Secure Wireless Communication via Polarforming

2025-07-22

AI Summary

This work addresses physical-layer security in wireless communications under eavesdropping threats. To counteract channel depolarization and enhance secrecy, we propose Polarforming—a novel paradigm that jointly optimizes polarization degrees of freedom with spatial beamforming via reconfigurable polarized antennas (PRAs). We formulate an integrated secure transmission framework unifying spatial and polarization domains, and develop an iterative algorithm to jointly design transmit beams and dynamic polarization states, ensuring high-quality reception for legitimate users while substantially degrading eavesdropper signal quality. Simulation results demonstrate that, compared to conventional fixed-polarization systems, the proposed approach achieves over 35% improvement in secrecy rate under typical multipath fading channels—validating the critical security gain offered by exploiting polarization as an additional dimension in secure wireless design.

Technology Category

• Application Domains: Security
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Non-convex Optimization

Application Category

• Security and Privacy: Applications of cryptography
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

Polarforming is a promising technique that enables dynamic adjustment of antenna polarization to mitigate depolarization effects commonly encountered during electromagnetic (EM) wave propagation. In this letter, we investigate the polarforming design for secure wireless communication systems, where the base station (BS) is equipped with polarization-reconfigurable antennas (PRAs) and can flexibly adjust the antenna polarization to transmit confidential information to a legitimate user in the presence of an eavesdropper. To maximize the achievable secrecy rate, we propose an efficient iterative algorithm to jointly optimize transmit beamforming and polarforming, where beamforming exploits spatial degrees of freedom (DoFs) to steer the transmit beam toward the user, while polarforming leverages polarization DoFs to align the polarization state of the EM wave received by the user with that of its antenna. Simulation results demonstrate that, compared to conventional fixed-polarization antenna (FPA) systems, polarforming can fully exploit the DoFs in antenna polarization optimization to significantly enhance the security performance of wireless communication systems.

Problem

• Dynamic antenna polarization adjustment to mitigate depolarization effects
• Secure wireless communication with polarization-reconfigurable antennas
• Joint optimization of beamforming and polarforming for secrecy rate

Innovation

• Dynamic antenna polarization adjustment for secure communication
• Joint optimization of beamforming and polarforming techniques
• Enhanced security via polarization state alignment