Research On Upstream Dynamic Resource Management In Passive Optical Networks

With the development of "Internet+",the data will usher in a more explosive growth which drive the development of communication areas.And the original copper wire access network can't meet the bandwidth demand of users,so the deployment of optical fiber access network will become an important measure.Passive Optical Network will become one of the most prospect of access network technologies because of its advantages.The structure of the PON is point to multipoint,therefore,the resource scheduling algorithm is a key technology.With the development of the structure,the MAC layer of uplink bandwidth allocation algorithm need to constantly improve.The paper mainly do the research of the wavelength and bandwidth allocation algorithms in Long Reach-Passive Optical Networks(LR-PON)and Time and Wavelength Division Multiplexing-Passive Optical Networks(TWDM-PON).Main work and research contents of the paper are as follows:1)The thesis focuses on the study of the LR-PON bandwidth allocation,analyzes the architecture and the algorithm-Multi Thread Polling(MTP)algorithm in LR-PON.The thesis summarizes the advantages and deficiencies of MTP algorithm,and proposes a more flexible multithread polling algorithm-Inter Mutli Thread Polling Dynamic Bandwidth Allocation algorithm(IMTP-DBA).IMTP-DBA allocates the threads for each ONU more flexible,respectively,the heavily loaded ONU will allocate more number of threads in a cycle time,and the lightly loaded ONU will distribute less number of threads.Compares with MTP algorithm,when the network load in the system unbalanced,IMTP-DBA algorithm can reduce the delay and improve the bandwidth utilization of heavily loaded ONUs.2)The thesis analyzes the architecture and of TWDM-PON,and at the same time,it also analyzes the algorithms in the mixed TDM/WDM PON.The only significant new component in TWDM-PON is the tunable lasers at the ONU,and the tuning time(TT)in some extent has a large impact on the performance of the dynamic wavelength and bandwidth allocation algorithm.So the paper proposes a Minimum Wavelength Tuning scheme for dynamic wavelength and bandwidth allocation algorithm(MWT-DWBA algorithm).The main principle of the algorithm is changing the polling sequence of the ONUs.First,we recorded the transmission wavelength of each ONU,and the ONUs occupying the same wavelength can be set in a group.Then in the next cycle,choose the first finish wavelength at the same time preferentially get the ONU that last cycle transmit on this wavelength.The algorithm reduces the frequency of wavelength tuning in a cycle.The simulation results show that the algorithm can improve the utilization of upstream bandwidth,and reduce the average delay greatly.