Efficient Physical-Layer Secret Key Generation in Satellite Communication System

Although physical-layer secret key generation (SKG) techniques generally show promising performance in many wireless communication systems, they may not be applicable to satellite systems mainly because of the long coherence time. For the satellite systems, we need a technique to introduce randomness and it should be resistant to long round-trip delays. To achieve this, this paper proposes a novel SKG scheme using the information contained in the transmitted data, which can act as a random signal, instead of additionally generating random probing signals. The proposed method effectively increases secret key rates, without security risk. Simulation results demonstrated that the proposed scheme enhances the data transmission efficiency while maintaining lower secret key disagreement rate.