Adaptive pre-compensation of LEDs for improved decoding of N-CSK in visible light communication

Abstract

We propose an adaptive pre-compensation with second order memory less polynomial to mitigate dynamic nonlinearity in LEDs. The scheme improves the performance of IEEE 802.15.7 standard N-level colour shift keying (N-CSK) modulation for indoor visible-light optical wireless communication system. LED linearization technique is implemented for 16-CSK system and its decoding performance is analyzed employing Voronoi cell segmentation of constellations. The decoding performance of 16-CSK is further improved by optimizing the distance between adjacent signal constellations in the transmitter. The performance of the scheme is simulated by Monte Carlo method and verified experimentally. The symbol error rate and error vector magnitude at the receiver shows significant improvement of decoding performance of 16-CSK through optimized modulation and pre-distortion compensation of LEDs.