MOBICOM

The review article [Kilfoyle and Baggeroer, IEEE Journal of Oceanic Engineering, 25(1), 4-27 (2000)] surveyed the literature for underwater acoustic communication up to January 2000. This presentation attempts to update the literature review since then. ...

In this paper we document the design, implementation and testing of a scheduling-based MAC protocol, called PMAC, for a 2012's sea trial, and experience gained from this process. In this experiment, the topology was a straight line, and PMAC is ...

We propose a novel optimal time slot allocation scheme for clustered underwater acoustic sensor networks that leverages physical (PHY) layer information to minimize the energy consumption due to unnecessary retransmissions thereby improving network ...

As the sleeping quality of a person would decline with repeated waking at night, similarly, for a sensor node in wireless sensor networks (WSN), waking up from dormancy frequently could cause energy waste by repeatedly switching on/off circuits and ...

Underwater acoustic networks (UWANs) offer potential in a wide range of applications, but conventional MAC protocols do not work well due to the long propagation delays relative to packet duration. Even for some innovative MAC protocols that show ...

Media Access Control (MAC) protocols are an important part of network operations and should be selected according to the application and scale of the network. In this paper we have studied two such protocols and present the results of simulation and ...

Due to the long preamble problem in underwater acoustic networks (UANs), traditional sender initiated handshaking MAC protocols are facing high overhead of control messages. To mitigate this problem, we propose a traffic estimation based receiver ...

We have designed and developed a new acoustic system for monitoring rip currents. The system consists of one dual-frequency acoustic fishfinder, two broad-band acoustic transducers, a set of sound reflectors and a data acquisition network. The ...

We consider the channel capacity of underwater wireless optical communication (UWOC) links with inter-symbol interference (ISI). We present a UWOC system model with the channel characterized by double Gamma functions and the receiver modeled by the ...

MPSK and MFSK are two common modulation schemes for coherent and incoherent digital communications respectively. Despite wide applications in underwater acoustic communications, they are not suitable for confidential application scenarios due to their ...

This study simulated amplitude variation in the time varying surfaces effect for an underwater communication testing platform (a wave making towing tank of 176m x 8m x 4m). The interaction between signals and boundaries on the testing platform causes a ...

To improve the channel efficiency, a bidirectional TDMA protocol is proposed for UWASNs in the paper. In proposed protocol, each time slot is divided into two parts, the DATA transmission/reception part and the ACK transmission/reception part. Two ...

Today, the terrestrial Internet can be easily accessed via various types of terminals almost anytime and anywhere. But this is not yet the case in the ocean, mainly due to huge differences between the terrestrial and marine environments. Although ...

A structure for decision feedback equalization (DFE) with low density parity code (LDPC) decoding is introduced for anti-multipath communication over underwater acoustic channels. The decoding performance of irregular LDPC codes is investigated. ...

The single-carrier block transmission (SCBT) method has been considered for bandwidth efficiency in underwater acoustic (UWA) communication recently. The cyclic prefix (CP) in the SCBT method should be longer than the multipath spread, but a long CP ...

Distributed systems using many inexpensive sensors widely distributed over a large area presents an alternative way for target detection and potential paradigm change in environmental sensing. Treating the acoustic signal as a communication signal, ...

The sensitivity of an underwater acoustic sensor is the most important characteristic to measure in a calibration experiment. In this paper, a theoretical sensitivity formulation for the second-order quantities of underwater acoustic dyadic sensors ...

This work shows some results of synchronization and channel estimation in simple underwater acoustic communication systems using On-off keying and binary phase-shift keying.

The main problems for a frogman in the shallow water are bubbles in the breath mask, environmental noise and low channel capacity. This paper studies the speech signal of a contact conduction transmitter that can avoid interference. A mixed excitation ...

There is increasing interest in ocean transect sampling missions to do environmental (pollution, coral reef, seismic, ocean current, etc.) monitoring, oceanography parameter gathering (CO2, temperature, current, etc.), oceanographic investigation, and ...

While our understanding of underwater acoustic communications has improved, communications involving mobile assets, e.g., gliders and AUVs, remains quite challenging. In September 2011, the MArine Cable Hosted Observatory (MACHO) was launched in the ...

Due to limited bandwidth and slow propagation speed, acoustic multi-hop connections in conventional underwater networks are much less efficient than terrestrial networks. To solve these problems, we propose the concept of amphibious networks, which are ...

Due to the differences of scattering areas and directions, the sound scattering influences imposed by a cylindrical baffle on a vector sensor are different when the sensor is installed at different locations. Using the BEM method, the directivities of ...

Underwater communication network simulators play a very important role in underwater network research due to the cost of field experiments. Several simulators have been proposed for tackling this problem in past years, such as Aqua, UAN, DESERT and ...

With more and more marine missions such as oceanic environment monitoring, oceanographic investigation, and underwater engineering construction, there is an increasing interest for the R&D of the frequency hopped UWA modem due to its robustness to inter-...

With increasing concern for the oceanic environmental problems caused by artificial pollution or natural disasters, there is a rapidly increasing requirement for dense and low cost monitoring of oceanographic parameters such as CO₂, nutrition, O₂, etc. ...

The performance of underwater acoustic communications is linked to the capability of a communication system to cope with a large variety of underwater acoustic channel dynamics, which are dependent on the environmental and seasonal acoustic propagation ...

Experimental testing of underwater network systems in real ocean environments has surged in recent years. The result of these at-sea experiments has led to a rise in discovery of practical issues for real systems and network protocol design. In this ...

The combination of ocean acoustical physics and signal processing has been the central theme of our research over the last twenty years. In particular, the thrust of our research has been in matched field processing, waveguide invariant physics, time ...

A parallel combinatory (PC) multicarrier frequency-hopped spread spectrum (FHSS) underwater acoustic (UWA) communication system is proposed in this paper. Parallel combinatory is first applied in FHSS system to accomplish the subcarrier mapping, which ...