In this paper, we propose an orthogonal frequency division multiplexing–based (OFDMbased) underwater acoustic multimedia system. An essential feature of this system is that it offers greater power and schemes with significant error protection for the transmission of sensor data information requiring a higher quality of service (QoS). To realize maximum resource utilization or minimum total tran...

Time synchronization is very crucial for the implementation of energy constricted underwater wireless sensor networks (UWSN). The purpose of this paper is to present a time synchronization algorithm which is suitable to UWSN. Although several time synchronization protocols have been developed, most of them tend to break down when implemented on mobile underwater sensor networks. In this paper, ...

In this paper, we propose an orthogonal frequency division multiplexing (OFDM) based underwater acoustic multimedia system. An essential feature of this system is that it offers larger power and schemes providing significant error protection for the transmission sensor data information that requires higher quality of service (QoS). To realize maximum resource utilization, or minimum total trans...

The use of an autonomous surface vehicle as an auxiliary agent to improve connectivity in a network of autonomous underwater vehicles is investigated. An algorithm is developed that consists of an optimal waypoint generator and a minimum-time guidance law that is used to steer the vehicle to the waypoint. This algorithm is used together with a communication architecture to improve underwater ve...

The interest in monitoring applications using underwater sensor networks has been growing in recent years. The severe communication restrictions imposed by underwater channels make that efficient monitoring be a challenging task. Though a lot of research has been conducted on underwater sensor networks, there are only few concrete applications to a real-world case study. In this work, hence, we...

This paper presents a design of DFT-spread OFDM system applied to an underwater acoustic channel. It does not only combine all the advantages of a conventional OFDM system but also reduces the peak-to-average power ratio of the transmit signal. Besides, the scheme spreads the information over several subcarriers as a result of the application of an additional DFT operation and leads to a divers...

In this paper, we propose a cluster-based synchronization algorithm for underwater acoustic sensor networks based on MU-Sync, called EMU-Sync. Time synchronization is an important part of many services. Although many time synchronization protocols for terrestrial wireless sensor networks have been well-developed, none of them can be applied directly in underwater wireless sensor networks. The c...

In this paper several computer simulations and pool experiments have been carried out to verify and demonstrate underwater communication between moving acoustic sensor nodes over different distances achieving optimum mutual information. We have developed GUI software “SAM-control” that generates m-sequences of 1023 length, handles their transmission and communications between sensor nodes. In a...

Underwater vision is one of the dominant senses and has shown great prospects in ocean investigations. In this paper, a hierarchical Independent Component Analysis (ICA) framework has been established to explore and understand the functional roles of the higher order statistical structures towards the visual stimulus in the underwater artificial vision system. The model is inspired by character...

In order to realize feature extraction and classification for underwater target signals, instead of the empirical mode decomposition (EMD) method, a new Ensemble EMD (EEMD) is used in the Hilbert-Huang transform when underwater target signals are analyzed. By the EEMD and Hilbert-huang transform, some feature parameters are extracted and applied to the classification of underwater target signal...