Soft-Input Soft-Output Run-Length Limited Decoding for Visible Light Communication

In this letter, we propose a new decoding algorithm based on a soft-input soft-output run-length limited (RLL) decoder in visible light communication (VLC) with on-off keying (OOK) modulation and Reed-Solomon (RS) codes. Conventional RLL codes are used for dimming adjustments in VLC; however, in our receiver model, the posterior probability matrix is produced by the new RLL decoder, and it can be matched as the input of the soft RS decoder to enhance the throughput in the VLC system. A significant advantage of our proposed method is that it leads to the enhancement of bit error rate (BER) and frame error rate (FER) performances without any change in the transmitter in VLC systems. The simulation results show that the majority of the BER and FER performances of our proposed method are better than those of hard-input hard-output RLL decoding and soft-input hard-output RLL decoding methods.