Study On The Key Parameter In Elastic Optical Network Based On Orthogonal Frequency Division Multiplexing

In recent years,scholars have proposed a new type of optical network with flexible data rates,reconfigurable spectrum,and high resource utilization.That is,Elastic Optical Networking(EON)based on Coherent Optical Orthogonal Frequency Division Multiplexing(CO-OFDM),which may also be abbreviated as OFDM-EON.This new network architecture not only has the characteristics of large capacity,ultra-high transmission rate,flexible data rate,low cost and robustness to polarization mode dispersion,but also compares with the traditional wavelength division multiplexing(WDM)system.The spectrum efficiency of the network system can be improved by 5-95%.Therefore,based on these unique features,OFDM-EON is considered to be the most likely alternative for the next generation of backbone networks.This dissertation mainly focuses on the identification of the key parameters of OFDM-EON system received signals,such as sub-carriers number,bandwidth,modulation format of each sub-carrier,cyclic prefix length and so on.In the OFDM-EON system,these parameters are dynamically adjusted according to the distance traveled by the signal,the optical channel noise characteristics and the change of the user traffic,and we cannot know these in advance when demodulating the signal on the receiving end in the practical application scenario.Therefore,it is necessary to intelligently identify some key parameters in the system.The main contents of this thesis are as follows:(1)In the absence of a priori information,this paper first proposes the use of cyclic stationary characteristics of digital signals to identify the number of sub-carriers in the new OFDM-EON architecture.The core idea is to identify the number of sub-carriers in an OFDM-EON system based on the fact that the high-order cyclic cumulant of a cyclostationary signal has a value only when the cyclic frequency equals the sub-carrier frequency.In this paper,we also carry out the related performance analysis of the scheme through simulation and experiment.The analysis results show that the scheme can accurately identify the number of subcarriers in the system.(2)In the absence of a priori information,in order to accurately identify the modulation format identification of each sub-carrier in the new structure of OFDM-EON,this paper proposes different modal mean square values based on different modulation formats to identify the system sub-carrier modulation format.The simulation results show that the scheme can accurately identify the modulation format selected by the system.