Movable antennas improve wireless signals and fight jamming attacks
Movable Antenna Enabled Anti-Jamming: From Local Optimality Guaranteed Design to a Unified Antenna Position Optimization Framework
Information Theory
Summary
Wireless receivers usually have antennas fixed in place, which limits how well they can block bad signals called jamming. The authors study how moving antennas can help by changing their positions to get better signal quality and reduce interference. They create algorithms that efficiently find good antenna placements to improve communication even when there are multiple jammers or complex signal paths. Their work shows better anti-jamming performance with lower computational cost compared to traditional setups.
What this means in practice
- •For wireless network engineers: Improve wireless receivers' resilience to jamming by integrating movable antennas with optimized placement algorithms.
- •For military communication teams: Enhance battlefield communication capability through movable antenna setups that better resist electronic interference.
Authors
Lebin Chen, Ming-Min Zhao, Lipeng Zhu, Zhenyu Xiao, Min-Jian Zhao, Rui Zhang
Abstract
Anti-jamming capability is of paramount importance in modern wireless communications, yet conventional receivers are severely constrained by their fixed array geometries, which limit the available spatial degrees of freedom and leave performance highly susceptible to strong interference. By contrast, movable antennas (MAs) provide additional spatial degrees of freedom through antenna-position optimization. This paper investigates MA-enabled anti-jamming by jointly optimizing the antenna-position vector (APV) and receive beamformer to maximize the output signal-to-interference-plus-noise ratio (SINR). For the canonical setting with a single jammer and a single line-of-sight (LoS) propagation path on the legitimate link, we develop a damped projected-gradient descent (DPGD) algorithm with low computational complexity, which scales linearly with the number of receive MAs. We establish a generic active strict-saddle landscape for the resulting steering-coherence minimization problem and prove that DPGD converges almost surely to a local minimizer rather than merely to a Karush-Kuhn-Tucker (KKT) point. For the general setting with multiple channel paths on the legitimate link and/or multiple jammers, we derive an equivalent ridge least-squares formulation and develop a low-complexity soft-active projected-gradient (SAPG) algorithm, which also scales linearly with the number of receive MAs. We further show that the proposed antenna position optimization framework applies to both minimum variance distortionless response (MVDR) and zero-forcing (ZF) reception. Numerical results validate the proposed algorithms, demonstrating substantial gains in both anti-jamming performance and computational efficiency.