
Researchers at Boston University have developed a technique to increase visible light communication (VLC) data transmission rates by 20 megabits per second. Using an approach called overlapping pulse-position modulation to control dimming and data transmission, John E. Gancarz, Hany Elgala, and Thomas D.C. Little found that this novel approach resulted in a gain of data throughput over similar, two-level schemes, according to an article just published in the Journal of Solid State Lighting.
The synthesis of visible light communication (VLC) and lighting state control necessitates data-light modulation that can accommodate intensity control. A number of techniques that enable both optical wireless data transmission and intensity control of light-emitting diodes (LEDs) have been proposed as a response to this need. Relevant schemes leverage amplitude modulation (AM)/continuous current reduction (CCR) and/or pulse-width modulation (PWM) for dimming capability. In this paper, the authors survey and compare the most commonly-investigated two-level techniques: on-off keying with compensation time (OOK + CT), variable pulse position modulation (VPPM), and multiple pulse position modulation (MPPM).
They then propose a novel approach towards dimming and data transmission through the variation of codeword weights in overlapping pulse-position modulation (OPPM). The proposed approach has comparatively high spectral efficiency. Using realistic constraints of a practical VLC system, their analysis reveals that OPPM can increase data rates by more than 20Mbps over expected performance of related, two-level schemes, when using LEDs suitable for lighting that have relatively low modulation bandwidths.
Full details of the study are here.
WOW, another impressive LED technology application!
Thanks for sharing such a informative information with us, Its really helpful for me.
Best led bulbs in uk
-Lovely Sharing ! We are leading manufacturers of top quality led lights in india known for its open-minded products and a combination LED lighting range.