High-Speed Visible Light Communications: State-of-the-Art
Jelena Vucic and Klaus-Dieter Langer

In proceedings of OFC 2012
paper OTh3G.3

Abstract: Communication via visible light is constantly gaining attention in R&D, driven by progress on LED technology for solid-state lighting. This paper reviews the state-of-the-art in VLC and points out its potentials in various application environments.

Exploring the Potentials of Optical-Wireless Communication using White LEDs
K.-D. Langer, J. Vucic , C. Kottke, L. Fernández, K. Habel, A. Paraskevopoulos, M. Wendl and V. Markov

In proceedings of 13th International Conference on Transparent Optical Networks (ICTON) 2011

Abstract: This paper reviews the main experimental results achieved by our research group in the area of high-speed wire-less visible light communication (VLC). Depending on the modulation complexity and receiver sensitivity, various links operating at rates in the range of 10-800 Mbit/s have been demonstrated using off-the-shelf optical components.

Optical wireless network built on white-light LEDs
reaches 800Mb/s
Anagnostis Paraskevopoulos, Jelena Vucic, Christoph Kottke,
Luz Fernández, Kai Habel and Klaus-Dieter Langer

SPIE Newsroom 2011
http://spie.org

803 Mbit/s visible light WDM link based on DMT modulation
of a single RGB LED luminary
J. Vucic et al

In proceedings of OFC 2011

Abstract: We report the first visible light link based on WDM and DMT modulation of a single RGB-type white LED, operating at an aggregate rate of 803 Mbit/s within the FEC 2·10^-3 limit.

EU FP7 Project Home Gigabit Access (OMEGA)
www.ict-omega.eu

Efficient signal processing in OFDM-based indoor
optical wireless links
J. Grubor and K.-D. Langer

Journal of Networks 2010

Abstract: We propose a rate-adaptive optical wireless transmission system based on orthogonal frequency division multiplexing for indoor communications. The investigations rely on realistic parameters of the key system components and focus on throughput maximization. We will show that a dynamically adaptive system can greatly enhance performance when compared to static operation, and how a loading algorithm, which optimally performs in powerlimited systems, needs to be adjusted if the specific terms of the optical wireless channel are to be rigorously obeyed. Our  investigations include scenarios in which the non-negativity constraint on the optical source driving signal is strictly met and in which a certain amount of symmetric clipping is tolerated. In the latter case, the system can be regarded as power-limited and conventional loading algorithms are hence the most suitable. We will show that the transmission rate can be significantly improved even further by accepting a minor increase in the error rate as a result of controlled clipping, and we will compare our results with the upper system capacity limit.

513 Mbit/s visible light communications link based on DMT-modulation of a white LED, IEEE Journal of Lightwave Technology
J. Vucic et al

IEEE Journal of Lightwave Technology 2010
Vol. 28, No. 24

Abstract: We report a visible-light wireless point-to-point communication
link operating at 513 Mbit/s gross transmission rate (net 450 Mbit/s). The bit-error ratio of the uncoded data was smaller than 2 · 10^-3 for an illumination level of 1000 lx. The link was based on a commercial thin-film high-power phosphorescent white LED, an avalanche photo diode, and off-line signal processing of discrete multitone signals. Quadrature-amplitude modulation, bit- and power-loading, as well as symmetrical clipping were successfully employed in pushing the gross transmission rate beyond 500 Mbit/s. Adaptation of the clipping level increased the data rate only by 2%, while simulations predicted an enhancement of 20%. Obstacles towards  higher data rates as well as potential remedies are discussed.We predicted that data rates of over 1 Gbit/s can be achieved with the same setup and  under the same experimental conditions if these obstacles are overcome.

230 Mbit/s via wireless visible-light link based on OOK modulation of phosphorescent white LEDs, paper OThH3
J. Vucic et al

In proceedings of OFC 2010

Abstract: We report a first indoor wireless visible-light link operating up to 230 Mbit/s by use of on-off-keying and with bit-error-ratios below 2·10-3. The results were achieved for illuminance levels recommended by lighting standards.

Implementation of a real-time DMT-based 100 Mbit/s visible-light link
J. Vucic et al

In proceedings of ECOC 2010
paper We.7.B.1

Abstract: For the first time, we show an implementation of a real-time DMT-based system operating at 100 Mbit/s over a visible-light link using a low-cost commercially available white LED devised for illumination. Additionally, we demonstrate transmission of a video signal over this link.