Protection for an Immediate Split Structure of Tree-Based EPON Architecture-Ideal Condition Analysis

Mohammad Syuhaimi Ab-Rahman,Siti Asma Che Aziz,Kasmiran Jumari

doi:10.3844/ajeassp.2009.372.380

Mohammad Syuhaimi Ab-Rahman, Siti Asma Che Aziz + Show 1 more

Open Access

https://doi.org/10.3844/ajeassp.2009.372.380

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Abstract

Problem statement: Ethernet Passive Optical Network (EPON) was proposed to overcome the bandwidth bottleneck at the Access Networks due to its simplicity, cost effective and wide spread deployment. A failure in access networks can cause serious problems, because access network transmit aggregated high speed traffic from hundreds of subscribers. Protection and restoration mechanisms have been applied in backbone networks, but access networks are not considered significantly in the scope of survivability. Approach: In this study, we proposed a cost effective protection scheme for a novel tree-based EPON architecture. Immediate Split Structure (ISS) means the signal was totally split after pass through the first optical splitter. This was the second proposal method after first suggestion using Optical Cross Add and Drop Multiplexer (OXADM) as a restoration switch. In this study we used only 2 × 2 and 2 × 1 optical switches combination to divert the traffic to the alternative path. Three faulty conditions were considered in this research and OptiSystem, Inc software was used to prove the solution feasibility. Results: The Bit Error Rate (BER) performances were measured by a 1.25 Gb sec-1 Non-Return-to-Zero (NRZ) pseudo random binary sequence (PRBS) with a pattern length of 231-1 for the downstream traffic between the OLT and 8 ONUs. Our results were obtained by observing bit error rates, eye diagrams and optical power levels in ideal condition. Conclusion: The survivability of EPON is necessary to provide seamless services and ensure network reliability. Single failure in the line connected will activate dedicated protection while shared protection was activated when both fiber (working and standby fiber) are breakdown. We analyzed the system in ideal condition to prove the system feasibility.

Highlights

New broadband deployments are frequently justified primarily by today’s applications rather than anticipated demands
The unique monitoring system architecture requires a single switch element and coupler connection between the Access Control System (ACS) and Protection mechanism type A: Downstream optic signal with λ1 = 1480 nm and λ2 = 1550 nm wavelength will be transmitted from central office (OLT) through the feeder region
Protection type A: Fig. 8 shows the eye diagram for downstream wavelength with Max Q Factor and minimum Bit Error Rate (BER) value for three different wavelengths measured at Optical Network Units (ONUs) 1

Summary

Introduction

New broadband deployments are frequently justified primarily by today’s applications rather than anticipated demands. Some service providers are already offering 1 Gbit sec−1 access to residential customers today and there are substantial deployments of 100 Mbit sec−1 networks in some European countries. These bit rates can only be provided via FTTH. It has long been thought that fiber’s very significant bandwidth would open the way to new applications by the consumer, but it is only recently with the advent of the Internet and the expansion of copper based broadband that this vision may become reality. It corresponds to the demarcation point between the access network and the metro backhaul network[1]

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