Physically Secure mm-Wave Wireless Links with Spatio-temporal Modulated Arrays

Security is emerging as one of the grand challenges for future wireless networks for 5G and beyond, particularly for applications demanding multi-Gbps mm-Wave links with low latency and high energy efficiency. To address these challenges of security when implemented at the network and applications layers, there has been renewed interest in physical layer security techniques that exploit channel propagation characteristics to impart security features. Phased arrays incorporate some amount of physical layer security through directive links. However, it also transmits the indentical constellation outside the main beam, opening itself to potential eavesdropper attacks. In this paper, we will discuss out recent works on spatio-temporal modulated arrays that forces spectral aliasing, constellation scrambling and loss of information outside the main beam to mitigate eavesdropper attacks. We will discuss silicon integrated architectures and show experimental results of these security features with fully integrated spatio-temporal modulated arrays in 65 nm CMOS operating at 76 GHz in 2-element and 4-element array configuration and packaged antennas. Such architectures can enable future deployment of large-scale mmWave wireless networks establishing dynamically reconfigurable physically secure links.