Katsuya Nakahira

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Delay-tolerant networks (DTNs) are a promising network architecture which can provide reliable multi-hop message transmission between participating mobile nodes in an unfavorable environment that is prone to link disruption and disconnection by replicating and relaying messages without any need of physical infrastructure. Additionally, DTNs can also operate(More)
Hybrid networks constructed from cellular networks and Delayand Disruption-Tolerant Networks (DTNs) are one of the solutions for providing reliable communications to mobile nodes in base-station-starved areas regardless of node mobility or density. However, no routing scheme in DTNs has considered the adaptation to other networks, i.e., cellular networks.(More)
To obtain large capacity, high quality future mobile satellite communication systems, we must use a multi-beam that has extremely high levels of frequency reuse. This paper describes a novel resource allocation scheme for multi-beam satellite communication systems that can dynamically offer maximum communication capacity without compromising quality. The(More)
We propose an efficient channel control scheme for gathering data from many observation points scattered over an ultra-wide area using a satellite communication system. There are a huge number of observation points, and the data packets to be transmitted are relatively short. To implement the system economically, the proposed scheme is expected to manage(More)
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