scholarly journals A Chaos-Based Encryption Scheme for DCT Precoded OFDM-Based Visible Light Communication Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Zhongpeng Wang ◽  
Shoufa Chen

This paper proposes a physical encryption scheme for discrete cosine transform (DCT) precoded OFDM-based visible light communication systems by employing chaos scrambling. In the proposed encryption scheme, the Logistic map is adopted for the chaos mapping. The chaos scrambling strategy can allocate the two scrambling sequences to the real (I) and imaginary (Q) parts of OFDM frames according to the initial condition, which enhance the confidentiality of the physical layer. The simulation experimental results prove the efficiency of the proposed encryption method for DCT precoded OFDM-based VLC systems. The experimental results show that the proposed security scheme can protect the DCT precoded OFDM-based VLC from eavesdropper, while keeping the advantage of the DCT precoding technique, which can reduce the PAPR and improve the BER performance of OFDM-based VLC.

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 453
Author(s):  
Pu Miao ◽  
Weibang Yin ◽  
Hui Peng ◽  
Yu Yao

The inherent impairments of visible light communication (VLC) in terms of nonlinearity of light-emitting diode (LED) and the optical multipath restrict bit error rate (BER) performance. In this paper, a model-driven deep learning (DL) equalization scheme is proposed to deal with the severe channel impairments. By imitating the block-by-block signal processing block in orthogonal frequency division multiplexing (OFDM) communication, the proposed scheme employs two subnets to replace the signal demodulation module in traditional system for learning the channel nonlinearity and the symbol de-mapping relationship from the training data. In addition, the conventional solution and algorithm are also incorporated into the system architecture to accelerate the convergence speed. After an efficient training, the distorted symbols can be implicitly equalized into the binary bits directly. The results demonstrate that the proposed scheme can address the overall channel impairments efficiently and can recover the original symbols with better BER performance. Moreover, it can still work robustly when the system is complicated by serious distortions and interference, which demonstrates the superiority and validity of the proposed scheme in channel equalization.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Haitham F. Abdalla ◽  
Emad S. Hassan ◽  
Moawad I. Dessouky

AbstractFilter bank multicarrier (FBMC) is a new waveform candidate in the visible light communication system (VLC). FBMC is a particular sort of multi-carrier modulation that can be viewed as an option in contrast to orthogonal frequency division multicarrier (OFDM) with CP (cyclic prefix). The point is to defeat some innate disadvantages of the normally utilized optical OFDM schemes. The principles of key transceiver should be intended to suit the necessities of the channel of IM/DD. Peak to average power ratio (PAPR) and bit error rate (BER) performance of FBMC based VLC are discussed and compared with scheme of optical OFDM. FBMC based VLC system with clipping technique has the lowest PAPR and good BER performance compared to conventional system in this paper. This paper recommends that FBMC based VLC has an incredible potential for optical wireless communication systems with high-speed. Matlab program simulations confirm the analysis. The results may shed light into potential research line on FBMC based VLC systems.


2018 ◽  
Vol 39 (4) ◽  
pp. 427-435 ◽  
Author(s):  
Haitham Freag ◽  
Emad S. Hassan ◽  
Sami A. El-Dolil ◽  
Moawad I. Dessouky

Abstract Orthogonal frequency division multiplexing (OFDM) is used with visible light communication (VLC) systems to reduce the effects of inter-symbol interference (ISI) and to achieve communication with high speed of data transmission and huge bandwidth. However, OFDM-based VLC systems suffer from high peak-to-average power ratios (PAPRs). This paper proposes a new hybrid PAPR reduction technique based on signal transformation combined with clipping. The Hadamard transform is used in the proposed technique due to its advantages in reducing the PAPR without affecting the bit error rate (BER) of VLC systems. The optimum clipping threshold at which we can simultaneously reduce the PAPR and improve the BER of VLC systems is also determined. In this paper, we also propose a new OFDM structure based on using discrete cosine transform (DCT) precoding before inverse fast Fourier transform (IFFT) stage to further improve the PAPR reduction capability and BER performance. Several experiments are carried out to test the performance of the proposed technique in terms of complementary cumulative distribution function (CCDF) and the BER. The obtained results show that the proposed technique can simultaneously reduce the PAPR and achieve good BER performance when compared to the original OFDM-based VLC system.


2019 ◽  
Vol 78 (13) ◽  
pp. 1213-1222
Author(s):  
A. A. Abdulkafi ◽  
S. M. Hardan ◽  
M. K. Hussein ◽  
Ibrahim K. Sileh

2015 ◽  
Vol 7 (5) ◽  
pp. 1-12 ◽  
Author(s):  
Bingyan Yu ◽  
Hongming Zhang ◽  
Ling Wei ◽  
Jian Song

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