عنوان مقاله [English]
In recent years, the development of UAVs has been a fundamental and innovative strategic change in wireless communication systems. Recently, a new and efficient security solution called physical layer secret key generation has attracted the attention of researchers and industrialists. This method is attractive for UAV applications due to its lightweight and easy scalability. However, in static UAV communication, secret key generation faces two major challenges: low key generation rate and the existence of vulnerable areas. To overcome the first weakness, local random generators can be used by the UAVs themselves. Specifically, in this paper, the channel probe signals sent by UAVs have random phases. Also, to increase the key generation rate, it is suggested that an external node called relay (which is untrusted) cooperates in the key generation process. For this collaborative key generation scheme, while presenting possible attacks for eavesdroppers, it is evaluated from the perspective of geometric secrecy. The simulation results show that the proposed scheme has less vulnerable areas compared to the recent reference (without relay).