Jamming mitigation via hyperchaos underactuated synchronization

Chaos-based synchronization has attracted significant attention in secure communications due to the inherent unpredictability, broadband characteristics, and high sensitivity of chaotic dynamics. However, many existing synchronization frameworks still suffer from significant limitations, including discontinuous control laws, limited robustness against uncertainties and external perturbations, high structural complexity, and considerable computational burden. These limitations become even more critical in practical communication environments, such as vehicle-to-everything (V2X) and large-scale cyber-physical systems, where low latency, scalability to multi-node networks, robustness against uncertainties such as external disturbances and jamming, and secure information exchange constitute fundamental operational requirements. Under such conditions, disturbances, jamming, and implementation constraints can significantly degrade synchronization quality and communication reliability. To address these issues, this paper proposes a robust underactuated synchronization framework for a high-dimensional hyperchaotic system based on Lyapunov theory and investigates its application to secure communications. The proposed approach employs a single scalar linear feedback control law, thereby reducing structural complexity while preserving robustness properties. Disturbances and jamming signals are explicitly incorporated into the stability analysis. It is shown that the synchronization error and the corresponding message-decryption error are uniformly ultimately bounded and converge to a residual neighborhood of the origin. The synchronizer gain provides a practical tuning parameter that can influence the residual synchronization region, although the corresponding Lyapunov estimate is conservative and does not imply an arbitrary monotonic reduction of the actual synchronization error. A comprehensive simulation study is conducted to evaluate synchronization performance, robustness, and secure message recovery under adverse operating conditions. The obtained results demonstrate that the proposed framework achieves robust synchronization and reliable secure communication with reduced actuation complexity, highlighting its potential applicability to practical secure communication systems operating under disturbances and jamming conditions.