Anti-Interception Countermeasure for Air-Space-Ground-Maritime Integrated Networks: From Signal Concealment to Defensive Deception

Due to the open channel and broadcasting nature of cross-domain wireless transmission, the air-space-ground-maritime integrated network is vulnerable to many security threats, especially signal interception. The conventional anti-interception methods, such as spread spectrum and physical layer security, are primarily designed to prevent the eavesdropper from focusing on the energy of the received signals, achieving signal concealment. We find that in wide-area signal interception across the air-space-ground-maritime domain, eavesdroppers are required to align the directions of the transmitter first and perform directional interception to enhance the receiving gain. To this end, we consider a defensive deception concept for anti-interception, which disguises the signal features, including latency and Doppler shift, by constructing continuously varied time-frequency components, thereby misleading the direction cognition and alignment of eavesdroppers. Considering this paradigm shift, we first elucidate typical signal interception techniques that may be encountered in the air-space-ground-maritime integrated network. Then, we summarize the current anti-interception methods based on signal concealment and analyze their characteristics. Further, we analyze the methods of defensive deception and propose an example of a deception waveform to disrupt adversary analysis about the range and velocity of the transmitter, suppressing the capability of directional interception. Finally, future research directions for defensive deception methods are discussed.