The physical layer security of radio-over-fiber (RoF) system is a very important problem for future communication. In this paper, novel probabilistic shaping (PS) based constellation encryption scheme proposed in which two bit-level operations are firstly performed according to chaotic sequences and hash values. generated by hyperchaotic values obtained SHA-512. Then PS applied enhance transmission performance. After PS-16-quadrature amplitude modulation (QAM), implemented aiming at...

A real-time base-band orthogonal frequency division multiplexing (OFDM) transceiver with a simple symbol synchronization and channel estimation scheme is implemented on only one off-the-shelf commercial field programmable gate array (FPGA). The optical OFDM long-reach passive network (PON) system direct detection over 100 km standard single-mode fiber (SSMF) employing cost-effective directly modulated distributed feedback (DFB) laser has been successfully demonstrated experimentally....

Underwater optical wireless communication (UOWC) is of great interest to the academic and industry community. In this article, we propose a low-complexity effective joint transmitter-side digital signal processing (DSP) including geometric shaping, time-domain tone reservation (TR), clipping. The peak-to-average power ratio reduction performance implementation complexity proposed TR are extensively analyzed. We then develop real-time 2.2-Gb/s system, which optimized for its shaping clipping...

In this paper, high-level quadrature amplitude modulation (QAM)-encoded real-time orthogonal frequency division multiplexing (OFDM) transceivers are implemented with two field programmable gate arrays and high-resolution digital-to-analog converter (DAC) analog-to-digital (ADC). Some key digital signal processing (DSP) algorithms for direct-detection optical OFDM (DDO-OFDM) system presented described in detail. To improve the effective number of bits ADC reduce quantization noise, DAC...

The security of orthogonal-frequency-division-multiplexing-based passive optical network (OFDM-PON) systems has been an important problem recently. In this paper, a time–frequency domain encryption technique based on multi-chaotics for physical layer and selected mapping (SLM) peak-to-average-power ratio (PAPR) reduction is proposed experimentally demonstrated in OFDM-PON system. scheme Lozi Logistic maps can generate chaotic sequences to scramble the subcarrier both time frequency domains...

This paper proposes a novel hybrid secure method based on improved deoxyribonucleic acid (DNA) encoding encryption and spiral scrambling in chaotic OFDM-PON for enhancing the physical-layer security. In DNA encryption, odd-even cross-bit encoding, base base-level substitution are determined by sequences. For each binary base, selected rules methods dynamically changing, which enhances robustness against malicious attacks attackers. process, QAM symbol matrix is divided into several blocks,...

In this Letter, an effective integrated waveform generation method where orthogonal frequency division multiplexing (OFDM)-based non-orthogonal multiple access (NOMA) communication signal combined with a linear modulation (LFM) radar is proposed and experimentally demonstrated in W-band detection system. The can generate signals simultaneously. addition, user multi-target be realized. Furthermore, for the OFDM-NOMA signal, discrete Fourier transform (DFT) precoding used to keep optimal power...

In this Letter, a modulated-symbol domain matched filtering scheme based on orthogonal frequency division multiplexing (OFDM) is proposed for the photonic-assisted W-band integrated sensing and communication (ISAC) system. The ISAC system single OFDM waveform experimentally demonstrated. By using waveform, it can improve spectrum efficiency achieve dual functionalities of radar detection simultaneously. optical heterodyne used to generate signal experimental results show that data rate up...

Attention classification based on EEG signals is crucial for brain-computer interface (BCI) applications. However, noise interference and real-time signal fluctuations hinder accuracy, especially in portable single-channel devices. This study proposes a robust Kalman filtering method combined with norm-constrained extreme learning machine (ELM) to address these challenges. The proposed integrates Discrete Wavelet Transformation (DWT) Independent Component Analysis (ICA) removal, followed by...

Inflammation is a significant risk factor for preterm birth. enhances glycolytic processes in various cell types and contributes to the development of myometrial contractions. However, potential inflammation activate glycolysis pregnant murine uterine smooth muscle cells (mUSMCs) its role promoting inflammatory birth remain unexplored. In this study, lipopolysaccharide was employed establish both animal models. We found that mUSMCs during late pregnancy could initiate promoted contraction....

Introduction Motor imagery functional near-infrared spectroscopy (MI-fNIRS) offers precise monitoring of neural activity in stroke rehabilitation, yet accurate cross-subject classification remains challenging due to limited training samples and significant inter-subject variability. This study proposes a Cross-Subject Heterogeneous Transfer Learning Model (CHTLM) enhance the generalization MI-fNIRS signal patients. Methods CHTLM leverages labeled electroencephalogram (EEG) data from healthy...

Visible light communication (VLC) with emitting diodes (LEDs) is an emerging technology for 5G wireless communications. Recently, using complementary metal-oxide-semiconductor (CMOS) image sensor as VLC receiver developed owing to its flexibility and low-cost. However, two illumination levels such on-off keying (OOK) signal are used. To improve the system throughput reduce complexity of hardware design, in this paper, we propose experimentally demonstrate a multilevel modulation scheme...

In this paper, an offset QAM/OFDM combined with non-orthogonal multiple access (OQAM/OFDM-NOMA) modulation technique is proposed and experimentally demonstrated in a multi-user asynchronous multi-cell visible light communication (VLC) system. OQAM/OFDM-NOMA can effectively improve system capacity flexibility owing to non-requirement of cyclic prefix (CP) flexible power allocation strategies. We evaluate the performance comparison between conventional OFDM-NOMA VLC Each cell consists...

Probabilistically shaped orthogonal frequency-division multiplexing (PS-OFDM) signal is proposed and experimentally demonstrated in a low-cost intensity-modulation direct-detection (IM-DD) system for optical access networks. The concatenation of constant composition distribution matcher (CCDM) low-density parity-check (LDPC) code sequentially implements probabilistic amplitude shaping (PAS) channel coding. Thanks to the precoding scheme, all data subcarriers can be treated equally by one...

As an application of visible light communication (VLC), positioning (VLP) technology has great potential for vehicle due to its characteristics no electromagnetic interference, low cost, and high accuracy. In addition, the emitting diode (LED) in street lights, traffic lights lighting systems makes this solution attractive vehicular applications. However, modulated LED signal will bring blooming effects on images captured by a complementary metal oxide semiconductor (CMOS) camera. And it...

In this letter, a 10.4-Gb/s real-time baseband orthogonal frequency division multiplexing (OFDM) receiver utilizing 256/64/16-quadrature amplitude modulation (QAM) adaptive format, incorporating several key functionalities, including symbol synchronization, channel equalization, as well sampling clock synchronization is successfully implemented using commercial field programmable gate array chip and sample rate of 5-GS/s analog-to-digital converter. The performance the OFDM experimentally...

In the paper, a flexible multiband orthogonal frequency-division multiplexing (OFDM) ultra-wideband service based on optical frequency combs is proposed and experimentally demonstrated for 5G wireless communications. By using comb technology, flexibility capacity of wavelength-division passive networks (WDM-PONs) can be improved. Meanwhile, different sub-bands OFDM signals are modulated with modulation formats to ensure data rate needs users. An adaptively...

We propose and experimentally demonstrate an optical camera communication (OCC) supporting user mobility. A mobile test platform is designed to emulate In the scenario, dynamic column matrix selection algorithm proposed select appropriate with high extinction-ratio (ER) while avoiding blooming effect. The phone placed on moving track receive visible light at a vertical distance of 60 cm. By varying speed 20, 40, 60, 80, 100 cm/s lateral 50 70 cm respectively, system performance using...

In visible light communication (VLC) systems, the nonlinear effects induced by many devices, such as electrical amplifiers and optoelectronic can significantly degrade overall system performance. this letter, to mitigate distortion effects, a clustering algorithm based on k-means is proposed experimentally demonstrated in VLC systems. The experimental results show that with help of compensate bit error rate (BER) be reduced from 2.4×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

In this letter, a net data rate of 5.55-Gb/s real-time baseband 1024-quadratic-amplitude modulation-encoded orthogonal frequency division multiplexing (OFDM) transmitter with an electrical spectral efficiency (SE) up to 8.88 b/s/Hz is successfully implemented on single-field programmable gate array chip incorporating 2.5 GS/s 14-b digital-to-analog converter. The transmission performance investigated in simple intensity-modulated and direct-detection, standard single-mode fiber (SSMF),...

We propose and demonstrate a real-time software reconfigurable dynamic power-and-subcarrier allocation scheme for orthogonal frequency division multiplexing based non-orthogonal multiple access (OFDM-NOMA) in visible light communications (VLC) systems. The key digital signal processing algorithms OFDM-NOMA implementations are illustrated details. With the help of technique, power ratios different sub-bands can be dynamically adjusted according to channel conditions, resulting superior user...

A global optimization technique is applied to solve the optimal transmitter placement problem for indoor wireless systems. An efficient pattern search algorithm - DIviding RECTangles (DIRECT) of Jones et al.- has been connected a parallel three-dimensional radio propagation ray tracing modeler running on 200-node Beowulf cluster Linux workstations. Surrogate functions wideband code-division multiple-access (WCDMA) simulator were used estimate system performance algorithm. Power coverage and...