Visible-Light Localization Server Using Sequential TDoA Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for localizing mobile terminals using visible-light wireless communication systems face challenges in accuracy and cost, with conventional ID-based methods offering low accuracy and multi-PD systems providing higher accuracy but at a higher cost.
Innovation Solution
A localization method employing a TDoA scheme using visible-light signals, where multiple visible-light transceivers sequentially transmit signals without overlapping, allowing a mobile terminal to compute its position based on receiving times, and a localization server controls these transmissions to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PDs are arranged in a circular formation to measure position using intensities and incident angles of visible light, then localization accuracy is improved, but system cost increases
Solution Approach 1:
The system divides the localization function into two parts: multiple LEDs transmit signals sequentially (simple structure), while a single PD in the mobile terminal performs reception and processing (accurate measurement). This segmentation allows achieving high localization accuracy without requiring multiple PDs in the terminal, thereby reducing system cost and complexity.
2Device complexity
If multiple LEDs transmit visible-light signals simultaneously with their IDs for localization, then system establishment cost is reduced, but localization accuracy decreases
Solution Approach 1:
Multiple LEDs transmit visible-light signals sequentially rather than simultaneously, with each LED transmitting during its designated time period. This periodic action prevents signal interference and allows the mobile terminal to accurately identify which LED transmitted the signal and when, thereby achieving high localization accuracy while maintaining simple system establishment.
3Ease of operation
If visible-light signals are transmitted without time coordination, then transmission simplicity is maintained, but signal interference occurs reducing localization precision
Solution Approach 1:
The localization server performs preliminary scheduling of transmission time periods for each LED before the actual signal transmission begins. This preliminary action assigns specific time windows to each LED, ensuring that signals are transmitted in a coordinated manner without interference, thereby maintaining transmission simplicity while achieving high localization precision.
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
This approach enhances localization accuracy by preventing signal interference and reduces system costs by optimizing the transmission schedule of visible-light signals, enabling precise positioning of mobile terminals.
Implementation Method 1
a visible-light receiver 120 may be composed of a PD (121) that detects the on/off states of the visible light to receive the visible-light signals
Implementation Method 2
the visible-light transceiver 110 may be composed of an LED 111 that emits visible light
Data Source
AI summary
A mobile terminal capable of localization, a localization server, and a method for localizing the mobile terminal using the localization server are disclosed. The disclosed localization server includes a control unit configured to control transmissions of visible-light signals from a multiple number of visible-light transmitting devices; and a position computing unit configured to compute a position of a mobile terminal based on time information regarding when the visible-light signals transmitted respectively from the plurality of visible-light transmitting devices were received at the mobile terminal, where the control unit controls the transmissions such that each of the plurality of visible-light transmitting devices sequentially transmits the visible-light signal for a particular first time period with no overlapping of transmission times of the visible-light signals transmitted respectively from the plurality of visible-light transmitting devices.