Xiao Yaoqiang, Zhou Chunxi, Jiang Linrong, An Zhaoyu, Li Yuqing
Opt Lett. 2024 Jun 1;49(11):2998-3001. doi: 10.1364/OL.525571.
In this Letter, a delta-sigma modulation (DSM) encryption technique in a W-band RoF system is proposed. By performing DSM with different over-sample ratios (OSRs) on the OFDM signal based on the controlled keys generated by the chaotic system at the transmitter and performing constellation masking to disturb the transmitting signal for encryption, a high-order QAM-OFDM-DSM encrypted signal is achieved. In order to further improve the security of the system, bit bidirectional diffusion scrambling is used to resist chosen-plaintext attacks. After experimental verification, under the same transmission power, the encrypted DSM signal can achieve better security than single OSR of DSM signals through a 50-km standard single-mode fiber (SSMF) and a 3-m wireless channel, with the gain of sensitivity increased by ∼1 dBm. From the reliability of the system, the encrypted signal of the proposed scheme can be recovered, which meets a hard decision-forward error correction (HD-FEC) threshold of 3.8 × 10.
在本信函中，提出了一种W波段RoF系统中的三角积分调制（DSM）加密技术。通过基于发射端混沌系统生成的受控密钥对正交频分复用（OFDM）信号执行不同过采样率（OSR）的DSM，并执行星座图掩码以干扰发射信号进行加密，实现了高阶正交幅度调制-正交频分复用-三角积分调制（QAM-OFDM-DSM）加密信号。为了进一步提高系统的安全性，采用比特双向扩散加扰来抵抗选择明文攻击。经过实验验证，在相同发射功率下，加密的DSM信号通过50千米标准单模光纤（SSMF）和3米无线信道传输时，比单OSR的DSM信号具有更好的安全性，灵敏度增益提高了约1分贝毫瓦。从系统的可靠性来看，所提方案的加密信号能够被恢复，满足3.8×10的硬判决前向纠错（HD-FEC）阈值。
