An unmanned aerial vehicle communication network intelligent cooperative switching system for suppressing multi-station interference

Abstract

The application discloses an unmanned aerial vehicle communication network intelligent cooperative switching system for suppressing multi-station interference, and belongs to the technical field of wireless communication networks.The technical problem to be solved by the application is how to actively avoid or reduce the same-frequency interference of unmanned aerial vehicles when communicating in the overlapping area of multiple ground stations, realize stable and efficient seamless switching, and improve the spectrum utilization and communication reliability of the whole network.The technical scheme adopted is as follows: the system comprises a synchronous ground station group, a network cooperative controller and an intelligent unmanned aerial vehicle terminal.The synchronous ground station group is the infrastructure of the communication network formed by multiple ground stations with time synchronization function, and each ground station has interference measurement and reporting functions.The network cooperative controller is used for acquiring global information including the position information of the intelligent unmanned aerial vehicle terminal and the network information of the subnetwork where the intelligent unmanned aerial vehicle terminal is located in real time, and constructing a network topology connection graph by using the global information, and dynamically constructing and maintaining a network interference relationship graph.

Description

Technical Field

[0001] This invention relates to the field of wireless communication network technology, specifically to an intelligent collaborative handover system for UAV communication networks used to suppress multi-station interference. Background Technology

[0002] To extend the operational range of drones, multiple ground stations are typically deployed to form a communication network. When drones fly in areas where the coverage of multiple ground stations overlaps, they face severe co-channel interference problems, specifically as follows: ① Downlink interference: The UAV receives signals from multiple ground stations at the same time, and these signals interfere with each other, resulting in a decrease in signal-to-interference-plus-noise ratio (SINR) and a deterioration in communication quality.

[0003] ② Uplink interference: The uplink signal of the UAV can be received by multiple ground stations. If these ground stations lack coordination, they will interfere with each other during demodulation.

[0004] ③ Disadvantages of traditional handover: In areas with severe interference, due to the similar strength and drastic fluctuations of multiple signals, handover algorithms based on fixed thresholds are prone to the "ping-pong effect" (frequent handover between multiple ground stations). This not only fails to alleviate interference but also exacerbates network burden and communication instability due to frequent signaling interactions.

[0005] ④ Resource conflict: Multiple drones may simultaneously attempt to switch to the same ground station that "seems to be the best" but is actually overloaded or heavily interfered with, causing resource contention and system performance degradation.

[0006] Existing technologies lack the ability to perceive and proactively coordinate the overall network interference situation, and cannot fundamentally solve the problem of co-channel interference in areas with overlapping coverage of multiple ground stations, thus hindering the development of high-density, high-reliability UAV networks.

[0007] Therefore, how to proactively avoid or mitigate co-channel interference when UAVs communicate in overlapping areas of multiple ground stations, achieve stable and efficient seamless switching, and improve the spectrum utilization and communication reliability of the entire network are technical problems that urgently need to be solved. Summary of the Invention

[0008] The technical objective of this invention is to provide an intelligent collaborative switching system for UAV communication networks to suppress multi-station interference, thereby addressing the problem of how to proactively avoid or mitigate co-channel interference when UAVs communicate in overlapping areas of multiple ground stations, achieve stable and efficient seamless switching, and improve the spectrum utilization and communication reliability of the entire network.

[0009] The technical objective of this invention is achieved as follows: an intelligent cooperative handover system for suppressing multi-station interference in a drone communication network, comprising a synchronous ground station group, a network cooperative controller, and an intelligent drone terminal. A synchronous ground station cluster is the infrastructure of a communication network consisting of multiple ground stations with time synchronization capabilities. Each ground station has interference measurement and reporting capabilities. The network cooperative controller acquires global information in real time, including the location information of the intelligent UAV terminal and the network information of the subnet in which the intelligent UAV terminal is located. It uses the global information to construct a network topology connection map and dynamically constructs and maintains a network interference relationship map. The network topology connection map serves as one of the criteria for guiding the intelligent UAV terminal to switch between ground stations. By planning flight routes and the ground station network connection map, it avoids ping-pong switching of the intelligent UAV terminal in the direction of travel. The network interference relationship map is constructed based on the geographical location, transmission power, terrain data, and real-time measured uplink interference noise level of the ground stations, using the signal-to-interference ratio (SIR) as the quantitative indicator of the interference map. The network cooperative controller collects the SIR reported by the intelligent UAV terminal and allocates resources in the time domain of each subnet according to the criterion of minimizing the overall network SIR, and provides flight path suggestions for the intelligent UAV terminal. Intelligent unmanned aerial vehicle (UAV) terminals refer to UAVs that possess multi-signal measurement, interference detection, and protocol execution capabilities.

[0010] As a preferred method, when the intelligent drone terminal connects to the ground station, the SINR is calculated using the following formula: ; in, This represents the signal-to-interference ratio (SIR) of ground station k. This represents the transmission power of ground station k; These represent the gains of the transmitting antenna of ground station k and the receiving antenna of the UAV, respectively. This represents the path loss of the service link (for UAV communication, path loss typically includes distance-determined path loss and fading-determined loss). This represents the small-scale fading power gain of the service link; N is the total number of working nodes (including ground stations and UAVs) in the same frequency link; This indicates the transmit power of ground station i; These represent the gains of the transmitting antenna of ground station i and the receiving antenna of the UAV, respectively. This represents the path loss of the i-th link; The term represents the small-scale fading power gain of the i-th link (in a wireless channel, due to signal reflections from different paths, the superposition of signals results in variations in signal amplitude due to different phases; this is called small-scale fading, and the amplitude variation corresponds to the change in signal power); noise term. This represents the receiver's additive white Gaussian noise power. ; Represents the Boltzmann constant; B represents absolute temperature; B represents system bandwidth. This represents the receiver noise figure.

[0011] Ideally, the information broadcast by the ground station is expanded to include "neighbor and interference situation information," which, in addition to the neighbor list, also includes the following: The current interference / noise level of this ground station's channel / time slot; The handover threshold offset values ​​recommended by this ground station and applicable to overlapping areas; wherein, the handover threshold offset values ​​are calculated and distributed by the network co-controller to suppress ping-pong handover; The intelligent drone terminal continuously measures the signal strength (RSSI) of each ground station and simultaneously listens to the broadcast information of each ground station to obtain the target of the broadcast information and to initially perceive the interference level of the current area. The neighbor list is a list used to record and present information about all subnets that have direct neighbors or relationships; a neighbor refers to any two subnets whose central nodes have an edge when the network topology connection graph is constructed. Even better, when the intelligent drone terminal is in flight, based on its own position, flight path and network interference relationship diagram, when it predicts that it is about to enter a known strong interference overlap area or when the measured SINR (calculated by combining the main service signal and the strongest interference signal) begins to deteriorate, it actively sends a pre-handover and interference report to the network cooperative controller. The pre-switching and interference report includes a list of candidate ground stations (signal strength > detection threshold), the measured signal-to-interference ratio of each candidate ground station, and the current location and flight path of the intelligent UAV terminal.

[0012] More preferably, after receiving the pre-handover and interference reports, the network coordination controller executes a globally optimized interference coordination algorithm to make a decision, as follows: Communication ground station list creation / update: Based on the current location and flight path of the intelligent drone terminal, query the network topology connection map to determine the optional switching ground stations in the flight direction of the intelligent drone terminal; Candidate station interference assessment: Examine the signal strength of the candidate ground stations themselves and assess the impact of selecting the appropriate ground station on the overall network interference. Interference to the intelligent drone terminal itself: After selecting the corresponding ground station, use the network interference graph relationship to predict which other ground stations will interfere with the intelligent drone terminal; Interference with the network: After the intelligent drone terminal connects to the corresponding ground station, how much interference will the uplink signal of the intelligent drone terminal cause to other ground stations that are communicating? Target ground station selection: Selecting a ground station that minimizes global signal power after the intelligent drone terminal switches means not choosing the one with the best signal quality, but choosing the one with the lowest total transmission power after the switch, thereby minimizing the system's interference power and providing the drone with a longer loiter time.

[0013] More preferably, the optimization problem in the target ground station selection process is achieved through modeling, and the modeling method is as follows: satisfy ; in, The signal-to-interference ratio threshold must be met for normal operation.

[0014] Ideally, the network coordinating controller also needs to allocate resources, specifically by assigning dedicated channels, time slots, or codewords to the ground stations for the intelligent UAV terminal to further isolate interference, and sending adjusted switching parameters (such as hysteresis, trigger time, etc.) to the relevant ground stations and intelligent UAV terminals to stabilize the switching behavior.

[0015] Ideally, the network coordination controller sends the handover decision to the intelligent drone terminal, the target ground station, and neighboring ground stations that may cause interference. The neighboring ground stations perform power control or silent scheduling at the moment of handover to create an "interference-free window" for the target handover. The intelligent drone terminal quickly completes the handover on the designated resources, thereby smoothly transitioning to a network connection point with better interference.

[0016] The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks of the present invention has the following advantages: (i) In view of the problem of co-channel interference between different subnets when the self-organizing network is networked in the same frequency, this invention proposes to reduce the problem of co-channel interference between subnets of the self-organizing network in the same frequency by using a handover coordination strategy based on the optimization of the network-wide SIR and a prediction strategy based on the location of the handover destination base station. (ii) This invention employs interference coordination and link management technology in UAV mobile communication, particularly a method that suppresses co-channel interference and ensures UAV communication quality through coordinated scheduling and predictive handover in scenarios with dense deployment of multiple ground stations (GS). (iii) This invention actively avoids or reduces co-channel interference when UAVs communicate in overlapping areas of multiple ground stations through centralized network intelligent collaboration and predictive link management, thereby achieving stable and efficient seamless switching and improving the spectrum utilization and communication reliability of the entire network. (iv) This invention changes the approach from "switching after interference occurs" to "predicting and avoiding interference", which fundamentally reduces the degradation of UAV communication performance in overlapping areas and achieves active interference suppression; (v) The switching decision of the present invention is based on the consideration of minimizing global interference, realizing network-level interference coordination and optimizing the overall network capacity, rather than the local optimization of a single link, so as to achieve the goal of global interference optimization. (vi) This invention effectively avoids frequent switching caused by signal fluctuations and suppresses the ping-pong effect by centrally controlling, dynamically adjusting switching parameters, and planning flight paths using the real-time location of the UAV, combined with the network topology map to select a more stable access point. Attached Figure Description

[0017] The invention will be further described below with reference to the accompanying drawings.

[0018] Appendix Figure 1 This is a schematic diagram of an intelligent collaborative handover system for UAV communication networks used to suppress multi-station interference. Detailed Implementation

[0019] The following detailed description of an intelligent collaborative switching system for suppressing multi-station interference in a drone communication network, based on the accompanying drawings and specific embodiments, is provided in reference to the present invention.

[0020] Example: As attached Figure 1 As shown, this embodiment provides an intelligent collaborative handover system for UAV communication networks to suppress multi-station interference. The system includes a synchronous ground station group, a network collaborative controller, and an intelligent UAV terminal. A synchronous ground station cluster is the infrastructure of a communication network consisting of multiple ground stations with time synchronization capabilities. Each ground station has interference measurement and reporting capabilities. The network cooperative controller acquires global information in real time, including the location information of the intelligent UAV terminal and the network information of the subnet in which the intelligent UAV terminal is located. It uses the global information to construct a network topology connection map and dynamically constructs and maintains a network interference relationship map. The network topology connection map serves as one of the criteria for guiding the intelligent UAV terminal to switch between ground stations. By planning flight routes and the ground station network connection map, it avoids ping-pong switching of the intelligent UAV terminal in the direction of travel. The network interference relationship map is constructed based on the geographical location, transmission power, terrain data, and real-time measured uplink interference noise level of the ground stations, using the signal-to-interference ratio (SIR) as the quantitative indicator of the interference map. The network cooperative controller collects the SIR reported by the intelligent UAV terminal and allocates resources in the time domain of each subnet according to the criterion of minimizing the overall network SIR, and provides flight path suggestions for the intelligent UAV terminal. Intelligent unmanned aerial vehicle (UAV) terminals refer to UAVs that possess multi-signal measurement, interference detection, and protocol execution capabilities.

[0021] The working process of this system is as follows: S1. Network Synchronization and Interference Map Construction: All ground stations synchronize their times. The network cooperative controller not only constructs a network topology connection map, but more importantly, dynamically constructs and maintains a "network interference relationship map." The network topology connection map can serve as one of the criteria for guiding UAVs to switch between ground stations, avoiding ping-pong switching of the UAV in the direction of travel by using planned flight routes and the ground station network topology map. Interference map construction is based on: the geographical location, transmit power, and terrain data of the ground stations, as well as the uplink interference noise level measured in real time (the interference intensity reported by each station in its receiving frequency band), with the signal-to-interference ratio (SIR) used as the quantitative indicator of the interference map.

[0022] When a smart drone terminal connects to a ground station, the SINR is calculated using the following formula: ; in, This represents the signal-to-interference ratio (SIR) of ground station k (the SIR is the ratio of signal to interference; this value is used to measure signal quality, and the larger the value, the better the signal quality). This represents the transmission power of ground station k; These represent the gains of the transmitting antenna of ground station k and the receiving antenna of the UAV, respectively. This represents the path loss of the service link (for UAV communication, path loss typically includes distance-determined path loss and fading-determined loss). This represents the small-scale fading power gain of the service link; N is the total number of working nodes (including ground stations and UAVs) in the same frequency link; This indicates the transmit power of ground station i; These represent the gains of the transmitting antenna of ground station i and the receiving antenna of the UAV, respectively. This represents the path loss of the i-th link; The term represents the small-scale fading power gain of the i-th link (in a wireless channel, due to signal reflections from different paths, the superposition of signals results in variations in signal amplitude due to different phases; this is called small-scale fading, and the amplitude variation corresponds to the change in signal power); noise term. This represents the receiver's additive white Gaussian noise power. ; Represents the Boltzmann constant; B represents absolute temperature; B represents system bandwidth. This represents the receiver noise figure.

[0023] S2. Jamming Situation Broadcast and UAV Sensing: The information broadcast by the ground station is expanded to "neighbor and jamming situation information," which, in addition to the neighbor list, also includes the following: ① Interference and noise levels of the current channel / time slot at the local ground station; ② The handover threshold offset value recommended by the local ground station and applicable to the overlapping area; wherein, the handover threshold offset value is calculated and issued by the network co-controller to suppress ping-pong handover; ③ The intelligent UAV terminal continuously measures the signal strength (RSSI) of each ground station and simultaneously listens to the broadcast information of each ground station to obtain the target of the broadcast information reception and to initially perceive the interference level of the current area; The neighbor list is a list used to record and present information about all subnets that have direct neighbors or relationships. A neighbor is a node that exists between the central nodes of any two subnets when the network topology connection graph is constructed. The central node broadcasts system information through a broadcast channel, sending it periodically without needing to receive confirmation.

[0024] S3. Predictive handover triggering and interference reporting: When the intelligent drone terminal is in flight, based on its own position, flight path and network interference relationship diagram, when it predicts that it is about to enter a known strong interference overlap area or when the measured SINR (calculated by combining the main service signal and the strongest interference signal) begins to degrade, it will actively send a pre-handover and interference report to the network cooperative controller. The pre-switching and interference report includes a list of candidate ground stations (signal strength > detection threshold), the measured signal-to-interference ratio of each candidate ground station, and the current location and flight path of the intelligent UAV terminal.

[0025] S4. Centralized handover decision based on interference coordination: After receiving the pre-handover and interference reports, the network cooperative controller executes a globally optimized interference coordination algorithm to make a decision, as follows: S401, Communication Ground Station Linked List Establishment / Update: Based on the current location and flight path of the intelligent UAV terminal, query the network topology connection diagram to determine the optional switching ground stations in the flight direction of the intelligent UAV terminal; S402. Candidate Ground Station Interference Assessment: Examine the signal strength of the candidate ground stations themselves and assess the impact of selecting the appropriate ground station on the overall network interference. ① Interference with the intelligent drone terminal itself: After selecting the corresponding ground station, use the network interference graph relationship to predict which other ground stations will interfere with the intelligent drone terminal; ② Interference with the network: After the intelligent drone terminal connects to the corresponding ground station, how much interference will the uplink signal of the intelligent drone terminal cause to other ground stations that are communicating? S403. Target Ground Station Selection: Selecting the ground station that minimizes global signal power after the intelligent UAV terminal handover means not choosing the one with the best signal quality, but rather the one that minimizes the system's total transmit power after the handover, thereby minimizing system interference power and providing the UAV with a longer loiter time. The optimization problem in the target ground station selection process is achieved through modeling. The modeling method is: to make... satisfy ; in, The signal-to-interference ratio threshold must be met for normal operation.

[0026] Meanwhile, the network coordinating controller also needs to allocate resources, specifically: assigning dedicated channels, time slots or codewords to the ground stations for intelligent UAV terminals to further isolate interference, and sending adjusted switching parameters (such as hysteresis, trigger time, etc.) to relevant ground stations and intelligent UAV terminals to stabilize switching behavior.

[0027] S5. Network-assisted interference-free / low-interference handover execution: The network cooperative controller sends the handover decision to the intelligent UAV terminal, the target ground station, and adjacent ground stations that may cause interference. The adjacent ground stations perform power control or silent scheduling at the moment of handover to create an "interference-free window" for the target handover. The intelligent UAV terminal quickly completes the handover on the designated resources, thereby smoothly transitioning to a network connection point with better interference.

[0028] This embodiment dynamically selects a suitable handover communication station by minimizing the overall network signal-to-interference ratio (SIR). Simultaneously, based on location and operating threshold information, it avoids the "ping-pong effect" that easily occurs with handover algorithms based on simple fixed thresholds. The ping-pong effect occurs because the signal strength received by the UAV from the source and target central nodes changes alternately along its flight path (this is due to small-scale fading of the wireless signal, which is unavoidable), causing the UAV to switch back and forth between the source and target base stations. Since the UAV's flight path is pre-set, this information, combined with the network's central node topology diagram, allows the network platform to directly issue a handover command based on the UAV's flight path and measurement results when the UAV's measured SIR is less than the threshold (as described in the aforementioned setting method), thus avoiding repeated handovers.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A smart cooperative handover system for UAV communication networks to suppress multi-station interference, characterized in that, The system includes a synchronous ground station cluster, a network collaborative controller, and intelligent unmanned aerial vehicle (UAV) terminals; A synchronous ground station cluster is the infrastructure of a communication network consisting of multiple ground stations with time synchronization capabilities. Each ground station has interference measurement and reporting capabilities. The network cooperative controller acquires global information in real time, including the location information of the intelligent UAV terminal and the network information of the subnet in which the intelligent UAV terminal is located. It uses the global information to construct a network topology connection map and dynamically constructs and maintains a network interference relationship map. The network topology connection map serves as one of the criteria for guiding the intelligent UAV terminal to switch between ground stations. By planning flight routes and the ground station network connection map, it avoids ping-pong switching of the intelligent UAV terminal in the direction of travel. The network interference relationship map is constructed based on the geographical location, transmission power, terrain data, and real-time measured uplink interference noise level of the ground stations, using the signal-to-interference ratio (SIR) as the quantitative indicator of the interference map. The network cooperative controller collects the SIR reported by the intelligent UAV terminal and allocates resources in the time domain of each subnet according to the criterion of minimizing the overall network SIR, and provides flight path suggestions for the intelligent UAV terminal. Intelligent unmanned aerial vehicle (UAV) terminals refer to UAVs that possess multi-signal measurement, interference detection, and protocol execution capabilities.

2. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 1, characterized in that, When a smart drone terminal connects to a ground station, the SINR is calculated using the following formula: ; in, This represents the signal-to-interference ratio (SIR) of ground station k. This represents the transmission power of ground station k; These represent the gains of the transmitting antenna of ground station k and the receiving antenna of the UAV, respectively. This indicates the path loss of the service link; This represents the small-scale fading power gain of the service link; N is the total number of working nodes in the same frequency link. This indicates the transmit power of ground station i; These represent the gains of the transmitting antenna of ground station i and the receiving antenna of the UAV, respectively. This represents the path loss of the i-th link; Represents the small-scale fading power gain of the i-th link; noise term This represents the receiver's additive white Gaussian noise power. ; Represents the Boltzmann constant; B represents absolute temperature; B represents system bandwidth. This represents the receiver noise figure.

3. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 1 or 2, characterized in that, The information broadcast by the ground station has been expanded to include "neighbor and interference situation information," which, in addition to the neighbor list, also includes the following: The current interference / noise level of this ground station's channel / time slot; The handover threshold offset values ​​recommended by this ground station and applicable to overlapping areas; wherein, the handover threshold offset values ​​are calculated and distributed by the network co-controller to suppress ping-pong handover; The intelligent drone terminal continuously measures the signal capabilities of ground stations in various locations and simultaneously listens to the broadcast information of ground stations in various locations, thereby identifying the recipients of the broadcast information and initially perceiving the interference level of the current area; The neighbor list is a list used to record and present information about all subnets that have direct neighbors or relationships; a neighbor refers to any two subnets whose central nodes have an edge when the network topology connection graph is constructed.

4. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 3, characterized in that, When the intelligent drone terminal is in flight, based on its own position, flight path and network interference relationship map, when it predicts that it is about to enter a known strong interference overlap area or when the measured SINR begins to deteriorate, it will actively send a pre-handover and interference report to the network cooperative controller. The pre-switching and interference report includes a list of candidate ground stations, the measured signal and interference ratio of each candidate ground station, and the current location and flight path of the intelligent UAV terminal.

5. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 4, characterized in that, After receiving the pre-handover and interference reports, the network coordination controller executes a globally optimized interference coordination algorithm to make a decision, as follows: Communication ground station list creation / update: Based on the current location and flight path of the intelligent drone terminal, query the network topology connection map to determine the optional switching ground stations in the flight direction of the intelligent drone terminal; Candidate station interference assessment: Examine the signal strength of the candidate ground stations themselves and assess the impact of selecting the appropriate ground station on the overall network interference. Interference to the intelligent drone terminal itself: After selecting the corresponding ground station, use the network interference graph relationship to predict which other ground stations will interfere with the intelligent drone terminal; Interference with the network: After the intelligent drone terminal connects to the corresponding ground station, how much interference will the uplink signal of the intelligent drone terminal cause to other ground stations that are communicating? Target ground station selection: Select a ground station that can minimize global signal power after the intelligent drone terminal switches over.

6. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 5, characterized in that, The optimization problem in the target ground station selection process is achieved through modeling. The modeling method is as follows: satisfy ; in, The signal-to-interference ratio threshold must be met for normal operation.

7. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 6, characterized in that, The network coordination controller also needs to allocate resources, specifically: assigning dedicated channels, time slots or codewords to the ground stations for the intelligent UAV terminals to further isolate interference, and sending adjusted switching parameters to the relevant ground stations and intelligent UAV terminals to stabilize the switching behavior.

8. The intelligent cooperative handover system for suppressing multi-station interference in UAV communication networks according to claim 7, characterized in that, The network coordination controller sends the handover decision to the intelligent drone terminal, the target ground station, and neighboring ground stations that may cause interference. The neighboring ground stations perform power control or silent scheduling at the moment of handover to create an "interference-free window" for the target handover. The intelligent drone terminal quickly completes the handover on the designated resources, thereby smoothly transitioning to a network connection point with better interference.

Images