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2007
Conference Paper
Titel
High-speed wireless indoor communication via visible light
Alternative
Schnelle drahtlose Gebäudekommunikation über sichtbares Licht
Abstract
Durch doppelte Nutzung ermöglichen Weißlicht-LEDs Synergie von Raumbeleuchtung und drahtloser optischer Kommunikation/Nachrichtenverteilung. Für einen mit LEDs gut ausgeleuchteten mittelgroßen Büroraum wird die erreichbare Datenrate bei Basisband- und DMT-Übertragung (Discrete Multitone) ermittelt, wobei der Einsatz handelsüblicher LEDs und Photodioden angenommen wird. Die Resultate zeigen, dass trotz relativ geringer Systembandbreite Bitraten von mehr als 100 Mbit/s zu erwarten sind. Der Übertragungskanal erwies sich als flach, wobei die Anwendung von DMT vorteilhaft ist. Das komlexere DTM-System kann mittels FPGAs und DSPs realisiert werden. Emergence of white-light LEDs allows synergy oflighting and broadcast/communicationfunction in one optical source. We investigate possible data transmission rates in a moderate-size office room where we assume illumination conforming to standards and the use of commercially available LEDs and photodiodes. The performances of systems relying on base-band and DMT transmission show that data rates ofmore than 100 Mbit/s can be expected despite the rather low bandwidth of the system. It are investigated achievable transmission rates in a medium-sized room model. The transmission channel is found to be flat, due to distributed high power via many LOS. System performances were compared, assuming base-band and DMT modulation. It was found that the deployment of DMT brings advantages even in the flat channel (due to advantage in efficiency of QAM over PAM). It can be expected that its benefits are even more pronounced in the ISI degraded environment. Achievable speeds with DMT in the investigated flat channel were about 200 Mb/s. Even though an DMT system is more complex, it can be fully realized with standard FPGAs and DSP units.