A security transmission optimization method, system and device of a space-ground cooperative communication network and a storage medium

Abstract

The application discloses a kind of security transmission optimization method, system, device and storage medium of air-ground cooperative communication network, belong to information communication technical field.Method includes obtaining the parameter information of target air-ground cooperative communication network;According to the parameter information of air-ground cooperative communication network, constructs air-to-ground transmission channel model and ground end-to-end transmission channel model, and obtains the channel error of air-to-ground transmission channel model and ground end-to-end transmission channel model;After processing to channel error, obtain air-to-ground transmission robust channel information and ground end-to-end transmission robust channel information;Air-to-ground transmission robust channel information and ground end-to-end transmission robust channel information are input into the transmission optimization model that is well constructed, and security transmission optimization scheme is obtained.The application effectively counteracts the attack of jammer and eavesdropper, and improves the security of air-to-ground downlink data transmission.

Description

Technical Field

[0001] This invention belongs to the field of information and communication technology, and specifically relates to a secure transmission optimization method, system, device and storage medium for air-ground cooperative communication networks. Background Technology

[0002] High Altitude Platforms (HAPs) possess the capability to provide seamless network services to users in space, air, sea, and on the ground, meeting the network demands of future ubiquitous communication. They are considered to have enormous potential applications in future wireless networks and have been designated as a 5G radio access platform by the Third Generation Partnership Project (3GPP). HAPs have strong data processing and payload capabilities, allowing for the deployment of large-scale antenna arrays to provide fast, reliable, and continuous communication services to terrestrial networks, such as computing, relaying, storage, and positioning applications. They have been extensively researched in both academia and industry.

[0003] The inherent openness and broadcast nature of wireless channels make ground nodes vulnerable to enemy jammers and eavesdropping devices in adversarial communication environments. Jammers reduce the received signal of legitimate nodes by applying strong jamming signals, causing legitimate link communication to be interrupted. Eavesdropping devices aim to intercept legitimate data; when the channel capacity of the eavesdropping link is higher than that of the legitimate link, the information of legitimate nodes will be leaked and eavesdropped. When jammers and eavesdropping devices are present simultaneously, the secure transmission performance of air-to-ground downlink data transmission is difficult to guarantee. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a secure transmission optimization method, system, device and storage medium for air-to-ground cooperative communication networks, which can effectively combat attacks from jammers and eavesdropping devices and improve the security of air-to-ground downlink data transmission.

[0005] This invention provides the following technical solution:

[0006] In a first aspect, a secure transmission optimization method for an air-ground cooperative communication network is provided, comprising: acquiring parameter information of a target air-ground cooperative communication network including an airborne platform, ground nodes, eavesdropping devices, and jammers, wherein the ground nodes include blocking nodes that cannot directly receive signals transmitted by the airborne platform and cooperative nodes for forwarding the transmitted signals of the airborne platform to the blocking nodes.

[0007] Based on the parameter information of the air-to-ground cooperative communication network, an air-to-ground transmission channel model and a ground end-to-end transmission channel model are constructed, and the channel errors of the air-to-ground transmission channel model and the ground end-to-end transmission channel model are obtained.

[0008] After processing the channel error, robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission are obtained.

[0009] The air-to-ground transmission robust channel information and the ground end-to-end transmission robust channel information are input into a pre-constructed transmission optimization model to obtain a secure transmission optimization scheme.

[0010] The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking node while satisfying the constraints. The original optimization problem is transformed into an alternating optimization of the air beamforming vector and the anti-interference alliance, so that the transmission rate of the blocking node is maximized while satisfying the constraints.

[0011] The constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints. The air beamforming vector represents the beamforming vector used by the launch platform to transmit signals. The anti-interference alliance includes several cooperative nodes, with each blocking node corresponding to an anti-interference alliance.

[0012] As an optional technical solution of the present invention, based on the parameter information of the air-to-ground cooperative communication network, an air-to-ground transmission channel model and a ground end-to-end transmission channel model are constructed, including:

[0013] The air-to-ground transmission channel model includes the transmission channel model from the airborne platform to the eavesdropping device, represented as follows:

[0014] ;

[0015] in, Indicates the first A launch platform and a listening device The channel gain vector between them This represents the channel gain at a distance of 1m. Indicates the first A launch platform and a listening device The distance between them Indicates the first A launch platform and a listening device Path loss index between and These represent the number of NLoS paths and the Rice factor, respectively. and Representing the departure elevation angle and the first [angle] of the Loss path, respectively. The departure elevation angle of the NLoS path, and Representing the departure azimuth and the first azimuth of the LosS path, respectively. The departure azimuth of the NLoS path, and The antenna array responses on one side and the other side of the launch platform are respectively represented as follows:

[0016] ;

[0017] ;

[0018] in, , This indicates the antenna spacing on one side of the launch platform. This indicates the area between the antennas on the other side of the launch platform. Indicates wavelength. Indicates the Kronecker product. This indicates the number of antennas on one side of the launch platform. This indicates the number of antennas on the other side of the launch platform. Indicates transpose;

[0019] The ground end-to-end transmission channel model includes the transmission channel model from the jammer to the ground node and the transmission channel model from the eavesdropping device to the ground node, which are represented as follows:

[0020] ;

[0021] ;

[0022] in, Indicates jammer With the Channel gain vector between ground nodes Indicates eavesdropping device With the Channel gain vector between ground nodes Indicates jammer With the Communication distance of each ground node Indicates eavesdropping device With the Communication distance of each ground node Indicates jammer With the Path loss index of each ground node. Indicates eavesdropping device With the Path loss index of each ground node. and These represent the total number of paths and the Rice factor in the ground network, respectively. Represents the non-line-of-sight component. Represents the first in the terrestrial network A path.

[0023] As an optional technical solution of the present invention, the channel error in the transmission channel model of the eavesdropping device by the launch platform is expressed as follows:

[0024] ;

[0025] in, This represents the channel error in the transmission channel model for the eavesdropping device from the launch platform. and They represent the first A launch platform and a listening device Between the angle of departure The upper and lower bounds, and They represent the first A launch platform and a listening device Between the azimuth angles The upper and lower bounds, This represents a collection of launch platforms;

[0026] The channel error in the transmission channel model of the jammer to the ground node is expressed as:

[0027] ;

[0028] in, This represents the channel error in the transmission channel model from the jammer to the ground node. and Representing the jammer and the... Channel gain between ground nodes The upper and lower bounds, Represents the set of ground nodes;

[0029] The channel error in the transmission channel model of the eavesdropping device to the ground node is expressed as:

[0030] ;

[0031] in, This represents the channel error in the transmission channel model from the eavesdropping device to the ground node. and They represent the eavesdropping device and the... Channel gain between ground nodes The upper and lower bounds.

[0032] As an optional technical solution of the present invention, after processing the channel error, robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission are obtained, including:

[0033] By using a generalized discretization method, the channel error in the transmission channel model of the airborne platform to the eavesdropping device is determined. Departure angle and departure azimuth Uniform sampling within the error range is expressed as follows:

[0034] ;

[0035] ;

[0036] in, Indicates the first The departure elevation angle of each sample, Indicates the first The azimuth angle of each sample departure. and These represent the number of sampling points for departure from elevation angle and departure from azimuth angle, respectively. , ;

[0037] Based on uniform sampling, the robust channel for the eavesdropping device transmission of the launch platform is represented as follows:

[0038] ;

[0039] in, This represents the robust channel vector for transmission to eavesdropping devices from the launch platform. , Indicates in The channel response vector at that location, Indicates to The conjugate transpose of;

[0040] For the channel error in the transmission channel model of the jammer to the ground node Channel error in the transmission channel model of the eavesdropping device to the ground node ,make , The corresponding robust transmission channel is then obtained.

[0041] As an optional technical solution of the present invention, the optimized representation of the air beamforming vector is as follows:

[0042] ;

[0043] in, This represents an expression for optimizing the aerial beamforming vector. Let represent the objective function for optimizing the airborne beamforming vector. Represents the set of blocked nodes. This indicates finding the maximum value. Represents the aerial beamforming vector. The transmission rate of the b-th blocked node is represented as: , Indicates the first There are 1, 2, 3, 4, 5, 6, 7, 8, 9, 1 Indicates the first The conjugate transpose of the channel gain vectors of the first launch platform and the b-th blocking node. Represents a set of collaborating nodes. Represents binary variables , This indicates that the ground node is a cooperative node. This indicates that the ground node is a blocked node. Represents binary variables , Indicates the first The collaborating nodes participated in the first... Cooperative transmission of a blocked node This indicates that they will not participate in the collaborative transmission. This represents the forwarding power amplification factor of the cooperating nodes. Indicates the first The first collaborative node and the first Channel gain between blocking nodes Indicates the jammer and the first Channel gain between blocked nodes Indicates the jammer's transmission power. This indicates that the blocking node receives Gaussian white noise. variance ; This indicates a rate constraint for cooperating nodes. Indicates the rate of the collaborating nodes. This represents the minimum rate of the collaborating nodes. This indicates a constraint on the rate of the eavesdropping link. Indicates the rate of the eavesdropping link. This indicates the maximum rate of the eavesdropping link. This indicates the launch power constraint of the launch platform. Indicates the launch platform's transmission power. This indicates the maximum transmission power of the launch platform. This represents a collection of launch platforms;

[0044] Introducing several auxiliary variables, the above objective function and constraints , , Transform the problem into a convex optimization problem; introduce auxiliary variables to the objective function. The conversion is performed, and it is represented as:

[0045] ;

[0046] in, These represent the first auxiliary variable, the second auxiliary variable, and the third auxiliary variable, respectively.

[0047] Referencing auxiliary slack variables New constraints Perform the conversion to obtain and The two constraints are expressed as follows:

[0048] ;

[0049] ;

[0050] Will Defined as an air beamforming vector The The result of the next iteration, through Perform a first-order Taylor series expansion and add new constraints. middle ;

[0051] Add new constraints Convert to constraints , is represented as:

[0052] ;

[0053] in ;

[0054] Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as:

[0055] ;

[0056] ;

[0057] ;

[0058] in, These represent the fourth and fifth auxiliary variables, respectively. This indicates that the cooperating nodes receive Gaussian white noise. variance Indicates the jammer and the first Channel gain between cooperating nodes Indicates the first The first launch platform and the first Channel gain vector of each cooperating node The conjugate transpose of;

[0059] Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as:

[0060] ;

[0061] ;

[0062] in, Represents the sixth auxiliary variable. Indicates the first The conjugate transpose of the channel gain vector between the launch platform and the eavesdropping device. This indicates that the eavesdropping device receives Gaussian white noise. The variance;

[0063] For constraints Performing a first-order Taylor series expansion, we obtain :

[0064] ;

[0065] in, Represents the sixth auxiliary variable No. The result of the next iteration;

[0066] Finally, the objective function and constraints for optimizing the aerial beamforming vector are transformed into:

[0067] .

[0068] As an optional technical solution of the present invention, the anti-interference alliance is optimized as follows:

[0069] ;

[0070] in, This represents the expression used to optimize the anti-interference alliance. Let represent the objective function for optimizing the anti-interference alliance. This represents the anti-interference alliance corresponding to the b-th blocking node. Indicates the first Anti-interference alliances corresponding to each blocked node Represents the set of collaborating nodes and the set of blocked nodes There is no overlap between them. This means that each collaborating node can only join one anti-interference alliance;

[0071] In the initial anti-interference alliance, all cooperating nodes randomly select the blocking node to relay information, forming several initial anti-interference alliances.

[0072] Any cooperating node The current initial anti-jamming alliance is Calculate the initial anti-interference alliance utility function , is represented as:

[0073] ;

[0074] in, Indicates the initial anti-interference alliance Except for the cooperative nodes Other collaborative nodes give the first The transmission rate brought about by a blocked node Indicates the first The transmission rate of a blocked node;

[0075] The cooperative node Randomly select another blocking node b, and calculate the anti-interference alliance of blocking node b. utility function , is represented as:

[0076] ;

[0077] in, Indicates Anti-Interference Alliance Except for the cooperative nodes The transmission rate provided by other cooperating nodes to the b-th blocking node, This represents the transmission rate of the b-th blocked node. ;

[0078] Comparison of initial anti-jamming alliances utility function and Anti-interference Alliance utility function ,like Then the cooperating node Leave the old league Join the new league ;

[0079] The current iteration optimization of the anti-interference alliance is completed when all the cooperative nodes no longer undergo alliance changes. The result of the nth iteration of the anti-interference alliance is represented as... .

[0080] As an optional technical solution of the present invention, in each round of iterative optimization, the optimization of the airborne beamforming vector and the optimization of the anti-jamming alliance are performed alternately, including:

[0081] Obtain the first anti-interference alliance generated by the transmission optimization model. The result of the second iteration Based on the transformed objective function and constraints, the airborne beamforming vector is optimized in its nth iteration. The result of the nth iteration of the airborne beamforming vector is expressed as follows: ;

[0082] The received signal-to-noise ratio of the ground node is calculated and expressed as:

[0083] ;

[0084] in, Indicates the first The received signal-to-noise ratio of each ground node Indicates the first The first launch platform and the first The conjugate transpose of the channel gain vector of each ground node. Indicates the jammer and the first Channel gain between ground nodes This represents the variance of the Gaussian white noise received by the ground node;

[0085] If the first Signal-to-noise ratio of each ground node Greater than or equal to the received signal-to-noise ratio threshold Then the first The first ground node will be used as a collaborating node; otherwise, the second will be used. Each ground node acts as a blocking node, and the set of cooperating nodes is updated. and the set of blocked nodes ;

[0086] After the nth iteration of optimization of the air beamforming vector is completed, based on the updated set of cooperative nodes... Set of blocked nodes and the nth iteration result of the aerial beamforming vector The anti-interference alliance is optimized in the nth iteration to obtain the nth iteration result. ;

[0087] Recalculate the received signal-to-noise ratio (SNR) of all ground nodes and compare it with the received SNR threshold. Compare and update the set of collaborating nodes again. and the set of blocked nodes ;

[0088] The nth iteration optimization of the anti-jamming alliance is completed, and the air beamforming vector and the nth iteration optimization of the anti-jamming alliance are performed. Continuous optimization through iterations until the maximum number of iterations is reached. The result of the last iteration of the air beamforming vector optimization is taken as the optimal air beamforming vector. The result of the last iteration of the anti-interference alliance is taken as the optimal anti-interference alliance. .

[0089] Secondly, a secure transmission optimization system for an air-ground cooperative communication network is provided, comprising: a parameter acquisition module for acquiring parameter information of a target air-ground cooperative communication network including an airborne platform, ground nodes, eavesdropping devices, and jammers, wherein the ground nodes include blocking nodes that cannot directly receive signals transmitted by the airborne platform and cooperative nodes that forward the transmitted signals of the airborne platform to the blocking nodes.

[0090] The channel model construction module is used to construct an air-to-ground transmission channel model and a ground end-to-end transmission channel model based on the parameter information of the air-to-ground cooperative communication network, and to obtain the channel error of the air-to-ground transmission channel model and the ground end-to-end transmission channel model.

[0091] The error processing module is used to process channel errors to obtain robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission.

[0092] The scheme generation module is used to input the air-to-ground transmission robust channel information and the ground end-to-end transmission robust channel information into a pre-constructed transmission optimization model to obtain a secure transmission optimization scheme.

[0093] The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking node while satisfying the constraints. The original optimization problem is transformed into an alternating optimization of the air beamforming vector and the anti-interference alliance, so that the transmission rate of the blocking node is maximized while satisfying the constraints.

[0094] The constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints. The air beamforming vector represents the beamforming vector used by the launch platform to transmit signals. The anti-interference alliance includes several cooperative nodes, with each blocking node corresponding to an anti-interference alliance.

[0095] Thirdly, a secure transmission optimization device for an air-ground cooperative communication network is provided, including a processor and a storage medium;

[0096] The storage medium is used to store instructions;

[0097] The processor is configured to operate according to the instructions to execute the steps of the secure transmission optimization method for the air-ground cooperative communication network described in the first aspect.

[0098] Fourthly, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that, when the program is executed by a processor, it implements the steps of the secure transmission optimization method for the air-ground cooperative communication network described in the first aspect.

[0099] Compared with the prior art, the beneficial effects of the present invention are:

[0100] This invention provides a secure transmission optimization method for air-to-ground cooperative communication networks. By optimizing the aerial beamforming vector, it reduces information leakage from the direction of eavesdropping devices. At the same time, it optimizes the anti-jamming alliance to effectively resist attacks from jammers, significantly improving the transmission security in air-to-ground cooperative networks. Under the constraint conditions, it maximizes the transmission rate of blocked nodes, which can more effectively utilize the resources of air-to-ground cooperative networks and significantly improve the transmission performance of blocked nodes. Attached Figure Description

[0101] Figure 1 This is a schematic diagram of the system structure of the air-ground cooperative communication network in an embodiment of the present invention;

[0102] Figure 2 This is a flowchart of a secure transmission optimization method for an air-ground cooperative communication network according to an embodiment of the present invention;

[0103] Figure 3 This is a performance comparison chart of alliance formation algorithms under different alliance preference criteria in the embodiments of the present invention;

[0104] Figure 4 This is a graph showing the relationship between the blocking node rate and the number of HAP antennas in an embodiment of the present invention;

[0105] Figure 5 This is a graph showing the relationship between the blocking node rate and the jammer's transmission power in an embodiment of the present invention. Detailed Implementation

[0106] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0107] Example 1

[0108] like Figure 1 As shown, a transmission system model of an air-to-ground cooperative communication network in a complex electromagnetic environment is presented, in which a lift-up platform (HAP) transmitter carrying a Uniform Planar Array (UPA) transmits to... Each single-antenna node broadcasts data information, where the airborne HAP set and the ground node set are respectively represented as follows: and . No. Taiwan HAP and the The coordinates of the ground nodes are respectively represented as: and ,in This is the fixed flight altitude of the HAP. The number of antennas on each side of the HAP antenna is as follows: and Therefore, the total number of antennas in the UPA is While HAP downlink broadcast data was being transmitted, two single-antenna malicious attack devices were simultaneously present, one of which was a passive eavesdropping device. and active jammer When a bugging machine With sufficient legitimate information, broadcast signals from HAP can be eavesdropped on; jammers By transmitting jamming signals to reduce the received signal-to-noise ratio, the jammer's strong full-band interference suppression can cause a sharp decline in the data transmission quality of some nodes, resulting in some ground nodes being unable to receive broadcast signals normally. These ground nodes are referred to as blocking nodes. Due to path loss and fading in the jamming link, the power-limited jammer cannot block the signal reception of all ground nodes. Therefore, ground nodes that can normally demodulate and receive broadcast signals from the airborne HAP are referred to as cooperative nodes. Cooperative nodes act as ground relays, forming an anti-jamming alliance to transmit information to severely jammed blocking nodes, thereby improving the reception performance of the blocking nodes. Cooperative nodes can distribute information from the HAP to severely jammed blocking nodes through D2D links, forming an anti-jamming subnet. While forming the anti-jamming subnet, the impact of eavesdropping devices on transmission security needs to be considered to prevent information leakage during relay forwarding. It is assumed that both the jammer and the eavesdropping device are equipped with omnidirectional antennas to jam and eavesdrop on nodes in all directions.

[0109] Based on the aforementioned air-to-ground cooperative communication network, this embodiment provides a method for optimizing secure transmission in such a network. For example... Figure 2 As shown, the specific steps include the following:

[0110] Step 1: Obtain parameter information of the target air-ground cooperative communication network, including the launch platform, ground nodes, eavesdropping devices, and jammers. The ground nodes include blocking nodes that cannot directly receive signals transmitted by the launch platform and cooperative nodes that forward the signals transmitted by the launch platform to the blocking nodes.

[0111] The parameter information of the target air-to-ground cooperative communication network includes the flight altitude of the HAP, antenna array parameters (such as the number of antennas, antenna spacing, wavelength, etc.), the location information of ground nodes, jammers and eavesdropping devices, path loss index, Rice factor, and upper and lower bounds of channel gain.

[0112] Step 2: Based on the parameter information of the air-to-ground cooperative communication network, construct the air-to-ground transmission channel model and the ground end-to-end transmission channel model, and obtain the channel error of the air-to-ground transmission channel model and the ground end-to-end transmission channel model.

[0113] In air-to-ground cooperative communication networks, there are two types of channel models: air-to-ground transmission channel model and ground end-to-end transmission channel model.

[0114] (1) The air-to-ground transmission channel model includes the transmission channel model of the airborne platform to the eavesdropping device and the transmission channel model of the airborne platform to the ground node.

[0115] The transmission channel model for the eavesdropping device from the airborne platform is represented as follows:

[0116] ;

[0117] in, Indicates the first A launch platform and a listening device The channel gain vector between them N represents the total number of antennas. This represents the channel gain at a distance of 1m. Indicates the first A launch platform and a listening device The distance between them eavesdropping device The coordinates are represented as , Indicates the first A launch platform and a listening device Path loss index between and These represent the number of NLoS paths and the Rice factor, respectively. and Representing the departure elevation angle and the first [angle] of the Loss path, respectively. The departure elevation angle of the NLoS path, and Representing the departure azimuth and the first azimuth of the LosS path, respectively. The departure azimuth of the NLoS path, and The antenna array responses on one side and the other side of the launch platform are respectively represented as follows:

[0118] ;

[0119] ;

[0120] in, , This indicates the antenna spacing on one side of the launch platform. This indicates the area between the antennas on the other side of the launch platform. Indicates wavelength. Indicates the Kronecker product. This indicates the number of antennas on one side of the launch platform. This indicates the number of antennas on the other side of the launch platform. This indicates transpose.

[0121] The transmission channel model from the launch platform to the ground node is represented as follows:

[0122] ;

[0123] in, Indicates the first The first launch platform and the first Channel gain vector between ground nodes , Indicates the first The first launch platform and the first The distance between each ground node , Indicates the first The first launch platform and the first Path loss index between ground nodes.

[0124] (2) The ground end-to-end transmission channel model includes the transmission channel model of jammer to ground node, the transmission channel model of eavesdropping machine to ground node and the transmission channel model of cooperative node to blocking node.

[0125] The transmission channel model of the jammer to the ground node is represented as follows:

[0126] ;

[0127] The transmission channel model of the eavesdropping device to the ground node is represented as follows:

[0128] ;

[0129] The transmission channel model for the cooperating node to the blocking node is represented as follows:

[0130] ;

[0131] in, Indicates jammer With the Channel gain vector between ground nodes Indicates eavesdropping device With the Channel gain vector between ground nodes Represents a collaborative node With blocking nodes The channel gain vector between them Indicates jammer With the Communication distance of each ground node Indicates eavesdropping device With the Communication distance of each ground node Represents a collaborative node With blocking nodes Communication distance, Indicates jammer With the Path loss index of each ground node. Indicates eavesdropping device With the Path loss index of each ground node. Represents a collaborative node With blocking nodes The path loss index. and These represent the total number of paths and the Rice factor in the ground network, respectively. Represents non-line-of-sight components, obeying , Represents the first in the terrestrial network A path.

[0132] For legitimate communication links ( Figure 1 (Solid line link in the middle) , The information can be accurately obtained throughout the transmission process. However, since the eavesdropping and jamming devices are not cooperative with the ground nodes, the channel state information of the jamming and eavesdropping channels is difficult to obtain through estimation or prediction. By measuring the jamming signal and the power leakage signal of the eavesdropping device's local oscillator, the relative positions of the jammer and ground eavesdropping devices with the legitimate transmitter can be roughly obtained, but there is a certain estimation error.

[0133] (1) The channel error in the transmission channel model of the eavesdropping device from the launch platform is expressed as:

[0134] ;

[0135] in, This represents the channel error in the transmission channel model for the eavesdropping device from the launch platform. and They represent the first A launch platform and a listening device Between the angle of departure The upper and lower bounds, and They represent the first A launch platform and a listening device Between the azimuth angles The upper and lower bounds, This refers to a collection of launch platforms.

[0136] (2) The channel error in the transmission channel model of the jammer to the ground node is expressed as:

[0137] ;

[0138] in, This represents the channel error in the transmission channel model from the jammer to the ground node. and Representing the jammer and the... Channel gain between ground nodes The upper and lower bounds, This represents the set of ground nodes.

[0139] (3) The channel error in the transmission channel model of the eavesdropping device to the ground node is expressed as:

[0140] ;

[0141] in, This represents the channel error in the transmission channel model from the eavesdropping device to the ground node. and They represent the eavesdropping device and the... Channel gain between ground nodes The upper and lower bounds.

[0142] Step 3: After processing the channel error, we obtain robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission.

[0143] From the perspective of countering interference and eavesdropping, under the condition of channel error, the air beamforming vector is jointly optimized. and Anti-interference Alliance The goal is to maximize the sum of the rates of the blocking nodes, while satisfying the constraints on the rates of the cooperating nodes, the eavesdropping link, and the launch platform's transmit power. Therefore, the original optimization problem can be expressed as:

[0144] ;

[0145] in, This represents the original optimization problem. This indicates finding the minimum value. and These represent the rate constraints for legitimate links and eavesdropping links, respectively. This indicates the launch power constraint of the launch platform. This means that the set of cooperating nodes and the set of blocking nodes cannot overlap. This means that each cooperating node can only relay data to one blocking node via unicast at most.

[0146] Due to channel error Due to the influence of the original optimization problem, which exhibits infinite nonconvexity, a generalized discretization method is adopted to address this issue.

[0147] (1) The channel error in the transmission channel model of the airborne platform to the eavesdropping device Departure angle and departure azimuth Uniform sampling within the error range is expressed as follows:

[0148] ;

[0149] ;

[0150] in, Indicates the first The departure elevation angle of each sample, Indicates the first The azimuth angle of each sample departure. and These represent the number of sampling points for departure from elevation angle and departure from azimuth angle, respectively. , .

[0151] Based on uniform sampling, the robust channel for the eavesdropping device transmission of the launch platform is represented as follows:

[0152] ;

[0153] in, This represents the robust channel vector for transmission to eavesdropping devices from the launch platform. , Indicates in The channel response vector at that location, Indicates to The conjugate transpose of .

[0154] After discretization, the original optimization problem It can be removed.

[0155] (2) Channel error in the transmission channel model of the jammer to the ground node Channel error in the transmission channel model of the eavesdropping device to the ground node ,make , The corresponding robust transmission channel is then obtained. At this point, the transmission rates of the interference link and the eavesdropping link are at their maximum, ensuring that the objective function is maximized under any possible channel error conditions.

[0156] After handling channel errors, the original optimization problem... and It can be removed, which can effectively improve the robustness of aerial beamforming and cooperative transmission.

[0157] Step 4: Input the air-to-ground robust channel information and the ground end-to-end robust channel information into the pre-constructed transmission optimization model to obtain a secure transmission optimization scheme.

[0158] The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking nodes while satisfying constraints. The original optimization problem is transformed into alternating optimization of the airborne beamforming vector and the anti-jamming alliance, so that the transmission rate of the blocking nodes is maximized while satisfying constraints. These constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints.

[0159] The original optimization problem is decoupled into separate problems for the airborne beamforming vector. and Anti-interference Alliance The two optimization sub-problems are: Sub-problem 1: Optimize the airborne beamforming vector given an anti-jamming alliance; Sub-problem 2: Optimize the anti-jamming alliance given the airborne beamforming vector. Here, the airborne beamforming vector represents the beamforming vector used by the launch platform to transmit signals; the anti-jamming alliance includes several cooperating nodes used to forward the launch platform's transmitted signals to blocking nodes, with each blocking node corresponding to an anti-jamming alliance.

[0160] (1) Given an anti-jamming alliance, the optimized representation of the airborne beamforming vector is as follows:

[0161] ;

[0162] in, This represents an expression for optimizing the aerial beamforming vector. Let represent the objective function for optimizing the airborne beamforming vector. Represents the set of blocked nodes. This indicates finding the maximum value. Represents the aerial beamforming vector. The transmission rate of the b-th blocked node is represented as: , Indicates the first There are 1, 2, 3, 4, 5, 6, 7, 8, 9, 1 Indicates the first The conjugate transpose of the channel gain vectors of the first launch platform and the b-th blocking node. Represents a set of collaborating nodes. Represents binary variables , This indicates that the ground node is a cooperative node. This indicates that the ground node is a blocked node. Represents binary variables , Indicates the first The collaborating nodes participated in the first... Cooperative transmission of a blocked node This indicates that they will not participate in the collaborative transmission. This represents the forwarding power amplification factor of the cooperating nodes. Indicates the first The first collaborative node and the first Channel gain between blocked nodes Indicates the jammer and the first Channel gain between blocked nodes Indicates the jammer's transmission power. This indicates that the blocking node receives Gaussian white noise. variance ; This indicates a rate constraint for cooperating nodes. Indicates the rate of the collaborating nodes. This represents the minimum rate of the collaborating nodes. This indicates a constraint on the rate of the eavesdropping link. Indicates the rate of the eavesdropping link. , This indicates the maximum rate of the eavesdropping link. This indicates the launch power constraint of the launch platform. Indicates the launch platform's transmission power. This indicates the maximum transmission power of the launch platform. This refers to a collection of launch platforms.

[0163] Introducing several auxiliary variables, the above objective function and constraints , , Transform the problem into a convex optimization problem; introduce auxiliary variables to the objective function. The conversion is performed, and it is represented as:

[0164] ;

[0165] in, These represent the first auxiliary variable, the second auxiliary variable, and the third auxiliary variable, respectively.

[0166] Referencing auxiliary slack variables New constraints Perform the conversion to obtain and The two constraints are expressed as follows:

[0167] ;

[0168] ;

[0169] Will Defined as an air beamforming vector The The result of the next iteration, through Perform a first-order Taylor series expansion and add new constraints. middle .

[0170] Add new constraints Convert to constraints , is represented as:

[0171] ;

[0172] in .

[0173] Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as:

[0174] ;

[0175] ;

[0176] ;

[0177] in, These represent the fourth and fifth auxiliary variables, respectively. This indicates that the cooperating nodes receive Gaussian white noise. variance Indicates the jammer and the first Channel gain between cooperating nodes Indicates the first The first launch platform and the first Channel gain vector of each cooperating node The conjugate transpose of .

[0178] Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as:

[0179] ;

[0180] ;

[0181] in, Represents the sixth auxiliary variable. Indicates the first The conjugate transpose of the channel gain vector between the launch platform and the eavesdropping device. This indicates that the eavesdropping device receives Gaussian white noise. The variance.

[0182] For constraints Performing a first-order Taylor series expansion, we obtain :

[0183] ;

[0184] in, Represents the sixth auxiliary variable No. The result of the next iteration.

[0185] Finally, the objective function and constraints for optimizing the aerial beamforming vector are transformed into:

[0186] .

[0187] Therefore, the air beamforming vector The original non-convex problem is transformed into a convex problem, which can be solved using the CVX toolbox in MATLAB to obtain the optimization results for each iteration.

[0188] (2) Given an air beamforming vector, optimize the anti-jamming alliance, including:

[0189] The optimized representation of the anti-interference alliance is as follows:

[0190] ;

[0191] in, This represents the expression used to optimize the anti-interference alliance. Let represent the objective function for optimizing the anti-interference alliance. This represents the anti-interference alliance corresponding to the b-th blocking node. Indicates the first Anti-interference alliances corresponding to each blocked node Represents the set of collaborating nodes and the set of blocked nodes There is no overlap between them. This means that each collaborating node can only join one anti-interference alliance;

[0192] In the initial anti-interference alliance, all cooperating nodes randomly select the blocking node to relay information, forming several initial anti-interference alliances.

[0193] Any cooperating node The current initial anti-jamming alliance is Calculate the initial anti-interference alliance utility function , is represented as:

[0194] ;

[0195] in, Indicates the initial anti-interference alliance Except for the cooperative nodes Other collaborative nodes give the first The transmission rate brought about by a blocked node Indicates the first The transmission rate of a blocked node;

[0196] The cooperative node Randomly select another blocking node b, and calculate the anti-interference alliance of blocking node b. utility function , is represented as:

[0197] ;

[0198] in, Indicates Anti-Interference Alliance Except for the cooperative nodes The transmission rate provided by other cooperating nodes to the b-th blocking node, This represents the transmission rate of the b-th blocked node. ;

[0199] Based on the bilateral best criterion, compare the initial anti-interference alliances. utility function and Anti-interference Alliance utility function ,like Then the cooperating node Leave the old league Join the new league ;

[0200] The current iteration optimization of the anti-interference alliance is completed when all the cooperative nodes no longer undergo alliance changes. The result of the nth iteration of the anti-interference alliance is represented as... .

[0201] Further proof that the increment of the utility function is the same as the increment of the sum of the transmission rates of the blocked nodes:

[0202] The potential energy function is defined as the sum of the transmission rates of all blocked nodes, expressed as:

[0203] ;

[0204] When cooperating nodes leaving the league and joined the alliance At that time, the change in the potential energy function is:

[0205] ;

[0206] in, This indicates that among all anti-interference alliances, besides the alliance... Other alliances besides [the other ones].

[0207] Due to collaborative nodes Changing its alliance choice only affects the new alliance. and the old alliance The transmission rate of the blocked nodes in the network will be reduced without affecting the transmission rate of nodes outside the consortium. and Other alliances, namely

[0208] ;

[0209] Therefore, the increment of the potential energy function is expressed as:

[0210] ;

[0211] Meanwhile, the change in the potential energy function is expressed as:

[0212] ;

[0213] Therefore, the increase in the potential function is equal to the increase in the coalition formation utility function. If any cooperating node changes its coalition choice to increase its coalition formation utility function, the potential function can increase accordingly.

[0214] (3) In each round of iterative optimization, the optimization of the air beamforming vector and the optimization of the anti-jamming alliance are performed alternately. Specifically, as follows:

[0215] Obtain the first anti-interference alliance generated by the transmission optimization model. The result of the second iteration Based on the transformed objective function and constraints, the airborne beamforming vector is optimized in its nth iteration. The result of the nth iteration of the airborne beamforming vector is expressed as follows: .

[0216] The received signal-to-noise ratio of the ground node is calculated and expressed as:

[0217] ;

[0218] in, Indicates the first The received signal-to-noise ratio of each ground node Indicates the first The first launch platform and the first The conjugate transpose of the channel gain vector of each ground node. Indicates the jammer and the first Channel gain between ground nodes This represents the variance of the Gaussian white noise received by the ground node.

[0219] If the first Signal-to-noise ratio of each ground node Greater than or equal to the received signal-to-noise ratio threshold Then the first The first ground node will be used as a collaborating node; otherwise, the second will be used. Each ground node acts as a blocking node, and the set of cooperating nodes is updated. and the set of blocked nodes .

[0220] After the nth iteration of optimization of the air beamforming vector is completed, based on the updated set of cooperative nodes... Set of blocked nodes and the nth iteration result of the aerial beamforming vector The anti-interference alliance is optimized in the nth iteration to obtain the nth iteration result. .

[0221] Recalculate the received signal-to-noise ratio (SNR) of all ground nodes and compare it with the received SNR threshold. Compare and update the set of collaborating nodes again. and the set of blocked nodes .

[0222] The nth iteration optimization of the anti-jamming alliance is completed, and the air beamforming vector and the nth iteration optimization of the anti-jamming alliance are performed. Continuous optimization through iterations until the maximum number of iterations is reached. The result of the last iteration of the air beamforming vector optimization is taken as the optimal air beamforming vector. The result of the last iteration of the anti-interference alliance is taken as the optimal anti-interference alliance. The secure transmission optimization scheme includes the optimal airborne beamforming vector. and the best anti-interference alliance .

[0223] In this embodiment, the number of iterations needs to be set before the iteration begins. and maximum number of iterations Generate an initial feasible solution .

[0224] Example 2

[0225] This embodiment, based on Embodiment 1, demonstrates the effectiveness of the method by combining three comparative schemes. The three comparative schemes are an SCA-based beamforming optimization scheme, a CFG-based anti-interference alliance formation optimization scheme, and a random beamforming and relay forwarding scheme.

[0226] like Figure 3 As shown, the Pareto criterion has limited ability to improve the rate of blocked nodes. Once a cooperating node joins a non-interference alliance, it is difficult for it to leave the current alliance due to the strict alliance switching conditions under the Pareto criterion. The selfish criterion, when selecting an alliance, only focuses on the transmission rate of blocked nodes in the new alliance, ignoring the transmission rate of blocked nodes in other alliances. This may result in improving the rate of blocked nodes in the new alliance while harming the rate of other blocked nodes. Compared with the other two alliance preference criteria, the bilateral optimal criterion proposed in this method can achieve the highest rate of blocked nodes. This is because the bilateral optimal criterion considers the sum of the rates of the old and new alliances, which not only relaxes the strict requirements of alliance switching in the Pareto criterion, but also guarantees the improvement of the rate of blocked nodes.

[0227] like Figure 4 As shown, in all four schemes, the blocking node rate and the sum of the values ​​increase with the number of HAP antennas. This is because increasing the number of antennas can significantly improve the resolution and gain of the spatial beam, enabling the formation of a stronger beam pointing. When a large number of antennas are deployed in the HAP, such as... At that time, the performance of the beamforming optimization scheme based on SCA was significantly improved, and its performance was similar to that of the air-ground cooperative joint optimization scheme proposed in this method. This shows that the spatial gain brought by a larger number of antennas can effectively improve the secure transmission performance of blocking nodes.

[0228] like Figure 5As shown, the performance of all four schemes degrades with increasing jammer power. The proposed air-to-ground cooperative joint optimization scheme, by scheduling air-to-ground communication resources and considering both beamforming effects and anti-jamming alliance formation, effectively improves the transmission rate of blocking nodes while meeting the eavesdropping link rate constraint, thus achieving anti-jamming transmission. The CFG-based anti-jamming alliance formation optimization scheme and the SCA-based beamforming optimization scheme are limited by the limited number of antennas and transmission power of the HAP and cooperating nodes, making them unable to combat malicious interference in jamming environments, resulting in some blocking nodes failing to meet rate constraints. The random beamforming and relay forwarding schemes do not fully utilize and optimize air-to-ground communication resources, thus yielding the worst performance.

[0229] Example 3

[0230] This embodiment provides a secure transmission optimization system for an air-to-ground cooperative communication network, including:

[0231] The parameter acquisition module is used to acquire parameter information of the target air-ground cooperative communication network, including the launch platform, ground nodes, eavesdropping devices and jammers. The ground nodes include blocking nodes that cannot directly receive signals transmitted by the launch platform and cooperative nodes that forward the signals transmitted by the launch platform to the blocking nodes.

[0232] The channel model construction module is used to construct an air-to-ground transmission channel model and a ground end-to-end transmission channel model based on the parameter information of the air-to-ground cooperative communication network, and to obtain the channel error of the air-to-ground transmission channel model and the ground end-to-end transmission channel model.

[0233] The error processing module is used to process channel errors to obtain robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission.

[0234] The scheme generation module is used to input the air-to-ground transmission robust channel information and the ground end-to-end transmission robust channel information into a pre-constructed transmission optimization model to obtain a secure transmission optimization scheme.

[0235] The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking node while satisfying the constraints. The original optimization problem is transformed into an alternating optimization of the air beamforming vector and the anti-interference alliance, so that the transmission rate of the blocking node is maximized while satisfying the constraints.

[0236] The constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints. The air beamforming vector represents the beamforming vector used by the launch platform to transmit signals. The anti-interference alliance includes several cooperative nodes, with each blocking node corresponding to an anti-interference alliance.

[0237] Example 4

[0238] This embodiment provides a secure transmission optimization device for an air-to-ground cooperative communication network, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the secure transmission optimization method for the air-to-ground cooperative communication network described in Embodiment 1.

[0239] Example 5

[0240] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the secure transmission optimization method for the air-ground cooperative communication network described in Embodiment 1.

[0241] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0242] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0243] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0244] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0245] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A secure transmission optimization method for an air-to-ground cooperative communication network, characterized in that, include: Acquire parameter information of the target air-ground cooperative communication network, including the launch platform, ground nodes, eavesdropping devices, and jammers. The ground nodes include blocking nodes that cannot directly receive signals transmitted by the launch platform and cooperative nodes that forward the signals transmitted by the launch platform to the blocking nodes. Based on the parameter information of the air-to-ground cooperative communication network, an air-to-ground transmission channel model and a ground end-to-end transmission channel model are constructed, and the channel errors of the air-to-ground transmission channel model and the ground end-to-end transmission channel model are obtained. After processing the channel error, robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission are obtained. The air-to-ground transmission robust channel information and the ground end-to-end transmission robust channel information are input into a pre-constructed transmission optimization model to obtain a secure transmission optimization scheme. The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking node while satisfying the constraints. The original optimization problem is transformed into an alternating optimization of the air beamforming vector and the anti-interference alliance, so that the transmission rate of the blocking node is maximized while satisfying the constraints. The constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints. The air beamforming vector represents the beamforming vector used by the launch platform to transmit signals. The anti-jamming alliance includes several cooperative nodes, with each blocking node corresponding to an anti-jamming alliance. The construction of the air-to-ground transmission channel model and the ground end-to-end transmission channel model includes: The air-to-ground transmission channel model includes the transmission channel model from the airborne platform to the eavesdropping device, represented as follows: ； in, Indicates the first A launch platform and a listening device The channel gain vector between them This represents the channel gain at a distance of 1m. Indicates the first A launch platform and a listening device The distance between them Indicates the first A launch platform and a listening device Path loss index between and These represent the number of NLoS paths and the Rice factor, respectively. and Representing the departure elevation angle and the first [angle] of the Loss path, respectively. The departure elevation angle of the NLoS path, and Representing the departure azimuth and the first azimuth of the LosS path, respectively. The departure azimuth of the NLoS path, and The antenna array responses on one side and the other side of the launch platform are respectively represented as follows: ； ； in, , This indicates the antenna spacing on one side of the launch platform. This indicates the area between the antennas on the other side of the launch platform. Indicates wavelength. Indicates the Kronecker product. This indicates the number of antennas on one side of the launch platform. This indicates the number of antennas on the other side of the launch platform. Indicates transpose; The ground end-to-end transmission channel model includes the transmission channel model from the jammer to the ground node and the transmission channel model from the eavesdropping device to the ground node, which are represented as follows: ； ； in, Indicates jammer With the Channel gain vector between ground nodes Indicates eavesdropping device With the Channel gain vector between ground nodes Indicates jammer With the Communication distance of each ground node Indicates eavesdropping device With the Communication distance of each ground node Indicates jammer With the Path loss index for each ground node. Indicates eavesdropping device With the Path loss index for each ground node. and These represent the total number of paths and the Rice factor in the ground network, respectively. Represents the non-line-of-sight component. Represents the first in the terrestrial network A path.

2. The secure transmission optimization method for air-to-ground cooperative communication networks according to claim 1, characterized in that, The channel error in the transmission channel model of the eavesdropping device from the launch platform is expressed as: ； in, This represents the channel error in the transmission channel model between the launch platform and the eavesdropping device. and They represent the first A launch platform and a listening device Between the angle of departure The upper and lower bounds, and They represent the first A launch platform and a listening device Between the azimuth angles The upper and lower bounds, This represents a collection of launch platforms; The channel error in the transmission channel model of the jammer to the ground node is expressed as: ； in, This represents the channel error in the transmission channel model from the jammer to the ground node. and Representing the jammer and the... Channel gain between ground nodes The upper and lower bounds, Represents the set of ground nodes; The channel error in the transmission channel model of the eavesdropping device to the ground node is expressed as: ； in, This represents the channel error in the transmission channel model from the eavesdropping device to the ground node. and They represent the eavesdropping device and the... Channel gain between ground nodes The upper and lower bounds.

3. The secure transmission optimization method for air-to-ground cooperative communication networks according to claim 2, characterized in that, After processing the channel error, robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission are obtained, including: By using a generalized discretization method, the channel error in the transmission channel model of the airborne platform to the eavesdropping device is determined. Departure angle and departure azimuth Uniform sampling within the error range is expressed as follows: ； ； in, Indicates the first The departure elevation angle of each sample, Indicates the first The azimuth angle of each sample departure. and These represent the number of sampling points for departure from elevation angle and departure from azimuth angle, respectively. , ; Based on uniform sampling, the robust channel for the eavesdropping device transmission of the launch platform is represented as follows: ； in, This represents the robust channel vector for transmission to eavesdropping devices from the launch platform. , Indicates in The channel response vector at that location, Indicates to The conjugate transpose of; For the channel error in the transmission channel model of the jammer to the ground node Channel error in the transmission channel model of the eavesdropping device to the ground node ,make , The corresponding robust transmission channel is then obtained.

4. The secure transmission optimization method for air-to-ground cooperative communication networks according to claim 1, characterized in that, The optimized representation of the air beamforming vector is as follows: ； in, This represents an expression for optimizing the aerial beamforming vector. Let represent the objective function for optimizing the airborne beamforming vector. Represents the set of blocked nodes. This indicates finding the maximum value. Represents the aerial beamforming vector. The transmission rate of the b-th blocked node is represented as: , Indicates the first There are 1, 2, 3, 4, 5, 6, 7, 8, 9, 1 Indicates the first The conjugate transpose of the channel gain vectors of the first launch platform and the b-th blocking node. Represents a set of collaborating nodes. Represents binary variables , This indicates that the ground node is a cooperative node. This indicates that the ground node is a blocked node. Represents binary variables , Indicates the first The collaborating nodes participated in the first... Cooperative transmission of a blocked node This indicates that you will not participate in the collaborative transmission. This represents the forwarding power amplification factor of the cooperating nodes. Indicates the first The first collaborative node and the first Channel gain between blocking nodes Indicates the jammer and the first Channel gain between blocking nodes Indicates the jammer's transmission power. This indicates that the blocked node receives Gaussian white noise. variance ; This indicates a rate constraint for cooperating nodes. Indicates the rate of the collaborating nodes. This represents the minimum rate of the collaborating nodes. This indicates a constraint on the rate of the eavesdropping link. Indicates the rate of the eavesdropping link. This indicates the maximum rate of the eavesdropping link. This indicates the launch power constraint of the launch platform. Indicates the launch platform's transmission power. This indicates the maximum transmission power of the launch platform. This represents a collection of launch platforms; Introducing several auxiliary variables, the above objective function and constraints , , Transform the problem into a convex optimization problem; introduce auxiliary variables to the objective function. The conversion is performed, and it is represented as: ； in, These represent the first auxiliary variable, the second auxiliary variable, and the third auxiliary variable, respectively. Referencing auxiliary relaxation variables New constraints Perform the conversion to obtain and The two constraints are expressed as follows: ； ； Will Defined as an air beamforming vector The The result of the next iteration, through Perform a first-order Taylor series expansion and add new constraints. middle ; Add new constraints Convert to constraints , is represented as: ； in ; Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as: ； ； ； in, These represent the fourth and fifth auxiliary variables, respectively. This indicates that the cooperating nodes receive Gaussian white noise. variance Indicates the jammer and the first Channel gain between cooperating nodes Indicates the first The first launch platform and the first Channel gain vector of each cooperating node The conjugate transpose of; Introducing auxiliary variables to constraints The constraints are obtained by performing the transformation. , respectively represented as: ； ； in, Represents the sixth auxiliary variable. Indicates the first The conjugate transpose of the channel gain vector between the launch platform and the eavesdropping device. This indicates that the eavesdropping device receives Gaussian white noise. The variance; For constraints Performing a first-order Taylor series expansion, we obtain : ； in, Represents the sixth auxiliary variable No. The result of the next iteration; Finally, the objective function and constraints for optimizing the aerial beamforming vector are transformed into: 。 5. The secure transmission optimization method for air-to-ground cooperative communication networks according to claim 4, characterized in that, The optimized representation of the anti-interference alliance is as follows: ； in, This represents the expression used to optimize the anti-interference alliance. Let represent the objective function for optimizing the anti-interference alliance. This represents the anti-interference alliance corresponding to the b-th blocking node. Indicates the first Anti-interference alliances corresponding to each blocked node Represents the set of collaborating nodes and the set of blocked nodes There is no overlap between them. This means that each collaborating node can only join one anti-interference alliance; In the initial anti-interference alliance, all cooperating nodes randomly select the blocking node to relay information, forming several initial anti-interference alliances. Any cooperating node The current initial anti-jamming alliance is Calculate the initial anti-interference alliance utility function , is represented as: ； in, Indicates the initial anti-interference alliance Except for the collaborative nodes Other collaborative nodes give the first The transmission rate brought about by a blocked node Indicates the first The transmission rate of a blocked node; The cooperative node Randomly select another blocking node b, and calculate the anti-interference alliance of blocking node b. utility function , is represented as: ； in, Indicating Anti-Interference Alliance Except for the collaborative nodes The transmission rate provided by other cooperating nodes to the b-th blocking node, This represents the transmission rate of the b-th blocked node. ; Comparison of initial anti-jamming alliances utility function and Anti-interference Alliance utility function ,like Then the cooperating node Leave the old league Join the new league ; The current iteration of the anti-interference alliance optimization is completed when all the cooperative nodes no longer undergo alliance changes. The result of the nth iteration of the anti-interference alliance is represented as... .

6. The secure transmission optimization method for air-to-ground cooperative communication networks according to claim 5, characterized in that, In each round of iterative optimization, the optimization of the airborne beamforming vector and the optimization of the anti-jamming alliance are performed alternately, including: Obtain the first anti-interference alliance generated by the transmission optimization model. The result of the second iteration Based on the transformed objective function and constraints, the airborne beamforming vector is optimized in its nth iteration. The result of the nth iteration of the airborne beamforming vector is expressed as follows: ; The received signal-to-noise ratio of the ground node is calculated and expressed as: ； in, Indicates the first The received signal-to-noise ratio of each ground node, Indicates the first The first launch platform and the first The conjugate transpose of the channel gain vector of each ground node. Indicates the jammer and the first Channel gain between ground nodes This represents the variance of the Gaussian white noise received by the ground node; If the first Signal-to-noise ratio of each ground node Greater than or equal to the received signal-to-noise ratio threshold Then the first The first ground node will be used as a collaborating node; otherwise, the second will be used. Each ground node acts as a blocking node, and the set of cooperating nodes is updated. and the set of blocked nodes ; After the nth iteration of optimization of the air beamforming vector is completed, based on the updated set of cooperative nodes... Set of blocked nodes and the nth iteration result of the aerial beamforming vector The anti-interference alliance is optimized in the nth iteration to obtain the nth iteration result. ; Recalculate the received signal-to-noise ratio (SNR) of all ground nodes and compare it with the received SNR threshold. Compare and update the set of collaborating nodes again. and the set of blocked nodes ; The nth iteration optimization of the anti-jamming alliance is completed, and the air beamforming vector and the nth iteration optimization of the anti-jamming alliance are performed. Continuous optimization through iterations until the maximum number of iterations is reached. The result of the last iteration of the air beamforming vector optimization is taken as the optimal air beamforming vector. The result of the last iteration of the anti-interference alliance is taken as the optimal anti-interference alliance. .

7. A secure transmission optimization system for an air-to-ground cooperative communication network, characterized in that, A method for optimizing secure transmission in an air-to-ground cooperative communication network according to any one of claims 1 to 6, comprising: The parameter acquisition module is used to acquire parameter information of the target air-ground cooperative communication network, including the launch platform, ground nodes, eavesdropping devices and jammers. The ground nodes include blocking nodes that cannot directly receive signals transmitted by the launch platform and cooperative nodes that forward the signals transmitted by the launch platform to the blocking nodes. The channel model construction module is used to construct an air-to-ground transmission channel model and a ground end-to-end transmission channel model based on the parameter information of the air-to-ground cooperative communication network, and to obtain the channel error of the air-to-ground transmission channel model and the ground end-to-end transmission channel model. The error processing module is used to process channel errors to obtain robust channel information for air-to-ground transmission and robust channel information for ground end-to-end transmission. The scheme generation module is used to input the air-to-ground transmission robust channel information and the ground end-to-end transmission robust channel information into a pre-constructed transmission optimization model to obtain a secure transmission optimization scheme. The original optimization problem of the transmission optimization model is to maximize the transmission rate of the blocking node while satisfying the constraints. The original optimization problem is transformed into an alternating optimization of the air beamforming vector and the anti-interference alliance, so that the transmission rate of the blocking node is maximized while satisfying the constraints. The constraints include cooperative node rate constraints, eavesdropping link rate constraints, and launch platform transmit power constraints. The air beamforming vector represents the beamforming vector used by the launch platform to transmit signals. The anti-interference alliance includes several cooperative nodes, with each blocking node corresponding to an anti-interference alliance.

8. A secure transmission optimization device for an air-to-ground cooperative communication network, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the secure transmission optimization method for the air-ground cooperative communication network according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the secure transmission optimization method for the air-ground cooperative communication network as described in any one of claims 1 to 6.

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