Non-Hermitian symmetry orthogonal frequency division multiplexing for multiple-input multiple-output visible light communications

Chen, Chen, Zhong, Wen-De and Wu, Dehao (2017) Non-Hermitian symmetry orthogonal frequency division multiplexing for multiple-input multiple-output visible light communications. Journal of Optical Communications and Networking, 9 (1). pp. 36-44. ISSN 1943-0620

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Abstract

Multiple-input multiple-output (MIMO) is a natural and effective way to increase the capacity of white light-emitting diode (LED) based visible light communication (VLC) systems. Orthogonal frequency division multiplexing (OFDM) using high-order modulation is another widely used technique in VLC systems. Due to the intensity modulation and direct detection nature of VLC systems, Hermitian symmetry is usually imposed in OFDM so as to obtain a real-valued signal. In this paper, we investigate a non-Hermitian symmetry OFDM (NHS-OFDM) scheme for MIMO-VLC systems. By transmitting the real and imaginary parts of a complex-valued OFDM signal via a pair of white LEDs, NHS-OFDM circumvents the constraint of Hermitian symmetry. We evaluate the performance of an indoor 2 × 2 MIMO-VLC system using conventional Hermitian symmetry-based OFDM (HS-OFDM) and NHS-OFDM, where both a non-imaging receiver and an imaging receiver are considered. Analytical results show that the system using NHS-OFDM achieves superior bit error rate (BER) performance to that using HS-OFDM, with lower or nearly the same computational complexity. The superior BER performance of NHS-OFDM-based MIMO-VLC is further verified by experiments. The experimental results demonstrate that, in a 400 Mb/s 2×2 MIMO-VLC system with an imaging receiver, NHS-OFDM improves the communication coverage by about 30% compared with conventional HS-OFDM for a target BER of 3.8×10 -3.

Item Type: Article
Keywords: OFDM,MIMO,Light emitting diodes,Optical receivers,Bit error rate,Integrated optics
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Advanced Communications, Mobile Technology and IoT (ACMI)
Depositing User: Dehao Wu
Date Deposited: 17 Oct 2019 14:08
Last Modified: 17 Oct 2019 14:15
URI: http://sro.sussex.ac.uk/id/eprint/87185

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