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Most of wireless sensor network nodes are powered not by main power but by batteries. A node which runs out of batteries cannot serve as a component of a network. This is why minimizing energy consumption of a node is important. Energy is consumed with various environment such like sensing, data processing data communication and so on, and especially data(More)
Acoustic communication is one of the essential technologies for many promising underwater systems. In this paper, we focus on the research and development of an acoustic modem for a real-time water quality monitoring system using bio-mimetic fish robots. Challengeable issues from the viewpoint of acoustic communication for the application are first(More)
The underwater sensor network environment differs substantially from a terrestrial sensor network in the aspect of the communication medium so Acoustic communication is alternative, which is relatively very slow and narrow bandwidth compared with Radio Frequency. In this paper, we propose an underwater sensor network architecture and then present the(More)
Recently, there has been large interest on short and medium range underwater communication systems for various applications. In this work, we investigate a moving communication system equipped with bio-inspired fish robots. A protocol stack encompassing physical layer, medium access control layer and network layer is designed for a packet-based hierarchical(More)
A new media access control protocol for a wireless sensor network is presented in this paper, configured with sensor nodes which have several directional antennas. There are lots of cases to need data retransmission because of excessive channel competition and data collisions due to the use of one omnidirectional antenna and single channel in a wireless(More)
Underwater acoustic communication can be applied to many fields, such as oceanic data collection, undersea exploration, disaster prevention, underwater environmental monitoring, and tactical surveillance. Underwater environmental monitoring system is one of basic technologies in these application fields. Therefore, there is a growing need for researching(More)
IP-based IMT Network Platform(IP 2) is an ubiquitous platform supporting mobility using two step IP address mode converting – IP host address(IPha) and IP routing address(IPra) – in a backbone network. Mobile Node(MN) in IP 2 maintains its state as either active or dormant state, which is transferred to active state through Paging process when communication(More)
Many studies on sensor network have focused on energy efficiency in several layers on communication protocol. In order to increase energy efficiency in sensor network communication, MAC-layer energy efficiency needs to be considered. Even though MAC layer protocols for increasing energy efficiency at MAC layer have been proposed in several papers, there(More)