Abstract
Visible light communication (VLC) systems make use of the available LED lamps to realize a high spatial density of high-speed optical links superposed to their natural illumination function. Orthogonal frequency division multiplexing (OFDM) has been adopted for these intensity modulation/direct-detection optical channels. However, it suffers from low power efficiency or low spectral efficiency. In this paper, we aim to improve the performance of OFDM-based indoor VLC systems. By utilizing the principle of spatial summing, we propose an anti-periodic asymmetrically clipped OFDM scheme to make efficient use of both power and spectrum. In this scheme, the OFDM subcarriers are partitioned into multiple specific groups to form independent unipolar signals. These signals are simultaneously transmitted from different LEDs that are within the same light fixture and are summed in space before being detected by a conventional OFDM receiver. The computer simulation results show that the proposed approach can achieve lower PAPR and more robustness to the clipping distortion caused by the nonlinearities of LED leading to better bit error rate performance for the same spectral efficiency than that of the conventional DCO-OFDM and ACO-OFDM schemes do under both LOS and DOW channels.
Published Version
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