Optimized Analog Multi-Band Carrierless Amplitude and Phase Modulation for Visible Light Communication-Based Internet...

Area of Science:

• Electrical Engineering
• Optical Communications
• Internet of Things

Background:

• Visible Light Communication (VLC) offers a promising wireless technology for the Internet of Things (IoT).
• Integrating VLC with IoT requires efficient modulation schemes suitable for low-cost, low-power devices.
• Multi-band Carrierless Amplitude and Phase (m-CAP) modulation presents a viable option for enhancing VLC system capacity.

Purpose of the Study:

• To propose and evaluate a multi-user VLC-based IoT system utilizing m-CAP modulation.
• To investigate the impact of filtering stages and guard band strategies on system performance.
• To optimize the design for low-cost, low-power, and compact IoT devices.

Main Methods:

• A digital m-CAP modulator integrated into a ceiling LED fixture and analog receivers were employed.
• Performance was analyzed by simulating different emitter and receiver filter pairs (Bessel, Butterworth, raised cosine).
• Guard band strategies, including roll-off factor adjustment and even band suppression, were examined.

Main Results:

• The combination of a third-order Bessel filter in the receiver and a digital matched filter yielded the best performance.
• A Bit Error Rate (BER) below 10-3 was achieved at an Eb/No of 6 dB.
• Employing guard bands effectively mitigated inter-band interference for simultaneous multi-user communication.

Conclusions:

• The proposed VLC-IoT system with m-CAP modulation and optimized filtering demonstrates high efficiency.
• The Bessel filter and digital matched filter combination is optimal for achieving low BER in VLC-IoT systems.
• Guard bands are crucial for enabling reliable simultaneous communication among multiple users in VLC-IoT networks.