KMHCR: A Key-Controlled Signal-Domain Transformation for 5G IoT Security

Journal of Signal Processing Systems. 2026. Vol. 98. Article 31.

Ronglin Z., Wei L., Jiahong C., Yuxiang C., Zulong D., Zhongming F., Jigang W., Naixue X., Xiaoyan C., Avdoshin S. M.

To address the need for lightweight and low-latency protection in massive resource-constrained 5G Internet of Things (IoT) systems, this paper proposes Key-Controlled Modulation Hopping and Constellation Rotation (KMHCR). KMHCR is designed as a physical-layer confidentiality-enhancement mechanism that avoids bit-wise full-payload encryption in the protection pipeline. It uses a shared key derived from channel-reciprocity secret key generation to drive a stateless, counter-based pseudo-random function, which determines a 5G-compliant modulation scheme and a quantized constellation rotation angle for each packet without requiring fragile per-packet state synchronization. For legitimate users, these operations introduce only lightweight signal-domain processing, whereas an unauthorized receiver must jointly infer the modulation type and the phase rotation from the observed signal. To evaluate the robustness of the proposed mechanism against intelligent attacks, we construct a 3GPP-compliant 5G adversarial dataset covering six modulation types, multiple signal-to-noise ratio regimes, and realistic channel impairments. Experimental results with multiple state-of-the-art deep learning-based AMC models show that KMHCR can substantially reduce the recoverable throughput of unauthorized receivers under the considered adversarial setting. These results support the use of KMHCR as a lightweight complementary protection mechanism for 5G IoT communications.

Keywords: Deep learning, Physical layer security, 5G IoT, Automatic modulation classification, Constellation rotation, 5G adversarial dataset