标题： 基于OFDM信号的森林环境中空地一体化信道的测量与建模 显示英文标题

标题： Measurements and Modeling of Air-Ground Integrated Channel in Forest Environment Based on OFDM Signals

摘要： 森林经常受到气候条件、植被密度以及复杂的地形和地质的影响，这些因素导致自然灾害的发生。 在这样的环境中从事或支持救援行动的人员依赖于强大的通信系统来确保自身安全，这突显了在森林环境中进行信道测量的重要性。 然而，根据现有研究，目前文献中关于森林地区信道检测和建模的研究较少。 本文描述了内蒙古阿尔山国家森林公园的空中和地面信道测量活动。 它提供了地面到地面（G2G）和空中到地面（A2G）场景的测量结果和传播模型。 该测量活动使用中心频率为1.4 GHz的正交频分复用信号进行信道探测。 在G2G测量中，除了使用全向天线记录数据外，我们还使用定向天线记录信号到达接收器的角度信息。 在A2G测量中，我们预先规划无人机的飞行轨迹，使其能够以相对于地面的固定角度飞行。 我们基于测量结果的分析，提出了适用于森林环境中G2G和A2G的路径损耗模型。 结果表明，与其它路径损耗模型相比，所提出的模型减少了误差范围。 此外，我们推导了适用于森林环境的多径模型表达式，并对关键信道参数进行了统计分析，例如阴影衰落因子、均方根时延扩展和Rician K因子。 我们的研究发现，在A2G通信中，由于树冠造成的信号传播障碍比G2G通信中树干造成的障碍更为明显。 调整空中和地面之间的仰角可以提高通信质量。 显示英文摘要

摘要： Forests are frequently impacted by climate conditions, vegetation density, and intricate terrain and geology, which contribute to natural disasters. Personnel engaged in or supporting rescue operations in such environments rely on robust communication systems to ensure their safety, highlighting the criticality of channel measurements in forest environments. However, according to current research, there is limited research on channel detection and modeling in forest areas in the existing literature. This paper describes the channel measurements campaign of air and ground in the Arxan National Forest Park of Inner Mongolia. It presents measurement results and propagation models for ground-to-ground (G2G) and air-to-ground (A2G) scenarios. The measurement campaign uses orthogonal frequency division multiplexing signals centered at 1.4 GHz for channel sounding. In the G2G measurement, in addition to using omnidirectional antennas to record data, we also use directional antennas to record the arrival angle information of the signal at the receiver. In the A2G measurement, we pre-plan the flight trajectory of the unmanned aerial vehicle so that it can fly at a fixed angle relative to the ground. We present path loss models suitable for G2G and A2G in forest environments based on the analysis of measurement results. The results indicate that the proposed model reduces error margins compared with other path loss models. Furthermore, we derive the multipath model expression specific to forest environments and conduct statistical analysis on key channel parameters e.g., shadow fading factor, root mean square delay spread, and Rician K factor. Our findings reveal that signal propagation obstruction due to tree crowns in A2G communication is more pronounced than tree trunk obstructions in G2G communication. Adjusting the elevation angle between air and ground can enhance communication quality.