Multi-Cell Link Establishment Through Optical-RF Access Point Selection

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Solution Overview

Problem

Existing wireless communication technologies face challenges in supporting high data rates and ensuring secure, interference-free connectivity in multi-cell wireless networks, particularly in environments with electromagnetic interference, where optical wireless communication (Li-Fi) is needed to complement or replace radio-based systems.

Innovation Solution

A method and apparatus for an end device to establish a data link by monitoring optical signaling channels for identification codes, selecting an access point based on signal quality, and adjusting hardware settings to connect via optical or RF channels, using orthogonal Hadamard codes for interference management and flexible network selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If optical access points are deployed in overlapping areas to provide coverage, then network coverage and capacity are improved, but interference between adjacent cells increases

Engineering Contradiction:
Improvecoverage areaVSAvoidinterference
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The optical signaling band is segmented into multiple orthogonal sub-bands, with each adjacent optical access point assigned a different sub-band. This frequency division allows overlapping coverage areas while minimizing interference between cells through orthogonal signaling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each optical access point transmits its identification code with locally optimized characteristics including specific sub-band assignment, transmission power level, and timing offset tailored to its local environment and coverage requirements, enabling differentiated local optimization in overlapping areas.

Inventive Principle:
Principle #3Local quality

2Reliability

If end devices continuously monitor optical signaling channels to select optimal access points, then connection quality is improved, but device energy consumption increases

Engineering Contradiction:
Improveconnection qualityVSAvoiddevice energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

End devices perform periodic monitoring of optical signaling channels at predetermined intervals rather than continuously, detecting identification codes and selecting access points at scheduled times. This periodic approach maintains connection quality while significantly reducing energy consumption compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system enables end devices to autonomously monitor channels, detect identification codes, evaluate signal quality, and select access points without requiring continuous network control or assistance, optimizing the balance between connection quality and energy consumption through self-directed periodic operations.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If multiple identification codes are transmitted simultaneously by adjacent optical access points, then access point identification capability is improved, but signal detection accuracy deteriorates due to interference

Engineering Contradiction:
Improveidentification capabilityVSAvoidsignal detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The optical signaling band is divided into multiple orthogonal sub-bands, with each identification code transmitted in a dedicated sub-band. This segmentation enables simultaneous transmission of multiple identification codes by adjacent access points without mutual interference, as orthogonal sub-bands do not overlap in frequency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Orthogonal sub-bands act as intermediaries that separate and isolate the identification codes transmitted by different access points. These frequency-based intermediaries enable simultaneous transmissions while preventing direct interference, allowing receivers to accurately detect the intended identification code by filtering to the appropriate sub-band.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables robust, high-data-rate communication with reduced interference by allowing seamless switching between optical and RF networks, ensuring reliable connectivity and efficient resource utilization in overlapping cell areas.

Implementation Method 1

an optical receiver configured to detect one or more identification codes from one or more optical access points

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4154435B1Link establishment in a multi-cell wireless network
Publication Date: 2025.10.01 SIGNIFY HOLDING BV
  • EP4154435B1 patent drawingFigure 1
  • EP4154435B1 patent drawingFigure 2~3
  • EP4154435B1 patent drawingFigure 4

AI summary

In a multi-cell wireless communication system (100) with at least one optical access point (120) and at least one radio frequency access point (120), more flexibility is provided to an end device (110) in selecting an access point (120) for establishing a data link. Because of the line-of-sight characteristic of an optical link and the limited field of view of an optical receiver, optical cells are typically deployed with a relatively high density and adjacent optical cells may have an overlapping area. This invention discloses a method of an end device (110) for selecting a favorable access point (120) with reduced overhead, even when the end device is located in the overlapping area of two adjacent optical cells.