Wireless Light Communication System Using AC Zero Crossing Synchronization
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Solution Overview
Problem
In wireless light communication systems using LED lighting, overlapping optical signals can interfere with each other, leading to inaccurate location determination due to the difficulty in ensuring that there are no shadow areas and non-overlapping signal transmission zones.
Innovation Solution
Implementing a wireless light communication method where multiple light transmitting units driven by the same AC power use different channels by detecting zero crossings to synchronize and transmit optical signals, preventing interference by assigning distinct time slots for each channel, allowing for accurate analysis of location information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LED lighting is provided such that there is no shadow area, then location determination accuracy is improved, but signal interference increases due to overlapping optical signals
Solution Approach 1:
The patent applies periodic action by dividing the transmission time into distinct time slots, where each light transmitting unit transmits optical signals in specific time slots rather than continuously. This time-division multiplexing approach allows multiple units to operate in overlapping areas without interference, as each unit has its own designated transmission period. The controller coordinates these time slots to ensure that signals from different units do not overlap in time, resolving the contradiction between complete area coverage and signal interference.
2Area of stationary object
If multiple light transmitting units transmit optical signals in overlapping areas, then area coverage is improved, but signal reception accuracy deteriorates due to interference
Solution Approach 1:
The patent implements periodic action through time-division multiplexing, where each light transmitting unit is assigned specific time slots for signal transmission. This allows multiple units to cover overlapping areas simultaneously without interference, as their transmissions are separated in time. The controller manages the time slot allocation to ensure complete area coverage while maintaining signal reception accuracy in overlapping regions.
Solution Approach 2:
The patent applies segmentation by dividing the transmission timeline into distinct time slots for different light transmitting units. This temporal segmentation allows the system to manage multiple transmitters in overlapping areas by assigning them non-overlapping time periods, thus maintaining both area coverage and signal accuracy.
3Reliability
If channel synchronization is implemented using zero crossing detection, then signal interference is prevented, but system complexity increases
Solution Approach 1:
The patent applies self-service by using the zero crossing points of the AC power supply as a natural synchronization reference for all light transmitting units. Since all units are powered by the same AC source, they automatically synchronize their time slots based on the common zero crossing events, eliminating the need for complex external synchronization mechanisms. This approach maintains high transmission reliability while minimizing system complexity by leveraging the existing power infrastructure.
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 enables accurate and stable communication by preventing signal interference, allowing for the determination of location information even in areas where multiple signals overlap, while maintaining the functionality of LED lighting as general illumination.
Implementation Method 1
detecting zero crossing of the AC power, synchronizing channels by using the detected zero crossing
Implementation Method 2
a light generator for generating a light
Implementation Method 3
transmitting an optical signal through the set channel by using the plurality of light transmitting units
Data Source
AI summary
A wireless light communication system and method using a plurality of light transmitting units driven by a same alternating current (AC) power, and a light receiving unit for receiving optical signals transmitted by the plurality of light transmitting units are provided. The wireless light communication method includes setting a channel for each of the plurality of light transmitting units such that light transmitting units having an overlapping area that is reachable by optical signals use different channels, detecting zero crossing of the AC power, synchronizing channels by using the detected zero crossing, and transmitting an optical signal through the set channel by using the plurality of light transmitting units, and receiving the optical signal transmitted by each of the plurality of light transmitting units by using the light receiving unit, and analyzing information included in the received optical signal.