Spatio-temporal modulated mm-Wave arrays for physical layer security and resiliency against distributed eavesdropper attacks

Ensuring security for the next-generation of millimeter-Wave and Terahertz networks, while simultaneously ensuring multi-Gbps data rates and ultra-low latency (sub-millisecond) is becoming increasingly challenging. Physical layer security that exploits the physics of wireless propagation to incorporate security features into the signal is becoming increasingly popular as a component for a holistic approach towards ensuring security. In this regard, there are prior works that have exposed severe vulnerabilities in the well-established principle of security that involve directional narrow beams. In this article we highlight security features using mm-Wave interface design, and present a generalized approach towards physical-layer security. Security in our approach is ensured by enforcing fundamental loss of information by selective spectral aliasing towards the direction of eavesdroppers while maintaining robust, high fidelity wireless link towards the intended receiver. In a custom-designed integrated transmitter array, spectral aliasing is achieved by dynamically reconfigurable symbol-to-antenna mapping principle that can synthesize a fast time-varying channel towards the direction of the eavesdroppers. We demonstrate this principle experimentally for the first time with mm-Wave directional links (71-76 GHz unlicensed spectrum). We also experimentally show the resilience of such links against distributed and synchronized eavesdropper attacks for the first time in the mm-Wave bands.