Study On OFDM-PON Physical-layer Security Technology Based On Chaotic Three-dimensional Constellation Modulation

With the rapid development of information and communication technology,the information security of communication networks has become a strategic issue that has been attracting global concern.Both of the China's national cyber development strategy and cyberspace security development strategy have listed the development of cyber information security as an important development content.As a critical element of the communication networks,optical fiber access network is the closest segment to the users,as such it is especially essential to ensure the transmission security of information in the optical fiber access network.At present,the information security of the access networks mainly depends on the data encryption at the MAC layer and its upper layers,while researches on the enhancement of information security at the physical layer is rare.However,the physical layer is the"frontier battlefield"to prevent information leakage and eavesdropping.The security of physical layer information at optical fiber access network is of great significance to ensure the information security of the entire communication network.In recent years,orthogonal frequency division multiplexing passive optical network?OFDM-PON?has attracted worldwide concern,because of its advantages such as simplicity,flexibility,and high speed.It has become one of the key technologies for next-generation fiber access networks.This dissertation is focused on improving the physical layer information security of the OFDM-PON,in virtue of the chaos scrambling technology and three-dimensional constellations.Herein,the three-dimensional constellation is developed to enrich the dimension of encryption,and the chaos scrambling is adopted to improve the physical-layer security.Based on these two technologies,the developed OFDM-PON shows advantage in security.The main work of the paper is as follows:1.The fundamental characteristics of chaos and its advantages applied in the security field are analyzed,and two mainstream digital encryption technologies are discussed:constellation scrambling technology and constellation transformation technology,both advantages and disadvantages of them are compared and analyzed.2.Based on the lattice theory,the two main factors that determine the performance of the constellations are analyzed:the basic coding gain and the boundary shaping gain.Based on this,two novel types of three-dimensional 16QAM constellation are designed which have better performance compared with existing constellations.3.Based on the proposed novel three-dimensional 16QAM constellations and constellation scrambling technology,a secure OFDM-PON based on chaotic constellation rotation encryption is proposed,which can encrypt data effectively and improve the security of system.4.Based on the proposed novel three-dimensional 16QAM constellations and constellation transformation technology,a secure OFDM-PON based on chaotic selective mapping encryption is proposed.The encrypted constellation reaches higher information entropy with chaotic selective mapping,the symbol information can be hided effectively,as a result,the security of the system is guaranteed.The results of theoretical analysis and simulation demonstrate that a key space larger than 10⁶⁰ can be provided in both of the two abovementioned secure OFDM-PON based on chaotic three-dimensional constellation modulation,this guarantees security of the system effectively.Simultaneously,the proposed secure OFDM-PONs show better signal-to-noise performance,with respect to the traditional OFDM-PON.