Study On The Modulation Formats Identification Of Signal In Elastic Optical Network Based On Orthogonal Frequency Division Multiplexing

In recent years,with the huge development and commercial application of broadband data services,the communication traffic of the core network is increasing with almost 2 times annually,and the trend of growth is also increasing.So network providers should update their devices to support the wide application of high data rate products.Due to the rapid growth of the traffic demand,the system of optical communication needs large capacity and low price optical fiber transmission system to achieve the future of optical networks.While at present,wavelength division multiplexing(WDM)technology has reached its limit,400Gb/s,so optical transmission and network technology should develop in the direction of more efficient,flexible and scalable in order to meet the needs of the Internet in the future.So,in order to improve the coefficient of utilization of the spectrum in WDM network structure,which is widely used in Business field,experts and scholars has proposed some new network structures on the basis of the existing networks,and now the flexible optical network(EON)based on orthogonal frequency division multiplexing(OFDM)has been considered as the best alternative of the current WDM network structure in next generation networks because it has so much outstanding advantages.Therefore,under the condition of lack of prior information,how to identify the random parameters of multi-carriers in the new network structure,OFDM-based EON,has great influence on whether this new network structure can be widely applied or not.In OFDM-based EON,the various parameters of the signal are in the unknown state,so it is very important to carry out the adaptive parameters identification of the signal at the receiving terminal in the absence of priori information.At the same time,the progress of the modulation format identification is in the front of progress of the signal parameters identification,so the accuracy and efficiency of the modulation format recognition is related to the accuracy and efficiency of the following identifications of other parameters.Therefore,the author has considered and consulted the method of modulation format recognitions in other fields,then the author improve the methods have been used and firstly use them in OFDM-based EON.The main contents of this paper are as follows:(1)In the new network structure,OFDM-based EON,under the condition of lack of prior information,the author adds firstly the calculation of high-order cyclic cumulants into the modulation formats identification in optical OFDM signal.In the progress of the calculation,the author obtains high-order cyclic cumulant value of the wide-used low and high order modulation formats,and has proposed the modulation formats recognition interval based on the calculation results,and finally the performance of the modulation formats recognition interval has been tested in simulation.(2)In the new network structure,OFDM-based EON,under the condition of lack of prior information,the constellation clustering has been firstly introduced in and the author has proposed an improved algorithm based on the constellation clustering to carry out the modulation format recognition for optical OFDM signal.The simulation system has built the system model of in OFDM-based EON,and the performance of the algorithm is verified in simulation.