Research On Latency Optimization For Uplink Transmission In Multiple Service Twdm-pon

With the rapid development of the 5th generation mobile communication technology,Passive Optical Network(PON)has become an important scene for fixed and mobile service access.The efficient synergy of status-request dynamic bandwidth allocation(SR-DBA)and cooperative dynamic bandwidth allocation(CO-DBA)for mobile fronthaul can achieve the convergence of fixed and mobile services,which is the focus of PON research currently.However,a conflict between CO-and SR-DBA is to arise when using an emerging 5G new radio interface based on the mini-slot.This conflict will increase the upstream transmission latency of fronthaul services in the PON.Therefore,this thesis studies the latency optimization for uplink transmission in multiple service time and wavelength multiplexed PON(TWDM-PON)and research work and innovations are as follows:(1)The bandwidth allocation conflict between CO-DBA and SR-DBA will increase the waiting latency of the fronthaul service in the ONU in the mobile fronthaul scenario based on mini-slot.In this study,we propose a latency optimization scheme based on wavelength bandwidth preemption.This secheme allows high-priority fronthaul services to preempt the wavelength and bandwidth resources of low-priority fixed services when bandwidth allocation conflicts,and then allocate the front transmission window.Simulation results show that,compared with the traditional CO-DBA and SR-DBA cooperation scheme(non-preemptive mode),the proposed secheme can effectively reduce the upstream transmission latency of the fronthaul service,especially under high load conditions,the upper bound of the fronthaul service latency can meet requirements.(2)In the existing TWDM-PON upstream transmission latency optimization scheme,shortening the burst length will increase the guard interval in the upstream frame,which results in lower upstream bandwidth efficiency.In this study,we propose an latency optimization scheme based on burst control-wavelength bandwidth preemption.Simulation results show that compared with the wavelength bandwidth preemption scheme without burst control,this scheme can reduce the upstream transmission latency of the fronthaul service while maintaining a higher bandwidth efficiency.We also analyze the influence of factors such as the total network load,the ratio of fronthaul ONUs and the standard deviation of fixed ONU load on the latency of fronthaul and fixed services.