Li-Fi Directional Adaptation for Interference Reduction
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Solution Overview
Problem
Light-based communications, such as Li-Fi, are susceptible to interference from multiple transmitting light sources due to the lack of a carrier frequency, leading to signal interference when multiple signals are received at similar power levels.
Innovation Solution
A system with adaptable receiving and transmitting directions in the second device, utilizing low-frequency light signals for positioning and selecting the optimal transmitting device, and high-frequency light signals for data transmission, which allows for directional optimization to maximize signal-to-noise ratio and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple transmitting light sources are used to increase coverage area, then the area of stationary object is improved, but signal interference increases due to lack of carrier frequency
Solution Approach 1:
The system segments the coverage area into multiple zones, each served by a different transmitting light source. The receiving device selectively communicates with only one transmitter at a time based on directional alignment, effectively dividing the overall coverage into non-interfering segments.
Solution Approach 2:
The receiving device dynamically adapts its receiving direction to align with the optimal transmitting device. This dynamic directional adjustment allows the system to maintain clear signal paths while covering a large area through multiple transmitters, preventing signal interference despite the presence of multiple light sources.
2Reliability
If directional adaptation is implemented to reduce interference, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical directional adjustment mechanisms with optical field-based directional selection. The system uses the natural directionality of light propagation and simple optical components to achieve directional adaptation, avoiding complex mechanical systems while maintaining signal quality.
Solution Approach 2:
The system introduces an intermediary selection mechanism that identifies and selects the optimal transmitting device based on signal characteristics. This intermediary layer simplifies the complexity by providing a clear selection criterion rather than requiring direct complex directional control.
3Reliability
If low-frequency signals are used for positioning and high-frequency signals for data transmission, then communication reliability is improved, but system complexity increases
Solution Approach 1:
The communication spectrum is segmented into two frequency bands: low-frequency signals are dedicated to positioning and identification functions, while high-frequency signals handle data transmission. This functional segmentation allows each frequency band to be optimized for its specific purpose, improving overall communication reliability.
Solution Approach 2:
The transmitting light sources serve multiple functions simultaneously: they provide illumination, transmit low-frequency positioning signals, and transmit high-frequency data signals. This multi-functionality reduces system complexity by consolidating multiple functions into a single integrated system rather than requiring separate systems for each function.
Data Source
AI summary
A system comprising: a plurality of first devices, each configured to transmit a low-frequency, LF, light signal comprising an identifier of the respective first device, and to transmit and/or receive a high-frequency, HF, light signal comprising data content; and a second device configured to receive a LF light signal from each of the first devices, and to transmit and/or receive a HF light signal from at least one first device, wherein the second device has an adaptable receiving and/or transmitting direction for respectively receiving and/or transmitting the HF light signal, and wherein the second device comprises a controller configured to: based on the identifiers encoded in the LF light signals, determine a position of the second device relative to the first devices and select a first device; and based on the determination, adapt the receiving and/or transmitting direction toward the selected first device.