Sectorized LiFi Receiver Handover Using Transmission Gaps

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Solution Overview

Problem

Existing optical wireless networks face challenges in seamless handover and interference management between neighboring access points (APs) without requiring substantial hardware modifications or sacrificing channel time.

Innovation Solution

A sectorized receiver with multiple photodetectors having different fields of view is used to detect modulated light signals during transmission interruption times, allowing for efficient handover by switching to a photodetector with stronger signal strength without interrupting communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple photodetectors are used for handover detection, then handover reliability is improved, but device complexity increases

Engineering Contradiction:

Improvehandover reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The receiver is divided into multiple photodetectors, each with a different field of view oriented toward different access points. This segmentation allows the system to detect signals from multiple APs simultaneously, improving handover reliability by enabling seamless switching between APs without requiring the entire receiver to be complex.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multiple photodetectors serve a dual function: they enable handover detection by monitoring signals from neighboring access points, and they maintain continuous communication with the current access point. This multi-functionality improves reliability without proportionally increasing complexity, as the same hardware components serve multiple purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If photodetector testing is performed continuously, then signal detection accuracy is improved, but channel time is lost

Engineering Contradiction:

Improvesignal detection accuracyVSAvoidchannel time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Photodetector testing is performed periodically during transmission interruption times rather than continuously. The system exploits the natural gaps in transmission schedules to switch between photodetectors and detect signals from neighboring access points. This periodic action maintains measurement precision while minimizing channel time loss, as testing occurs only when the current transmission is temporarily suspended.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system maintains continuous communication by ensuring that photodetector testing and handover detection occur during existing transmission interruptions without extending the overall communication timeline. The useful action of data transmission continues uninterrupted except for the brief moments when signal strength measurements are taken during scheduled interruptions.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If hardware modifications are made for handover control, then handover capability is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improvehandover capabilityVSAvoidease of manufacture

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The system achieves handover capability through dynamic switching between photodetectors based on real-time signal strength measurements, rather than through complex hardware modifications. The photodetectors are statically positioned with different fields of view, but the system dynamically selects which photodetector to use based on current communication conditions. This dynamic approach improves handover capability while keeping the hardware simple and easy to manufacture.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs self-service handover control by autonomously monitoring signal strengths from multiple access points and automatically switching between photodetectors without requiring external control mechanisms or complex hardware modifications. Each photodetector independently detects signals, and the system self-determines when to switch based on predefined signal strength thresholds, simplifying the manufacturing process while maintaining advanced handover capability.

Inventive Principle:

Principle #25Self-service

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 seamless handover and reduced interference between APs by utilizing existing network gaps for detection, minimizing hardware requirements and maintaining continuous data transmission.

Implementation Method 1

A communication signal can be embedded in a modulated light signal emitted by an illumination source... information in the coded light can be detected using any suitable light sensor or photodetector

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS12526047B2Method and apparatus for handover control in an optical wireless communication network

Publication Date: 2026.01.13 SIGNIFY HOLDING BV

AI summary

In optical wireless communication networks (e.g. LiFi networks), comprised of multiple access points (201, 202), APs, a mechanism is provided for seamless handover between two overlapped neighboring APs, wherein a sectorized endpoint (209) is configured to exploit knowledge of channel turnaround to detect the presence of neighboring AP(s) in an efficient manner and select a relevant segment (PD1, PD2, PD3, PD4) for handover.