Abstract As the dominant information carrier in water, acoustic wave is widely used for underwater detection, communication and imaging. Even though has been greatly improved past decades, it still suffers from slow transmission speeds low capacity. The recently developed orbital angular momentum (OAM) multiplexing promises a high efficiency, large capacity fast speed communication. However, cu...

In this paper we investigate the creation of an underwater acoustic network to support marine operations based on static and mobile nodes. Each underwater device combines communication, networking, and sensing capabilities, and cooperates with the other devices in coordinated missions. The proposed system is built upon the SUNSET framework, providing acoustic communications and networking capab...

Underwater acoustic channel makes high data rate transmission a very challenging task, due to the extended multipaths delay spread and large Doppler spread [1]-[2]. To increase the data rate or spectral efficiency of underwater acoustic communication, people resort to the spatial structure of the oceans by employing multiple-input, multipleoutput (MIMO) technology. With MIMO technology, very hi...

Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed metho...

Broadband underwater acoustic communication signals undergo either a compression or dilation in the presence of relative motion between a source and a receiver. Consequently, underwater acoustic communications with a mobile source/receiver require Doppler compensation through resampling. However, resampling may not be necessary when a channel-estimate-based time reversal approach is applied wit...

To overcome the poor communication environment between the underwater acoustic signal transmitter and receiver, previous research applied underwater acoustic OFDM communication system which had efficient bandwidth capacity and could mitigate multi-path delay spread effect via guard interval. Concurrently with this OFDM signal, additional data could be transmitted through spread spreading techni...

In this paper, we propose a new metric to measure the spatial reuse efficiency in networks: the spatial reuse index. We observed that the spatial reuse index in Underwater Sensor Networks (UWSNs) is significantly lower than in RF networks due to the relatively low spreading loss of acoustic signals. As a result, UWSNs generally have much lower network throughput. To address this problem, we pro...

High cost and high power consumption of underwater acoustic modem have limited the applications and researches of underwater wireless sensor networks (UWSN). This paper presents a node architecture and its low-cost realization to deal with such problems as high cost, high power consumption, large volume, and relative localization in a dense UWSN. Some fundamental functions like short range unde...