基于阈值判断的无人机辅助卫星通信系统中断性能分析

Outage Performance for UAV Assisted Satellite Cooperative Networks Based on Threshold

近年来,无人机(Unmanned Aerial Vehicle, UAV)作为一种灵活的中继平台受到了国内外学者的广泛关注。该文研究了基于阈值判断的无人机辅助卫星通信系统中断性能。具体来说,如果直传链路的信噪比(signal-to-noise ratio, SNR)大于满足要求的阈值,地面用户直接接收卫星信号。否则,卫星覆盖区域内配置多根天线的无人机作为一个中继,采用译码转发(decode-and-forward, DF)协议将接收到的信息转发给用户。在卫星-无人机链路和卫星-用户链路均服从莱斯分布,而无人机-用户链路服从瑞利分布的情况下,该文考虑了路径损耗等实际参数的影响,首先得到系统的输出SNR表达式,然后推导出系统的中断概率理论表达式。计算机仿真验证理论推导的正确性,并且定量分析了无人机天线数目以及阈值大小对系统中断性能的影响,从而为实际的系统设计和应用提供参考和依据。

In recent years,unmanned aerial vehicle(UAV)as a flexible relay platform has been widely concerned by scholars at home and abroad.This paper studies the outage performance of UAV aided satellite communication system based on threshold judgment.Specifically,if the signal-to-noise ratio(SNR)of the direct transmission link is greater than the required threshold value,the ground users directly receive the satellite signal.Otherwise,the UAV equipped with multiple antennas in the satellite coverage area serves as a relay and forwards the received information to the user using decode and forward(DF)protocol.In the case that both satellite UAV link and satellite user link follow Rician distribution,while UAV user link follows Rayleigh distribution,this paper considers the influence of path loss and other practical parameters.Firstly,the output SNR expression of the system is obtained,and then the theoretical expression of system outage probability is derived.Computer simulation verifies the correctness of the theoretical derivation,and quantitatively analyzes the impact of the number of UAV antennas and threshold size on the system outage performance,so as to provide reference and basis for the practical system design and application.