Wavelet transform based non-hermitian symmetry OFDM technique for indoor MIMO-VLC system with an imaging receiver

Khalid, Arslan

doi:10.1007/s11276-021-02762-4

Cited by 9 publications

(6 citation statements)

References 37 publications

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“…For any digital multimedia video image, each reconstruction vector c l can be deduced according to formula (13), and all c l obtained can be calculated to generate a table a [20].…”

Section: Wavelet Transform and Vector Quantization Of Multi-resolutio...mentioning

confidence: 99%

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Simulation of Video Image Fault Tolerant Coding Transmission in Digital Multimedia

2022

Mathematical Problems in Engineering

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In order to effectively improve the quality of video image transmission, this paper proposes a method of digital multimedia video image coding. The transmission of digital multimedia video image fault-tolerant coding requires sparse decomposition of a digital multimedia video image to obtain the linear form of the image and complete the transmission of video image fault-tolerant coding. The traditional method of fault-tolerant coding is based on human visual characteristics but ignores the linear form of the digital multimedia video image, which leads to the unsatisfactory effect of coding and transmission. In this paper, a fault-tolerant coding method based on wavelet transform and vector quantization is proposed to decompose and reconstruct digital multimedia video images. The smoothness of wavelet transform can remove visual redundancy; the decomposed image is vector quantized. The mean square deviation method and the similar scalar optimal quantization method are used to select and calculate the image vector, construct the over complete database of a digital multimedia video image, and normalize it; the digital multimedia video image is thinly decomposed by asymmetric atoms, and a linear representation of the image is obtained. According to the above-given operations, we can master the distribution range and law of pixels and realize fault-tolerant coding. The experimental results show that when the number of iterations is 15, the CR index is the same, PSNR increases by 8.7%, coding is 23.7% faster and decoding is 15% faster. Conclusion. The proposed method can not only improve the speed of fault-tolerant coding but also improve the quality of video image transmission.

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“…For any digital multimedia video image, each reconstruction vector c l can be deduced according to formula (13), and all c l obtained can be calculated to generate a table a [20].…”

Section: Wavelet Transform and Vector Quantization Of Multi-resolutio...mentioning

confidence: 99%

“…Analyze the data calculated by formula (20), understand, and master the distribution range and distribution law of digital multimedia video image pixels, so as to realize faulttolerant coding [24].…”

Section: Multiresolution Image Coding Based On Waveletmentioning

confidence: 99%

Simulation of Video Image Fault Tolerant Coding Transmission in Digital Multimedia

2022

Mathematical Problems in Engineering

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“…9 Commercially available LEDs have modulation bandwidths ranging from 2 to 20 MHz. 10 To realize high-speed data transfer in VLC, the low LED modulation bandwidth (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) necessitates the use of multi-carrier modulation (MCM) methods. 11 Nowadays, orthogonal frequency division multiplexing (OFDM) has been widely utilized as an MCM technique in VLC.…”

Section: Introductionmentioning

confidence: 99%

“…16 For this, it may be useful to take advantage of the signal's Hermitian symmetry (HS) in the frequency domain. 17 In the literature, several approaches are presented for getting a non-negative signal. They are DCO-OFDM, ACO-OFDM, flip-OFDM, and pulse amplitude-modulation-discrete multi-tone (PAM-DMT).…”

Section: Introductionmentioning

confidence: 99%

An ADO‐OFDM with integrated precoding, companding and optimized power allocation methods for high‐speed data transmission in visible light communication

S.,

N. R.

2024

Trans Emerging Tel Tech

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Visible light communications (VLC) has received a lot of attention in recent studies because of its benefits over radio‐frequency (RF) communications. It is a short‐range optical wireless communication system that uses light‐emitting diodes (LEDs) as transmitters. Optical orthogonal frequency division multiplexing (OFDM) is an auspicious technology for VLC high‐speed data transfer. The use of OFDM in a VLC system raises the system's peak‐to‐average power ratio (PAPR). The intrinsic non‐linearity of LED is a key concern in an asymmetrically clipped DC‐biased optical OFDM (ADO‐OFDM) system due to its high PAPR. Also, conventional ADO‐OFDM modulation scheme cannot be used for accommodating different demands of services in downlink multiple access due to the restriction of direct current biased optical OFDM (DCO‐OFDM) and asymmetrically clipped optical (ACO‐OFDM) transmission on odd and even subcarriers. To tackle this issue, a modified ADO‐OFDM (MADO‐OFDM) is proposed that adjusts the numbers of subcarriers required for the transmission of ACO‐OFDM and DCO‐OFDM adaptively based on the requests of services in downlink multiple access. Also, the proposed MADO‐OFDM is integrated with a discrete Hartley Matrix transform (DisHMT) precoder and Generalized Piecewise Linear Compander (GPLD) to provide high‐speed data transmission with less PAPR. In addition, the power is allocated to the proposed MADO‐OFDM system optimally by maximizing the channel capacity based on the Aquila optimizer algorithm. The simulation results reveal that the suggested system's PAPR is reduced by 2.4 dB and 0.8 dB, respectively, compared to conventional ADO and hybrid ADO‐OFDM. It also confirms that the suggested generalized PLC can greatly increase BER without affecting the PAPR performance.

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“…The Wavelet Transform theory, as a time-domain analysis method developed by inheriting the Fourier Transform, has gradually emerged and has been applied to the extraction technology of vital signs in recent years [ 16 ]. Wavelet Transform can perform a time-frequency joint analysis of signals, with high resolution, and can effectively denoise and extract non-stationary signals [ 17 , 18 ]. Kumar used Wavelet Transform to process ECG signals with an improved threshold algorithm to remove the influence of baseline drift, power frequency interference and EMG interference [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

A Vital Signs Fast Detection and Extraction Method of UWB Impulse Radar Based on SVD

Liu

Cheng

et al. 2022

Sensors

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The identification of weak vital signs has always been one of the difficulties in the field of life detection. In this paper, a novel vital sign detection and extraction method with high efficiency, high precision, high sensitivity and high signal-to-noise ratio is proposed. Based on the NVA6100 pulse radar system, the radar matrix which contains several radar pulse detection signals is received. According to the characteristics of vital signs and radar matrices, the Singular Value Decomposition (SVD) is adopted to perform signal denoising and decomposition after preprocessing, and the temporal and spatial eigenvectors of each principal component are obtained. Through the energy proportion screening, the Wavelet Transform decomposition and linear trend suppression, relatively pure vital signs in each principal component, are obtained. The human location is detected by the Energy Entropy of spatial eigenvectors, and the respiratory signal and heartbeat signal are restored through a Butterworth Filter and an MTI harmonic canceller. Finally, through an analysis of the performance of the algorithm, it is proved to have the properties of efficiency and accuracy.

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Wavelet transform based non-hermitian symmetry OFDM technique for indoor MIMO-VLC system with an imaging receiver

Cited by 9 publications

References 37 publications

Simulation of Video Image Fault Tolerant Coding Transmission in Digital Multimedia

Simulation of Video Image Fault Tolerant Coding Transmission in Digital Multimedia

An ADO‐OFDM with integrated precoding, companding and optimized power allocation methods for high‐speed data transmission in visible light communication

A Vital Signs Fast Detection and Extraction Method of UWB Impulse Radar Based on SVD

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