| Summary: | 碩士 === 國立臺北科技大學 === 資訊工程系研究所 === 99 === In recent years, PON has been considered as one of the appropriate solutions to deal with the transmission bottleneck between backbone network and access network. TDM-EPON shows the advantages of both low cost and easy implementation, but it has to take time-synchronization issue of upstream transmission into account. Therefore, it is very important to design an effective dynamic bandwidth allocation scheme for such a network system.
This thesis proposes a dynamic bandwidth allocation scheme based on the architecture of offline scheduling. The design goal of this scheme is to reduce the idle time when the system is already overloaded. To achieve this goal, a few packets with the higher priority are allowed to be transmitted during the idle time. The packet delay、packet dropping ratio and utilization level are used as the metrics of performance measurement. We compare the simulation results with the other proposed schemes. Under some specific traffic input conditions, our scheme can achieve better performance results. However, we also observe that the performance behaviors of the proposed scheme are highly sensitive to the traffic input patterns. We also apply our proposed schemes on Long Reach PON to observe the simulation results. It is found that with the increase of transmission distance, the performance of the proposed scheme gets worse. We thus discuss and identify the future research directions and possible solutions.
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