On Performance Analysis and Code Design for Visible Light Communication

Visible light communication (VLC) uses run length limited (RLL) code for avoiding flicker and supporting various dimming ranges. In this paper, we propose a low complexity split phase code as RLL code in serial concatenation with a convolutional code as a forward error correction (FEC) code for VLC. We use the extrinsic information transfer (EXIT) chart to explain the iterative decoding behavior of the proposed serial concatenated scheme. We also use puncturing and compensation symbols to support various dimming range in VLC. Thereafter, we derive an expression for upper bound to the average probability of bit error for the proposed VLC system, under maximum likelihood decoding. Furthermore, we propose a method of code mixing in inner RLL code to improve the bit error rate performance in the low signal to noise ratio regime. EXIT chart is used to analyze the effect of RLL code mixing on the convergence threshold of iterative concatenated coding scheme.