Opt Lett. 2023 Feb 1;48(3):684-687. doi: 10.1364/OL.480981.
We propose a chaotic region-optimized probabilistic constellation shaping (CRPCS) scheme to enhance the security and the resistance to turbulence for free-space optical (FSO) communications. For this approach, a four-dimensional hyperchaotic system generates a pseudorandom sequence to rotate and encrypt the constellation. Constellation distribution of short pseudorandom sequences behaves as the law of a non-uniform character. Grouping long pseudorandom sequences and counting the characteristics of constellation distribution can realize probabilistic constellation shaping with low and fixed redundant information. We demonstrate a 56 Gbyte/s coherent FSO communication system based on log-normal and Gamma-Gamma turbulence models with a key space of 10. The results show that the optical receiver sensitivity is improved by 0.3-1.1 dB, and the transmission distance is also improved by 3.2%-7.0% in different shaping cases.
我们提出了一种混沌区域优化的概率星座成形（CRPCS）方案，以提高自由空间光（FSO）通信的安全性和抗湍流能力。对于这种方法，一个四维超混沌系统生成一个伪随机序列来旋转和加密星座。短伪随机序列的星座分布表现出非均匀特征的规律。通过对长伪随机序列进行分组并统计星座分布的特征，可以实现具有低且固定冗余信息的概率星座成形。我们在对数正态和 Gamma-Gamma 湍流模型下展示了一个 56Gbit/s 的相干 FSO 通信系统，其密钥空间为 10。结果表明，在不同的成形情况下，光接收器灵敏度提高了 0.3-1.1dB，传输距离也提高了 3.2%-7.0%。
