Research On Resource Management In Time And Wavelength Division Multiplexing Passive Optical Networks

To improve the optical access network capacity, it is urgent to smoothly upgrade the existing access networks to the next generation optical access network:Time and Wavelength Division Multiplexing-Passive Optical Networks (TWDM-PON). TWDM-PON increases the access rate by stacking multiple Time Division Multiplexing-Passive Optical Networks (TDM-PON) in manner of Wavelength Division Multiplexing (WDM). TWDM-PON is a promising network for surpassing both TDM-PON and WDM-PON, which combines the advantages of these two technologies and avoids their weaknesses. As TWDM-PON has a point-to-multiple-points topology, the upstream bandwidth allocation scheme plays a vital role in ensuring the network performance.This thesis has studied the upstream bandwidth allocation schemes of TDM-PON and WDM-PON, on basis of which we proposed a dynamic wavelength and bandwidth allocation (DWBA) scheme named large request first-fair excess allocation scheme (LRF-FE) to manage the resources in TWDM-PON. LRF-FEAS is an integral resource management scheme and LRF-FE algorithm is the core, which exploits both inter-channel and intra-channel statistical multiplexing. LRF-FE effectively reduces unused time slots in channels, therefore network average delay drops and utilization of the expensive wavelengths improves. On the other hand, LRF-FE fairly allocates the bandwidth among optical network units (ONUs).Simulation results show that compared with two existing schemes in TDM/WDM EPON, the average packet delay of networks is reduced at most46.19%and18.45%, the resource utilization is also higher by an amount at most 31.6%and15.6%and the service offered to different users is much fairer. In conclusion, LRF-FEAS is an effective and fair resource scheme applied in TWDM-PON.