The Research Of Dynamic Wavelength Assignment Algorithm Of WDM-PON

With the rapid development of Internet technology,a large number of new businessesconstantly emerged and quickly integrated into people’s lives,then people’s requirement forthe communication network technology has become more sophisticated.These makes thecommunication network to proceed along digitization and integration directions.Recently,thebackbone’s development already has meet the people communication needs,while accessnetwork which is slowly developed has become the “bottleneck” of the entire communicationnetwork development.In the access network,optical fiber as the primary transmission mediumhas advantages of a bandwidth resources,long-distance and small loss.Passive OpticalNetwork(PON) which uses optical fiber as a transmission medium and passive components isan attractive network.The main object of this paper is the wavelength division multiplexing technology appliedto optical access networks—WDM-PON system.In WDM-PON system proposed twocolorless ONU remodulation technology program, then achieved the ONU colorless, at sametime proposed a wavelength allocation algorithm based on remodulation technique.The maincontents are listed as follows:Firstly, paper is research the colorless ONU technology based on WDM-PON system.The paper elaborated two technical solutions of re-modulation technique to achieve colorlessONU:technical solution based on IL re-modulation and technical solution based on RSOAre-modulation.In the technical solution based on IL re-modulation,an optical carrier throughdual-arm modulation using an optical carrier suppression and separation to generate twooptical carriers,these carriers separated by IL,after separation a carrier is loaded downlink dataand another carrier is transmitted to the ONU which used to complete the uplink datatransmission.In the technical solution based on RSOA re-modulation places RSOA in ONU,the downlink carrier being recovered using RSOA’s characteristics,then the uplink data isdirectly loaded into the recovered carrier from downlink carrier.These two solutions are bothrealized ONU’s colorless.Secondly,the two solutions are simulated with Optisystem,by analysis of multiplexingspectrum diagram、demultiplexing spectrum diagram、time-domain diagram and eye diagramindicates that the downlink transmission performance is better than the uplink transmissionperformance and system is able to accurately receiver both uplink and downlink,then verifythe feasibility of solutions.Lastly,in order to resolve the number of users is greater than the number of wavelengthswhich the system provided,the paper proposed an dynamic wavelength assignmentalgorithms.At the beginning,elaborate the structure and working principle of SUCCESS-DWA,which is proposed by Standford University,and then analyzed a simpledynamic wavelength allocation algorithm based on re-modulation technique.On the based ofexisting dynamic wavelength assignment,a differerntiated service level wavelength algorithmhas been put forward which take the service level differences into consideration,then the twoalgorithm has been simulated and compared.Simulation results indicates that the newwavelength assignment algorithm give priority to ensuring a high level of demand forbandwidth, and the network’s delay in particular the high priorith transmission delay is beingreduced.The system has a high bandwidth utilization and delay of good charateistics.