Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Secure Multiuser Beamforming With Movable Antenna Arrays

Zhenqiao Cheng, Chongjun Ouyang, Boqun Zhao, Xingqi Zhang

TL;DR

The paper tackles secure multiuser transmission by leveraging movable antennas (MAs) to enhance physical-layer security. It derives secrecy-rate expressions grounded in secure-channel coding and solves a non-convex sum-rate maximization via fractional programming (FP) and a block coordinate descent (BCD) that jointly optimizes digital beamforming and MA placement, with updates that are either closed-form or low-complexity. Key contributions include a FP-based variational reformulation with auxiliary variables and an efficient BCD algorithm that updates ${\bf W}$, MA positions, and auxiliary variables, plus a coordinate-search for MA placement that achieves substantial secrecy-rate gains over fixed-position arrays. The results demonstrate that MA deployment provides additional degrees of freedom and spatial diversity to suppress eavesdropping in multiuser MIMO, enabling higher secrecy rates in practical networks, with the overall secrecy rate expressed as $${\mathcal{R}}=\sum_{k=1}^K [\log_2(1+\gamma_k) - \log_2(1+\hat{\gamma}_k),0]^+.$$

Abstract

A movable antennas (MAs)-enabled secure multiuser transmission framework is developed to enhance physical-layer security. Novel expressions are derived to characterize the achievable sum secrecy rate based on the secure channel coding theorem. On this basis, a joint optimization algorithm for digital beamforming and MA placement is proposed to maximize the sum secrecy rate via fractional programming and block coordinate descent. In each iteration, every variable admits either a closed-form update or a low-complexity one-dimensional or bisection search, which yields an efficient implementation. Numerical results demonstrate the effectiveness of the proposed method and show that the MA-enabled design achieves higher secrecy rates than conventional fixed-position antenna arrays.

Secure Multiuser Beamforming With Movable Antenna Arrays

TL;DR

The paper tackles secure multiuser transmission by leveraging movable antennas (MAs) to enhance physical-layer security. It derives secrecy-rate expressions grounded in secure-channel coding and solves a non-convex sum-rate maximization via fractional programming (FP) and a block coordinate descent (BCD) that jointly optimizes digital beamforming and MA placement, with updates that are either closed-form or low-complexity. Key contributions include a FP-based variational reformulation with auxiliary variables and an efficient BCD algorithm that updates , MA positions, and auxiliary variables, plus a coordinate-search for MA placement that achieves substantial secrecy-rate gains over fixed-position arrays. The results demonstrate that MA deployment provides additional degrees of freedom and spatial diversity to suppress eavesdropping in multiuser MIMO, enabling higher secrecy rates in practical networks, with the overall secrecy rate expressed as

Abstract

A movable antennas (MAs)-enabled secure multiuser transmission framework is developed to enhance physical-layer security. Novel expressions are derived to characterize the achievable sum secrecy rate based on the secure channel coding theorem. On this basis, a joint optimization algorithm for digital beamforming and MA placement is proposed to maximize the sum secrecy rate via fractional programming and block coordinate descent. In each iteration, every variable admits either a closed-form update or a low-complexity one-dimensional or bisection search, which yields an efficient implementation. Numerical results demonstrate the effectiveness of the proposed method and show that the MA-enabled design achieves higher secrecy rates than conventional fixed-position antenna arrays.
Paper Structure (17 sections, 4 theorems, 31 equations, 5 figures, 2 algorithms)

This paper contains 17 sections, 4 theorems, 31 equations, 5 figures, 2 algorithms.

Table of Contents

  1. Introduction
  2. System Model
  3. Channel Model
  4. Mutiuser Secure Transmission
  5. Problem Formulation
  6. Secure Beamforming Design
  7. Reformulation of Problem \ref{['P_1']}
  8. The Proposed BCD-Based Algorithm
  9. Subproblem in $\mathbf W$
  10. Subproblem in $\mathbf T$
  11. Subproblem in ${\mathbf b}$
  12. Subproblems in the Auxiliary Variables
  13. Overall Algorithm, Convergence, and Complexity
  14. Numerical Results
  15. Conclusion
  16. ...and 2 more sections

Key Result

Lemma 1

Let ${\mathbf b}=[b_1,\ldots,b_K]^{\mathsf T}$. Problem P_1 is equivalent to the problem defined as follows: Moreover, the optimal $\{{\mathbf W},{\mathbf T}\}$ is identical for P_1 and P_2.

Figures (5)

  • Figure 1: Illustration of MA-empowered MIMO architecture.
  • Figure 2: Illustration of a multiuser wiretap channel.
  • Figure 3: Sum secrecy rate vs. the SNR. $K=6$ and $M=6$.
  • Figure 4: Sum secrecy rate vs. (a) the antenna number and (b) the UT number. $J=4$.
  • Figure 5: Sum secrecy rate vs. the number of iterations. $J=6$.

Theorems & Definitions (5)

  • Lemma 1
  • Lemma 2
  • Lemma 3
  • Lemma 4
  • Remark 1