Coverage Enhancement of Underwater Internet of Things Using Multilevel Acoustic Communication Networks

Abstract

Underwater acoustic communication networks (UACNs) are considered a key-enabler to the underwater internet of things (UIoT). UACN is regarded as essential for various marine applications such as monitoring, exploration, and trading. However, a large part of existing literature disregards the 3-dimensional (3D) nature of the underwater communication system. In this paper, we propose a K-tier UACN that acts as a gateway that connects the UIoT with the Space-Air-Ground-Sea Integrated System (SAGSIS). The proposed network architecture consists of several tiers along the vertical direction with adjustable depths. On the horizontal dimension, the best coverage probability (CP) is computed and maximized by optimizing the densities of surface stations (SSs) in each tier. On the vertical dimension, the depth of each tier is also optimized to minimize inter-tier interference and maximize overall system performance. Using tools from stochastic geometry, the total CP of the proposed K-tier network is analyzed. For given spatial distribution of UIoT device's depth, the best CP can be achieved by optimizing the depths of the transceivers connected to the SSs through a tether. We verify the accuracy of the analysis using Monte-Carlo simulations. In addition, we draw multiple useful system-level insights that help optimize the design of underwater 3D networks based on the given distribution of UIoT device's depths.

Three-Hop Underwater Wireless Communications: A Novel Relay Deployment Technique

“…A bigger VDA in the first hop, θ tf , can cover a greater area on the SOFAR plane at a given depth of the transmitter so that a better CP performance will be achieved in the first hop. Since there is a symmetricity between the first hop and the third hop, we can have the same figure of CP performance when VDA in the third hop, θ sr , equals [5,10,15,20,25,30,35,40] • and z t varies from 1.2 km to 8 km. Similar to Fig.…”

“…The underwater acoustic channel model and the transmission loss calculation can be found in detail in [40], and here we list the channel model for simplicity as follows.…”

“…In (38), we can see that the CP of the second hop is related to the first and the third hops. Based on (40),…”

“…where f R tf (r tf ) = 2γ rs πr tf exp(−γ rs πr 2 tf ), f Rsr (r sr ) = 2γ rs πr sr exp(−γ rs πr 2 sr ), f A (a), f B (b) are shown in (39), A, B, C are shown in ( 27), ( 33), (40),…”

Space-Air-Ground-Sea Integrated Networks: Modeling and Coverage Analysis

“…But for the devices, stations, and users farther from the coastline, the connection is unavailable. Undoubtedly, Low Earth Orbit (LEO) satellites can achieve global connectivity [9], [10], but the disadvantages of long latency, low data rate, and unstable connection greatly restrict the explorations with higher requirements in large-scale and far-reaching ocean, such as marine environmental monitoring or underwater communication [11], [12] achieved by Underwater Internet of Things (UIoT), underwater terrain exploration or mapping [13] executed by autonomous underwater vehicle (AUV), underwater sensor and communication systems for target detection and tracking [14], to name a few [15]- [18], where all of these applications require a high data rate and stable communication between surface stations or end-users and terrestrial core connected base station (CCBS). Motivated by the requirements of wireless communication in a large-scale and far-reaching ocean, a Space-Air-Ground-Sea integrated network is proposed to provide a reliable connection to applications in a largescale ocean, for example, fishing boats in various marine fishing areas, offshore oil/gas drilling platforms, transoceanic freighters, and marine environment monitoring base stations, etc.…”