• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.53-57
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• 2009

Unmanned surface vehicles (USVs) conduct various missions while exchanging information with control centers. Maritime security, coastal surveillance, and sea surface and undersea inspections are included in the important missions of USVs. To carry out these missions, large amounts of information are required from sensors, such as cameras, radars, and sonars. High bandwidth wireless communication is necessary to send this information to the control center in real time. In general, USVs are made using small boats. The motions of small boats are easily influenced by sea waves and the magnitude of changes in the attitude is large and the period of the changes is short in comparison with large ships. Thus, the direction of an antenna beam pattern for a wireless communication system in a USV can change rapidly, and with a large magnitude. In addition, since the reflection of electromagnetic waves on the sea surface is not negligible, the effect of multipath noises on the wireless communication system must be considered carefully. There are also several other elements that negatively affect wireless communication systems in USVs. This paper presents the wireless communication environment to be considered in the design and implementation of wide bandwidth communication systems for USVs. Short test results for wireless communication on the sea are also given.

• Journal of information and communication convergence engineering
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• v.4 no.2
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• pp.62-66
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• 2006

The objective of this thesis is to measure the limit of the real space where wireless Local Area Network (LAN) is used, and to apply this result as reference to set up a real Wireless LAN environment. The organized circumference was composed of Wireless LAN based on IEEE 802.11b of the American standard, and the examination is carried out on the campus. On the real condition of office environment and open space, the ratio of available distance to a signal at each distance was measured and this result was studied as data to embody wireless LAN on the campus. The measurement under an indoor environment was executed under circumstance having two walls and open space, however, was executed respectively under three circumstances: Where no obstacle, where one wall exists, and where two or more walls exist.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.280-281
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• 2023

Wireless communication in marine environments requires a significant amount of power for long-range communication, resulting in high energy consumption. Moreover, the numerous constraints in marine environments make it difficult to apply existing wireless communication technologies, necessitating the development of new technologies to address these issues. This paper investigates beam selection technology for marine environments, which reduces overall power consumption and minimizes interference between signals by selecting and transmitting necessary beams for communication in a specific area, enabling better quality communication. We validate the energy efficiency of the beam selection technology through simulations and compare it with existing wireless communication technologies. The results show that beam selection technology consumes less power and provides better communication quality than existing wireless communication technologies. Therefore, beam selection technology plays a critical role in establishing efficient communication systems in marine environments, and its application can improve communication quality over a broader area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.542-547
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• 2018

Various countries around the world are conducting various studies to apply information and communication technology to marine safety. Based on this, the International Maritime Organization (IMO) has established the e-Navigation standard to apply the latest information and communication technology to marine services. In Korea, the Ministry of Maritime Affairs and Fisheries is promoting Korean e-navigation considering domestic marine environment and is trying to apply LTE communication method as a high-speed wireless communication method at sea. In this paper, we describe the development of an LTE based marine router system supporting 700Mhz frequency band allocated for high speed maritime wireless communication service. Experiments on the possibility of 100km distance communication from base station using LTE based ship router are shown. LTE - based high - speed maritime wireless communication router system can provide communication infrastructure necessary to develop various accident prevention technologies that may occur at sea.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.384-390
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• 2005

This paper addresses the design and implementation of a wireless network. proposed as a cost-effective support platform for PLCs. With this network. one or more supervising stations may access remote equipment like PLCs. An applicable communication methods are described and we applied efficient method among them to PLCs communication. The paper specifies these requirements and indicates methods to fulfill them. Also. it provides to the model of operation, and focuses on the implementation approach. The hardware and software design is described together with a number of critical points related to wireless communication on the Cnet. Furthermore, a discussion on system expandability and performance is tackled and some observations are stated. The main conclusion is, that the proposed method can feature good performance under normal operating conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2140-2146
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• 2014

Ocean buoys are operated for safe navigation and collecting ocean data. Recently, to reducing marine buoy's damage by ocean weather's bad condition and collision with vessels has been conducted in several field research. This paper's experiment is buoy condition monitoring about predefined data form by users. As a result using Wireless remote control board applying a radio signal processing algorithms, it can observe buoy's state at an interval of three minutes on the land. Acquired data type is changeable according to ocean weather condition or buoy's purpose of using in advance. Also, this paper conducted an experiment such as data-transmission's stability and wireless communication's availability. As results of the analysis of the transmitted data, the solar, wind and wave power indicates the maximum amount of power, 50 W, 20 W and 40 W respectively. The communication system proven through this research can apply to buoy or other ocean facility.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.70-75
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• 2017

In this paper, we studied the RF characteristics of a voltage-controlled artificial transmission line employing periodically arrayed diodes for application to highly miniaturized wireless communication systems on an MMIC (monolithic microwave integrated circuit). According to the results, the novel voltage-controlled artificial transmission line employing periodically arrayed diodes exhibited a short wave length, which was only 35.2% that of the conventional transmission line, owing to increasing capacitance. In addition, it's effective permittivity and effective propagation constant exhibited considerably higher values than those of the conventional transmission line. Furthermore, attenuation constant of the voltage-controlled artificial transmission line was far higher than that of the conventional transmission line. Using the closed-form equation, we theoretically analyzed the equivalent circuit of the voltage-controlled artificial transmission line.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.269-274
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• 2020

It has used buoy for efficient domestic farm operations and fishermen fish. Buoy uses IoT-based communication to transmit water temperature, salinity, humidity, wind speed, etc. to fishers in real time. In this paper, we utilize LoRa, which enables communication in the marine environment, to construct a network and apply it to an actual buoy for monitoring. The implemented LoRa uses the 900MHz band to configure the network. The sensor consisted of a sensor that can monitor the atmospheric environment and a sensor that can monitor the marine environment. In addition, the information received in real time will be provided to the fishing village host. The fishermen were fully aware of this and took appropriate measures to conduct sea trials.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1159-1164
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• 2010

The current maritime data communications mainly depend on radio and satellite which have restrictions on data rate and cost. That leads to needs of novel relatively-high-speed data communication systems at sea just like on land. This paper proposes a routing protocol (MWR) for newly designed model of ship-to-ship communication networks at sea. The MWR protocol finds out an optimal route by selecting an optimal network for each specific application from overlapped networks of available wireless media at sea.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.2
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• pp.156-162
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• 2017

This paper investigates two-hop extension communication in wireless body area networks. Many previous studies have demonstrated that two-hop extended topology outperforms single-hop topology. Although many researchers have proposed using two-hop extension communication to improve link reliability, no one has considered using a relay selection algorithm or provided a suitable solution for wireless body area networks. The design goal of the proposed algorithm is selecting a proper relay node to retransmit failed packets distributively. The proposed algorithm configures the carrier sensing period to choose one relay node promptly without requiring additional interaction. We analyze the link conditions corresponding to various body postures and investigate which factors are proper to determine the carrier sensing period. The empirical results show that the proposed algorithm reduces the expected number of transmissions required to deliver a packet successfully.