空中转信平台下地空信道的传输特性

Transmission characteristics of air-ground channel in aerial communication platform

卫星通信解决了全球广域的通信问题,但不易部署,星上资源有限,使用飞行器搭载卫星通信载荷,在距地不超过10 km处构造空中转信平台与地面节点实现互通,从而弥补了传统卫星通信的不足。针对转信平台与地面通信时电波传输损耗进行分析,提出了转信平台下的Ku/Ka波段宽带信道模型,理论分析和仿真结果均表明,该信道的衰落十分明显,对信息传输性能造成不可忽略的影响。尤其在低仰角传输时,多径效应使得莱斯因子较小,应用OFDM技术可以对抗多径衰落,实现转信平台与地面节点之间的宽带通信。

Satellite communication can solve the problem of global communication,at the same time,it follows the problems of difficult deploy and limited satellite resources.Aerial communication platform is consisted of aircraft with payload communication and not more than 10 km from ground.The platform communicating with ground nodes can solve the weakness of traditional satellite communication.The loss of air-to-ground channel was analyzed to model the air-to-ground wideband channel in Ku and Ka band.The consequence of theory and simulation demonstrates that the fading of the model has serious influence on transmission performance.In low elevation transmission,the value of K-factor is small because of multipath reception.Simulation results show that orthogonal frequency division multiplexing（OFDM） can be a good candidate for wideband communications to transmit payload data from aerial platform to ground station.