Unmanned aerial vehicle (UAV)-based air-to-ground hybrid communication method, device and communication system

Abstract

The invention discloses a UAV-based air-to-ground hybrid communication method, device and communication system, and the method comprises the steps: designing a hybrid communication architecture and building a channel model for a scene containing a plurality of UAVs and UEs; in the hybrid communication architecture, each time slot is divided into an uplink transmission stage and a downlink transmission stage based on the TDD technology, and the transmission duration is divided according to the uplink and downlink proportion; based on the FDMA technology, dividing the total frequency bandwidth of the system in each time slot into the sub-frequency bandwidth of each UE according to a plurality of sub-bandwidth division proportions matched with the number of the UEs; based on the hybrid communication architecture and the channel model, uplink and downlink data transmission rates between the UAV and the UE in each time slot are calculated as communication rate calculation results; and determining a communication decision in each time slot based on a communication rate calculation result between the UAV and the UE, thereby realizing air-to-ground communication between the UAV and the UE. According to the invention, the UAV communication performance and efficiency can be improved by configuring the uplink and downlink proportion division and the sub-bandwidth division proportion.

Description

Technical Field

[0001] The present invention belongs to the technical field of network communication and signal processing, and in particular relates to an air-to-ground hybrid communication method, device and communication system based on UAV. Background Art

[0002] With the continuous exploitation of earth resources, the ecological balance has been severely damaged, resulting in a significant increase in sudden natural disasters. In post-disaster rescue, the collection and real-time transmission of information are the key to the rescue process. Natural disasters such as earthquakes, rainstorms, and strong winds can destroy the communication network in the disaster-stricken areas, hindering the timely transmission of information to the outside world. In this case, drones equipped with airborne communication base station systems can integrate aerial networking and image transmission technologies to achieve vertical and horizontal interconnection of images, voice, and data. Compared with traditional emergency rescue, UAVs (Unmanned Aerial Vehicles) can get rid of the limitations of optical cables and electricity in the original infrastructure and realize the rapid deployment of emergency communications. Due to the large number of ground nodes and limited spectrum resources, it is difficult to achieve communication coverage while ensuring communication quality, which requires continuous optimization of relevant parameters through advanced algorithms.

[0003] In the prior art, Gui Jinsong et al. proposed a millimeter wave heterogeneous cellular network with wireless self-backhaul in the patent "Gui Jinsong, Chen Can, Deng Xiaoheng. Self-backhaul millimeter wave cellular network communication method based on dynamic time division duplex communication [P]. Hunan Province: CN202310462350.9, 2024-02-02.", including a macro cell and N small cells. In the target network, the macro base station, small base station, and user equipment are equipped with wireless interfaces of millimeter wave frequency band and sun-6GHz frequency band, which are used for data transmission and control information exchange, respectively. The uplink and downlink communication requirements are realized by configuring the communication frame ratio in the time-division long-term evolution scheme; the in-band transmission mode is adopted for transmission, and the joining link and the backhaul link share the same spectrum resources.

[0004] However, in the above scheme, the uplink and downlink communication requirements are only achieved by configuring the communication frame ratio, but the same spectrum resources are shared and the spectrum resources are not optimized, which will lead to spectrum resource waste and signal interference problems. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides an air-to-ground hybrid communication method, device and communication system based on UAV. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides an air-to-ground hybrid communication method based on a UAV, the method comprising:

[0007] For scenarios with multiple UAVs and user nodes UE, a hybrid communication architecture is designed, and a channel model between UAVs and UEs is established; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to multiple sub-bandwidth division ratios matching the number of UEs;

[0008] Based on the hybrid communication architecture and the channel model, calculating an uplink data transmission rate and a downlink data transmission rate between the UAV and the UE in each time slot as a communication rate calculation result of the corresponding time slot;

[0009] In each time slot, based on the calculation result of the communication rate between the UAV and the UE, a communication decision between the UAV and the UE is determined to indicate whether a communication connection is to be established, and the air-to-ground communication between the UAV and the UE in the scenario is achieved through the communication decision.

[0010] In one embodiment of the present invention, in the scenario, J UAVs are deployed above the ground, represented as There are I UEs deployed on the ground, represented by

[0011] For the above scenario, the designed hybrid communication architecture includes:

[0012] The communication cycle of the UAV in the scenario is divided into T equal time periods, expressed as Each time period is a time slot, which is represented by duration τ, and τ is small enough; each time slot t is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration of the uplink transmission phase and the downlink transmission phase is divided according to the uplink and downlink ratio k, and the value of k is between 0 and 1; kτ represents the transmission duration of the uplink transmission phase in a time slot, and (1-k)τ represents the transmission duration of the downlink transmission phase in the same time slot; in each time slot t, the total frequency bandwidth of the system is divided into the sub-frequency bandwidth of each UE according to the I sub-bandwidth division ratio; w is used to represent the size of the total frequency bandwidth of the system, and the divided sub-frequency bandwidth of I UE is expressed as a i is the sub-bandwidth allocation ratio of the i-th UE.

[0013] In one embodiment of the present invention, the channel model covers two types: line-of-sight and non-line-of-sight.

[0014] In one embodiment of the present invention, the process of establishing a channel model between a UAV and a UE includes:

[0015] Determine the UAV in time slot t j and UE iThe line-of-sight connection probability and the non-line-of-sight connection probability are expressed as:

[0016]

[0017] Among them, LoS and NLoS represent line-of-sight and non-line-of-sight respectively; UAV j represents the jth UAV; UE i represents the i-th UE; represents the UAV in time slot t j and UE i The probability of line-of-sight connection between represents the UAV in time slot t j and UE i The probability of non-line-of-sight connection between α and β; α and β are environmental constants; represents the UAV in time slot t j and UE i The elevation angle between

[0018] Determine the UAV in time slot t j and UE i The average LoS path loss and the average NLoS path loss between are expressed as:

[0019]

[0020] and They represent the UAVs in time slot t. j and UE i The average LoS path loss and the average NLoS path loss between them; f represents the UAV j and UE i The channel transmission frequency, in Hz; represents the UAV in time slot t j and UE i The distance between them; c represents the speed of light; η LoS and η NLoS They represent the additional loss on the LoS path and the additional loss on the NLoS path respectively;

[0021] According to the UAV in time slot t j and UE i The probability of line-of-sight connection and non-line-of-sight connection between UAVs in time slot t j and UE i The average LoS path loss and the average NLoS path loss between them are used to determine the UAV j and UE i The average path loss between is expressed as:

[0022]

[0023] in, is the UAV in time slot t j and UE i The average path loss between is used to characterize the channel status.

[0024] In one embodiment of the present invention, the formula for calculating the uplink data transmission rate between the UAV and the UE in each time slot is:

[0025]

[0026] The formula for calculating the downlink data transmission rate between the UAV and the UE in each time slot is:

[0027]

[0028] in, is the UAV in time slot t j and UE i Uplink data transmission rate; is the UAV in time slot t j and UE i Downlink data transmission rate; P ij Indicates UE i Transmit power to the UAV; represents the UAV in time slot t j and UE i The average path loss between ji Represents UAV j and UE i The transmission power; represents the UAV in time slot t j and UE i The average path loss between equal σ0 represents the power spectral density of the additive white Gaussian noise at the receiving end.

[0029] In one embodiment of the present invention, the calculation formula of the communication decision is:

[0030]

[0031] in, Indicates UE in time slot t i With UAV j The comprehensive data transfer rate, Indicates UE i With UAV j Uplink data transmission rate; Indicates UE i With UAVj The downlink data transmission rate; m represents the weight of the uplink rate, and n represents the weight of the downlink rate;

[0032] Indicates UE in time slot t i communication decisions, Indicates UE i The maximum combined data rate of all UAVs, like Indicates UE i With UAV j Establish a communication link within the communication coverage; if Indicates UE i With UAV j The communication link has not been established and the device is not within the communication coverage area.

[0033] In a second aspect, an embodiment of the present invention provides an air-to-ground hybrid communication device based on a UAV, the device comprising:

[0034] A hybrid communication architecture and channel model building module is used to design a hybrid communication architecture for a scenario containing multiple UAVs and user nodes UE, and to establish a channel model between the UAVs and the UEs; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to a plurality of sub-bandwidth division ratios matching the number of UEs;

[0035] A communication rate calculation result obtaining module, used to calculate the uplink data transmission rate and the downlink data transmission rate between the UAV and the UE in each time slot based on the hybrid communication architecture and the channel model as the communication rate calculation result of the corresponding time slot;

[0036] The communication decision calculation module is used to determine the communication decision between the UAV and the UE in each time slot based on the communication rate calculation result between the UAV and the UE to indicate whether to establish a communication connection, and realize the air-to-ground communication between the UAV and the UE in the scenario through the communication decision.

[0037] In a third aspect, an embodiment of the present invention provides a communication system, comprising a plurality of unmanned aerial vehicles (UAVs) and user nodes (UEs), wherein the communication system implements air-to-ground communication by using the UAV-based air-to-ground hybrid communication method described in the first aspect.

[0038] Beneficial effects of the present invention:

[0039] In the solution provided by the embodiment of the present invention, a hybrid communication architecture is proposed based on the TDD technology and the FDMA technology, wherein each time slot is divided into uplink and downlink transmission stages based on the TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on the FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to a plurality of sub-bandwidth division ratios matching the number of UEs; the present invention simultaneously considers the parameter configuration of the time domain and the frequency domain, which is more comprehensive than the existing solutions, and can provide new ideas for the optimization goals such as the total system throughput and the number of UAV deployments in the later stage under the premise of achieving full coverage of ground nodes of UAV network communication, and provides a new solution for ground node access of UAV-assisted communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic flow chart of a UAV-based air-to-ground hybrid communication method provided in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a scenario including multiple unmanned aerial vehicles (UAVs) and user nodes (UEs) according to an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the structure of a hybrid communication architecture provided by an embodiment of the present invention;

[0043] Figure 4 A schematic structural diagram of a UAV-based air-to-ground hybrid communication device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0045] In order to simultaneously consider the influencing factors in the time domain and frequency domain for optimization and achieve the purpose of optimizing communication performance, the embodiment of the present invention provides an air-to-ground hybrid communication method and device based on UAV, and further provides a communication system that can be used in the field of social public safety, such as emergency communications.

[0046] It should be noted that the execution subject of the UAV-based air-to-ground hybrid communication method provided in the embodiment of the present invention may be a UAV-based air-to-ground hybrid communication device, which may be run in an electronic device. The electronic device may be a server, a cloud server, a drone edge computing device, etc. in a backend control center, but is certainly not limited thereto.

[0047] In a first aspect, an embodiment of the present invention provides an air-to-ground hybrid communication method based on a UAV, such as Figure 1 As shown, the method may include the following steps:

[0048] S1, for the scenario with multiple UAVs and user nodes UE, a hybrid communication architecture is designed, and a channel model between UAVs and UEs is established; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to multiple sub-bandwidth division ratios matching the number of UEs;

[0049] Figure 2 is a schematic diagram of a scenario containing multiple UAVs and user nodes UE; in the scenario, J UAVs are deployed above the ground, the purpose is to use UAVs as air base stations to quickly restore communication, and J UAVs are represented as There is one UE deployed on the ground, and the UE may be a communication device of a user in a disaster area. One UE is represented as

[0050] For the above scenario, the hybrid communication architecture designed is referred to as HybridComm. It is divided into two layers. The upper layer adopts TDD technology to achieve full-duplex communication; the lower layer adopts FDMA to achieve multiple access to multiple nodes on the ground. For this hybrid communication architecture, please refer to Figure 3 Understanding, which specifically includes:

[0051] The communication cycle of the UAV in the scenario is divided into T equal time periods, expressed as Each time period is a time slot, represented by duration τ, and τ is small enough;

[0052] In order to realize the full-duplex communication function, each time slot t is divided into uplink and downlink transmission phases based on TDD technology. The transmission duration of the uplink transmission phase and the downlink transmission phase is divided according to the uplink-downlink ratio k, and the value of k is between 0 and 1. The specific value of k can be set as needed, and can be a fixed value predetermined by a large amount of data, or a value that is continuously adjusted according to the change of communication time slot demand, and there is no restriction here. kτ represents the transmission duration of the uplink transmission phase in a time slot, and (1-k)τ represents the transmission duration of the downlink transmission phase in the same time slot.

[0053] In order to realize the ground multi-node multiple access function, the embodiment of the present invention realizes simultaneous communication of multiple users by dividing the available spectrum into multiple independent frequency channels. Each user is assigned a fixed frequency bandwidth, which can be used continuously during the call to ensure that the signals between different users do not interfere with each other. FDMA supports parallel communication, allowing multiple users to transmit data at the same time, and can reuse the same frequency in different geographical areas to improve spectrum utilization. Specifically, in each time slot t, the total frequency bandwidth of the system is divided into the sub-frequency bandwidth of each UE according to the ratio of I sub-bandwidths; w is used to represent the size of the total frequency bandwidth of the system, and the sub-frequency bandwidth of I UE divided is expressed as a i is the sub-bandwidth allocation ratio of the i-th UE, and the value range is between 0 and 1. The sum of all sub-bandwidth allocation ratios is 1. Similarly, the specific values ​​of these sub-bandwidth allocation ratios can also be set as needed and are not limited here.

[0054] In the embodiment of the present invention, a designed hybrid communication architecture is adopted, and the uplink and downlink ratios and the sub-bandwidth division ratios are considered simultaneously as time domain and frequency domain influencing factors respectively. Through the configuration of these two parameters, the performance and efficiency of UAV communication can be improved, providing new possibilities for the optimization of the integrated space-ground communication system.

[0055] In the embodiment of the present invention, the corresponding communication system can be transmitted on an air-to-ground (A2G) channel in a relatively open area with a limited number of buildings and vegetation. Therefore, the channel model covers both line-of-sight and non-line-of-sight types.

[0056] In an optional implementation manner, the process of establishing a channel model between the UAV and the UE includes:

[0057] ① Determine the UAV in time slot t j and UE i The line-of-sight connection probability and the non-line-of-sight connection probability are expressed as:

[0058]

[0059] Among them, LoS and NLoS represent line-of-sight and non-line-of-sight respectively; UAV j represents the jth UAV; UE i represents the i-th UE; represents the UAV in time slot t j and UE i The probability of line-of-sight connection between represents the UAV in time slot t j and UE i The probability of non-line-of-sight connection between α and β; α and β are environmental constants; represents the UAV in time slot tj and UE i The elevation angle between

[0060] ② Determine the UAV in time slot t j and UE i The average LoS path loss and the average NLoS path loss between are expressed as:

[0061]

[0062] in, and They represent the UAVs in time slot t. j and UE i The average LoS path loss and the average NLoS path loss between them; f represents the UAV j and UE i The channel transmission frequency, in Hz; represents the UAV in time slot t j and UE i The distance between them; c represents the speed of light; η LoS and η NLoS They represent the additional loss on the LoS path and the additional loss on the NLoS path respectively;

[0063] ③According to the UAV in time slot t j and UE i The probability of line-of-sight connection and non-line-of-sight connection between UAVs in time slot t j and UE i The average LoS path loss and the average NLoS path loss between them are used to determine the UAV j and UE i The average path loss between is expressed as:

[0064]

[0065] in, is the UAV in time slot t j and UE i The average path loss between is used to characterize the channel status.

[0066] S2, based on the hybrid communication architecture and the channel model, calculating an uplink data transmission rate and a downlink data transmission rate between the UAV and the UE in each time slot as a communication rate calculation result of the corresponding time slot;

[0067] The formula for calculating the uplink data transmission rate between the UAV and the UE in each time slot is:

[0068]

[0069] The formula for calculating the downlink data transmission rate between the UAV and the UE in each time slot is:

[0070]

[0071] in, is the UAV in time slot t j and UE i Uplink data transmission rate; is the UAV in time slot t j and UE i Downlink data transmission rate; P ij Indicates UE i Transmit power to the UAV; represents the UAV in time slot t j and UE i The average path loss between ji Represents UAV j and UE i The transmission power; represents the UAV in time slot t j and UE i The average path loss between equal σ0 represents the power spectral density of the additive white Gaussian noise at the receiving end.

[0072] In each time slot, the uplink data transmission rate and the downlink data transmission rate between the UAV and the UE are calculated as the communication rate of the corresponding time slot.

[0073] S3, in each time slot, based on the communication rate calculation result between the UAV and the UE, determine the communication decision between the UAV and the UE to indicate whether to establish a communication connection, and realize the air-to-ground communication between the UAV and the UE in the scenario through the communication decision.

[0074] The embodiment of the present invention constructs a communication link establishment rule by determining the communication decision between the UAV and the UE in each time slot.

[0075] The calculation formula of the communication decision is:

[0076]

[0077] in, Indicates UE in time slot t i With UAV j The comprehensive data transfer rate, Indicates UE i With UAV j Uplink data transmission rate; Indicates UE iWith UAV j The downlink data transmission rate; m represents the weight of the uplink rate, and n represents the weight of the downlink rate; the value range of m and n is between 0 and 1, and the specific values ​​of m and n can be adjusted according to the user's situation. For example, if the user thinks that the uplink is more important, m>n can be configured.

[0078] Indicates UE in time slot t i communication decisions, Indicates UE i The maximum value of the combined data transmission rate with all UAVs is like Indicates UE i With UAV j Establish a communication link within the communication coverage; if Indicates UE i With UAV j The communication link has not been established and the device is not within the communication coverage area.

[0079] Through the calculation of the above communication decision, it can be determined in each time slot whether the UAV and the UE are connected or not, thereby realizing air-to-ground communication.

[0080] In the solution provided by the embodiment of the present invention, a hybrid communication architecture is proposed based on the TDD technology and the FDMA technology, wherein each time slot is divided into uplink and downlink transmission stages based on the TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on the FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to a plurality of sub-bandwidth division ratios matching the number of UEs; the present invention simultaneously considers the parameter configuration of the time domain and the frequency domain, which is more comprehensive than the existing solutions, and can provide new ideas for the optimization goals such as the total system throughput and the number of UAV deployments in the later stage under the premise of achieving full coverage of ground nodes of UAV network communication, and provides a new solution for ground node access of UAV-assisted communication.

[0081] In a second aspect, corresponding to the above method embodiment, the embodiment of the present invention further provides an air-to-ground hybrid communication device based on a UAV, such as Figure 4 As shown, the device comprises:

[0082] A hybrid communication architecture and channel model building module is used to design a hybrid communication architecture for a scenario containing multiple UAVs and user nodes UE, and to establish a channel model between the UAVs and the UEs; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to a plurality of sub-bandwidth division ratios matching the number of UEs;

[0083] A communication rate calculation result obtaining module, used to calculate the uplink data transmission rate and the downlink data transmission rate between the UAV and the UE in each time slot based on the hybrid communication architecture and the channel model as the communication rate calculation result of the corresponding time slot;

[0084] The communication decision calculation module is used to determine the communication decision between the UAV and the UE in each time slot based on the communication rate calculation result between the UAV and the UE to indicate whether to establish a communication connection, and realize the air-to-ground communication between the UAV and the UE in the scenario through the communication decision.

[0085] For the specific processing process of each module of the device, please refer to the relevant content of the first aspect and will not be repeated here.

[0086] In a third aspect, an embodiment of the present invention further provides a communication system, comprising a plurality of unmanned aerial vehicles (UAVs) and user nodes (UEs), wherein the communication system implements air-to-ground communication by using the UAV-based air-to-ground hybrid communication method described in the first aspect.

[0087] The system can be found in Figure 2 Please refer to the relevant content of the first aspect for the specific communication method, which will not be elaborated here.

[0088] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0089] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A UAV-based air-to-ground hybrid communication method, characterized in that: include: For scenarios with multiple UAVs and user nodes UE, a hybrid communication architecture is designed, and a channel model between UAVs and UEs is established; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to multiple sub-bandwidth division ratios matching the number of UEs; Based on the hybrid communication architecture and the channel model, calculating an uplink data transmission rate and a downlink data transmission rate between the UAV and the UE in each time slot as a communication rate calculation result of the corresponding time slot; In each time slot, based on the calculation result of the communication rate between the UAV and the UE, a communication decision between the UAV and the UE is determined to indicate whether a communication connection is to be established, and the air-to-ground communication between the UAV and the UE in the scenario is achieved through the communication decision.

2. The UAV-based air-to-ground hybrid communication method according to claim 1, characterized in that: In the scenario, there are J UAVs deployed above the ground, represented as There are I UEs deployed on the ground, represented by For the above scenario, the designed hybrid communication architecture includes: The communication cycle of the UAV in the scenario is divided into T equal time periods, expressed as Each time period is a time slot, which is represented by duration τ, and τ is small enough; each time slot t is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration of the uplink transmission phase and the downlink transmission phase is divided according to the uplink and downlink ratio k, and the value of k is between 0 and 1; kτ represents the transmission duration of the uplink transmission phase in a time slot, and (1-k)τ represents the transmission duration of the downlink transmission phase in the same time slot; in each time slot t, the total frequency bandwidth of the system is divided into the sub-frequency bandwidth of each UE according to the I sub-bandwidth division ratio; w is used to represent the size of the total frequency bandwidth of the system, and the divided sub-frequency bandwidth of I UE is expressed as a i is the sub-bandwidth allocation ratio of the i-th UE.

3. The UAV-based air-to-ground hybrid communication method according to claim 2, characterized in that: The channel model covers two types: line-of-sight and non-line-of-sight.

4. The UAV-based air-to-ground hybrid communication method according to claim 3, characterized in that: The process of establishing the channel model between the UAV and the UE includes: Determine the UAV in time slot t j and UE i The line-of-sight connection probability and the non-line-of-sight connection probability are expressed as: Among them, LoS and NLoS represent line-of-sight and non-line-of-sight respectively; UAV j represents the jth UAV; UE i represents the i-th UE; represents the UAV in time slot t j and UE i The probability of line-of-sight connection between represents the UAV in time slot t j and UE i The probability of non-line-of-sight connection between α and β; α and β are environmental constants; represents the UAV in time slot t j and UE i The elevation angle between Determine the UAV in time slot t j and UE i The average LoS path loss and the average NLoS path loss between are expressed as: in, and They represent the UAVs in time slot t respectively. j and UE i The average LoS path loss and the average NLoS path loss between them; f represents the UAV j and UE i The channel transmission frequency, in Hz; represents the UAV in time slot t j and UE i The distance between them; c represents the speed of light; η LoS and η NLoS They represent the additional loss on the LoS path and the additional loss on the NLoS path respectively; According to the UAV in time slot t j and UE i The probability of line-of-sight connection and non-line-of-sight connection between UAVs in time slot t j and UE i The average LoS path loss and the average NLoS path loss between them are used to determine the UAV j and UE i The average path loss between is expressed as: in, is the UAV in time slot t j and UE i The average path loss between is used to characterize the channel status.

5. The UAV-based air-to-ground hybrid communication method according to claim 4, characterized in that: The formula for calculating the uplink data transmission rate between the UAV and the UE in each time slot is: The formula for calculating the downlink data transmission rate between the UAV and the UE in each time slot is: in, is the UAV in time slot t j and UE i Uplink data transmission rate; is the UAV in time slot t j and UE i Downlink data transmission rate; P ij Indicates UE i Transmit power to the UAV; represents the UAV in time slot t j and UE i The average path loss between ji Represents UAV j and UE i The transmission power; represents the UAV in time slot t j and UE i The average path loss between equal σ0 represents the power spectral density of the additive white Gaussian noise at the receiving end.

6. The UAV-based air-to-ground hybrid communication method according to claim 5, characterized in that: The calculation formula of the communication decision is: in, Indicates UE in time slot t i With UAV j The comprehensive data transfer rate, Indicates UE i With UAV j Uplink data transmission rate; Indicates UE i With UAV j The downlink data transmission rate; m represents the weight of the uplink rate, and n represents the weight of the downlink rate; Indicates UE in time slot t i communication decisions, Indicates UE i The maximum combined data rate of all UAVs, like Indicates UE i With UAV j Establish a communication link within the communication coverage; if Indicates UE i With UAV j The communication link has not been established and the device is not within the communication coverage area.

7. A UAV-based air-to-ground hybrid communication device, characterized in that: include: A hybrid communication architecture and channel model building module is used to design a hybrid communication architecture for a scenario containing multiple UAVs and user nodes UE, and to establish a channel model between the UAVs and the UEs; wherein, in the hybrid communication architecture, each time slot is divided into uplink and downlink transmission phases based on TDD technology, and the transmission duration is divided according to the uplink and downlink ratio; based on FDMA technology, the total frequency bandwidth of the system in each time slot is divided into sub-frequency bandwidths of each UE according to a plurality of sub-bandwidth division ratios matching the number of UEs; A communication rate calculation result obtaining module, used to calculate the uplink data transmission rate and the downlink data transmission rate between the UAV and the UE in each time slot based on the hybrid communication architecture and the channel model as the communication rate calculation result of the corresponding time slot; The communication decision calculation module is used to determine the communication decision between the UAV and the UE in each time slot based on the communication rate calculation result between the UAV and the UE to indicate whether to establish a communication connection, and realize the air-to-ground communication between the UAV and the UE in the scenario through the communication decision.

8. A communication system, characterized in that: The communication system comprises a plurality of unmanned aerial vehicles (UAVs) and user nodes (UEs), and the communication system adopts the UAV-based air-to-ground hybrid communication method as described in any one of claims 1 to 6 to realize air-to-ground communication.

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