Adaptive Light Modulation for Indoor Positioning
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Solution Overview
Problem
Existing GPS and Wi-Fi-based navigation systems are impractical for indoor navigation due to limited accuracy and availability, especially in environments like retail stores, where security restrictions and environmental factors hinder effective positioning.
Innovation Solution
A light-based communication system using solid-state luminaires that transmit pulsing light signals encoded with data, detectable by smartphones and other mobile devices, which dynamically adjust modulation depth and utilize ambient light sensors to maintain constant light levels and minimize perceivable flicker, allowing for accurate indoor positioning without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light modulation depth is increased to improve data transmission quality, then signal-to-noise ratio is improved, but light quality degradation and perceivable flicker increase
Solution Approach 1:
The system dynamically adjusts modulation depth based on ambient light conditions. In brighter environments, higher modulation depths are used to maintain signal-to-noise ratio, while in darker environments, modulation depth is reduced to prevent perceivable flicker. This dynamic adaptation resolves the contradiction between transmission quality and light quality.
Solution Approach 2:
The system changes the modulation depth parameter according to ambient light levels detected by the ambient light sensor. By varying this key parameter, the system optimizes the balance between signal-to-noise ratio and perceptibility, using higher values for better SNR when needed and lower values to maintain natural light appearance when possible.
2Productivity
If modulation frequency is increased to improve baud rate, then data transmission speed is improved, but driver electronics complexity increases
Solution Approach 1:
The system uses periodic pulse-width modulation to transmit data at high baud rates. By encoding data in the width of light pulses rather than requiring extremely high frequency modulation, the system achieves high data transmission speeds while keeping driver electronics complexity manageable. The periodic nature of the modulation allows for efficient encoding and decoding.
3Device complexity
If fixed modulation depth is used to simplify system design, then device complexity is reduced, but communication reliability in varying ambient light conditions deteriorates
Solution Approach 1:
The system incorporates an ambient light sensor that continuously monitors ambient light levels and provides feedback to the modulation depth controller. This feedback loop enables the system to automatically adjust modulation depth to maintain optimal communication reliability across varying ambient light conditions, from bright outdoor environments to dark indoor settings, without requiring complex manual configuration.
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
The system provides precise indoor navigation by enhancing baud rate and signal-to-noise ratio, reducing data packet collisions, and maintaining reliable communication, even in environments with varying ambient light conditions, thus overcoming the limitations of traditional GPS and Wi-Fi systems.
Implementation Method 1
an ambient light sensor configured to detect ambient light levels
Implementation Method 2
at least one solid-state light source configured to output light
Data Source
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AI summary
Techniques are disclosed for adaptively modulating light in light-based communication (LCom). In accordance with some embodiments, the disclosed techniques can be used, for example, to dynamically adjust light modulation depth based, at least in part, on ambient light levels. In some cases, using the disclosed adaptive light modulation scheme, a given LCom-enabled luminaire (100) may be configured to adjust the modulation depth dynamically and/or control the signal-to-noise ratio (SNR) such that the average light signal is kept constant, regardless of what LCom data is being transmitted. In some cases, the disclosed techniques can be used, for example, to dynamically adjust light modulation depth according to a given minimum light modulation depth assessed by measuring the ambient lighting conditions of the environment of the LCom-enabled luminaire (100). In some instances, an optimized or other target SNR can be provided using the disclosed techniques.