2.5Gbps CSK-OCDMA光隐匿通信系统实验

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"基于CSK-OCDMA技术的光隐匿通信系统实验" 这篇研究论文主要探讨了如何利用码移键控光码分多址(CSK-OCDMA)技术来提升光隐匿通信系统的安全性。光隐匿通信是一种安全通信方式,其目标是将秘密信息隐藏在正常通信信号中,使得不法分子难以察觉和解析。在这个实验中,研究人员提出了一种基于CSK-OCDMA的新方法,并构建了一个2.5 Gbps的实验系统来验证其性能。 CSK-OCDMA技术结合了码移键控(Code Shift Keying)和光码分多址(Optical Code Division Multiple Access)的概念。码移键控是一种调制技术,通过改变编码序列的位置来传输信息,而OCDMA则利用独特的光码(或称为光签名)使得多个用户可以在同一频谱上同时传输数据,而不会相互干扰。这种技术在光通信中的应用有助于提高信道利用率和安全性。 在实验装置中,研究团队使用了成本较低的分布反馈半导体激光器作为隐匿光源,以降低成本并确保隐蔽性。宿主光源则采用了接近实际波分复用(WDM)光网络的光波长转换板(OTU),这使得实验更接近实际通信环境。实验结果显示,隐匿信道可以在背靠背配置下实现无误码传输,对宿主信道接收机的灵敏度影响极小,仅为0.1 dBm。此外,即使在宿主与隐匿信号之间存在高达24.6 dBm的功率差,也能保证隐匿信道的无误码传输。 为了进一步增强系统的抗错误能力,研究人员还加入了前向纠错设备(FEC)。通过FEC的使用,他们成功地实现了光隐匿通信系统在100 km距离下的无误码传输,这表明该系统在长距离通信中的可行性。 关键词包括:光通信、光隐匿、码移键控和偏振调制器,这些都与实验的核心技术和手段密切相关。这篇论文的贡献在于提供了一种改进的光隐匿通信方案,通过CSK-OCDMA技术提高了系统的安全性和可靠性,对于未来光通信领域尤其是安全通信的研究具有重要的参考价值。

Unlike the classical encryption schemes,keys are dispensable in certain PLS technigues, known as the keyless secure strat egy. Sophisticated signal processing techniques such as arti- ficial noise, beamforming,and diversitycan be developed to ensure the secrecy of the MC networks.In the Alice-Bob-Eve model, Alice is the legitimate transmitter, whose intended target is the legitimate receiver Bob,while Eve is the eavesdropper that intercepts the information from Alice to Bob.The secrecy performance is quantified via information leakagei.ethe dif ference of the mutual information between the Alice-Bob and Alice-Eve links. The upper bound of the information leakage is called secrecy capacity realized by a specific distribution of the input symbols, namely,capacity-achieving distribution.The secrecy performance of the diffusion-based MC system with concentration shift keying(CSK)is analyzed from an informa- tion-theoretical point of view,providing two paramount secrecy metrics, i.e., secrecy capacity and secure distance[13].How ever, only the estimation of lower bound secrecy capacity is derived as both links attain their channel capacity.The secrecy capacity highly depends on the system parameters such as the average signal energy,diffusion coefficientand reception duration. Moreover, the distance between the transmitter and the eavesdropper is also an important aspect of secrecy per- formance. For both amplitude and energy detection schemes secure distance is proposed as a secret metricover which the eavesdropper is incapable of signal recovery. Despite the case with CSK,the results of the secure metrics vary with the modulation type(e.g.pulse position,spacetype) and reception mechanism(e.g.passive,partially absorbingper fectly absorbing).For ease of understanding,Figure 3 depicts the modulation types and the corresponding CIRs with different reception mechanisms. Novel signa processing techniques and the biochemical channel properties can further assist the secrecy enhancement in the MC system.The molecular beam forming that avoids information disclosure can be realized via the flow generated in the channel.Besidesnew dimensions of diversity, such as the aforementioned molecular diversity of ionic compounds, can beexploited. Note that the feasibility of these methods can be validated by the derived secrecy metrics.

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