PON Activation Multiplexing Spreading Codes Low Latency

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Solution Overview

Problem

Existing passive optical networks (PONs) face challenges in activating optical network units (ONUs) without disrupting delay-sensitive transmissions, often requiring quiet windows that can limit activation opportunities and increase costs with separate channels for activation.

Innovation Solution

Implementing a method that multiplexes spreading codes with upstream transmissions during an activation window, allowing the optical line terminal (OLT) to receive both low latency and activating transmissions on the same channel, reducing delays and collisions by distinguishing between synchronized and activating ONU transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If quiet windows are used for ONU activation, then activation can be performed, but transmission opportunities are limited and separate channels are required

Engineering Contradiction:

ImproveONU activation capabilityVSAvoidchannel structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines activation transmissions and low latency transmissions into a single shared upstream channel by using code division multiplexing. Different ONUs are assigned orthogonal spreading codes, allowing the OLT to distinguish between activation requests from unsynchronized ONUs and data transmissions from synchronized ONUs without requiring separate physical channels or quiet windows.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The upstream channel is designed to serve multiple functions simultaneously: it handles both activation requests from unsynchronized ONUs and data transmissions from synchronized ONUs. The orthogonal spreading codes enable the channel to universally accommodate different transmission types without functional separation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If quiet windows are used for ONU activation, then activation can be performed, but transmission delays increase

Engineering Contradiction:

ImproveONU activation capabilityVSAvoidtransmission delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The upstream channel operates continuously without requiring quiet windows or transmission pauses for activation. Synchronized ONUs can transmit data continuously while unsynchronized ONUs insert activation requests with appropriate spreading codes, eliminating idle periods and reducing activation time.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If separate channels are used for activation, then activation can be performed, but network costs increase

Engineering Contradiction:

ImproveONU activation capabilityVSAvoidchannel resources

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges activation and data transmission functions into a single shared upstream channel, reducing the total number of channels required from two (separate activation and data channels) to one (multiplexed channel), thereby conserving network resources and reducing costs.

Inventive Principle:

Principle #5Merging (Combining)

4Quantity of substance

If activation and low latency transmissions share the same channel, then costs are reduced, but collisions may occur

Engineering Contradiction:

Improvechannel resourcesVSAvoidtransmission reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent segments the shared channel into orthogonal code spaces using spreading codes. Each ONU is assigned a unique orthogonal code, effectively dividing the channel into non-interfering virtual sub-channels that prevent collisions even when multiple ONUs transmit simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Orthogonal spreading codes act as intermediaries that enable the OLT to distinguish between different ONUs' transmissions on the shared channel. The codes mediate the separation of signals, allowing reliable identification of activation requests versus data transmissions without physical channel separation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250096920A1Optical network unit activation and low latency transmissions in delay sensitive networks

Publication Date: 2025.03.20 MAXLINEAR INC

AI summary

According to an aspect of an embodiment, a method may include assigning an activation window by an optical line terminal during a portion of an upstream transmitting window in a passive optical network (PON). The method may include performing a first modification to a first upstream transmission. The method may include performing a second modification to a second upstream transmission. The method may include receiving the first upstream transmission from a first optical network unit (ONU) during the activation window, the first ONU synchronized in the PON. The method may include receiving a second upstream transmission from a second ONU during the activation window, the second ONU requesting activation in the PON.