Performance-Enhanced Three-Dimensional Trellis Coded Modulation Based on Four-Winged Fractional-Order Chaotic Encryption For Physical Layer Security

In this paper, an encrypted three-dimensional (3D) trellis-coded modulation (TCM) based on mapping by set-partitioning (MSP) of 3D constellation is proposed, for highly reliable and secure short-reach transmission. 3D-TCM encoder encryption and 3D constellation rotation are realized with the implementation of a 4D four-winged fractional-order chaotic (FWFC) system and MSP of 3D constellation, the suggested approach demonstrates higher coding gain and chaotic encryption. A 35 Gb/s (5 Gb/s × 7) encrypted 3D-TCM-32CAP signal transmission over ∼2 km seven-core fiber is experimentally demonstrated. The results show that the encrypted 3D-TCM-32CAP obtains a 2.9 dB and 3.8 dB gain in receiver sensitivity at a bit error rate (BER) of 10^-4 under the same bit rate, when compared with conventional 2D-TCM-32CAP and 3D-32CAP, respectively. Furthermore, a handsome key space of the proposed scheme is obtained ∼2.205 × 10¹⁶⁰, which is large enough to effectively guard against malicious attacks from illegal optical network units. In a nutshell, the experimental results indicate the proposed encrypted 3D-TCM-32CAP scheme combines the superiority of BER and security performance.