Experimental investigation of multi-band OCT precoding for OFDM-based visible light communications.

Area of Science:

• Optical Communications
• Signal Processing
• Wireless Networks

Background:

• Visible Light Communications (VLC) face severe frequency-selective fading.
• Existing precoding techniques like MB-DFT have limitations in combating fading.
• Adaptive-loaded Discrete Multitone (DMT) offers good performance but can be complex.

Purpose of the Study:

• To propose and demonstrate a novel channel-independent multi-band orthogonal circulant matrix transform (MB-OCT) precoding technique for VLC.
• To analyze the impact of system parameters on the Bit Error Rate (BER) performance.
• To compare MB-OCT with conventional MB-DFT and adaptive-loaded DMT.

Main Methods:

• Experimental demonstration of MB-OCT precoding in a VLC system.
• Investigation of parameters: sub-band number, signal bandwidth, and cyclic prefix (CP) length.
• Comparative analysis of BER performance against MB-DFT and adaptive-loaded DMT.

Main Results:

• MB-OCT precoding achieves a desirable ladder-like SNR profile, enabling differential QAM loading.
• The proposed MB-OCT precoding significantly reduces BER compared to MB-DFT and single-band systems.
• MB-OCT demonstrates comparable BER performance to adaptive-loaded DMT with reduced implementation complexity.

Conclusions:

• MB-OCT precoding is an effective method for mitigating frequency-selective fading in VLC systems.
• The technique offers significant BER reduction and improved performance across various data rates.
• MB-OCT presents a promising, efficient solution for enhancing VLC system reliability.