• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1252-1260
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• 2017

As digital communication technology evolves, the diversity of maritime communication methods has benn increasing due to the emergence of new maritime communication technologies such as digital very high frequency (VHF) communication systems and LTE-M as well as traditional conventional maritime communication systems. At sea, all maritime communication methods may be available, but only some communication methods may be available depending on the location. In this paper, we propose a multi-band network selection (MNS) system that can provide seamless maritime communication service by switching to an optimal communication band among available communication systems, depending on network environment and user requirements. The proposed MNS system in the middleware layer is designed to be able to interface with two types of digital VHF communication systems that satisfy Annex 1 and Annex 4 of ITU-R M. 1842-1, LTE, and high frequency (HF) communication systems. We assign priority to each communication band, and design an optimal communication band determination algorithm based on this priority.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.139-148
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• 2011

This paper presents the minimum-cost network selection scheme which determines the transmission instance in the multi-band maritime communication system, so that the shipment-related real-time information can be transmitted within the maximum allowed period. The transmission instances and the corresponding network selection process are modeled by a Markov Decision Process (MDP), for the channel model in the 2-state Markov chain, which can be solved by stochastic dynamic programming. It derives the minimum-cost network selection rule, which can reduce the network cost significantly as compared with the straight-forward scheme with a periodic transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.517-529
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• 2011

In this paper, the parameters of the RTT (Radio Transmission Techniques) for SANET (Ship Ad-hoc NETwork), which is considered for the next generation maritime communication systems, are set up. A channel model has been analyzed based on the practical measured maritime wireless channel in VHF (Very-High Frequency) for SANET system. Also, by considering the frame structure including preamble, guard time and pilots for both single and multi-carrier systems, the BER (Bit Error Rate) performances are evaluated and analyzed in the aspects of channel compensation and channel coding techniques. Based on the simulation results, optimal modulation & coding schemes are suggested for SANET. That is, in single-carrier system by using differential modulation schemes, channel compensation is not necessary. However, channel coding is helpful to achieve additional gain. On the other hand, when 16-QAM modulation is employed in multi-carrier system, the implementation of both channel compensation and channel coding techniques show huge performance gain for various of K values, which are related to different maritime environments, and the rolling effects of wave.