Robust Beamfocusing for Secure NFC with Imperfect CSI.

Area of Science:

• Wireless communication
• Information security
• Signal processing

Background:

• Near-field communication (NFC) systems with massive MIMO arrays create security challenges due to eavesdroppers near the transmitter.
• Accurate near-field channel models are crucial for understanding and mitigating these security risks.
• Imperfect channel state information (CSI) complicates the design of secure communication protocols.

Purpose of the Study:

• To investigate physical layer security (PLS) in NFC systems with eavesdroppers.
• To propose and evaluate two novel schemes for enhancing PLS under imperfect CSI.
• To develop robust beamforming and artificial noise (AN) strategies to minimize eavesdropping.

Main Methods:

• Considered two PLS schemes: one with a multiple-input multiple-output multiple-antenna eavesdropper (MIMOME) and AN from the transmitter, and another with a full-duplex (FD) receiver emitting AN.
• Jointly designed beamforming and AN vectors to degrade the eavesdropper's signal-to-interference-plus-noise ratio (SINR).
• Proposed an iterative algorithm for power minimization with quality-of-service (QoS) constraints, decomposing the robust optimization problem into solvable sub-problems using generalized Rayleigh quotient and semi-definite programming (SDP).

Main Results:

• The proposed iterative algorithm effectively minimizes power consumption while meeting QoS requirements.
• The joint design of beamforming and AN vectors significantly degrades the eavesdropper's reception quality.
• Simulation results validate the effectiveness of the developed protection zone strategies in NFC systems with imperfect CSI.

Conclusions:

• The proposed methods provide a viable approach to enhance physical layer security in near-field communication systems.
• The study demonstrates the effectiveness of artificial noise and optimized beamforming in creating secure communication zones.
• The findings are crucial for securing future NFC applications operating under realistic channel conditions.