Design and Performance Analysis of Underwater Acoustic Networks

Abstract

Abstract-We analyze the performance of underwater acoustic ad-hoc networks in the presence of interference. We assume a uniform distribution of nodes over a finite area, and focus for simplicity on a two-dimensional network. The node-to-node channel is modeled using frequency dependent path loss and Ricean fading. We adopt a communication theoretic approach and study the sustainable number of hops through the network as an indicator of the network connectivity, as well as power and bandwidth requirements. The network operation is highly dependent on the node density with two distinct regions of limited performance: the coverage-limited region, where the number of nodes in the network is small, and the interference-limited region, where the number of nodes is large. We show that a desired level of connectivity can be achieved through a judicious selection of the operating frequency, power and bandwidth. Numerical examples illustrate the results of the analysis.These results motivate us to propose a hierarchical underwater acoustic sensor network architecture in which the sensors and the collector stations operate in distinct layers. The hierarchical architecture is supported by the property of the acoustic underwater transmission medium that for each transmission distance there exists an operating frequency for which the narrowband signal-to-noise ratio is maximized. The sensors and the collector stations are consequently allocated different operating frequencies. We assume a uniform distribution of both sensors and collector stations over the finite area of the sensing field, and model the channel accordingly. The analysis is performed under the assumption that there is interference from other nodes within the same layer of the hierarchy. Numerical examples illustrate the network performance and demonstrate that the preferred operating frequencies ensure network operation without any cross-interference between the collector network and the sensor network.Index Terms-Underwater acoustic networks, ad-hoc networks, connectivity, hierarchical sensor networks.

Distortion Performance of Convolutionally Coded Underwater Acoustic Networks

“…The circular network area is . Fixed losses are neglected [4]. The frame size is bits, and the bandwidth is kHz.…”

“…The topology is based on a two dimensional network model of nodes that are bottom mounted and provide coverage over a finite area [4]. The node distribution is assumed to be uniform as shown in Figure 1.…”

“…Consider a source to a destination transmission as illustrated in Figure 2. The considered interference model is based on a protocol constraint [4], where nodes which distance to the destination is the same as the source node distance to the destination are not permitted to transmit on the same frequency and in the same time slot as the source during its transmission. As it is assumed that all nodes transmit with a constant p.s.d.…”

“…There have been significant recent research efforts focused on the analysis and design of underwater networks [1][2][3][4], including medium access control [5][6][7][8], and routing protocols [9][10][11][12][13]. The study of underwater acoustic networks needs to take into consideration a number of design aspects that arise due to the underwater transmission medium.…”

Delay-Sensitive Routing Schemes for Underwater Acoustic Sensor Networks

“…[25] is the combined noise loss due to shipping, wind, turbulence, and thermal activities in dB and ini shows the initial energy of nodes in . Nodes having low and will have lesser DSH than the other neighbours and will be selected as suitable forwarder.…”