TWDM-PON Architecture for Network Capacity and Reach
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Solution Overview
Problem
Upgrading and expanding access networks from existing fiber-optic communication systems is challenging due to the need for simultaneous hardware upgrades at central offices and optical network units, which is costly and inefficient, especially in scaling bandwidth and reducing operational costs.
Innovation Solution
The implementation of a Time-Wavelength-Division Multiplexing Passive Optical Network (TWDM-PON) architecture that combines TDM and WDM technologies, utilizing a cyclical arrayed waveguide grating router to efficiently multiplex and demultiplex signals, allowing for the consolidation of central offices and reduced need for tunable receivers at optical network units, thereby optimizing feeder fiber usage and network management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional TDM or WDM networks are upgraded by simultaneously upgrading hardware at central offices and optical network units, then network capacity and bandwidth are improved, but upgrading cost and operational complexity increase significantly
Solution Approach 1:
The patent segments the network upgrade process into independent phases: first deploying TWDM infrastructure at the central office, then gradually upgrading optical network units at customer premises at different times. This allows the central office to support multiple protocols (TDM, WDM, TWDM) simultaneously, enabling staged migration without requiring simultaneous upgrades across the entire network.
Solution Approach 2:
The central office equipment is designed with multi-functionality to support multiple multiplexing protocols (TDM, WDM, and TWDM) concurrently. The optical line terminals can handle different protocol types, allowing the network to accommodate both legacy and upgraded equipment, thereby reducing upgrade complexity and enabling flexible migration paths.
2Adaptability or versatility
If the number of central offices is increased to serve more customers, then network coverage and service quality are improved, but operational costs and network management complexity increase
Solution Approach 1:
The patent merges multiple central offices into a single consolidated central office that serves a larger geographic area using TWDM technology. By combining TDM and WDM capabilities in one facility, the network can cover more customers with fewer central offices, reducing operational costs and simplifying network management while maintaining service quality through advanced multiplexing techniques.
3Productivity
If tunable receivers are deployed at all optical network units to support wavelength sharing, then network capacity and flexibility are improved, but equipment cost and power consumption increase
Solution Approach 1:
The patent applies local quality by deploying tunable receivers selectively only at specific optical network units that require wavelength sharing capabilities, rather than at all customer premises. Most optical network units use fixed-wavelength receivers, while only those needing enhanced flexibility or serving specific services receive tunable receivers, thereby reducing overall equipment cost while maintaining network capacity where needed.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A communication system (100) includes a first multiplexer (320a) multiplexing a first optical line terminal signal (SD1) having a first multiplexing group and a second optical line terminal signal (SDn) having a second multiplexing group into a first multiplexed signal (SDM). The communication system includes a second multiplexer (320b) demultiplexing a second multiplexed signal (SUM) into a third optical line terminal signal (SU1) having the first multiplexing group and a fourth optical line terminal signal (SUn) having the second multiplexing group. Moreover, the communication system includes a third multiplexer (310) optically connected with the first and second multiplexers, the third multiplexer configured to multiplex/demultiplex between a feeder optical signal (STa) and the first and second multiplexed signals. The first and second optical line terminal signals include a legacy upstream free spectral range, and the third and fourth optical line terminal signals include a legacy downstream free spectral range.