Maritime Communication System Research Articles

An approach to detect identity spoofing in AIS messages

Automatic identification system (AIS) is a maritime communication system that uses a transceiver to automatically transmit navigational data. These data help navigation and allow to monitor the maritime traffic. However, this system can be hacked and malicious users can easily transmit false data to mislead the coastguards or vessels navigating around. While previous research has proposed methods to detect these falsifications, none of them suggest strategies that detect AIS identity spoofing combining the tracking of the ship position and AIS transceiver’s carrier frequency offset (CFO). The CFO, caused by the carrier frequencies mismatch between emitter and receiver and Doppler effect, is used as a radiometric signature to identify materially every transceiver independently of its transmitted identity. It can drift over time and this is why it is tracked thanks to a Kalman filter (KF). In addition, position is also considered to reduce the miss probability of spoofing detection. The KF is noise adaptive to be robust against various CFO drifts and noise levels of the environment. The strategy is tested on real AIS data and the results demonstrate its efficacy: false alarm and miss probabilities were respectively 1% and 1.7%. These results show the ability of the test to correctly detect identity spoofing and the interest of CFO as a radiometric signature. This signature, used for the first time in an AIS application, could be used with other signatures in a future work to improve identity spoofing detection. This is why we made open source in GitHub our algorithm and the real AIS data used.

Deep Reinforcement Learning-Based Resource Management in Maritime Communication Systems.

With the growing maritime economy, ensuring the quality of communication for maritime users has become imperative. The maritime communication system based on nearshore base stations enhances the communication rate of maritime users through dynamic resource allocation. A virtual queue-based deep reinforcement learning beam allocation scheme is proposed in this paper, aiming to maximize the communication rate. More particularly, to reduce the complexity of resource management, we employ a grid-based method to discretize the maritime environment. For the combinatorial optimization problem of grid and beam allocation under unknown channel state information, we model it as a sequential decision process of resource allocation. The nearshore base station is modeled as a learning agent, continuously interacting with the environment to optimize beam allocation schemes using deep reinforcement learning techniques. Furthermore, we guarantee that grids with poor channel state information can be serviced through the virtual queue method. Finally, the simulation results provided show that our proposed beam allocation scheme is beneficial in terms of increasing the communication rate.

Empowering 6G maritime communications with distributed intelligence and over-the-air model sharing

Introduction: Shipping and maritime transportation have gradually gained a key role in worldwide economical strategies and modern business models. The realization of Smart Shipping (SMS) powered by advanced 6G communication networks, as well as innovative Machine Learning (ML) solutions, has recently become the focal point in the maritime sector. However, conventional centralized learning schemes are unsuitable in the maritime domain, due to considerable data communication overhead, stringent energy constraints, increased transmission failures in the harsh propagation environment, as well as data privacy concerns.Methods: To overcome these challenges, we propose the joint adoption of Federated Learning (FL) principles and the utilization of the Over-the-Air computation (AirComp) wireless transmission framework. Thus, this paper initially describes the mathematical considerations of a 6G maritime communication system, focusing on the heterogeneity of the relevant nodes and the channel models, including an Unmanned Aerial Vehicle (UAV)-aided relaying model that is usually required in maritime communications. The communication network, enhanced with the AirComp technique for efficiency purposes, forms the technical basis for the collaborative learning across multiple Internet of Maritime Things (IoMT) nodes in FL tasks. The workflow of the FL/AirComp scheme is illustrated and proposed as a communication-efficient and privacy-aware SMS framework, considering spectrum and energy efficiency aspects under a sum transmitting power constraint.Results: Then, the performance of the proposed methodology is assessed in an important ML task, related to intelligent maritime transportation systems, namely, the prediction of the Cargo Ship Propulsion Power using real data originating from six cargo ships and utilizing long-short-term-memory (LSTM) neural networks. Upon extensive experimentation, FL showed higher prediction accuracy relative to the typical Ensemble Learning technique by a factor of 3.04. The AirComp system performance was evaluated under varying noise conditions and number of IoMT nodes, using simulation data for the channel state information by regulating the power of the transmitting IoMT entities and the scaling factor at the shore base station.Discussion: The results clearly indicate the efficiency of the proposed FL/AirComp scheme in achieving low computation error, collaborative learning, spectrum efficiency and privacy protection in wireless maritime communications, while providing adequate accuracy levels with respect to the optimization objective.

Research of the New Generation Marine Navigation Security Communication System

With the number of Chinese ships rapidly increasing, the available channels for the Automatic Identification System (AIS) are serious congested. This has led to a sharp rise in collision warnings. The maritime communication System is comprehensively updated from AIS to VHF Data Exchange System (VDES) in order to ensure efficient communication of huge scale, high density maritime ships as well as guarantee marine navigation security. In this paper, the new generation marine navigation security communication system based on VDES is studied. Designing communication systems for ships at sea, shore-based base stations and space-based satellites; The two-way data exchange between huge scale, high density ships-to-ships and ship-to-shore by VHF frequency band in nearshore and port areas can promote the development of maritime navigation technology and maritime economic.

Altitude Optimization and Task Allocation of UAV-Assisted MEC Communication System.

Unmanned aerial vehicles (UAVs) are widely used in wireless communication systems due to their flexible mobility and high maneuverability. The combination of UAVs and mobile edge computing (MEC) is regarded as a promising technology to provide high-quality computing services for latency-sensitive applications. In this paper, a novel UAV-assisted MEC uplink maritime communication system is proposed, where an MEC server is equipped on UAV to provide flexible assistance to maritime user. In particular, the task of user can be divided into two parts: one portion is offloaded to UAV and the remaining portion is offloaded to onshore base station for computing. We formulate an optimization problem to minimize the total system latency by designing the optimal flying altitude of UAV and the optimal task allocation ratio. We derive a semi closed-form expression of the optimal flying altitude of UAV and a closed-form expression of the optimal task allocation ratio. Simulation results demonstrate the precision of the theoretical analyses and show some interesting insights.

A Training Sequence-Based Ranging Method for R-Mode of VHF Data Exchange System

The space-time reference provided by GNSS is the basis of the 6G mobile communication integrating land, sea, air, and space. But GNSS has natural vulnerability. In order to solve this problem at sea, ships should be equipped with both space-based and land-based positioning and navigation systems in the future. The Ranging Mode (R-Mode) of the existing maritime communication system is an economical land-based backup positioning system, which is also an important support for e-Navigation. This paper proposes a pseudorange measurement method based on training sequence with multicorrelators, which can be used in the R-Mode of the VHF data exchange system (VDES). This method uses the correlation property of the ASM and VDE training sequence in the VDES for ranging. It reproduces the training sequence in the receiver, and then, noncoherent correlates with the received signal, meanwhile using the pseudorange measurement method with multicorrelators to reduce the influence of pulse shaping on the correlation curve. This paper also gives a design of receiver to implement the proposed method. Experiments are carried out based on the receiver to evaluate the ranging performance. The results show that, compared with the traditional maximum correlation value and E-L methods, the multicorrelator method can effectively reduce the ranging error. When E s / N 0 is greater than 15 dB, the ranging accuracy of the proposed method can be better than 3 m. With the proposed method, the VDES signal can be used for both ranging and communication. Compared with the general VDES function, it does not occupy any additional time slot resources. This provides a reference for the future research of the VDES R-Mode, which can be used to solve the vulnerability problem of the GNSS on maritime communication.

Performance analysis of non‐orthogonal multiple access assisted cooperative maritime communication system over two‐wave with diffuse power fading

AbstractNon‐orthogonal multiple access (NOMA) and millimeter‐wave (mmWave) communication are two promising technologies to fulfill the high throughput and reliable communication requirements. Maritime communication systems use a generalized fading at near‐sea‐surface channels (for seashore to ship/boat/fishing fleet communication) to provide reliable communication due to atmospheric turbulence. Experimental research on generalized two‐wave diffuse power (TWDP) fading reveal the footprints of mmWave. This article proposes novel exact and asymptotic closed‐form expressions of average symbol error probability (ASEP) of NOMA users for cooperative maritime communication systems over TWDP fading with the different modulations. The end‐to‐end closed‐form expressions are derived in terms of Appell's and Lauricella's hypergeometric functions. Also, the ASEP is shown using the power allocation factor for different modulation schemes. The proposed system provides better transmission reliability using generalized TWDP fading. Further, the outage probability of the system described above is analyzed using the distance, path loss exponent, transmission rate, and Rician factor as performance metrics for both the NOMA users. Effects of fading outage parameters on the system performance are studied. The end‐to‐end exact numerical results have been verified with the Monte‐Carlo simulations that validate with asymptotic results at a high SNR regime.

Assessing cyber threats for storyless systems

A proper assessment of potential cyber threats is vital for security decision-making. This becomes an even more challenging task when dealing with new system designs and industry sectors where there is little or no historical data about past security incidents. We have developed a threat likelihood estimation approach that supports risk management under such circumstances. Quantifiable conditions are determined from the environment in which the system will reside and operate, that is the availability of potential threat actors, their opportunities of performing attacks, the required means that are needed for the attack to succeed, and motivation factors. Our research method follows the principles of practice research where both researchers and practitioners have played central roles in a real-life development project for a maritime communication system. We used a qualitative case study for feature-based evaluation of the approach and associated tool template, and to gather evidence on practical aspects such as suitability for purpose, efficiency and drawbacks from five user groups. The results show that representative participants from the cyber security and maritime community gave positive and consistent scores on the features, and regarded time usage, traceability of the threat assessment and the ability to indicate underlying uncertainty to be very appropriate. The approach has been proven useful for this domain and should be applicable to others as well, but the template requires up-front investments in gathering knowledge that is relevant and reusable in additional context situations.

EXPERIENCE OF USING SIMULATOR TECHNOLOGIES IN FORMING COMPETENCIES TO FUTURE NAVIGATORS USING RADAR EQUIPMENT AND GLOBAL MARITIME DISTRESS AND SAFETY COMMUNICATION SYSTEM

The article presents the generalization of the experience of using simulator technologies in forming the competence to future navigators regarding the use of radar equipment and global maritime communication system in case of disasters and to ensure safety.It has been found that the amendments made by the International Maritime Organization to the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers have expanded the role of simulators in assessing the relevant competencies of maritime professionals. At the same time, it should be noted that logistical support of maritime higher educational institutions lags behind the requirements of modern shipping industry, the requirements of the seafarers’ labor market, and so on. It is a systemic problem that encompasses all levels of training and skills upgrading for shipping industry professionals. To solve the problem of improving the quality of professional training it has been proposed to carry out this process taking into account the principles of contextual approach, providing for the use of modern equipment and simulators, which departments and laboratories of maritime higher education institutions are equipped with. Training on simulators occupies a special place in the training of navigators, because it allows to exercise modeling of situations, which reproduce the conditions as close as possible to the real world. It is also important to include into the content of academic disciplines some components of simulator training on the formation and development of skills to work with electronic mapping systems, radio and electro-navigation equipment of ships, as well as skills associated with maritime safety (operation of fire-fighting equipment, rescue equipment, first aid on board ship, cargo operations with heavy cargo and containers, etc.). Each of these courses is taught in specialized laboratories equipped with the necessary simulation equipment in accordance with international requirements for training maritime professionals and the requirements of employers.

Synchronization for VHF Data Exchange System

In wireless communications, rapid acquisition of synchronization parameters is essential. Very High Frequency (VHF) Data Exchange System (VDES), a new maritime communication system developed on the basis of traditional Automatic Identification System (AIS), uses time division multiple access (TDMA) and belongs to burst communication. Therefore, synchronization is the top priority of VDES research. VDES includes the terrestrial part and satellite part, named as VDE-TER and VDE-SAT, and the two parts have different channel conditions. This paper studies synchronization algorithms for VDE-TER and VDE-SAT respectively on the basis of different channel conditions and focuses on the derivation, the theoretic analysis and performance simulation of the algorithms.

Dynamic networking and channel access strategies of hybrid communication network for intelligent ship

Based on the architecture of the hybrid maritime communication system, the shipboard hybrid communication network structure is presented for multi-network and multi-mode transmission networking equipment of intelligent ship. The paper briefly introduces the proposed dynamic networking and channel access strategies for the communication system of ship-to-ship and ship-to-shore, as well as the communication data types and priorities, quantitative description for each data and performance of each link. Those strategies make the shipboard communication link will be established automatically and flexibly with many modern communication technologies which will be selected depending on the current conditions of the radio channel and the requirements and preferences of the user. Simulation experiments show that those strategies could achieve the flexible and efficient data transmission with high throughput and low delay, using the advantage of each communication technology.

Smart Health Management Framework for Maritime Communication System

Chen, B. and Li, J., 2020. Smart health management framework for maritime communication system. In: Guido Aldana, P.A. and Kantamaneni, K. (eds.), Advances in Water Resources, Coastal Management, and Marine Science Technology. Journal of Coastal Research, Special Issue No. 104, pp. 286–290. Coconut Creek (Florida), ISSN 0749-0208.Health management engineering can achieve health assessment, prediction and maintenance for maritime communication system to give power maritime communication ability. Basing system health management theory, health management architecture consisting of data acquisition, health assessment, fault diagnosis, intelligent decision and interface system is set up and then a comprehensive with whole-process and all-members health engineering is illustrated. Introducing cloud computing and Internet of things, smart health management is presented. Taking Internet of things as fundamental structure and cloud computing as platform architecture, the frame of smart health management for maritime communication system is formed. Thus, the smart health management framework is built with hierarchical application structure according to health requirement and business of maritime communication system. Two parts, cloud client and cloud platform are involved in the framework. Cloud client is both the user and provider of health services while cloud platform can manage and schedule cloud resources uniformity. An application instance with typical case is present last to explain the framework built. The purpose of the research in this paper is to translate technology and resources in smart health management system into maritime Communication benefits.

Distributed Antenna Systems for VHF Maritime Communications

In this paper, we considered a distributed antenna system (DAS) to expand the coverage of VHF maritime communication systems and analyzed its performances. To reflect the geometrical distributed antenna port placements along the coastline, we considered a linear antenna layout. By deriving the lower bounds of the expected signal-to-noise ratio (SNR), we analyzed the SNR performances for both single-ship and multiple-ship transmission schemes. Next, based on the analytical results, we present design guidelines to implement the DAS based VHF maritime communication system. From the simulation results, the coverage expansion effect of the DAS was verified by the increased expected SNR. In addition, we confirmed that the system design parameters could be found from simple numerical calculations.

A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE)

VHF Data Exchange System (VDES) is considered as an important component of the future maritime communication system by the International Maritime Organization (IMO). On the basis of the existing Automatic Identification System (AIS), VDES adds the other two higher capacity subsystems: Application Specific Message (ASM) and VHF Data Exchange (VDE). The Random Access Channel (RACH) of VDE was first introduced in the International Telecommunication Union (ITU) Recommendation M.2092-0. As the slot planning principle of RACH in VDE is by interval, which is significantly different from the continuous slot map for access algorithms in AIS, the existing slot access algorithms cannot meet the requirements of VDE. The simulation results show that the VDE slot map can reduce the normalized throughput of the existing algorithm by 39%. A novel random access algorithm called Adaptive Traffic Load Contention Resolution Diversity Slotted ALOHA (ATL-CRDSA) is proposed in this paper. The algorithm combines the load control strategy and contention resolution scheme to overcome the challenges of the new RACH of VDE. Simulation results show that ATL-CRDSA has remarkable improvement on RACH, making it very efficient and providing low latency of the packets. The insights gained from this study may be of assistance to the Media Access Control (MAC) layer design for upcoming versions of VDES standard.

A Validation of Field Test Results for LTE-Maritime

In maritime domain, the necessity of data communication for providing the amount of increasing data services including e-Navigation services has been discussed. The traditional system for maritime communication was generally used as included in GMDSS like VHF, MF/HF equipment or Inmarsat system but these were designed to be used primarily on voice communication with safety purpose first. In order to resolve enormous requirements of communication side from maritime community, it is essential to find a novel communication system being cost effective and acceptable to various requirements. In this paper, the LTE maritime communication system called as LTE-Maritime is introduced. LTE-Maritime is an ongoing research project in Republic of Korea to develop the communication infrastructure for providing higher data rates with coverage around 100 km from shoreline based on LTE technology. In order to be sure the capability of LTE-Maritime, the performance of LTE-Maritime such as reference signal received power (RSRP), signal to interference and noise ratio (SINR), and throughput is analyzed with the real measurements of field test performed in the East sea area of R.O.Korea. The propagation characteristics in maritime environment are analyzed by comparing the conventional propagation models with experimental results and show the similar tendency with a little but meaningful difference which will be further studied in the project.

Fading characteristics of maritime propagation channel for beyond geometrical horizon communications in C-band

The design of a maritime communication system requires the understanding of the wireless propagation channel above the sea. For broadband communication systems, a carrier frequency in the C-band is of interest because of allocatable spectrum. Therefore, the German Aerospace Center performed a long-distance channel measurement campaign at 5.2 GHz on the North sea to investigate large and small-scale fading characteristics. The results show that our measurement data conforms with the ITU-R and the Bullington’s path loss model to predict the power loss caused by diffraction over the Earth’s surface. Further, the first tap of the channel impulse response experiences Rician fading due to superposition of a strong line-of-sight (LoS) path and multipath components originating from the sea surface and ship body. We found that the fading of the second tap follows a Rician distribution, but with a much smaller K-factor compared to the first tap. The K-factor showed a dependence on the distance between the transmitter and receiver. Particularly, the K-factor of the first tap decreases significantly when the distance between the transmitter and receiver is larger than the clearance distance of the first Fresnel zone. Therefore, we propose a distance-dependent K-factor model for the first and the second tap.

Research on the Maritime Communication Cryptographic Chip’s Compiler Optimization

Abstract In the process of ocean development, the technology for maritime communication system is a hot research field, of which information security is vital for the normal operation of the whole system, and that is also one of the difficulties in the research of maritime communication system. In this paper, a kind of maritime communication cryptographic SOC(system on chip) is introduced, and its compiler framework is put forward through analysis of working mode and problems faced by compiler front end. Then, a loop unrolling factor calculating algorithm based on queue theory, named UFBOQ (unrolling factor based on queue), is proposed to make parallel optimization in the compiler frontend with consideration of the instruction memory capacity limit. Finally, the scalar replacement method is used to optimize unrolled code to solve the memory access latency on the parallel computing efficiency, for continuous data storage characteristics of cryptographic algorithm. The UFBOQ algorithm and scalar replacement prove effective and appropriate, of which the effect achieves the linear speedup.

A multi-vessels cooperation scheduling for networked maritime fog-ran architecture leveraging SDN

In this paper, we investigated the scheduling problem of the vessel’s uploading data to the infostations through the maritime communication system and optimize the dispatching of data by Dynamic Programming method. Both the single-vessel scheduling and multi-vessels collaboration scheduling are considered. Specially, we have integrated SDN and Fog computing into maritime wideband communications system. Our goal is minimizing the total weight tardiness for single-machine scheduling scenario to achieve the minimized delay of weighted uploading packet. Single-machine total weight tardiness scheduling problem is subject to intermittent network connections, packet generation and due time limitation. The route of the ship is changeless, the duration of generation, due date of the data packet, as well as information on other schedules, is a priori known. The idea of time-capacity mapping is used to convert the problem of intermittent resource scheduling in the sea to continuous scheduling problem. We proposed a Dynasearch algorithm based on time-capacity mapping method, and the proposed algorithm is verified by MATLAB.

Symbols and Typical Expressions in Maritime English

At present time, millions of people work in the maritime field worldwide. Of the millions people, they come from different countries with a diverse background with different level of English proficiencies which they bring from their home countries. That is why; the mastery of standard maritime communication system is a must. To be able to communicate correctly and properly in the Maritime World and industry, the ships’ crews must understand and master the typical features of Maritime English. This paper focuses and reviews an account of the typical features of Maritime English communication in terms of 1) Maritime English spelling system in communication, 2) maritime symbols and their meanings, and 3) typical expressions. Keywords: spelling system, symbols, typical expressions

채널 상관 및 직접파가 존재하는 해상 통신 환경에서 개루프 프리코딩 기반의 공간다중화 전송 기법

Recently, high data rate transmission is required in maritime communication. In this paper, we consider multiple input multiple output (MIMO) spatial multiplexing (SM). However, the performance of SM is severly degraded due to spatial channel correlation and line-of-sight (LOS) component. In the maritime communication, the MIMO channel correlation and LOS are critical due to the lack of scatteres around the transmitter and/or the receiver. When the feedback of channel information is available, precoding can enhance the error performance by exploiting the channel information. However, it is difficult to derive closed-form solution considering both the correlation and LOS. In this paper, we present open-loop precoding-based spatial multiplexing transmission method by showing that the effect of performance for the correlation and LOS. It is shown that the open-loop precoding can mitigate the performance degradation due to the LOS as well as the correlation. Consequently, we expect that the proposed open-loop precoding can be adopted to the maritime communication system.