Redundant Access Network Secondary Path Design

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Solution Overview

Problem

Conventional protection methods for access networks with large coverage areas are costly due to the need for duplicating fiber infrastructure, which is expensive and inefficient, especially in passive optical networks where longer distances and higher terminal concentrations increase the risk of service disruptions affecting many users.

Innovation Solution

Implementing a protection concept that uses a secondary path with a lower transmission rate to maintain essential services like telephone service in case of primary path failure, utilizing additional power couplers to carry traffic on a reduced number of fibers, thereby reducing the number of fibers required and associated costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a second path is provided for every first path to ensure protection, then reliability is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveprotection mechanismVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by enabling a single secondary path to serve multiple primary paths simultaneously. The secondary path is designed to carry traffic for any number of primary paths that fail, making it a multi-functional protection resource rather than a dedicated one-to-one backup. This reduces the overall number of protection paths needed in the network.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple protection functions into a single secondary path. Instead of having separate secondary paths for each primary path, the invention combines the protection capability to handle failures from multiple primary paths through one shared secondary path, thereby reducing device complexity and resource requirements.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If fiber infrastructure is duplicated for protection, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveprotection mechanismVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple protection functions into a single secondary path, reducing the total amount of fiber infrastructure needed. By allowing one secondary path to protect multiple primary paths, the manufacturing cost of duplicating fiber infrastructure is significantly reduced while maintaining protection capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the operational parameters of the secondary path by allowing it to dynamically serve multiple primary paths depending on failure conditions. This parameter flexibility enables more efficient use of the fiber infrastructure, reducing the need for extensive physical duplication and thereby lowering manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If transmission rate is reduced on secondary path, then cost decreases, but productivity decreases

Engineering Contradiction:
ImprovecostVSAvoidtransmission rate
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies partial action by providing full transmission rate on primary paths while using reduced transmission rate only on secondary paths that are activated during failure conditions. This partial differentiation allows cost reduction on backup paths without significantly impacting overall network productivity, since the secondary paths are only used when primary paths fail.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent uses parameter changes by implementing different transmission rates for primary and secondary paths. The secondary path operates at a lower transmission rate parameter, reducing cost, while the primary paths maintain high transmission rates for normal operation. This parameter differentiation resolves the contradiction between cost and productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2426837B1Access network with redundant system design
Publication Date: 2014.06.25 DEUTSCHE TELEKOM AG
  • EP2426837B1 patent drawingFigure 1~2
  • EP2426837B1 patent drawingFigure 3~4
  • EP2426837B1 patent drawingFigure 5~6

AI summary

The network has first manifold (120) connected to load-side optical network unit (110), while another manifold (220) is connected to first manifold. A primary path (100) with first transmission rate is provided for connecting manifold (120) and optical line termination (130). A secondary path (200) with second transmission rate is provided for connecting manifold (220) and optical line termination (230), where first transmission rate is set greater than second transmission rate. The emergency telephone service is provided by reduced transmission rate of primary path through data link.