Bandwidth and availability enhancement in dense wavelength division multiplexing optical networks.
Mkhwanazi, Mnotho
Mkhwanazi, Mnotho
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Abstract
Since the introduction of 3G technology and, more recently, the emergence of 5G applications and services, mobile network subscribers have increased rapidly over the years and are more reliant on their mobile devices than in the past. This phenomenon has compelled mobile network operators to implement technologies capable of handling the traffic surge. Mobile devices are being used for both recreational and business purposes, prompting mobile network operators to give prominence to bandwidth and network availability as major contributors to customer satisfaction. Techniques and strategies that promote high bandwidth and network availability demand the adoption of advanced data-transmission technologies. One such
technology is Dense Wavelength Division Multiplexing (DWDM). This study delved deeper into DWDM technology, which is a transmission technology used in the optical networks of large mobile network operators around the world. The goal of this research was to investigate techniques and strategies to enhance bandwidth and network availability in DWDM optical networks. The study used a pragmatic approach that included quantitative and qualitative research methods. A desk research strategy was used to conduct a comprehensive literature review for the study. Secondary data for the desk research was acquired from various academic research databases, the internet, and data sheets from various DWDM vendors. The simulation was performed using the 1830 Engineering and Planning Tool, Release: 22.12.0, which is a Nokia proprietary planning tool for DWDM optical networks. The study found that Flex-Grid technology proved to be crucial in DWDM optical network capacity enhancement. 100/200/400 Gbit/s lambdas were simulated, and Flex-Grid technology outperformed Fixed-Grid in terms of spectral efficiency, number of transponders used, and power consumption. Transponder type, modulation scheme, baud rate, and optical signal-to-noise ratio margin were identified to be factors influencing a lambda’s reach. The verdict was that the Quadrature Phase Shift Keying modulation scheme is suitable for long-distance transmission, while higher-order modulation schemes like 16-Quadrature Amplitude Modulation are suited to higher line rate transmission over short distances. The study further found that a Reconfigurable Optical Add-Drop Multiplexer (ROADM) with colourless, directionless, C2 General and contentionless (CDC) features enabled effective and improved lambda restoration. The research demonstrated that combining Flex-Grid technology with CDC ROADM reduced Operational expenditure (OPEX) costs. On the simulated network, Service Level Agreement 2 with a mean time-to-repair of eight hours was recommended, which led to an OPEX saving of R26 346 600 per annum on dark-fibre leases. Another cost-cutting effort was comparing the power consumption of Fixed-Grid and Flex-Grid transponders. When using Flex-Grid transponders, power consumption was reduced by 69%. Finally, while the Flex-Grid technology and CDC
ROADM features can be deployed separately, the study recommends that they be deployed together to produce the most resilient, flexible, bandwidth-ready, and futureproof DWDM optical network.
Description
Submitted in the fulfilment of the requirements for the degree of Master of Engineering: Engineering Management in the Department of Industrial Engineering in the Faculty of Engineering and the Built Environment at the Tshwane University of Technology.
Date
2023-11-01
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Tshwane University of Technology
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Keywords
Wavelength, Optical networks, Flex-Grid technology