Chaotic Data Encryption And PAPR Reduction Algorithm Research In OFDM-PON

Due to the inherent advantages of high speed,large capacity and low loss,the optical fiber communications has become the backbone of global digital communications gradually after its birth of 50 years,which provides a reliable data transmission for human beings.Meanwhile,with the demand for broadband services increases rapidly,orthogonal frequency division multiplexing(OFDM)has been applied to the fiber communication system for the high spectral efficiency and strong tolerance to fiber dispersion properties,and attracted massive attention both at home and abroad in next generation passive optical network(PON).However,in the practical PON system,the broadcasting structure from the optical line terminal(OLT)to the optical network units(ONUs)makes the transmitted data easily suffer malicious eavesdropping and cause a potentially serious threat for the user data.Additionally,the high peak-to-average power ratio(PAPR)of OFDM signals would deteriorate optical/electronic components into nonlinear region,which distort the signal's amplitude and phase thereby severely deteriorating transmission performance.Therefore,the chaos map is proposed to combine with data encryption algorithm for secure transmission realization due to its specific characteristics,such as pseudo random,unpredictability and sensitivity to initial conditions.And,the chaos-based data encryption and PAPR reduction algorithm served as the encryption scheme in OFDM-PON can achieve the performance improvement and secure transmission simultaneously.This letter mainly research on the chaos-based data encryption and PAPR reduction schemes in OFDM-PON system.We firstly analyzed the algorithms feasibility of chaos-based key space extension,PAPR reduction,data encryption,chosen-plaintext attack(CPAs)resistance and keys protection by theoretical analysis and simulation.Then,experimentally demonstrate the transmitted performance of the above schemes in OFDM-PON,which mainly includes the following parts:(1)Firstly,we present the research significance,background,fundamental principles and partial key technologies of the OFDM-PON and chaotic encryption,and then demonstrates the detailed research status at home and abroad of chaotic encryption and PAPR reduction.(2)A key space extended encryption algorithm based on chaos map is studied in OFDM-PON system.To aim at the problem that the key space is too small to resist brutal force attack for the physical layer security,the chaos map based on its unique characteristic is proposed to completely permutated the time/frequency and pilots position,which can effectively enlarge the key space and achieve the capability of brutal force attack resistance.The feasibility of proposed encryption schemes are verified by the 10-Gb/s transmission experiment in OFDM-PON.(3)The chaos-based data encryption and PAPR reduction schemes are studied in OFDM-PON.To realize the performance improvement and secure transmission,the traditional PAPR reduction algorithms of discrete Fourier transform(DFT)matrix and Gray complementary sequence are encrypted by combining with the chaos map.A 10G/s secure transmission experiment in OFDM-PON is demonstrated to verify the feasibility of chaotic DFT encryption and chaotic Gray encryption schemes.(4)Chaos-based against CPAs and keys protection algorithms are proposed in this letter.To effectively present the illegal attackers from stealing data,this letter proposed a nonlinear dynamic encryption algorithm to resist the CPAs.Meanwhile,a chaotic modified Lagrange keys protection scheme is presented to avoid attackers cracking the encryption system directly via eavesdropping chaotic keys.The capability of CPAs resistance and keys protection algorithms are verified by the lOG/s transmission experiment in OFDM-PON system.