Abstract
Orthogonal frequency-division multiplexing (OFDM) has been widely used in visible light communication systems to achieve high-rate data transmission. Due to the nonlinear transfer characteristics of light emitting diodes (LEDs) and owing the high peak-to-average-power ratio of OFDM signals, the transmitted signal has to be scaled and biased before modulating the LEDs. In this contribution, an adaptive scaling and biasing scheme is proposed for OFDM-based visible light communication systems, which fully exploits the dynamic range of the LEDs and improves the achievable system performance. Specifically, the proposed scheme calculates near-optimal scaling and biasing factors for each specific OFDM symbol according to the distribution of the signals, which strikes an attractive trade-off between the effective signal power and the clipping-distortion power. Our simulation results demonstrate that the proposed scheme significantly improves the performance without changing the LED's emitted power, while maintaining the same receiver structure.
Highlights
Light emitting diodes (LEDs) have emerged as a power-efficient alternative to replace incandescent bulbs for illumination owing to their inherent benefits of bright output and long lifetime
A novel adaptive scaling and biasing scheme is proposed for OFDMbased visible light communications (VLC) systems, which fully exploits the dynamic range of the LEDs for each individual orthogonal frequencydivision multiplexing (OFDM) symbol in order to enhance the achievable system performance
Our simulation results show that this adaptive scaling and biasing scheme significantly improves the performance of OFDM-based VLC systems
Summary
Light emitting diodes (LEDs) have emerged as a power-efficient alternative to replace incandescent bulbs for illumination owing to their inherent benefits of bright output and long lifetime. Using constant scaling and biasing factors throughout the entire transmission period cannot fully exploit the linear range of LEDs, and will impose a performance degradation In this contribution, a novel adaptive scaling and biasing scheme is proposed for OFDMbased VLC systems, which fully exploits the dynamic range of the LEDs for each individual OFDM symbol in order to enhance the achievable system performance. The basic idea of the proposed scheme is based on the observation that different OFDM symbols require different optimal scaling and biasing factors for fully exploiting the linear range of the LEDs. the proposed scheme calculates near-optimal scaling and biasing factors for each specific OFDM symbol according to the signal’s distribution, which strikes an attractive compromise between the effective electronic power and the clipping distortion power.
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