FlexD: Enhancing Secrecy Performance of Wireless Networks with Dynamic Scheduling

This research introduces Flexible Duplex (FlexD) networks, which offer dynamic time/frequency scheduling for secure uplink and downlink communications. We present novel communication models and analytical tools to evaluate the security aspects of User-User and User-Access Point connections within FlexD networks, thereby bridging the gap between FlexD networks and physical layer security. Our work establishes an analytical framework with closed-form expressions for secrecy outage probability (SOP) in FlexD networks. We also propose a power allocation and user selection strategy to maximize secrecy rates. Additionally, we explore the security performance of FlexD networks when partial channel state information (CSI) and reciprocal CSI channels are available. Extensive simulations validate our theoretical findings and highlight the security benefits compared to traditional half-duplex and full-duplex technologies. Our results suggest that the proposed communication strategies hold promise for securing future tactical wireless networks, including Device-to-Device (D2D), Machine-to-Machine (M2M), and cellular/mobile networks.