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Multi-level Chaos-Shift-Keying for Non-Orthogonal Multiple Access with Physical Layer Security

To address the key issue of users’ privacy in future wireless communications, this work presents a generalized uplink secure code-domain non-orthogonal multiple access (SCD-NOMA) based on multi-level chaos-shift-keying (MCSK) signalling over Rician propagation environment. To have cost-effective physical layer security (PLS), the proposed scheme is designed by employing chaotic drive systems at the users’ side and a chaotic response system at the base station (BS) receiver. The transmitted signals are estimated efficiently at the BS through integrated maximum likelihood (ML) and chaos demodulation techniques. The efficacy of the proposed SCD-NOMA system is validated by intensive simulation results of the realized error rate, connectivity, and security gap, in comparison to the reference systems. Besides, the proposed scheme provides a huge keyspace to increase the system’s PLS and compact exhaustive brute-force attacks.