Constant weight polar coded orthogonal space-time block codes for dimmable indoor MIMO-VLC systems

Abstract

The concatenation of constant weight polar code (CWPC) with orthogonal space-time block code (OSTBC), known as CWPC-OSTBC scheme is proposed for the indoor multiple-input multiple output visible light communication (MIMO-VLC) systems in this letter. The CWPC helps to mitigate against flickering, provides desired dimming targets, and coding gain while the OSTBC achieves MIMO diversity gain. Flicker mitigation and dimming control are obtained based on the modified Knuth balancing method with enhanced prefix coding. This method does not utilise lookup table and thus, it is practicable in the real-time. Numerical results are presented to discuss the channel capacity and bit-error-rate (BER) performance of the proposed CWPC-OSTBC scheme considering different parameters. The results show that increasing the transmission antennas of the OSTBC system provides diversity gains. More so, the CWPC-OSTBC scheme yields an improved coding gain compared to polar code without balancing and other state-ofthe-art methods.