MOBICOM

Small and cheap micro AUVs enable diverse underwater monitoring applications in shallow inshore waters; e.g., inspection of underwater assets, observation of water quality, and identification of pollution sources. The formation and collaboration of ...

Orthogonal frequency division multiplexing (OFDM) has prevailed in high speed underwater acoustic(UWA) communications with obvious multipath effects. However, with the characteristic of being sensitive to the Doppler effect, the performance of an OFDM ...

This paper presents a hardware Doppler suppression method for underwater acoustic (UWA) communication with compact-sized underwater platforms such as autonomous underwater vehicles (AUVs). The proposed method adopts an adjustable AD (analog-to-digital) ...

The high peak-to-average power ratio (PAPR) and lack of frequency diversity are two well-known issues with orthogonal frequency-division multiplexing (OFDM) modulations, especially over underwater acoustic (UWA) channels. The precoding (spreading) ...

This paper presents a novel Kriged Compressive Sensing (KCS) approach for the reconstruction of underwater acoustic intensity fields sampled by multiple gliders following sawtooth sampling patterns. Blank areas in between the sampling trajectories may ...

Sound speed profiles (SSPs) have a great impact on the accuracy of underwater localization and sonar ranging. In traditional SSP inversion, the sound intensity distribution used in normal mode theory-based matching field processing (MFP) or the ...

The seafloor has a significant influence on sound propagation in deep water in the context of an incomplete sound channel. Using data collected during an experiment in the South China Sea, we study seafloor reflection effects on sound propagation in a ...

For setting the optimal transmitting power in underwater acoustic networks (UWAN), we need to measure the underwater ambient noise on different receiving stations so that we can get the better signal-to-noise (SNR), and make better use of the ...

The scattering of the rough surface leads to the attenuation and fluctuation of the sound field. This paper aims to investigate how rough surface influences the statistic characters of transmission loss (TL) for low frequencies in a homogenous shallow ...

Accurate calibration, of acoustic velocity in water is essential in acoustic measurement. In order to measure the acoustic velocity in water, a sound propagation delay detection device based on correlation method is designed. This paper gives a detailed ...

In this paper, we present the results of deploying the first test prototype of the USMART low cost underwater sensor network in sea trials in Fort William, United Kingdom, on 29 June 2018 and 3 July 2018. We demonstrate the first ever hardware ...

As use of underwater applications increases, simulation studies on underwater acoustic networks (UAN) have also increasingly appeared. At present, the commonly used network simulation platforms are NS2 and NS3, or are extended from them. These ...

With the development of marine exploration, underwater acoustic sensor networks (UASNs) are characterized by large-scale, high-flow loads. In addition, media access control (MAC) protocols have a significant impact on the performance of UASNs due to ...

With the development of underwater acoustic communication and networking, the past forty years have witnessed rapid progress in the application of underwater acoustic networks (UANs). As the necessary component of large-area underwater monitoring and ...

MAC protocols determine the way in which channels are shared between nodes[1]. In order to reduce and avoid data packet conflicting, a control mechanism needs to be determined to allocate the use of channel resources reasonably. The main task of a MAC ...

Underwater acoustic WiFi (UWA-WiFi) network is similar to the traditional terrestrial WiFi network, which provides wireless access services for underwater nodes (e.g., marine engineering equipment, underwater vehicles, divers, sensors, and so on). MAC ...

An energy efficiency routing protocol based on Depth-Based Routing (DBR) protocol for data collection scene is proposed. Protocol utilizes probe packet to calculate the difference between the minimum signal-to-noise ratio (SNR) required to correctly ...

The underwater acoustic channel exhibits many challenges for communications. Since the underwater environment is becoming crowded with both static and mobile users, additional noise is produced in the channel by the physical components of the nodes. In ...

Turbulence is an important cause of image distortion in an underwater ocean environment, along with light scattering and color reduction. Turbulence blur is a universal phenomenon of underwater image degradation, and causes a loss of high frequency ...

Magnetic Induction (MI) is a promising technique for near-field wireless underwater communications. Although the literature has some theoretical analyses and lab experiments for underwater MI communication, there is a lack of field tests in underwater ...

Existing ocean visualization studies are usually conducted independently using either sonar or optical imaging. However, they have shortcomings in different engineering applications. Acoustic imaging is not comprehensive enough to show the details of ...

Aiming at solving the problems of "halo pseudo-color" and detail blur of underwater image by existing algorithm, a new color restoration of multi-scale Retinex(MSRCR) image enhancement algorithm based on guided filter of sobel operator is proposed. ...

The paper focuses on wake-up mechanism for underwater acoustic communication (UAC) system. Wake-up mechanisms for UAC terminals play an important role in reducing the power consumption and extending the battery life. Compared with terrestrial wireless ...

Direct-sequence spread spectrum (DSSS) is a candidate technique for long-range underwater acoustic communication (UAC). However, its data rate is quite low. A coded M-ary DSSS (CM-DSSS) modulation scheme that adopts a pseudo-noise sequence (PNS) family ...

As the underwater channel environment changes frequently, it greatly affects the performance of underwater acoustic communication. Therefore, designing a communication system adaptive to the change is necessary for enabling stable communication in that ...

It is important to effectively allocate resources in an underwater acoustic orthogonal frequency division multiple access (OFDMA) downlink system. Traditional resource allocation algorithms in radio usually have high computational complexity, which is ...

In underwater acoustic channels with long time-delay, Alamouti space-time coded OFDM communication systems show poor performance, which is mainly caused by the unflat topology of the subband of severely frequency-selective channels. To solve this ...

A hardware solution for a collisonless underwater acoustic networks is proposed in this paper. Each node will be equipped with a horizontal circular array, by which signals from different sources located at different look directions, or bearings, will ...

We consider a multi-beam directional network where the nodes have digital antenna arrays capable of performing post-reception digital beamforming without prior knowledge of angle-of-arrival. Post-reception digital beamforming has greatly advanced ...

Multi-hop data transmission is necessary in many underwater scenarios, where instead of transmitting directly over one long hop from the source node to the destination node, multiple intermediate nodes are added between the source node and the ...