the i-th user .

3. The wide-area coverage star-sky integrated wireless transmission method for sharing millimeter-wave frequency bands according to claim 2, wherein Based on the channel state information, the satellite communication system groups satellite users within its coverage, including: Adopt a user grouping algorithm and define the correlation between two user groups as a cost function; In the initial state, regard each user as an independent user group. In each loop, pair the pair of user groups that minimizes the cost function to form a larger user group until all satellite users within the satellite coverage are grouped.

4. A wide-area coverage star-sky fusion wireless transmission device sharing a millimeter-wave frequency band, characterized in that It includes a processor and a storage medium; The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 3.

5. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method according to any one of claims 1 to 3.

Images