A node discovery protocol for ad hoc underwater acoustic networks

Abstract

A neighbor discovery protocol is proposed for initializing an ad-hoc deployable autonomous underwater system in which the nodes (floating sensors, crawlers, vehicles) have no knowledge of the system topology upon deployment. The goal is to establish multi-hop, minimum-power acoustic communication links over a given coverage area. The protocol uses distributed power control and random access to provide connectivity within a finite power budget and without global synchronization. Physical laws of acoustic propagation are taken into account, namely the distance-and frequency-dependent path loss, as well as large-scale fading which is modeled via log-normal distribution. Simulation results quantify the energy consumption, time to completion, and system reliability in the presence of fading. The key features of the protocol are simplicity of implementation and efficient use of power.

Implementation of Neighbor Discovery Protocol for Underwater Acoustic Communications

“…The authors provide deterministic and randomized algorithms to accomplish neighbor discovery. A decentralized node discovery procedure for an underwater acoustic network is proposed in [8] in which the nodes use random access and transmit at the minimum power level required to reach a particular neighbor. If the neighbors are not reachable with the present power level, the power level will be increased and the process is repeated for node discovery.…”

“…7 shows the comparison of average number of nodes discovered vs. actual number of nodes. The comparison is made for five different cases, (1) no fading, (2) End of Cycle Packet method (ECP) [8] at International Journal of Computer and Electrical Engineering maximal power, (3) DOA-NDP at maximal power, (4) ECP at minimal power transmissions, and (5) DOA-NDP at minimal power transmissions. It can be observed that in the first case, all nodes are discovered as none of advertisement/solicit messages are lost due to collision because of ideal channel condition.…”

Progressively communicating rich telemetry from autonomous underwater vehicles via relays

“…Recent research has shown that modulating the power of the transmitter based on the required transmission distance is an efficient way to minimize the energy spent successfully transmitting each bit across simulated networks. In [77], a decentralized neighbor discovery protocol is presented that builds on this cross-layer design by reaching out to nearby neighbors before expending power to communicate more broadly. In practice, most AUVs rely on some form of time-based multiplexing to allow for acoustic navigation and sensing.…”

Intermission-based adaptive structure estimation of wireless underwater networks

“…The attenuation and fluctuation of underwater sound is such that at one instant the nodes nearest to a sound source can detect it whereas at another instant detection could be prevented [10]. To deal with varying network structures, research groups focused on estimating the number of network nodes [11], [12], [13], [14], [15]. In [11], the author proposes techniques terminating when a probe encounters a previously-visited node, which triggers a peer-to-peer communication with the node that initiated the probe.…”

“…In addition to the previous geometry requirement, the approach in [14] assumes that the received power from each node is identical. The node discovery in [15] focuses on minimizing energy consumption and requires that each node knows the network size.…”