Effects of Modulation Techniques (Manchester Code, NRZ or RZ) on the Operation of Hybrid WDM/TDM Passive Optical Networks.

Kumbirayi Nyachionjeka,Wellington Makondo

doi:10.1155/2014/984157

Abstract

In this paper, the performance and feasibility of a hybrid wavelength division multiplexing/time division multiplexing passive optical network (WDM/TDM PON) system with 128 optical network units (ONUs) is analysed. In this system, triple play services (video, voice and data) are successfully communicated through a distance of up to 28 km. Moreover, we analysed and compared the performance of various modulation formats for different distances in the proposed hybrid WDM/TDM PON. NRZ rectangular emerged as the most appropriate modulation format for triple play transmission in the proposed hybrid PON.

Highlights

Telecoms operators are adapting their broadband access networks so as to enable these networks to support high bandwidth demanding services such as high-definition TV, interactive gaming and video conferencing
Recent increase in the demand for internet has brought focus on high bandwidth last mile access networks as these are the final hurdle to the consumer
The advent of wavelength division multiplexing (WDM) and TDM systems, as a solution to increase the density of customers, is being realised, and the coming in of these systems has led to reduced cost as there is sharing of equipment in the optical distribution network and the optical line terminal (ONU)

Summary

Introduction

Telecoms operators are adapting their broadband access networks so as to enable these networks to support high bandwidth demanding services such as high-definition TV, interactive gaming and video conferencing. The advent of WDM and TDM systems, as a solution to increase the density of customers, is being realised, and the coming in of these systems has led to reduced cost as there is sharing of equipment in the optical distribution network and the optical line terminal (ONU). To further reduce the overall cost, the optic fibre network is continuously being made passive., In TDM passive optical networks, the TDM scheme is used to distribute the overall capacity among many users and because of this, each user’s average bandwidth becomes limited to less than 100 Mb/s for GPONs and EPONs. In comparison, wavelength division multiplexing (WDM) PON is a strong alternative for future applications for access services requiring broadband.

Methods

Results

Conclusion