Dynamic PON Bandwidth Scheduling via OLT Extraction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In Passive Optical Network (PON) systems, upstream data packet traffic congestion occurs due to varying uplink bandwidth, leading to packet drops when Optical Network Units (ONUs) lack sufficient buffering capacity and complex scheduling mechanisms are required to maintain Quality of Service (QoS) standards.

Innovation Solution

Determining momentary parameter values of scheduling control parameters, such as uplink bandwidth capacity, and transmitting these values to downstream nodes with schedulers, allowing them to adapt and schedule upstream data packets according to the actual bandwidth, thereby moving QoS decisions away from the ONU and simplifying its scheduling tasks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If advanced scheduling mechanisms are implemented in the ONU to maintain QoS standards, then QoS performance is improved, but device complexity increases

Engineering Contradiction:

ImproveQoS performanceVSAvoidONU complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the scheduling function from the ONU and relocates it to the OLT. The ONU no longer performs complex scheduling operations, instead simply transmitting upstream traffic. The OLT receives scheduling control parameters from the NT and uses these to schedule upstream bandwidth allocation, thereby maintaining QoS performance while significantly reducing ONU complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If buffering capacity is increased in the ONU to handle bandwidth variations, then packet drop rate is reduced, but device complexity and cost increase

Engineering Contradiction:

Improvepacket drop rateVSAvoidbuffering capacity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the ONU transmits scheduling control parameters to the OLT, which then adjusts upstream bandwidth allocation based on actual network conditions. This dynamic feedback loop allows the system to adapt to bandwidth variations without requiring large buffering capacity in the ONU, as the scheduling is optimized in real-time at the OLT.

Inventive Principle:

Principle #23Feedback

3Productivity

If scheduling control parameters are determined at the ONU, then upstream bandwidth utilization is improved, but the need for buffering capacity increases

Engineering Contradiction:

Improveupstream bandwidth utilizationVSAvoidbuffering capacity

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent introduces the NT as an intermediary that determines scheduling control parameters based on PON uplink bandwidth conditions. The NT calculates these parameters and transmits them to the OLT, which then uses them for upstream bandwidth allocation. This intermediary approach enables efficient bandwidth utilization without requiring the ONU to perform complex scheduling or maintain large buffers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9270404B2Dynamic scheduling using PON bandwidth allocation on lower aggregation levels

Publication Date: 2016.02.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present invention relates transmission network, which involves Passive Optical Network and thereto connected units, e.g. Optical Network Units. It is an object of the present invention to provide a solution to the upstream data packet traffic congestion problem in transmission networks that comprises a PON system. Said problem is solved by providing adapted node devices and methods for such scheduling control that within the prescribed standard requirements, e.g. QoS, for passive optical network systems eliminate the congestion problem.