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Rotatable Antenna Enabled Covert Communication

Qi Dai, Beixiong Zheng, Yanhua Tan, Weidong Mei, Shiqi Gong, Jie Tang, Chengwen Xing

Abstract

Unlike conventional fixed-antenna architectures, rotatable antenna (RA) has shown great potential in enhancing wireless communication performance by exploiting additional spatial degrees of freedom (DoFs) in a cost-effective manner. In this letter, we propose a novel RA-enabled covert communication system, where an RA array-based transmitter (Alice) sends covert information to a legitimate user (Bob) in the presence of multiple wardens (Willies). To maximize the covert rate, we optimize the transmit beamforming vector and the rotational angles of individual RAs, subject to the constraints on covertness, transmit power, and antenna rotational range. To address the non-convex formulated problem, we decompose it into two subproblems and propose an efficient alternating optimization (AO) algorithm to solve the two subproblems iteratively, where the second-order cone programming (SOCP) method and successive convex approximation (SCA) approach are applied separately. Simulation results demonstrate that the proposed RA-enabled covert communication system can provide significantly superior covertness performance to other benchmark schemes.

Rotatable Antenna Enabled Covert Communication

Abstract

Unlike conventional fixed-antenna architectures, rotatable antenna (RA) has shown great potential in enhancing wireless communication performance by exploiting additional spatial degrees of freedom (DoFs) in a cost-effective manner. In this letter, we propose a novel RA-enabled covert communication system, where an RA array-based transmitter (Alice) sends covert information to a legitimate user (Bob) in the presence of multiple wardens (Willies). To maximize the covert rate, we optimize the transmit beamforming vector and the rotational angles of individual RAs, subject to the constraints on covertness, transmit power, and antenna rotational range. To address the non-convex formulated problem, we decompose it into two subproblems and propose an efficient alternating optimization (AO) algorithm to solve the two subproblems iteratively, where the second-order cone programming (SOCP) method and successive convex approximation (SCA) approach are applied separately. Simulation results demonstrate that the proposed RA-enabled covert communication system can provide significantly superior covertness performance to other benchmark schemes.
Paper Structure (12 sections, 22 equations, 4 figures, 1 algorithm)

This paper contains 12 sections, 22 equations, 4 figures, 1 algorithm.

Table of Contents

  1. Introduction
  2. System Model And Problem Formulation
  3. Antenna Boresight Rotation
  4. Channel Model
  5. Binary Hypothesis Testing at Willie
  6. Problem Formulation
  7. Proposed Algorithm
  8. Subproblem 1: Transmit Beamforming Optimization
  9. Subproblem 2: Antenna Rotation Optimization
  10. Overall Algorithm
  11. Simulation Results
  12. Conclusions

Figures (4)

  • Figure 1: System model of RA-enabled covert communication.
  • Figure 2: Convergence behavior of the proposed AO algorithm.
  • Figure 3: Covert rate $R_b$ versus the numbers of antennas $N$.
  • Figure 4: Covert rate $R_b$ versus the distance between Alice and Bob.