UAV relay communication technology is a kind of use of drones as relay nodes to improveWireless communicationSystem coverage and data transmissionperformancetechnology. The specific implementation methods and performance are as follows:
1. Specific implementation method
(1). Reconstructible Intelligent Ground (RIS) assisted UAV relay communication:
In such a system, RIS is installed on a drone and can be moved at high speed. Compared with traditional static RIS, this mobile RIS can provide better performance and greater flexibility. Maximize average throughput by jointly optimizing drone trajectory, RIS passive beamforming, and source power allocation per time slot.
(2). Multi-hop relay communication:
UAV relay forwards to target nodes in a multi-hop manner, achieving end-to-end throughput maximization through combined drone trajectory and transmission power optimization. This study assumes that full-duplex communication method is adopted.
(3). Short-wave radio technology:
Short-wave radios operate in the short-wave frequency band, which is sensitive to ionosphere reflection and can achieve longer-distance communication. Therefore, in the UAV communication relay, selecting a suitable short-wave frequency band can effectively improve the stability and distance of the communication.
(4).TPUNB andLoRaWireless communication technology:
The system adopts low-power and long-distance transmission TPUNB or LoRa wireless communication technology as a wake-up strategy, and can send device wake-up commands within 2.5km of the drone's arrival in the environmental monitoring area to achieve remote wake-up of high-power devices.
(5). Tied drone ad hoc network technology:
The tethered drone is connected to the ground station through cables, providing the drone with continuous and stable power supply and high-speed data transmission capabilities. This connection method allows the drone to not carry a large amount of batteries, which greatly reduces the weight of the fuselage and extends the drone's flight time.
2. Performance
(1). Maximize throughput:
By jointly optimizing drone trajectory, RIS passive beamforming, and source power allocation for each time slot, the average throughput of the system can be significantly improved.
The multi-hop relay communication system maximizes the minimum throughput of all ground users in downlink communication by optimizing multi-user communication scheduling and jointly optimizing drone trajectory and power control.
(2). InterruptPerformance Analysis：
Analysis of the performance of multi-UAV relay transmission interruption based on threshold judgment DF protocol shows that the relay cooperative transmission system is established when considering path lossModelIt can effectively reduce the probability of interruption.
The interrupt performance of the dual-hop drone relay communication system is close to the optimal choice, which shows that in the multi-hop relay communication network, a reasonable relay selection algorithm can significantly improve the reliability of the system.
(3). Application of ad hoc network technology:
Ad-hoc network is a wireless communication network that can be independently connected without relying on fixed infrastructure. Its characteristics include self-discovery, automatic configuration, self-organization and self-healing, etc. These characteristics make the drone relay communication system more flexible and efficient in data transmission.
5. Application and risk analysis of drones for communication through satellites.
UAVs communicate through satellites can provide a wider communication coverage and higher communication reliability, suitable for the following scenarios:
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Remote Regional Communication: UAVs can communicate through satellites to achieve communication needs in remote regions, such as oceans, deserts, mountains, etc.
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Disaster Rescue Communications: In the event of a disaster, ground communication facilities may be damaged, and drones communicate through satellites can provide communication services for rescue personnel and affected people.
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Military communication: UAVs can provide military communication services through satellites to achieve long-range combat command and intelligence collection requirements.
However, drones communicate through satellites also have the following risks:
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Communication delay problem: Since signals need to be transmitted through satellites, there may be a certain delay in communication between drones through satellites, which affects the real-time nature of communication.
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Satellite signal interference problem: Satellite signal may be affected by weather, terrain and other factors, resulting in interference and interruption of communication signals.
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Communication security issues: There may be security risks when drones communicate through satellites, such as signals being eavesdropped, data being tampered with, etc.
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Cost issue: UAVs need to use satellite communication equipment for communication through satellites, which is relatively expensive and may increase the cost of use.
Therefore, when using drones to communicate through satellites, risks need to be fully evaluated and managed, and corresponding measures should be taken to prevent and control risks.
The application of drones in complex environments through satellite communication technology has achieved some successful cases, such as emergency communication and data transmission and control. However, physical layer operation problems, transmission delay and cost,System integrationOptimization and the application of emerging technologies are still the main challenges that need to be overcome.