A Robust Physical Layer Security Scheme Based on Collaborative Beamforming for UAV Networks with Jitter

Uncrewed aerial vehicles (UAVs) are expected to play a crucial role in future sixth-generation systems and low-altitude communication networks owing to their mobility, flexibility, and wide-range coverage capability. However, the predominance of line-of-sight channels makes UAV communications highly susceptible to eavesdropping, posing significant challenges for secure transmission. Distributed collaborative beamforming has emerged as a promising physical layer security technique for the UAV networks, but its performance is fundamentally constrained by the intrinsic jitter of UAV platforms, which is unavoidable in practical systems. In this paper, a physical layer security scheme is proposed for UAV networks based on collaborative beamforming technologies, within which distinct algorithms are designed according to whether the location of the eavesdropper (EAV) is known or unknown. When the location of the EAV is unknown, the theoretical secrecy performance of the proposed method is derived, and a beamforming strategy is constructed based on the properties of the generalized Rayleigh quotient for the situation of known location. Then, the average secrecy rate of the proposed collaborative beamforming scheme is derived under jitter conditions, and a robust beamforming method is further developed for the scenario in which the location of the EAV is known. Simulation results demonstrate that the average secrecy rate is dramatically improved by the proposed collaborative beamforming scheme compared to the conventional approaches, and a substantial secrecy performance gain is maintained in the presence of UAV jitter.