Multilevel Transmission in Dimmable Visible Light Communication Systems

This paper proposes a multilevel transmission scheme for dimmable visible light communication systems. To provide dimming control of the multilevel modulation, the concatenation of different pulse-amplitude-modulated symbols is used to yield the overall signal with an average amplitude that matches the dimming requirement. This scheme also aims at arbitrary dimming adaptation by adjusting the composition of concatenated differently modulated symbols. To this end, the problem is formulated into linear programming with the objective of maximizing the transmission data rate and satisfying the dimming requirements. We present an achievable data rate of this transmission scheme and demonstrate the error performance under iterative decoding.