• Journal of Korea Multimedia Society
• /
• v.20 no.12
• /
• pp.1940-1950
• /
• 2017

The security threat types in underwater communication networks environment are almost the same as the terrestrial, but the security of mechanisms the terrestrial RF-based networks environment can not be directly applied due to not only the limited resources of each node but also unsafe channel such as low propagation delay, high bit error rate etc. Nevertheless there has not been much research on the security of underwater acoustic communication networks. Therefore, in this paper analyzes the differences between the terrestrial communication networks and underwater acoustic communication networks, and identifies issues that are the starting points of underwater communication networks security research.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.486-488
• /
• 2013

In the earth more than half of the space filled with water. In that water most of the part is in the form of oceans. The ocean atmosphere determines climate on the land. Combining the Underwater Acoustic Sensor Network (UWASN) system with Internet Of Things (IoT) is called Internet of Underwater Things (IoUT). Using IoUT we can find the changes in the ocean environment. Underwater sensor nodes are used in UWASN. Underwater sensor nodes are constructive in offshore investigation, disaster anticipation, data gathering, assisted navigation, pollution checking and strategic inspection. By using IoT components such as Database, Server and Internet, ocean data can be broadcasted. This paper introduces IoUT architecture and and explains fish forming application scenario with this IoUT architecture.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.250-253
• /
• 2010

Underwater sensor network has attracted more and more attention from the networking research community recently. Most of traditional studies focus on the topology with a single gateway. Underwater sensor network consists of a variable number of sensors and multi-gateway to ensure the reliability of the network. In this paper, we propose a new MAC protocol that can reduce collisions among sensor nodes and improve QoS(Quality of Service) for underwater sensor network with multi-gateway. We evaluate the performance of the proposed scheme through simulation. Simulation results show that the proposed scheme outperforms the existing MAC protocol.

• Information and Communications Magazine
• /
• v.33 no.8
• /
• pp.71-81
• /
• 2016

본 논문에서는 수중 통신을 위한 매체 접속 제어(Medium Access Control: MAC) 프로토콜에 대한 연구 동향을 소개한다. 먼저 수중 음향 센서 네트워크(Underwater Acoustic Sensor Network: UWASN)와 수중 음향 채널의 특성을 소개하고 이로 인한 수중 MAC 프로토콜 설계 시 고려 사항에 대해 정리한다. 본 논문에서는 수중 MAC 프로토콜을 크게 비경쟁(contention-free) 기반과 경쟁 기반(contention-based) 프로토콜로 나누어 각각의 대표적인 프로토콜들에 대한 핵심 동작 원리에 대해 설명한다. 마지막으로 MAC 프로토콜을 실제 해양 환경에 구현하기 위한 고려 사항에 대해 정리한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06b
• /
• pp.87-89
• /
• 2011

전 세계적으로 수중 또는 해양의 정보는 매우 중요하며 다양한 활용가치를 지닌다. 수중 또는 해양을 개발하고 활용하기 위해서는 실시간으로 지속적으로 모니터링하면서 데이터를 수집하고 필요에 따라 수중 장치나 장비를 제어하는 기술이 기본적으로 요구된다. 본 논문에서는 수중 센서네트워크에 특징에 대해서 알아보고 클러스터링을 적용한 수중 네트워크내의 전송 효율 향상에 대해 연구하고, 통신을 위하여 MAC 계층으로 협업 통신을 적용하는 가능성 그리고 몇 가지 주의점에 대하여 알아보았다. 본 연구를 통하여 수중 네트워크로의 협업 통신 적용은 큰 가능성을 지니고 있으며, 지상에서와의 다른 환경 때문에 프로토콜의 적절한 설계가 매우 필요하다는 것을 알았다.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.7 no.4
• /
• pp.187-191
• /
• 2012

In these days, there are huge increases of concerning underwater acoustic sensor networks (UWASNs) to explore marine resources and to monitor climate change. To collect information from sensor nodes which are randomly deployed in underwater, Multi-Dimensional Scaling (MDS) based locating methods have been recently introduced, which consider sound speed to be constant in underwater. However, underwater sound speed tends to vary depending on underwater environment factors, such as depth, temperature, and salinity. In this paper, we propose a method considering environment factors, can influence upon sound speed in underwater, and introduce experimental setup which can follow up environmental factors.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.6
• /
• pp.21-28
• /
• 2016

This paper presents a cooperative transmission scheme for underwater acoustic sensor networks to improve packet transmission rate and reduce energy consumption. Source node transmits duplicated information relayed by distributed antennas called a virtual antenna array. Destination node combines that information to reduce packet error rate. The suggested cooperative scheme enhances the reliability by providing high diversity gains through intermediate relay nodes to overcome the distinct characteristics of the underwater channel, such as high transmission loss, propagation delay, and ambient noises. It is suggested that the algorithm select destinations and potential relays from a set of neighboring nodes that utilize distance cost, the residual energy of each node and local measurement of the channel conditions into calculation. Simulation results show that the proposed scheme reduces average energy consumption, response time, and increases packet delivery ratio compared with the SPF(Shortest Path First) and non-cooperative scheme using OPNET Moduler.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.344-347
• /
• 2011

Unlike a terrestrial wireless sensor network which uses radio waves, UWASN(Underwater Acoustic Sensor Network) relies on acoustic waves. There are lots of ongoing researches for long latency and limited bandwidth of underwater sensor network by using acoustic wave. Packets transferred by node often colide in underwater sensor network due to long latency. To solve this kind of problem, in general, Back-off scheme which is used in wireless network is used. However, fixed Slot-time according to node allocation generates useless time delay, and this lowers network performance. In this thesis, active setting technique of Slot-time is proposed, and applied for already studied MAC protocol. At the conclusion, it was proved that the MAC protocol using the proposed scheme has better performance than existing MAC protocol as a result comparison.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.4
• /
• pp.106-114
• /
• 2015

Despite a series of various developments in underwater acoustic sensor networks, there are still occasions of loss of connection over the network. Because sufficient amounts of drawbacks causing disconnections posed particularly in the middle of connection over the network emerge in the ocean environment, there is a need of new testing mechanism for underwater acoustic networks. In this paper, we proposed to investigate the most vital parts of the network deployment whether they function well in order, without any failure so as to identify where exactly communication process problems and failures are. We introduce step-wised out-test mechanism for UWASNS and accomplished the mechanism by implementing experiments and rigorously checked all the underwater devices utilizing out-test function. Experimental results and out-test function are evinced by implementing, in order to explain our system and conclude with possible future improvements.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.1-10
• /
• 2021

The interest in underwater acoustic sensor networks (UWASNs), along with the rapid development of underwater industries, has increased. To operate UWASNs efficiently, it is important to adopt well-designed medium access control (MAC) protocols that prevent collisions and allow the sharing of resources between nodes efficiently. On the other hand, underwater channels suffer from a narrow bandwidth, long propagation delay, and low data rate, so existing terrestrial node pairing schemes for non orthogonal multiple access (NOMA) cannot be applied directly to underwater environments. Therefore, a multi-dimensional node pairing scheme is proposed to consider the unique underwater channel in UWASNs. Conventional NOMA schemes have considered the channel quality only in node pairing. Unlike previous schemes, the proposed scheme considers the channel gain and many other features, such as node fairness, traffic load, and the age of data packets to find the best node-pair. In addition, the sender employs a list of candidates for node-pairs rather than path loss to reduce the computational complexity. The simulation results showed that the proposed scheme outperforms the conventional scheme by considering the fairness factor with 23.8% increases in throughput, 28% decreases in latency, and 5.7% improvements in fairness at best.