High secure and reliable MMW-RoF based on CSI and dynamic key distribution

This paper proposes a channel state information-driven dynamic key distribution (CSI-DKD) scheme implementing a one-time pad (OTP) strategy in W-band millimeter-wave radio-over-fiber (MMW-RoF) system, achieving co-optimization of physical-layer security and transmission reliability. For high security, the strong randomness and fast time-varying nature of wireless channels are utilized and more complex key generation protocol is introduced to obtain keys with higher encryption strength, and synchronous sequences are used to achieve key distribution. Then, Chua’s and hyper chaotic systems are applied to generate non-linear encryption sequences, OFDM data are encrypted from three stages: bidirectional diffusion, constellation masking, and subcarrier scrambling. To improve the reliability of the system, polar codes are used to correct error bits. This scheme has been experimentally validated on the W-band MMW RoF system, and the results show that the proposed method has strong security, compared with the traditional OFDM signal, when the bit err rate is 10-3, the received optical power gain of the proposed scheme is ∼ 3.25 dB. And the analyses of the results show that the secure scheme can innovate the OTP system by dynamic key generation and distribution, effectively enhance system security and improve transmission performance.