An Efficient Flicker-Free FEC Coding Scheme for Dimmable Visible Light Communication Based on Polar Codes

TLDR

Visible light communication (VLC) offers short‑range optical wireless links with LED lighting, but conventional forward error correction codes lack dimming support and flicker mitigation, necessitating auxiliary coding that reduces efficiency and increases complexity. This work proposes a polar‑code based FEC scheme for dimmable VLC to improve coding efficiency and simplify the coding structure. The scheme employs polar codes to generate codewords with balanced 1s and 0s and short run lengths, enabling inherent dimming balance and flicker avoidance without additional line coding. Experimental results demonstrate that the polar‑code scheme achieves balanced codewords, short run lengths, roughly twice the coding efficiency of existing schemes, and a 3 dB higher coding gain than RS(64,32) at 50 % dimming and 1 dB higher than LDPC at 25 %/75 % dimming.

Abstract

Visible light communication (VLC) could provide short-range optical wireless communication together with illumination using LED lighting. However, conventional forward error correction (FEC) codes for reliable communication do not have the features for dimming support and flicker mitigation which are required in VLC for the main functionality of lighting. Therefore, auxiliary coding techniques are usually needed, which eventually reduce the coding efficiency and increase the complexity. In this paper, a polar codes-based FEC coding scheme for dimmable VLC is proposed to increase the coding efficiency and simplify the coding structure. Experimental results show that the proposed scheme has the following advantages: 1) equal probability of 1's and 0's in codewords, which is inherently supporting 50% dimming balance; 2) short run length property (about 90% bits have runs shorter than 5) which can avoid flickers and additional run-length limited line coding; 3) higher coding efficiency about twofold than that of other coding schemes; 4) capacity achieving error correction performance with low-complexity encoding and decoding, which is about 3 dB higher coding gain than that of RS(64,32) in IEEE standard for dimming ratio 50% and about 1 dB higher coding gain than that of LDPC codes for dimming ratio 25% (or 75%).