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Research On OCT-OFDM Adaptive Visible Light Communication

Posted on:2019-05-28Degree:MasterType:Thesis
Country:ChinaCandidate:S A LiuFull Text:PDF
GTID:2428330545957439Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
With the rapid development of cloud compute,big data,artificial intelligence,and unmanned driving,bring high efficiency and convenience to people's lives,the demand for transmission bandwidth has become greater.In order to meet the increasing transmission bandwidth requirements,the entire optical network must develop towards high-speed optical network.For visible light communication system,the coherent detection system commonly used in the long-distance optical communication system is high in complexity and relatively expensive,and the visible light communication based the laser diode is suitable for the short-distance optical communication system.At the same time,in order to meet the increasing transmission bandwidth and information security needs,visible light communication system must have high spectral efficiency and adopt encryption and decryption measures to ensure the security of information transmission,researches on orthogonal frequency division multiplexing(OFDM)with high spectral efficiency have been conducted.The main work carried out is as follows:1.In the laser diode(LD)based visible light communication system,an adaptive OFDM with Orthogonal circulant matrix transform(OCT)precoding scheme is proposed and verified.OCT precoding is proposed to provide better average BER performance and achieve a relatively flat SNR curve.The adaptive OCT precoding OFDM scheme could achieve better BER performanc e and higher raw bit rate.It is compared with the adaptive discrete Fourier transform(DFT-spread)OFDM scheme,32 Quadrature amplitude modulation(QAM)OCT precoding OFDM scheme,64 QAM OCT precoding OFDM scheme,and the proposed adaptive OCT precoding scheme could achieve an increase in BER performance.The experimental results showed that data rate is up to 5.04 Gb/s,and the spectral efficiency(SE)o f 4.2 bit/s/Hz could be successfully achieved.2.An adaptive OFDM encryption and decryption scheme based on Chebyshev scrambling sequence is proposed,the performance is research in the visible light communication system of light emitting diodes.Using two Chebyshev scrambling sequences to improve the security of data transmission for physical layer encryption.The experimental results show that the Chebyshev scrambling code sequence can achieve secure data transmission in the physical layer.Compared with the adaptive OFDM signal with encryption and the adapti ve OFDM without encryption,the encryption adaptive OFDM signal can achieve zero bit error rate.And the range of key values is large,which can effectively resist the exhaustive attacks from eavesdroppers.
Keywords/Search Tags:orthogonal frequency division multiplexing, laser diode visible light communication system, Orthogonal circulant matrix transform(OCT)
PDF Full Text Request
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