Wireless visible light communications employing feed-forward pre-equalization and PAM-4 modulation

X. Li; N. Bamiedakis; X. Guo; J. J.D. McKendry; E. Xie; R. Ferreira; E. Gu; M. D. Dawson; R. V. Penty; I. H. White

doi:10.1109/JLT.2016.2520503

Wireless visible light communications employing feed-forward pre-equalization and PAM-4 modulation

X. Li, N. Bamiedakis, X. Guo, J. J.D. McKendry, E. Xie, R. Ferreira, E. Gu, M. D. Dawson, R. V. Penty, I. H. White

Research output: Contribution to journal › Article › peer-review

64 Citations (SciVal)

Abstract

In this paper, feed-forward pre-equalization in conjunction with a PAM modulation scheme are proposed for use in wireless visible light communication (VLC) systems in order to enable the transmission of data rates >1 Gb/s. Simulation results demonstrate that simple few-tap feed-forward pre-equalization is able to remove the intersymbol interference caused by the limited link bandwidth of a line of sight VLC link, providing up to 5 dB better receiver sensitivity compared with postequalization. The pre-equalization scheme is implemented for a free-space VLC link using a PAM modulation scheme, which provides an enhanced spectral efficiency compared to NRZ modulation. Micropixelated LEDs (μLEDs) are used as the transmitter in this study, as they exhibit higher modulation bandwidth than conventional large-diameter LEDs. An avalanche photodiode is used at the receiver to provide an enhanced link power budget. Error-free (BER <10-12) 2 Gb/s free-space VLC transmission over 0.6 m is demonstrated experimentally using a simple 3-tap feed-forward pre-equalizer and a PAM-4 modulation scheme. The results show that feed-forward pre-equalization with only a few taps can improve the μLED-based link performance greatly, providing a simple and cost-effective solution for high-speed VLC links.

Original language	English
Article number	2520503
Pages (from-to)	2049-2055
Number of pages	7
Journal	Journal of Lightwave Technology
Volume	34
Issue number	8
Early online date	22 Jan 2016
DOIs	https://doi.org/10.1109/JLT.2016.2520503
Publication status	Published - 15 Apr 2016

Funding

This work was supported by the U.K. EPSRC via the Ultra Parallel Visible Light Communication (UPVLC) project. Additional data related to this publication is available at the data repository https://www.repository.cam.ac.uk/handle/1810/251457.

Keywords

APD
Feed-forward equalization
Micro-LED
Pre-equalization
Pulse amplitude modulation
Visible light communication

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics

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10.1109/JLT.2016.2520503

Cite this

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title = "Wireless visible light communications employing feed-forward pre-equalization and PAM-4 modulation",

abstract = "In this paper, feed-forward pre-equalization in conjunction with a PAM modulation scheme are proposed for use in wireless visible light communication (VLC) systems in order to enable the transmission of data rates >1 Gb/s. Simulation results demonstrate that simple few-tap feed-forward pre-equalization is able to remove the intersymbol interference caused by the limited link bandwidth of a line of sight VLC link, providing up to 5 dB better receiver sensitivity compared with postequalization. The pre-equalization scheme is implemented for a free-space VLC link using a PAM modulation scheme, which provides an enhanced spectral efficiency compared to NRZ modulation. Micropixelated LEDs (μLEDs) are used as the transmitter in this study, as they exhibit higher modulation bandwidth than conventional large-diameter LEDs. An avalanche photodiode is used at the receiver to provide an enhanced link power budget. Error-free (BER <10-12) 2 Gb/s free-space VLC transmission over 0.6 m is demonstrated experimentally using a simple 3-tap feed-forward pre-equalizer and a PAM-4 modulation scheme. The results show that feed-forward pre-equalization with only a few taps can improve the μLED-based link performance greatly, providing a simple and cost-effective solution for high-speed VLC links.",

keywords = "APD, Feed-forward equalization, Micro-LED, Pre-equalization, Pulse amplitude modulation, Visible light communication",

author = "X. Li and N. Bamiedakis and X. Guo and McKendry, {J. J.D.} and E. Xie and R. Ferreira and E. Gu and Dawson, {M. D.} and Penty, {R. V.} and White, {I. H.}",

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AU - Xie, E.

AU - Ferreira, R.

AU - Gu, E.

AU - Dawson, M. D.

AU - Penty, R. V.

AU - White, I. H.

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Wireless visible light communications employing feed-forward pre-equalization and PAM-4 modulation

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