Undersea Networks Research Articles

Federated learning for green and sustainable 6G IIoT applications

The 6th generation mobile network (6G) is expected to be launched in the early 2030s. The architecture of 6G will be the convergence of space, air, ground, and undersea networks. The power and intelligence of 6G based on advanced AI techniques will realize the concept of the Industrial Internet of Things (IIoT). In this study, we conduct a comprehensive survey of 6G IIoT applications based on Federated Learning (FL), starting from introducing recent advances in FL and IIoT systems to discussing how to integrate them. In particular, we highlight the potential of FL for supporting a range of IIoT systems such as smart medical, intelligent transportation, smart cities, unmanned aerial vehicles, and smart industry. The important discussions to drive FL into IIoT applications are emphasized. Finally, we present challenges and open issues for future research to realize green and suitable FL-based IIoT applications. Index TermsFederated Learning, Artificial Intelligence, Industrial Internet of Things, Smart IoT Applications

Interoperability Issues and Challenges in 6G Networks

Interoperability allows seamless data exchange among the heterogeneous networks and is a crucial problem for the growth of forthcoming 6G networks. The research has focussed on the interoperability issues in the Internet of Things (IoT) related to cross-domain and cross-platform applications. However, the future 6G communication networks are not limited to interoperating with IoT. The 6G networks must interoperate with the Wearable IoT (WIoT), brain abstracted Internet of Thinking (IoTk), Internet of Everything, and other space and undersea networks. The network softwarization, slicing, and intelligentization techniques are envisioned to support seamless data exchange between 6G and other heterogeneous networks. However, to successfully achieve the goal of global 360∘∘ connectivity in 3D space, interoperability issues with heterogeneous services, applications, protocols, networks, etc., must be solved. The integration and interoperability of 6G networks with all aforementioned heterogeneous networks are inevitable to realize the goals of 3D communication successfully. The paper proposes a taxonomy to provide deep insights into interoperability issues, challenges, and possible solutions for 6G interoperability with WIoT, IoTk, IoE, and other networks. Though the techniques mentioned above in 6G networks will allow interoperable solutions, the integration and interoperability issues persist due to heterogeneities in high-frequency bands, base stations, technologies, device identities, protocols, and interfaces. The paper summarizes significant challenges regarding interoperability issues in various areas related to 6G and highlights the broad scope to further research.

Guest Editorial Special Issue on “Green Communication and Computing Technologies for 6G Networks” in IEEE Transactions on Green Communications and Networking

The next of wireless networks (i.e., 6G) is envisioned to support communication in the three-dimensional space by integrating space, aerial, terrestrial, and undersea networks. The overall goal is to provide ubiquitous and unlimited connectivity to a massive number of Internet of Things (IoT) and machine-type devices/users having diverse Quality of Service (QoS) requirements, supporting substantial and heterogeneous traffic demands, and reducing the energy consumption with the help of highly energy-efficient communication protocols, transceivers and computing technologies. Out of several innovations 6G is targeting, this special issue focuses on green communications and computing technologies, which are crucial to reduce the overall energy consumption and operational cost from both the environmental and business viewpoints. To this end, the ever-increasing demand for advanced and ubiquitous applications over the recent years has shifted the paradigm of self-organizing networks to self-sustainable networks (SSNs). One main goal of SSNs is to eliminate the need for separate charging of heterogeneous devices by combining energy-efficient communication, energy harvesting/power transfer techniques, and offloading of energy-intensive processing from the edge-devices to the edge- and cloud-servers. However, the coexistence of wireless information and power transfer systems/links should be as seamless as possible for the end-users. Furthermore, providing network sustainability, and energy-efficient, energy-aware, and environment-aware connections to the massive number of devices and users having different levels of processing capabilities is one of the key challenges.

Environmentally adaptive acoustic sensing, communication, and navigation in distributed undersea networks

The explosive improvement in the capabilities of both hardware and software for unmanned underwater vehicles (UUV) is rapidly transforming the concept of operations for ocean science, exploration, surveillance and warfare. Thus, autonomous underwater vehicles, including autonomous gliders and propelled vehicles, are now standard tools on research vessels, cabled observatories and naval assets for environmental assessment on both local, regional and global scales. As was the case for manned undersea platforms, underwater acoustic s is critical to the operation of such systems, providing the only means for communicating information to, from and between undersea platform beyond a few tens of meters, and as such forms the basis for command and control, navigation, and remote sensing in the ocean. This in turn makes the operation of such systems highly sensitive to the acoustic environment with its convergence zones and extensive shadow regions, making it critical to robust operations to augment the network and platform control with an artificial intelligence framework which, using environmental acoustic modeling allows the network to autonomously adapt its configuration for optimal sensing, communication and navigation. Using the MOOS-IvP autonomy architecture, such a model-based environmental adaptation framework has been developed and demonstrated in simulation and in field deployments. [Work supported by ONR, DARPA, and Battelle.]

Book Review: The Undersea Network

Book Review: The Undersea Network

Review of The Undersea Network

In The Undersea Network, Nicole Starosielski traces transoceanic cable systems in order to illuminate their hidden narratives. Used to transmit the majority of Internet activity across the globe, these cables are seldom seen or thought of, notwithstanding their immense impact on global connectivity and the digital world.

Space-time block coding for undersea acoustic links

Current research in undersea communication scenario focuses on the applications of undersea acoustic networks in environmental data collection, pollution monitoring, offshore surveillance, coastal surveillance, etc. The various constraints encountered in undersea acoustic communications are mainly low bandwidth, high latency, high failure rates of acoustic links, and multipath propagation effects. Multipath effects in undersea environments are due to the reflection of sound by the sea surface and sea bottom as well as refraction of sound in water. As a result, the receiver gets a bewildering mix of signals. The receiving subsystems of the undersea networks perform special signal processing techniques for regenerating the data streams from the multipath composite signals in a MIMO configurable network. The performance of Space-Time Block Coding (STBC) diversity technique has been adopted in this paper for improving the reliability of the undersea network. In the simplest form of MIMO configuration, two transmitting transducers send out the data stream and its modified versions in two time slots on independently fading environments, leading to substantial improvements in the error rate performance. For a shallow water medium range channel, which exhibits the Rayleigh fading characteristics, the error rate performance has been found to be 7 x 10-6 for 16-QAM based STBC.

The undersea network

The undersea network

Cultural Techniques and Logistical Media: Tuning German and Anglo-American Media Studies

Cultural Techniques and Logistical Media: Tuning German and Anglo-American Media Studies

Cost-Effective, Cognitive Undersea Network for Timely and Reliable Near-Field Tsunami Warning

The focus of this paper is on developing an early detection and warning system for near-field tsunami to mitigate its impact on communities at risk. This a challenging task, given the stringent reliability and timeliness requirements, the development of such an infrastructure entails. To address this challenge, we propose a hybrid infrastructure, which combines cheap but unreliable undersea sensors with expensive but highly reliable fiber optic, to meet the stringent constraints of this warning system. The derivation of a low-cost tsunami detection and warning infrastructure is cast as an optimization problem, and a heuristic approach is used to determine the minimum cost network configuration that meets the targeted reliability and timeliness requirements. To capture the intrinsic properties of the environment and model accurately the main characteristics of the sound wave propagation undersea, the proposed optimization framework incorporates the Bellhop propagation model and accounts for significant environment factors, including noise, varying undersea sound speed and sea floor profile. We apply our approach to a region which is prone to near-field tsunami threats to derive a cost-effective under sea infrastructure for detection and warning. For this case study, the results derived from the proposed framework show that a feasible infrastructure, which operates with a carrier frequency of 12-KHz, can be deployed in calm, moderate and severe environments and meet the stringent reliability and timeliness constraints, namely 20 minutes warning time and 99 % data communication reliability, required to mitigate the impact of a near-field tsunami. The proposed framework provides useful insights and guidelines toward the development of a realistic detection and warning system for near-field tsunami.

Interesting (?) Applications for Acomms

Underwater acoustic communications (acomms) technology and capability have reached somewhat of an equivalence with the mobile cell phones of a decade ago. Commercial modems are available from more than a few vendors, but they mainly provide purely an acomms function. At the academic level technology development focuses on increased throughput (or data rate), and/or on the development of undersea networks. While we at Teledyne Benthos actively pursue both of these enhancements, our emphasis is to design for many auxiliary capabilities that, while not explicitly communications functions, rely on the communications capabilities and computing infrastructure of the modem. We are pursuing the “smart” phone approach wherein communications is but one capability of the device. The internal structure of the Telesonar modem is based on a file-sharing system which supports all aspects of the modem: acoustic and/or sensor (digital) data storage, stored wavefiles (for experimental transmissions), and algorithm implementations. In particular, it supports an SD-card data storage system, currently providing 64 Gbyte of storage. As an example, we can stream full bandwidth acoustic data, or serial data from an attached sensor in real-time to the SD card. Our form of storage is known to any remote modem such that any file or files can be uploaded and acoustically transmitted. The remote modem may also query any aspect of the stored data – the amount of storage used, the number of files stored, etc., without impact of any kind on the “modem” operations. The combination of arbitrary waveform transmission (from stored files) and acoustic data recording was recently used to demonstrate the ability of a specialized waveform for use in highly reverberant and physically constricted environments. This combination of capabilities enabled the complete design, testing, and data analysis to be completed in under one week without the necessity of embedded programming within the modem DSP.

A readout system-on-chip for a cubic kilometer submarine neutrino telescope

This contribution reports on the read-out system of the future KM3NeT undersea network of several thousands of synchronized optical detecting nodes. Each node embeds a specifically designed fully integrated communicating system based on Xilinx FPGA SoC technology. It runs the VxWorks real-time OS and DAQ software designed within the Ice middleware framework resulting in a highly flexible, controllable and scalable distributed application. Clock distribution and delay calibration over customized fixed latency gigabit Ethernet links enable synchronous time stamping of events with nanosecond precision.

Hot topics in underwater acoustics.

Research in underwater acoustics continues to evolve with the development of more capable acoustic systems, the introduction of new applications for underwater sensing, and with the emergence of integrated physics‐based processing approaches, which provide robustness in variable ocean environments. This talk provides an overview and examples of some of the active research areas in underwater acoustics, with particular emphasis on three topics. The first topic is the characterization and exploitation of underwater noise. This topic has research activities in both environmental monitoring (and potentially mitigation) of noise produced from anthropogenic activities, as well as the creative utilization of ambient noise structure for passive underwater sensing. The second topic area is the application of the waveguide invariant in active and passive sonar systems for enhanced detection, localization, classification. The invariance structure is being explored for deep water environments, with application to different sensor geometries and potentially new beamforming constructs. The final research area is underwater acoustic communications and networking. These systems are evolving to higher data rates (both single and multi‐carrier) with adaptive and self‐organizing algorithms to fully exploit the capabilities of distributed undersea networks.

System Design Considerations for Undersea Networks: Link and Multiple Access Protocols

We address several inter-related aspects of underwater network design within the context of a cross-layer approach. We first highlight the impact of key characteristics of the acoustic propagation medium on the choice of link layer parameters; in turn, the consequences of these choices on design of a suitable MAC protocol and its performance are investigated. Specifically, the paper makes contributions on the following fronts: a) Based on accepted acoustic channel models, the pointto- point (link) capacity is numerically calculated, quantifying sensitivities to factors such as the sound speed profile, power spectral density of the (colored) additive background noise and the impact of boundary (surface) conditions for the acoustic channel; b) It provides an analysis of the Micromodem-like linklayer based on FH-FSK modulation; and finally c) it undertakes performance evaluation of a simple MAC protocol based on ALOHA with Random Backoff, that is shown to be particularly suitable for small underwater networks.

Integrated sensing, modeling, and control in undersea sensor networks

The way forward in adaptively sampling the vast ocean environment is by deploying a network of sensors with different capabilities. Due to the complex nature of the environment, covering such an area cannot be achieved by simply deploying underwater sensor nodes at predefined locations. The undersea network topology should dynamically adapt to the events and changes in the environment. However, the main challenge for undersea network autonomy is due to the limitations in underwater acoustic communication. In order to overcome such limitations, Nested Autonomy architecture is being developed and demonstrated in programs such as PLUSNet and Ocean Observatories. This paper looks into the implementation of such autonomy architecture in different sensor nodes with different capabilities. This is achieved by separating the "low‐level" tasks of a sensor node with its "high‐level" tasks. Low‐level tasks will be sensor specific while the high‐level tasks looks into the autonomy required for the adaptive sampling applications, which here refers to as the "Backseat‐driver paradigm". The "backseat" carries the on‐board intelligence required for the mission at hand. Behavior‐based autonomy architecture which is used in the back‐seat significantly improves the sensor performance by selecting the best behavior for the given state of the vehicle, mission at hand and the observations being made.

Applying WDM technology to undersea cable networks

WDM technology is now being applied to international undersea fiber optic cable networks in order to provide enhancements such as increased network capacity and greater network flexibility. This article looks at what WDM technology can provide, the progress being made, and the special challenges in its application in undersea networks. We then describe several international undersea networks that, when completed by the end of 1999, will use WDM technology and will serve as a major part of the global undersea fiber optic infrastructure connecting the world.

Undersea Non-Repeatered Technologies, Challenges, and Products

Non-repeatered undersea lightwave transmission links, whose signals don't require periodic amplification or regeneration, have historically been deployed: — As part of larger, undersea networks that use repeaters, and — In domestic non-repeatered systems installed either between islands or looping a shoreline. With the world's transoceanic cable network rapidly expanding into a global undersea network — and transoceanic systems connected to regional systems, which are then connected to domestic systems — the market is moving towards an increased percentage of short-haul, non-repeatered systems. This paper discusses: — The technologies and products AT&T Submarine Systems, Inc. (AT&T-SSI) is developing for this market, — Future trends in non-repeatered technology and system design, and — Actual and planned system deployment of undersea optical cable throughout the world.

The Application of Undersea Cable Systems in Global Networking

Undersea fiber-optic systems have greatly expanded the capacity and capabilities of the global telecommunications network. These systems facilitated the exceptional growth of new services, which in turn contributed to the rise of multinational corporations and the development of a global economy. As they branch out, these corporations require the same variety and quality of services that are available in their home markets. Thus, the global demand for fiber-optic connectivity is increasing rapidly. This paper discusses the evolution and organization of the global undersea network and some of the key factors that are driving the technology's progress.

Real-time data acquisition from mid-ocean observatories

Recent advances in underwater acoustic communication have enabled real-time contact with ocean bottom instrumentation. This overview talk summarizes developments in acoustic, radio, and satellite communication links and in undersea networks constructed for telemetry from mid-ocean instrumentation. Acoustic communication has made major advances in terms of energy efficiency, data rate, and robustness. Data from several experiments illustrating capabilities of the acoustic modems, algorithm structure of the communication link, and its relationship to the characteristics of the acoustic channel are presented. Technology resulting from this work is incorporated in a line of underwater modems that are being used extensively by the oceanographic community. The modems are of course useful as direct point-to-point communication devices; however, incorporating modems into communication networks greatly increases their utility. Several deployed networks are discussed, in particular an under-ice system recently develoyed on Lake Winnipesaukee and in the Arctic off Pt. Barrow. The under-ice network is a part of the Autonomous Oceanographic Sampling Network (AOSN), a long-term development program aimed at improving the timeliness and cost-effectiveness of oceanographic data acquisition.