Enhanced physical layer security for 5G and beyond communication: A hamming window inspired randomized frequency diverse array-based directional modulation scheme with artificial noise

In this paper, we propose a Hamming window inspired random frequency diverse array based directional modulation with added artificial noise (RHFDA-DM-AN) scheme to enhance physical layer security for 5G and beyond wireless communication. By employing randomized Hamming window based frequency offsets for the transmit array of FDA, we achieve a significant improvement in range-angle uncoupled security through the generation of a pencil beam, surpassing the range-angle coupled security and angle only security offered by an FDA based DM and Phased Array (PA) based DM, respectively. Firstly, the frequency offsets are randomized considering the inherent thermal noise. Next, we derived an expression for the lower bound of the Ergodic Secrecy Capacity (ESC) in closed form for the proposed RHFDA-DM-AN scheme. Finally, the simulation results demonstrate that the proposed RHFDA-DM-AN scheme achieves improved performance and higher secrecy capacity compared to state of the art PA, FDA, and existing RFDA-based DM-AN schemes.