LCom Luminaire Modulation Depth Control for Indoor Positioning
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Solution Overview
Problem
Existing GPS-based and Wi-Fi-based navigation systems face limitations in indoor navigation due to accuracy issues, limited network availability, and security restrictions, making it impractical for precise location determination, especially in environments like retail stores.
Innovation Solution
A light-based communication system using LCom-enabled luminaires that transmit pulsing light signals encoded with data, detectable by smartphones and other mobile devices, which dynamically adjust modulation depth based on ambient light levels and utilize existing camera and sensor hardware to provide accurate and reliable positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light-based communication uses high modulation depth to improve data transmission rate, then communication speed increases, but light flicker becomes perceptible and degrades lighting quality
Solution Approach 1:
The system dynamically adjusts the modulation depth based on ambient light conditions and viewer presence. When ambient light is low or a viewer is detected, the modulation depth is reduced to minimize flicker. When ambient light is high or no viewer is present, modulation depth increases to maximize data transmission rate. This dynamic adaptation resolves the contradiction between transmission speed and lighting quality.
Solution Approach 2:
The patent changes the modulation parameter (modulation depth) based on environmental conditions. By monitoring ambient light levels and adjusting the modulation depth accordingly, the system optimizes both data transmission rate and perceived lighting quality. Higher modulation depths are used in bright environments where flicker is less noticeable, while lower modulation depths are used in dim environments to maintain comfortable lighting.
2Measurement precision
If the system uses multiple light-sensing devices to improve positioning accuracy, then measurement precision increases, but device complexity increases
Solution Approach 1:
The patent makes existing smartphone components (camera and ambient light sensor) perform dual functions: their primary functions remain intact while they also serve as light-sensing devices for VLC communication and positioning. The camera captures both images and modulated light signals, while the ambient light sensor monitors both ambient illumination and light source characteristics. This multi-functionality improves positioning accuracy without adding dedicated specialized hardware.
Solution Approach 2:
The system uses the smartphone's own existing sensors (camera and ambient light sensor) to perform the light detection and positioning functions. Rather than requiring external specialized hardware, the smartphone leverages its built-in components to receive and process VLC signals, determining position and orientation information. This self-service approach enhances measurement precision while avoiding increased device complexity.
3Reliability
If the system adapts modulation to ambient light levels to maintain constant signal quality, then reliability improves, but device complexity increases
Solution Approach 1:
The system implements a feedback mechanism where the ambient light sensor continuously monitors ambient illumination levels, and this information feeds back to the luminaire controller. The controller adjusts the modulation depth of the VLC signal based on the ambient light conditions to maintain optimal signal-to-noise ratio and constant signal quality. This feedback loop ensures reliable communication while adapting to changing environmental conditions.
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
Enhances indoor navigation precision and accuracy by minimizing perceivable light flicker, reducing the need for specialized hardware, and maintaining constant signal quality, enabling efficient and reliable data transmission even in dynamic environments.
Implementation Method 1
a light-sensitive device, such as a camera or a sensor native to smartphones and other mobile devices, to receive the pulsing light of an LCom signal
Data Source
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AI summary
Techniques are disclosed for selective use of light-sensing devices in light-based communication (LCom). In accordance with some embodiments, the disclosed techniques can be used, for example, in determining how and when to utilize a given light-sensitive device, such as a camera or an ambient light sensor, of a receiver device for purposes of detecting the pulsing light of LCom signals transmitted by an LCom-enabled luminaire. In accordance with some embodiments, determination of whether to utilize only a camera, only an ambient light sensor, or a combination thereof in gathering LCom data may be based, in part or in whole, on factors including time, location, and/or context. In some cases, improvements in system resource usage may be realized using the disclosed techniques.