Spatial Degrees of Freedom for Physical Layer Security in XL-MIMO

Physical Layer Security With Near-Field Beamforming

“…This work presents the PLS features of an ELAA considering near-field beamforming and both downlink and uplink communications. It is a profound extension of [27] and, contrarily to the approaches of [25], [26], it considers a channel model with all spherical wave particularities. This channel model is based on uniform rectangular arrays (URAs) with aperture antennas and captures polarization, amplitude, and phase Ref.…”

“…variations over the array. This substantially differs from the simplified spherical wave channel model of [25], [26], where ULAs with isotropic antennas are considered and only the nonlinear phase variations over the array are taken into account. Also, differently from [25]- [27], where optimized beamforming algorithms are presented, the main goal of this work is to highlight the benefits of the beam-focusing effect in PLS using propagation arguments such as the normalized antenna array gain.…”

Very large scale integration architectures of discrete transforms for digital signal processing applications

“…In addition, the authors developed a leakage subspace precoding technique for secure precoding and user scheduling [67]. This novel method increases the spectral secrecy efficiency by more than 40 percent compared to traditional zero-forcing approaches under various eavesdropper collusion strategies [195]. This finding highlights the capability of XL-MIMO technology to enhance the PLS of wireless communication systems.…”

“…The authors in [195] analyzed the distinctions between plane-wave (PW) and spherical-wavefront (SW) models regarding PLS for XL-MIMO systems with multiple eavesdroppers. They considered both colluding and non-colluding strategies of eavesdroppers, providing a comprehensive understanding of the PLS implications for various scenarios.…”

“…In addition, the authors in [195] investigated the effects of realistic propagation conditions on the achievable secrecy performance of MIMO systems in the presence of an eavesdropper (Eve), with a particular emphasis on the κ − µ shadowed fading model [196]. They derived closed-form expressions for secrecy performance metrics such as secrecy outage probability, probability of strictly positive secrecy capacity, and average secrecy capacity under two conditions: 1) the transmitter knew the CSI of the legitimate receiver (Bob) but not Eve's CSI, and 2) the transmitter knew the CSI of both the Bob's and Eve's channels [193].…”