LiFi Coordinator Time Slot Allocation for Overlap Interference

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Solution Overview

Problem

Existing wireless optical networks, such as LiFi, face interference issues due to coordinators not being able to directly measure interference from neighboring coordinators due to line-of-sight limitations, and rely on a central global controller that can cause system failures if unavailable.

Innovation Solution

Implementing an access point that automatically allocates reserved time slots for coordinators to send advertisements, exchanges information with neighboring access points, and updates time slot allocations to avoid interference, using both centralized and decentralized methods to manage neighbor relations and occupancy levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a centralized global controller is used to manage coordinators and handle interference, then interference management capability is improved, but system reliability deteriorates due to single point of failure

Engineering Contradiction:
Improveinterference management capabilityVSAvoidsystem reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments the centralized global controller function into distributed coordinator entities. Each coordinator independently manages its own OWPAN and can autonomously detect and handle interference from neighboring coordinators, eliminating the single point of failure while maintaining interference management capability through distributed decision-making

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables coordinators to perform self-service by autonomously detecting neighboring coordinators through beacon messages, measuring interference levels, and adjusting their own transmission parameters without requiring centralized control, thereby improving both reliability and interference management

Inventive Principle:
Principle #25Self-service

2Object-affected harmful factors

If a global controller is installed to manage multiple OWPANs, then interference handling capability is improved, but device complexity and installation difficulty increase

Engineering Contradiction:
Improveinterference handling capabilityVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent enables coordinators to autonomously perform interference detection and handling by receiving beacon messages from neighboring coordinators, measuring interference levels, and independently adjusting their transmission parameters, eliminating the need for complex centralized control infrastructure

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements feedback mechanisms where coordinators continuously monitor interference levels through beacon messages from neighboring coordinators and automatically adjust their transmission parameters based on the measured interference, enabling dynamic interference management without complex centralized control

Inventive Principle:
Principle #23Feedback

3Ease of operation

If coordinators operate without global control, then system simplicity and ease of deployment are improved, but interference detection capability deteriorates due to line-of-sight limitations

Engineering Contradiction:
Improveease of deploymentVSAvoidinterference detection capability
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses beacon messages as intermediaries to enable indirect interference detection. Since coordinators cannot directly measure interference from neighboring coordinators due to line-of-sight limitations, they use beacon messages transmitted by neighboring coordinators as a medium to infer the presence and activity of neighbors, thereby detecting potential interference sources

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements feedback mechanisms where coordinators continuously monitor beacon messages from neighboring coordinators and automatically adjust their transmission parameters based on the received signals, enabling autonomous interference management without global control infrastructure

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3884595B1Interference handling by automatic time slot allocation for multiple coordinators
Publication Date: 2026.01.07 SIGNIFY HOLDING BV
  • EP3884595B1 patent drawingFigure 1~2
  • EP3884595B1 patent drawingFigure 3
  • EP3884595B1 patent drawingFigure 4~5

AI summary

In a wireless optical network with multiple coordinators or other access points, the coverage area of coordinators may overlap. Interference in the communication between coordinators and devices may occur in these overlapping coverage areas. Various embodiments propose an automatic allocation of reserved time slots to coordinators. These time slots support the coordinators to advertise their presence without interference and enable device to detect the presence of a neighbour coordinator in a single MAC cycle. Fast detection allows fast re-scheduling of time slots in the wireless optical network in order to prevent interference when a device that enters the overlapping coverage area of two coordinators.