Research On Key Technologies Of High-security Optical Communication Based On Floating Constellation Mappin

With the opening of the Big Data era,the official commercial use of 5G and the advent of the Internet of Everything,the information explosion in various industries has brought greater challenges to the information industry,of which the optical communication industry is facing unprecedented pressure as the highway of the communication industry,while at the same time putting forward higher requirements for the security of information transmission.The physical layer of optical networks is vulnerable to external attacks,including electromagnetic interference,interruption blocking,eavesdropping and interception,so it is of great importance and long-term significance to ensure the security of the physical layer of optical networks in optical communications research.This paper firstly briefly introduces the coding and modulation schemes in the current optical communication system,including the probabilistic shaping technique and the aggregate shaping technique in the constellation shaping technology,analyses the advantages and disadvantages of this technology,and proposes improvement schemes;secondly,it introduces various multiplexing methods for speed and capacity expansion in optical communication research,including the space division multiplexing technology,the orthogonal frequency division multiplexing technology,and the carrier-free phase and amplitude modulation technology The experimental design is based on the above coding and modulation schemes.Finally,the chaos encryption theory is elaborated,and its special advantages are analysed in terms of their importance and feasibility for the security of optical communication systems.Based on the above techniques,two encryption schemes are proposed to improve system performance and enhance system security at the same time.The main innovative work in this thesis is as follows.（1）A two-layer secure encryption scheme based on floating probability shaping is proposed,which generates chaotic sequences from a four-dimensional hyperchaotic model for floating probability shaping and bubble sorting method encryption.The experimental results show that the receiver sensitivity of this scheme increases by 1.82 d B compared with the conventional uniform 16QAM-OFDM.due to its good transmission performance and security performance,this scheme has important application prospects in future optical access networks.（2）A high-security encryption scheme based on the dynamic constellation shaping of high-dimensional constellation is proposed,and the security of high-dimensional constellation is studied.The dynamic constellation shaping technology is used to improve the transmission performance of the system and enhance the security performance of the system,and the key space reaches 10¹⁷⁶.Experiments show that the sensitivity of the receiver is increased by 1.37d B compared with the traditional 3D-CAP signal.This scheme has a wide practical prospect for high-dimensional constellation coded modulation.In summary,this thesis is mainly developed from three aspects:theoretical analysis,scheme design and experimental proof,and addresses the two issues of how to optimise the transmission performance of optical communication systems and improve the security performance of optical communication systems in depth.The convertibility of coding modulation techniques and chaotic encryption techniques is analysed,and two security schemes based on floating constellation shaping are proposed on this basis,which enhance the transmission rate of the system while In this paper,we present two security schemes based on floating constellation shaping,which improve the transmission rate of the system and at the same time improve the confidentiality of the system.