Secrecy and Covertness Analysis of SWAN-Enabled Uplink EDMA-NOMA Systems
Environment division multiple access (EDMA) has recently emerged as a promising multiple-access paradigm by exploiting the wireless propagation environment for user separation, while physical-layer security, including secrecy and covert communication, is becoming increasingly important for protecting confidential information and user privacy. Motivated by these considerations, this paper proposes an EDMA-enabled non-orthogonal multiple access for secrecy and covert communications (EDMA-NOMA-SC) framework for uplink wireless systems. In the proposed framework, a segmented-waveguide-enabled pinching antenna system (SWAN) is employed, where a secrecy user and an intermittently active covert user share the same transmission resource through NOMA within each segment, while a malicious warden attempts to eavesdrop on the secrecy transmission and detect the presence of the covert communication. To capture practical operating conditions, distance-dependent blockage, inter-segment interference, in-waveguide attenuation, imperfect channel state information (ipCSI), and imperfect successive interference cancellation (ipSIC) are considered. Semi-analytical frameworks are developed to characterize the secrecy outage probability (SOP), average secrecy capacity (ASC), false alarm probability (FAP), missed detection probability (MDP), detection error probability (DEP), and covert rate (CR), with their accuracy verified through Monte Carlo simulations. Numerical results, including comparisons with conventional and EDMA-based benchmark schemes, show that the proposed framework generally achieves improved secrecy and covert-rate performance owing to reduced user-to-pinching-antenna propagation distances and in-waveguide attenuation. However, excessive segmentation can degrade performance when inter-segment interference outweighs these propagation benefits.