Unmanned aerial vehicle (UAV) has the advantages of large coverage and flexibility, which could be applied in disaster management to provide wireless services to the rescuers and victims. When UAVs forms an aerial mesh network, line-of-sight (LoS) air-to-air (A2A) communications have long transmission distance, which extends the coverage of multiple UAVs. However, the capacity of UAV is constrained due to the multiple hop transmissions in aerial mesh networks. In this paper, spectrum sharing between UAV enabled wireless mesh networks and ground networks is studied to improve the capacity of UAV networks. Considering two-dimensional (2D) and three-dimensional (3D) homogeneous Poisson point process (PPP) modeling for the distribution of UAVs within a vertical range {\Delta}h, stochastic geometry is applied to analyze the impact of the height of UAVs, the transmit power of UAVs, the density of UAVs and the vertical range, etc., on the coverage probability of ground network user and UAV network user. Besides, performance improvement of spectrum sharing with directional antenna is verified. With the object function of maximizing the transmission capacity, the optimal altitude of UAVs is obtained. This paper provides a theoretical guideline for the spectrum sharing of UAV enabled wireless mesh networks, which may contribute significant value to the study of spectrum sharing mechanisms for UAV enabled wireless mesh networks.

翻译：无人机具有覆盖范围广、灵活性高等优势，可应用于灾难管理场景，为救援人员和受灾群众提供无线服务。当无人机组成空中Mesh网络时，视距空对空通信具有远距离传输特性，从而扩展了多架无人机的覆盖范围。然而，空中Mesh网络中的多跳传输限制了无人机的容量。本文研究了无人机赋能无线Mesh网络与地面网络间的频谱共享问题，旨在提升无人机网络的容量。考虑无人机在垂直范围Δh内分布的二维和三维齐次泊松点过程模型，应用随机几何分析方法，评估了无人机高度、发射功率、分布密度及垂直范围等因素对地面网络用户和无人机网络用户覆盖概率的影响。此外，验证了采用定向天线频谱共享的性能提升效果。以最大化传输容量为目标函数，获得无人机的最优高度。本文为无人机赋能无线Mesh网络的频谱共享提供了理论指导，对相关频谱共享机制的研究具有重要参考价值。