PON Bandwidth Allocation Ring Architecture Scalability

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Solution Overview

Problem

Conventional bandwidth allocation methods in large-scale Passive Optical Networks (PONs) face scalability issues, leading to increased costs and performance degradation due to excessive loads on bandwidth allocation modules, resulting in inefficient bandwidth usage and delayed service cycles.

Innovation Solution

A bandwidth allocation equipment with a transmit/receive unit and multiple bandwidth allocation units connected in a ring, allowing for distributed processing of bandwidth allocation requests based on priority, enabling efficient allocation even with a large number of Optical Network Units (ONUs) without redundancy, and ensuring rapid processing and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional bandwidth allocation methods are used in large-scale PONs, then bandwidth allocation can be performed, but the bandwidth allocation modules experience excessive loads leading to scalability issues and performance degradation

Engineering Contradiction:

Improvebandwidth allocation efficiencyVSAvoidbandwidth allocation module load

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The bandwidth allocation function is divided into multiple independent bandwidth allocation units (BAUs), each responsible for allocating bandwidth to a specific ONU. This segmentation distributes the processing load across multiple units, preventing any single module from becoming overwhelmed and improving overall scalability and performance in large-scale PONs.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the number of ONUs increases in a PON system, then network coverage is improved, but the load on bandwidth allocation modules increases causing delayed service cycles

Engineering Contradiction:

Improvenumber of ONUsVSAvoidservice cycle delay

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

By segmenting the bandwidth allocation function into multiple BAUs, each handling a subset of ONUs, the system can accommodate a larger total number of ONUs without increasing the processing load on any single allocation unit. This maintains service cycle timing even as network scale expands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs bandwidth allocation in advance during the previous service cycle, allowing the allocated bandwidth information to be ready before the current service cycle begins. This preliminary action ensures that even with increased ONU density, the allocation decisions are made ahead of time, preventing service cycle delays.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If a single bandwidth allocation module is used, then device complexity is reduced, but bandwidth allocation performance degrades due to excessive load

Engineering Contradiction:

Improvebandwidth allocation speedVSAvoidnumber of bandwidth allocation units

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each bandwidth allocation unit is designed with identical functionality to allocate bandwidth to its assigned ONU. This universal design allows the system to scale by simply adding more identical units rather than designing increasingly complex single modules, maintaining performance while managing complexity through standardization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Productivity

If distributed bandwidth allocation processing is implemented, then bandwidth efficiency is maintained, but system complexity increases

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidbandwidth allocation system structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

All bandwidth allocation units are designed with identical structure and function, creating a homogeneous system that is easy to implement and maintain. This homogeneity reduces the actual complexity burden despite the distributed architecture, as each unit can be implemented using the same standardized design.

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS7609720B2Equipment and method for band allocation

Publication Date: 2009.10.27 NEC CORP

AI summary

A bandwidth allocation equipment in an optical line terminal, which allocates bandwidth for data to be transmitted from optical network units through an optical splitter, includes a transmit/receive unit and bandwidth allocation units. The transmit/receive unit receives an output request for requesting bandwidth allocation, and sends back a signal sending permission to the respective optical network units for specifying bandwidth to be allowed for transmitting the data in each service cycle. The bandwidth allocation units are connected to one another in a ring. Each bandwidth allocation unit is provided with corresponding to the optical network unit, and outputs the signal sending permission from the bandwidth allocation unit that has performed the last bandwidth allocation processing in the ring connection. The transmit/receive unit specifies the bandwidth allocation unit that performs the first bandwidth allocation processing by shifting one by one for each of the service cycles.