  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%).
