Smooth Upgrade To Next-generation Passive Optical Network PON

Passive optical network(PON)has become a popular optical access network solution due to its business transparency,high cost performance,energy saving,and high security.PON uses passive low-power devices and does not require power supply in the optical fiber distribution network.However,with the rapid development of Internet technology and smart terminals,Ethernet Passive Optical Network(EPON)and Gigabit Passive Optical Network(GPON)technologies have been unable to meet the long-term development needs of today's services.How to develop the next generation of PON(Next Generation PON,NGPON)has become a hot spot for domestic and foreign research.However,as an access network,PON is very cost-sensitive.If a new PON is to be installed every time,it is difficult for users to bear the high upgrade cost.Due to the large number and widespread distribution of existing optical network units(ONUs)in the PON,it is expensive to upgrade all of them.The construction cost of PON mainly lies in the infrastructure to be laid to avoid laying ODN again.A solution is needed.In the process of smooth evolution to NGPON,it is necessary to be compatible with the existing PON system,reuse the laid optical distribution network,eliminate the interference of new PON lines on existing lines,and realize the coexistence of new and old lines.How the existing PON can evolve to the next generation PON through low-cost and smooth upgrade is a hot topic of research.For this reason,this thesis proposes a smooth upgrade based on orthogonal superposition of line coding and mark ratio modulation based on pulse position modulation.The new and upgraded next-generation PONs continue to reuse existing infrastructure,coexist with existing PONs,and reduce upgrade costs.In most existing smooth upgrade solutions,new and old PONs must use different wavelengths.With the continuous introduction of new PONs,the available wavelength resources are gradually "stretched",and future PONs may not be able to be allocated to new wavelengths(some current PONs)The wavelength range has begun to overlap)must face the same wavelength upgrade,and did not consider the dynamic process of the old PON users gradually upgrade to the new PON line.This thesis mainly studies the application of simple line coding and mark ratio modulation based on pulse position modulation in the smooth upgrade of PON.We first studied the line coding based on orthogonal superposition to achieve smooth upgrade.Through testing and comparing the performance of Manchester,4b5b and 4b6b,the three simple line codes,the Manchester code has the best low frequency suppression effect,and it is determined to use Manchester code modulation to achieve smoothness.Upgraded downstream signal transmission to minimize crosstalk to traditional PON signals.Secondly,for wavelength resources,a superposition scheme in the optical and electrical domains is proposed,which makes the superposition scheme more flexible.Tests have shown that there is little crosstalk to the original signal after addition,which can cope with more upgrades.Scenes.To achieve the coexistence of future PON and existing PON.Finally,a mark rate modulation based on pulse position modulation is proposed,which uses the mark rate difference between the PPM symbol and the reverse PPM symbol to convey the superimposed signal.Compared with the traditional quadrature modulation,in the mark ratio modulation on PPM,ASK modulates the low-speed and high-speed information flow without sacrificing the extinction ratio,while maintaining the ease of reception.The PPM modulation in different formats was demonstrated through simulation.Considering the trade-off between the effective bit rate of the PPM signal and the quality of the additional superimposed signal,for the smooth upgrade of the PON,the feasibility of the solution was finally proved through software simulation.4PPM is a good first choice.