There are numerous studies showing that there is a constant increase in the ocean ambient noise level and ever-growing demand for developing algorithms detecting weak signals noise. In this study, we utilize dynamical statistical complexity to detect presence of ship embedded The were recorded South China Sea. multiscale entropy (MSE) method complexity-entropy causality plane (C-H plane) used quantify measured time series, respectively. We generated with varying signal-to-noise ratio (SNR)...

Abstract Peripheral nerve blockade (PNB) is a common treatment to relieve postoperative pain. However, local anesthetics alone have short duration of action and severe side effects during analgesia. In order overcome these limitations, the present study reported an injectable hydrogel with drug slow‐release profile for regional blockade. The was prepared by crosslinking gelatin NHS‐PEG‐NHS, which degradable in physiological environment displayed sustainable release locally, thus improving...

Underwater target passive tracking has ubiquitous applications in oceanic fields for both commercial and military purposes. The underwater wireless sensor networks (UWSNs) draw great interest become promising tools tracking. However, batteries provide power nodes the UWSNs, it is unrealistic to replace them when their energies are exhausted. Therefore, essential study on energy-efficient algorithm. To make a tradeoff between accuracy energy consumption, this paper proposes multi-sensor...

This paper presents new pseudolinear estimation algorithms for angle-of-arrival (AOA) target motion analysis when the sensor locations are not precisely known. Sensor location errors can cause significant performance degradation existing estimator (PLE) and its variants. In particular, we analytically show that, in presence of errors, well-known weighted instrumental variable (WIVE) is no longer asymptotically unbiased due to non-vanishing correlation between matrix noise vector. To...

In an energy-constrained underwater system environment, it is very important to find ways improve the life expectancy of sensors. The basic power control scheme has been proposed in MAC protocol design, which main idea use different levels for RTS-CTS and DATA. Specifically, maximum transmission used RTS-CTS, minimum required However, this mechanism would greatly degrade network throughput when MACA Underwater Wireless Sensor Networks (UWSNs). paper, we propose a MACA-based (MACA-PC)....

Orthogonal signal-division multiplexing (OSDM) is a promising modulation scheme that provides generalized framework to unify orthogonal frequency-division (OFDM) and single-carrier frequency-domain equalization. By partitioning each data block into vectors, it allows for flexible configuration trade off resource management flexibility with peak-to-average power ratio. In this paper, an OSDM system proposed underwater acoustic communications. The channel Doppler effect after front-end...

Energy-efficient and link-reliable underwater acoustic communication (UAC) systems are of vital importance to both marine scientific research oceanic resource exploration. However, owing the unique characteristics environments, (UWA) propagation experiences arguably harshest wireless channels in nature. As a result, traditional model-based approaches system design implementation may no longer be effective or reliable for UAC systems. In this article, we resort machine learning (ML)...

We study the problem of energy-efficient target tracking in underwater wireless sensor networks (UWSNs). Since sensors UWSNs are battery-powered, it is impracticable to replace batteries when exhausted. This means that battery life affects lifetime whole network. In order extend network lifetime, worth reducing energy consumption on premise sufficient accuracy. paper proposes an filter implements tradeoff between communication cost and Under distributed fusion framework, local should not...

Differential orthogonal frequency division multiplexing (OFDM) is practically attractive for underwater acoustic communications since it has the potential to obviate channel estimation. However, similar coherent OFDM, may suffer from severe inter-carrier interference over time-varying channels. To alleviate induced performance degradation, we adopt newly emerging partial fast Fourier transform (FFT) demodulation technique in this paper and propose an eigendecomposition-based algorithm...

This paper addresses sparse channels estimation problem for the generalized linear models (GLM) in orthogonal time frequency space (OTFS) underwater acoustic (UWA) system. OTFS works delay-Doppler domain, where time-varying are characterized as impulse responses. In fact, a typical doubly spread UWA channel is associated with several resolvable paths, which exhibits structured sparsity domain. To leverage of channel, we develop sparsity-based approximated message passing (GAMP) algorithm...

Underwater long-distance wireless communication (ULWC) is a critical challenge in many applications, such as marine environmental monitoring, underwater remote control, and navigation, to name few. However, very little literature focuses on ULWC, especially where the distance ups thousands of kilometers, which urgently required Internet Things (UIoT) large-scale deep sea. In this article, improve capacity at level we propose three-hop acoustic (3H-UWAC) structure based sound fixing ranging...

Orthogonal signal-division multiplexing (OSDM) is a generalized modulation scheme to bridge the gap between orthogonal frequency-division (OFDM) and single-carrier frequency-domain equalization. It allows significantly more flexibility in system design; however, over doubly-selective channels, it suffers from special signal distortion structure, namely inter-vector interference, which analogous inter-carrier interference conventional OFDM. To analyze its effect, this paper, complex...

Efficient target localization is critical to many marine applications in the Internet of Underwater Things (IoUT). Doppler effect becomes more predominant underwater environment when relative speed moving object, i.e., observer, signal propagation water much larger than that air. This along with observer-target geometry will bring a notable impact on performance. In this article, we derive Cramér–Rao lower bound (CRLB) and formulate A-optimality criterion-based observer trajectory...

Aimed at solving the problem of low data rate direct sequence spread spectrum underwater acoustic communication and that complexity receivers M-ary communication, cyclic shift keying is proposed based on good characteristic sequences. At transmitter, base waveform cyclically shifted according to input information. receiver, only one correlator used estimate time delay decode. Multi-code presented. Lake experiments both middle long range were conducted for methods. Single two code realized in...

Single carrier modulation with frequency domain equalizer is proposed for underwater acoustic channel. An unique training sequence, viewed as cyclic prefix, inserted into transmitted sequences so that low complexity minimum mean square error (MMSE) equalization (FDE) used combating the inter-symbol interference in receivers. Maximum likelihood estimation robust initial phase and Doppler shift are derived by using sequence. The receiver estimates error, channel block-by-block. Compare to zero...

Recently, single carrier block transmission (SCBT) has received much attention in high-rate phase-coherent underwater acoustic communication. However, minimum-mean-square-error (MMSE) linear FDE may suffer performance loss the severely time dispersive channel. To combat channel distortion, a novel multi-channel receiver with maximum ratio combining and low complex T/4 fractional iterative frequency domain equalization (FDE) is investigated to improve diversity gain bit error rate (BER)...

Abstract The increasing demand for exploring and managing the vast marine resources of planet has underscored importance research on advanced underwater acoustic communication (UAC) technologies. However, owing to severe characteristics oceanic environment, (UWA) propagation experiences nearly harshest wireless channels in nature. This article resorts perspective machine learning (ML) cope with major challenges adaptive modulation coding (AMC) design UACs. First, we present an ML AMC...

Acoustic communication between fast-moving underwater vehicles is difficult due to the fact ratio of vehicle speed sound many times exceeds its counterpart in mobile radio channels. Hence, symbol synchronization, as important carrier frequency identification, critical for wireless communication. In this paper, we propose a reliable using wideband chirp signals and novel self-synchronization method. The use takes advantage low Doppler sensitivity well their good autocorrelation properties....

Single-carrier with frequency domain equalization (SC-FDE) has been considered for bandwidth efficiency underwater acoustic (UWA) communication recently due to its reduced computational complexity and low peak-to-average power ratio. A multi-channel time-frequency method pseudurandom noise (PN) based SC-FDE is proposed in this paper. The equalizer includes a followed by order adaptive time decision feedback (DFE). algorithm applied the real data receiving from lake test conducted November...