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Yekeh Yazdandoost K.,Wireless Network Research Institute
2013 7th European Conference on Antennas and Propagation, EuCAP 2013 | Year: 2013

A low profile printed magnetic loop antenna, implanted in the human tissues (i.e. skin, fat, and muscle) is presented in this paper. The antenna has been studied for the performance of a communication link between the implanted antenna and on-body or outside the body antenna. Ultra Wideband (UWB) system for communication from in-body implanted device to on-body or outside the body is one of the strong candidate for wireless medical applications. Propagation paths of Wireless Body Area Network (WBAN) can experience fading due to energy absorption, reflection, diffraction, and polarization mismatch. In order to minimize the propagation losses a well design antenna will be needed, however, at the same time antenna should be designed with respect to body tissues electrical properties. Antennas implanted in a human body must be designed with in-deep understanding of surrounding environment, keeping in mind that tissue environment is different from free space. © 2013 EurAAP.


Hernandez M.,Wireless Network Research Institute | Miura R.,Wireless Network Research Institute
Proceedings - IEEE International Conference on Ultra-Wideband | Year: 2012

The paper describes a coexistence study of IEEE Std 802.15.6-2012 UWB devices with other UWB systems, in particular IEEE Std 802.15.4a-2007 (pico-nets) devices and IEEE 802.15.4f-2012 (RFID) devices. The recently published IEEE Std 802.15.6TM-2012 includes IR-UWB and FM-UWB technologies. The IR-UWB transceivers for BANs are based on the transmission of a single and relative long pulse per symbol (new paradigm in UWB) or a concatenation or burst of short pulses per symbol (legacy), while FM-UWB transceivers are based on the concatenation of a CP-2FSK signal and a wideband FM signal. Thus, coexistence between UWB devices becomes very important for reliable operation in medical applications. © 2012 IEEE.


Liu J.,Tohoku University | Jiang X.,Future University Hakodate | Nishiyama H.,Tohoku University | Miura R.,Wireless Network Research Institute | And 2 more authors.
IEEE Journal on Selected Areas in Communications | Year: 2012

This paper examines the optimal forwarding problem in mobile ad hoc networks (MANETs) based on a generalized two-hop relay with limited packet redundancy f (f-cast) for packet routing. We formulate such problem as a forwarding game, where each node i individually decides a probability τ-i (i.e., a strategy) to deliver out its own traffic and helps to forward other traffic with probability 1-τ-i, τ-i[0,1], while its payoff is the achievable throughput capacity of its own traffic. We derive closed-form result for the per node throughput capacity (i.e., payoff function) when all nodes play the symmetric strategy profiles, identify all the possible Nash equilibria of the forwarding game, and prove that there exists a Nash equilibrium strategy profile that is strictly Pareto optimal. Finally, for any symmetric profile, we explore the possible maximum per node throughput capacity and determine the corresponding optimal setting of f to achieve it. © 2012 IEEE.


Kadowaki N.,Wireless Network Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2012

The National Institute of Information and Communications Technology (NICT) has worked toward the research and development of various satellite communications and broadcasting technologies since the 1970s. NICT developed the basic laser communication experimental equipment (LCE) for the Engineering Test Satellite-VI (ETS-VI) and performed the world's first laser communication experiment using a satellite in orbit in 1994. The Optical Inter-orbit Communications Engineering Test Satellite (OICETS), called 'Kirari' in Japanese, was developed by the Japan Aerospace Exploration Agency (JAXA). Kirari project was put on hold after the protoflight test was completed. However, the Kirari was launched successfully in August 2005. After this, NICT guided and realized a joint international project of laser communication experiments between the Kirari and each of the four optical ground stations in various locations on the ground.


Kawasaki K.,Wireless Network Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2014

Experimental telecommunications equipment of the Ka and S band was installed in Engineering Test Satellite VIII (ETS-VIII: KIKU No.8) launched in December, 2006. To investigate the secular distortion of this experimental telecommunications equipment, five times performance evaluation experiment was done. This experiment result represents an evaluation for the secular distortion of the equipment equipped to the satellite on the orbit, and it becomes a help in designing and production of the equipment installed to the satellite in the future.


Orikasa T.,Wireless Network Research Institute | Fujino Y.,Toyo University
Journal of the National Institute of Information and Communications Technology | Year: 2015

Satellite antenna for STICS is consists of the deployable reflector and the phased array feed and performs the multi beam formation with the number of array elements and beams are about 100 respectively. Partial model was developed for functional confirmation of digital beam former and digital channelizer (DBF/channelizer). DBF/channelizer has excellent flexibility for beam shaping function. We combined the partial model of array feed, reflector and DBF/channelizer and measured the radiation pattern of that antenna and discuss the function of DBF/channelizer for 100 class multi beam forming function.


Orikasa T.,Wireless Network Research Institute | Fujino Y.,Toyo University
Journal of the National Institute of Information and Communications Technology | Year: 2015

For realization of STICS, a large satellite antenna is necessary. We have been studying the satellite antenna with approximately 30 m aperture size. For keeping the performance of beam shape, beam direction and sidelobe level, radiation pattern correction will be needed, because thermal distortion of reflector will be caused. In this section, radiation pattern correction experiment results are described, using developed digital beam forming network (DBF/channelizer) for studying ability of pattern correction of this DBF antenna.


Miura A.,Wireless Network Research Institute | Tsuji H.,Wireless Network Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2015

This paper summarizes the international standardization activities on the integration of satellite and terrestrial communication systems. On the system issue, regulations are approved in the Europe and the U.S. in the 2000s. After that, the discussions have been held on the standardization at the Asia-Pacific Telecommunity (APT) and the International Telecommunication Union Radiocommunication Sector (ITU-R). As for the radio interface issue, the radio interface for satellite communications corresponding to the terrestrial fourth-generation mobile communication has been discussed, and the ITU-R Recommendation has been approved.


Fujino Y.,Toyo University | Miura A.,Wireless Network Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2015

Onboard Low Noise Amplifier (LNA) and Solid State Power Amplifier (SSPA) of STICS (Satellite/Terrestrial Integrated mobile Communication System) satellite is assumed to meet large signal interference from huge numbers of terrestrial communication terminals or to amplify hundreds of channels simultaneously. So, LNA required having high linearity and low noise figure simultaneously. We developed S-band onboard LNA which can efficiently operate high level interference wave that is 40 dB higher than that of desired wave. Also, for SSPA, we developed high linearity and high efficiency SSPA using GaN device.


Minowa T.,Social Research Center | Miura A.,Wireless Network Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2015

This paper presents the satellite-terrestrial user coexisting schemes (frequency separation scheme, frequency sharing scheme) as a key technology of Satellite and Terrestrial Integrated mobile Communication System (STICS). The frequency sharing scheme, which is expected to realize high spectrum efficiency, is introduced with its principle, the interference problem, and the interference suppression/mitigation technologies. Then, theoretical analyses and computational simulations to compare the spectrum efficiencies between frequency separation and sharing schemes are carried out to show the effectiveness of the frequency sharing scheme.

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