513 Mbit/s Visible Light Communications Link Based on DMT-Modulation of a White LED

TLDR

Obstacles to higher data rates and potential remedies are discussed. The authors predict that data rates exceeding 1 Gbit/s are achievable with the same setup if those obstacles are overcome. The link employs a commercial thin‑film high‑power phosphorescent white LED, an avalanche photodiode, and offline discrete‑multitone signal processing. The system achieved a gross transmission rate of 513 Mbit/s, with QAM, bit‑ and power‑loading, and symmetrical clipping enabling rates beyond 500 Mbit/s, though adaptive clipping only raised the rate by 2 % versus a 20 % simulated gain.

Abstract

We report a visible-light wireless point-to-point communication link operating at 513 Mbit/s gross transmission rate (net Mbit/s). The bit-error ratio of the uncoded data was smaller than for an illumination level of 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.