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Energy management system (EMS) using renewable energy such as sunlight is expected to build a low-carbon society. In this paper, we report the modeling of EMS components using SPICE (simulation program with integrated circuit emphasis) and the estimation of the energy self-sufficiency rate by EMS simulation. We develop the simulation models of photovoltaic (PV) power generation system, storage battery...
We have proposed synchronized Spread-Spectrum Code-Division Multiple-Access (SS-CDMA) communication for location and short message communication system using Quasi-Zenith Satellite System (QZSS) as a safety confirmation system at the time of grade disaster. In this communication, the satellite reception timings of all uplink signals are synchronized using transmission timing control method in order...
The dependable network is needed to enable constantly communication ways since recent disaster such as the Great East Japan Earthquake. To ensure communications, satellite communications have been utilized. However, satellite communications have low throughput which is 60–2000 kbit/s and large time delay which is estimated as almost 240 ms in one way in the case of a stationary satellite. On the other...
We have proposed synchronized spread-spectrum code-division multiple-access (SS-CDMA) communication for location and short message communication system using Quasi-Zenith Satellite System (QZSS) as a safety confirmation system at the time of great disaster. In this communication, the satellite reception timings of all uplink signals are synchronized using transmission timing control method in order...
Energy management system (EMS) using natural energy such as sunlight is expected to build a low-carbon society. In this paper, we report the modeling of the Si-bifacial photovoltaic (PV) module and the accuracy evaluation of simulation at Hokuriku region where is one of heavy snowing area in Japan. We develop the simulation model of PV power generation using simulation program with integrated circuit...
The preparations for disasters are expected based on the lessons of large-scale disasters such as the Great East Japan Earthquake, Kanto and Tohoku Heavy Rain, and the Kumamoto Earthquake often occurred in Japan. We propose the hazard map utilization support system for flooding with positioning information, hazard information and database system. We develop a new system which allows the server to...
We have proposed spread spectrum code division multiple access (SS-CDMA) short message communication using Quasi-Zenith Satellite System (QZSS) as a safety confirmation system at the time of great disaster. Highly accurate timing and frequency synchronization among all mobile terminals (MTs) is necessary for the synchronized SS-CDMA system to provide high density user multiplexing using long spreading...
Quasi-Zenith Satellite System (QZSS) is expected to provide a high accurate positioning service and allows two-way communication which includes the terminal location and short messages. For QZSS short message spread-spectrum code-division multiple access (SS-CDMA) communication, Flag Method was proposed as access control scheme. It is always able to communicate in optimum state which channel efficiency...
For heterogeneous wireless network, the use of positioning information with global navigation satellite system (GNSS) such as global positioning system (GPS), quasi zenith satellites system (QZSS) in Japan and the global navigation satellite system in Russia (GLONASS) has been very effective. In this paper, the quantitative relation of positioning accuracy on various GNSS and sky view factor are described...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain the large capacity in the next generation mobile communication systems. For capacity expansion, small cells of multiple wireless network are deployed densely in these systems. Because a number of the cells overlap, users must discover a lot...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain higher throughput and wide coverage in the next generation mobile communication systems. A multimode receiver to demodulate signals with multiple air interfaces is required in the heterogeneous systems. In this paper, we discuss an implementation...
For large scale disaster relief, we propose a location and short message system using the Quasi-Zenith Satellite System (QZSS). The target capacity of the proposed system is the transmission of 3 million message data (MD) or more within one hour. To control random access of mobile terminal (MT), Frame Slotted ALOHA is used. Frame Slotted ALOHA cannot provide optimum control, since the hub station...
As a result of the great east Japan earthquake, terrestrial communication infrastructure was seriously damaged. Thus the importance of secure satellite communication measures based on very small aperture antenna terminal (VSAT) systems has been recognized. In order to satisfy the various demands for urgent life line recovery, we have started an R&D project of “Satellite Communication Networks...
We have proposed a hybrid single-carrier (SC) and multi-carrier (MC) system for next-generation mobile communication systems, where both high data rate and wide coverage system are attained by appropriately selecting SC or MC signal. We have confirmed effectiveness of the proposed hybrid system under single-cell environment. In this paper, the uplink throughput performance under multi-cell environment...
We have proposed a hybrid single-carrier (SC) and multi-carrier (MC) system for next-generation mobile communication systems. By appropriately selecting SC or MC signal, both high data rate and wide coverage system are attained in the hybrid system. In this paper, we discuss multi-antenna technology for the hybrid system. When space division multiplexing (SDM) is applied to the hybrid system, the...
With progression of scaling technique in silicon complementary metal-oxide semiconductor (Si-CMOS) process, it is available to produce radio frequency (RF) circuits using Si-CMOS for broadband wireless system, to reduce cost and size of devices. But in contrast, Si-CMOS RF circuit is deteriorated from circuits which use compound semiconductors. In order to reduce RF circuit's requirements, we propose...
For realizing over 2 Gbit/s transmission rate at portable terminals, we propose Advanced Kiosk Model (AKM) of 60 GHz band indoor multipath condition with hand tremor. In the AKM, coverage and bit error rate (BER) are defined as 10 m and 1 × 10-5 or less, respectively. Environment of multipath with Doppler effect by hand tremor causes serious inter-symbol interference (ISI). In this paper, we evaluate...
Multi-carrier (MC) transmission is attractive in next-generation mobile communication systems because of yielding high data rate and robustness against frequency-selective fading. An issue of the MC signal is high peak power. The MC signal is not effective for long distance transmission since longer distance requires higher output power. On the other hand, single-carrier (SC) transmission is effective...
We have proposed hotspot network based on layer 2 forwarding for seamless handover. A mobile terminal sends movement notification packet to new access point when the terminal changed connection from previous access point to the new access point. All nodes which received the movement notification packet change address table. The previous access point sends buffered packets to the new access point....
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