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Displaying 1-14 of 14 articles from this issue
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Article type: Cover
Pages Cover1-
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (10K) -
Article type: Index
Pages Toc1-
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
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Futa KIMURA, Daisuke UMEHARA, Hidekazu MURATA, Satoshi DENNOArticle type: Article
Session ID: BCT2015-25
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSPhysical-layer network coding (PNC) enables bi-directional communications with wireless decode-and-forward (DF) relaying to achieve the frame exchange within half of time slots required the conventional wireless DF relaying. However, to apply precoding to the frames transmitted from a terminal station to the relay station, the terminal station should acquire the channel state information (CSI) to the relay station before transmitting. In this manuscript, we propose a PNC-DF relaying protocol, in which a terminal station estimates the CSI to the relay station with echo-MIMO estimation. The throughput of the PNC-DF relaying protocol is evaluated using the CSI by echo-MIMO estimation and it compares with those of conventional relaying and XOR-NC relaying. As a result, the appricable domain of the PNC-DF relaying protocol is shown according to the distance between both of terminal stations.View full abstractDownload PDF (649K) -
Tosiki TANAKA, Hidekazu MURATAArticle type: Article
Session ID: BCT2015-26
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, collaborative interference cancellation (CIC), which is one of the multi-user MIMO system, is studied. The users share their received signals with neighboring users and generate weights for inter-user interference. In fast time-varying channel, there are channel fluctuation in each packet, so channel tracking for compensation is needed. Decision-directed tracking loop scheme is employed and the performance improvement on experimental system using a fading emulator than MMSE receiver is presented.View full abstractDownload PDF (3487K) -
Erina OGIDA, Yosuke KIMURA, Kazuaki HARASHIMA, Yuta KISHIMOTO, Hiroki ...Article type: Article
Session ID: BCT2015-27
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe propose an underwater optical transmission system that can send video signal by using retro-reflective sheet which covers the surface of a spherical repeater. It enables an optical transmitter keep covering the repeater with optical beam even if both move. We formulated reflection characteristic for observation angle based on Fraunhofer diffraction theory. It gave good agreement with result of the experiment.View full abstractDownload PDF (596K) -
Mahito Koizumi, Kazuyuki Saito, Koichi ItoArticle type: Article
Session ID: BCT2015-28
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSModern MRI systems employ high-frequency and high-powered radio frequency (RF) pulses. Given this, it is necessary to evaluate the specific absorption rate (SAR) of the irradiated human body. Recently, the materials and shapes of implantable medical devices such as artificial joints or pacemakers have become increasingly diverse. At once, making it more likely that subjects' implanted medical devices will potentially causing temperature increases in unexpected regions. Therefore, in order to consider the safety of patients with implanted medical devices during MR imaging, it is necessary to comprehend the detailed SAR distribution within the human body. In this study, we evaluated SAR for human body with carotid stent and DBS as one example of medical devices during MR imaging. In these results, SAR value increased around these devices. However, these values were below safety guideline sufficiently.View full abstractDownload PDF (7756K) -
Yohei SHIBATA, Tomoaki OHTSUKI, Jun MASHINO, Takatoshi SUGIYAMAArticle type: Article
Session ID: BCT2015-29
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSSuperposed multicarrier transmission scheme is known to improve frequency utilization efficiency where several wireless systems share spectrum. On superposed band, log likelihood ratio (LLR) cannot be set correctly because of interference, which results in BER (Bit Error Rate) degradation. To suppress the effect of interference, forward error correction (FEC) metric masking is proposed. In this technique, LLRs that correspond to superposed band is set to zero, because received bits that correspond to superposed band is unreliable. This scheme requires superposed band detection and does not consider channel estimation error. We proposed an iterative esimation technique for undesired signal power in [6]. Although, this scheme does not require superposed detection beforehand, due to the estimation error of undesired signal power, BER is degraded. In this report, we propose an estimation technique for undesired signal power and superposed band to calculate LLR correctly. This scheme estimates superposed band within 1 packet and using the information about superposed band, undesired signal power is estimated using pilot symbols. Simulation results show that as the number of pilot symbols increases, BER performs better than [6] and gets closer to the BER when the estimation of undesired signal power is perfect.View full abstractDownload PDF (607K) -
Koustubh GAIKWAD, Tomoaki OHTSUKIArticle type: Article
Session ID: BCT2015-30
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSLive media streaming has become one of the most important applications over the Internet. However, having an all-round scalable, reliable, responsive and cost-effective solution for delivery of live video over multiple platforms is still a challenge. To deliver live video over multiple platforms like laptops, mobile phones, tablets, gaming consoles, etc., the video needs to be encoded to appropriate format based on the device on which it is to be rendered. The traditional way of using hardware encoder has been known to be expensive and inefficient. Cloud provides virtually infinite on-demand resources where the software encoders can run and the tenants are charged only for the renting period. The main idea is to vary the number of encoding/transcoding and streaming servers dynamically based on the user demand for each type of stream. We propose a framework to deliver live video over multiple platforms and a neural network based prediction model to predict the video demand for each type of stream taking parameters like device type, region, etc. into consideration. The use of cloud for encoding and streaming video makes the overall implementation scalable and cost-effective.View full abstractDownload PDF (574K) -
Kenji SUGIYAMA, Naoyuki AWANO, Ayumu OIKE, Takuya KUSAJIMAArticle type: Article
Session ID: BCT2015-31
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSVery high resolution video system such as 4K/8K enables super close view, and, such very short distance causes significant different view in a picture. On the other hand, the human gaze mostly distribute to the center of the picture, and this is more significant in the large screen. Therefore, uniform coding for a picture may not be always best. In this report, the reduction of the number of pixels to be coded using the geometric image conversion is discussed on the viewpoint of processing power and coding efficiency. The basic method with two dimensional conversion based on the actual view and the horizontal vertical independent methods are compared. Furthermore, the quantization control using the contrast conversion to reduce the residual information in the independent method is discussed. As the results of experiments, the possibility of maximum 35 percent bit rate reduction is recognized with 50% processing power.View full abstractDownload PDF (9827K) -
Masafumi NAGASAKA, Susumu NAKAZAWA, Shoji TANAKAArticle type: Article
Session ID: BCT2015-32
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA 12-GHz (11.7 to 12.75 GHz) band satellite service with dual-circular polarization is expected for transmission channels to deliver advanced broadcasting services such as 8K (Super Hi-Vision). A right- and left-circularly polarized parabolic reflector antenna will make it possible to receive services provided over the dual-circular polarization with a single reflector antenna. Therefore, we designed a dual-polarization microstrip antenna array for the feed antenna of an offset parabolic reflector antenna. Simulation results showed the voltage standing wave ratio was less than 1.4 and the cross polarization discrimination (XPD) was more than 29 dB. A dual LNB (Low Noise Block Converter), which has two local oscillators corresponding to right- and left-circular polarizations, is also required for the dual-polarization receiving antenna to carry the received signals on a single cable. To evaluate the feasibility of the dual LNB, we fabricated and measured the LNB integrated with a parabolic reflector. The measured results showed the aperture efficiency was more than 76 %, XPD was more than 26 dB and the noise figure of the LNB was less than 1 dB. On the other hand, a 21-GHz (21.4 to 22.0 GHz) band satellite broadcasting system is also being studied as a means of delivering 8K, 3DTV, and other advanced forms of broadcasting. Then, we fabricated a 21-GHz band parabolic reflector antenna, which has a 60-cm offset reflector, for common reception equipments in condominiums and so on. The reflector is made of a metallic mesh and fiber reinforced-plastics for survival wind speed and weight saving. The measured results showed that the aperture efficiency was 74 % and that the radiation pattern complied with the reference pattern in Recommendation ITU-R BO.1900.View full abstractDownload PDF (15253K) -
Kazuhiro OTSUKIArticle type: Article
Session ID: BCT2015-33
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSAs the transport scheme for Super Hi-Vision satellite broadcasting systems, which would be launched in 2018, it would be assumed that MMT (MPEG Media Transport), of which standardization has been finalized in MPEG, is adopted since it enables hybrid delivery using broadcasting and broadband networks. For realizing the broadcast services using MMT, required signaling information should be defined. In this report, we proposed a migration of signaling information based on the service information of the current digital broadcasting systems. Since the migration would not cover all the necessary information, we also proposed additional signaling information. In Super Hi-Vision satellite broadcasting, it is required that transmitting data files in addition to video and audio and providing same services as current digital broadcasting. So, we arranged the requirements for transport scheme and proposed MMT-based Application transmission scheme. In addition, we compared this scheme with other scheme and evaluated its performance by simulation. As a result, we found that the Media Processing Unit (MPU) mode of the MMT protocol is suitable for the requirements of application transmission and is able to transport files like data carousel transmission in current digital broadcasting. We also described that two management tables function as separate directory layouts for production and transmission and that the acquisition time is shortened by increasing the maximum size of the transport packets.View full abstractDownload PDF (4830K) -
Article type: Appendix
Pages App1-
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (80K) -
Article type: Appendix
Pages App2-
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (80K) -
Article type: Appendix
Pages App3-
Published: February 12, 2015
Released on J-STAGE: September 22, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (80K)
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