Li-Fi Technology

Light Fidelity Communication System

Experimental Implementation & Results

By: Mehaibia Djamil Errahmane, Meguehout Seddik, Mihoubi Manel

Supervised by: Dr. Madoui Karema

What is Li-Fi?

Li-Fi (Light Fidelity) is a wireless communication technology that uses visible light instead of radio waves to transmit data.

  • Uses LED lights for data transmission
  • 10,000x more spectrum than radio frequency
  • Secure - light doesn't penetrate walls
  • Energy efficient - combines lighting & communication

Wi-Fi vs Li-Fi Spectrum

How Li-Fi Works

Basic Principle

LED intensity is modulated faster than the human eye can see, encoding binary data.

Key Components

  • Transmitter: LED + Arduino microcontroller
  • Receiver: Photodiode + amplifier
  • Modulation: On-Off Keying (OOK)
LED
→
Light Signal
→
Photodiode
→
Data

System Architecture

Transmitter

Arduino Uno

+ LED Driver

Light Signal

Receiver

Photodiode

+ Amplifier

+ Arduino

Complete Li-Fi communication system using off-the-shelf components

Experimental Setup

Hardware Used

  • Arduino Uno microcontrollers
  • White LED (high brightness)
  • BPW34 photodiode
  • TL071 operational amplifier
  • LM393 comparator

Test Conditions

  • Data rate: up to 9600 bps
  • Distance: 5-150 cm
  • Ambient light: 500-2000 lux

Lab Setup

Key Results

Data Rate

9600 bps at 75 cm distance

BER < 10⁻³

Range

Up to 95 cm at 4800 bps

Line-of-sight required

Ambient Light

Tolerant up to 1500 lux

Optical filter improves performance

Advantages of Li-Fi

Security

Light doesn't penetrate walls - natural security

Speed

Potential for Gbps speeds in optimal conditions

Eco-Friendly

Dual-purpose: lighting + communication

No Interference

Doesn't interfere with radio frequency devices

Current Challenges

Line-of-Sight: Direct light path required

Ambient Light: Interference from sunlight/artificial lights

Range: Limited compared to Wi-Fi

Bidirectional: Needs separate uplink channel

Future Applications

Aircraft

Safe high-speed internet without RF interference

Hospitals

Secure communication in medical environments

Smart Homes

Integrated lighting and data networks

Underwater

Communication where radio waves fail

Conclusion

Li-Fi technology demonstrates:

  • Feasibility of visible light communication
  • Successful prototype using low-cost components
  • Potential for high-speed, secure wireless communication
  • Complement to existing RF technologies
"As LED lighting becomes ubiquitous, Li-Fi could become a standard feature in smart homes, offices, and public spaces."

Thank You!

Questions & Discussion

Contact: djamierrahmane.mehaibia9804@univ-setif1.dz

Ferhat Abbas University Setif 1

Bachelor's in Instrumental Optics

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