Chair of Information and Coding Theory

Journal Publication on Visible Light Communications

Dec 15, 2017

G. J. M. Forkel and P. A. Hoeher, "Constrained intensity superposition: A hardware-friendly modulation method," IEEE/OSA Journal of Lightwave Technology, vol. 36, no. 3, pp. 658–665, Feb. 2018. DOI


One challenge in intensity modulation and direct detection communication systems is the power consumption at the transmitter-side driving circuit. For binary-switched LED-based transmission, boosting the data rate leads to an increased number of switching operations. Consequently, a larger fraction of the available power budget is dissipated in the driver. Hence the performance of communication and possibly illumination is affected by the reduced optical transmit power. The key idea is to lower the driver power consumption by decreasing the number of switching operations necessary for transmitting a fixed amount of data. This is possible by superimposing multiple binary sequences, where the individual sequences are matched to the hardware characteristics of the transmitter. We introduce a method to derive a graph-based representation for superimposing individually constrained binary sequences, and analyze the achievable constrained capacity.