Multi-Thread Fitting Scheduling Timing – Elastic Weighted Granting Algorithm to Overcome Performance Degradation in Long Reach TDM-PONs

Abstract

In recent years passive optical networks (PONs) have been widely chosen for deploying optical access networks With the widespread deployment of PONs research focus has shifted to their scalability with longer reach and higher split ratio By exploiting both optical amplifiers long-reach PONs (LR-PONs) extend the coverage of a PON from short-reach 20 km to 100 km and beyond By reducing the number of network elements the network’s Capital Expenditure (Capex) and Operational Expenditure (Opex) can be reduced On the other hand due to the increased distance between optical network terminal (OLT) and optical network unit (ONU) the propagation delay increases to 1ms When an ONU requests upstream bandwidth it will take a longer time to receive the acknowledgement from the OLT before it can transmit its upstream packets Thus the traditional dynamic bandwidth allocation (DBA) in LR-PONs must be redesigned and under review In this thesis we propose a multi-thread fitting scheduling timing-elastic weighted granting (MT-FST-EWG) dynamic bandwidth allocation algorithm (MT-FST-EWG) which is to merge the advantages of both fitting scheduling timing-elastic weighted granting (FST-EWG) and multi-thread polling (MTP) and improve the effectiveness of FST-EWG shortage in LR-PON We evaluate the throughput-delay performance of MT-FST-EWG FST-EWG and MTP We find that MT-FST-EWG gives lower delays and idle times than FST-EWG and MTP At the same time the propagation delay problem FST-EWG faced was solved by MT-FST-EWG

Date of Award	2014 Aug 24
Original language	English
Supervisor	Chuan-Ching Sue (Supervisor)