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Asymmetrically clipped absolute value optical OFDM for intensity-modulated direct-detection systems

Asymmetrically clipped absolute value optical OFDM for intensity-modulated direct-detection systems
Asymmetrically clipped absolute value optical OFDM for intensity-modulated direct-detection systems
Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems thanks to the inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAOOFDM) is proposed for intensity-modulated direct-detection (IM/DD) systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACO-OFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no DC biases. For AVOOFDM scheme, the frequency symbols are firstly modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterwards, the absolute values of the bipolar time-domain signals are taken to guarantee nonnegativity, while their signs are mapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated firstly, which are reconstructed and removed from the received signals. Afterwards, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency.
Intensity modulation with direct detection, orthogonal frequency division multiplexing, energy efficiency, spectral efficiency
0733-8724
Bai, Ruowen
bcdf3e3a-ba26-4948-ab25-1e3434e0567c
Wang, Qi
91220429-39a1-459a-9dfb-20fb90bfa974
Wang, Zhaocheng
e1eaf79b-f10f-43c7-a66a-8c3f1b58f456
Bai, Ruowen
bcdf3e3a-ba26-4948-ab25-1e3434e0567c
Wang, Qi
91220429-39a1-459a-9dfb-20fb90bfa974
Wang, Zhaocheng
e1eaf79b-f10f-43c7-a66a-8c3f1b58f456

Bai, Ruowen, Wang, Qi and Wang, Zhaocheng (2017) Asymmetrically clipped absolute value optical OFDM for intensity-modulated direct-detection systems. IEEE Journal of Lightwave Technology. (In Press)

Record type: Article

Abstract

Orthogonal frequency division multiplexing (OFDM) is attracting increasing attention in optical communication systems thanks to the inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAOOFDM) is proposed for intensity-modulated direct-detection (IM/DD) systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACO-OFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no DC biases. For AVOOFDM scheme, the frequency symbols are firstly modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterwards, the absolute values of the bipolar time-domain signals are taken to guarantee nonnegativity, while their signs are mapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated firstly, which are reconstructed and removed from the received signals. Afterwards, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency.

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AAO-OFDM - Accepted Manuscript
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Accepted/In Press date: 14 June 2017
Keywords: Intensity modulation with direct detection, orthogonal frequency division multiplexing, energy efficiency, spectral efficiency
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 411351
URI: https://eprints.soton.ac.uk/id/eprint/411351
ISSN: 0733-8724
PURE UUID: 525c3b14-722a-442f-b050-59c273903800
ORCID for Qi Wang: ORCID iD orcid.org/0000-0003-2645-5807

Catalogue record

Date deposited: 19 Jun 2017 16:31
Last modified: 14 Mar 2019 05:49

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