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91.
A Study of Shadowing on Indoor Visible-Light Wireless Communication Utilizing Plural White LED Lightings 总被引:3,自引:1,他引:2
Toshihiko Komine Shinichiro Haruyama Masao Nakagawa 《Wireless Personal Communications》2005,34(1-2):211-225
White LED is considered as a strong candidate for the future lighting technology. We have proposed an optical wireless communication
system that employs white LEDs for indoor wireless networks. In this system, LED is used not only as a lighting device, but
also as a communication device. The transmitter has large optical power and large emission characteristics to function as
lighting device. And the system has specific wireless channel impulse response differing from infrared wireless communication.
In this paper, we discuss about shadowing effect on the system utilizing plural LED lightings including the performance of
ISI based on the impulse response. We consider the downlink transmission based on TDMA and evaluate the shadowing effect caused
by pedestrians with computer simulation. When the shadowing often occurs at 800 Mb/s, the performance of outage call duration
rate and blocking rate are improved by using 3 LED lightings compared with 1 or 2 LED lightings. And, we show that the system
with the optimal number of the LED lighting is robust against shadowing and can accommodate more calls.
Toshihiko Komine was born in Shizuoka, Japan, on November 17, 1978. He received the B.E. and M.E. degrees in Information and Computer Science
from Keio University, Yokohama, Japan, in 2001 and 2003 respectively. He is currently studying for the Ph.D. degree at Department
of Information and Computer Science, Keio University. His current research interests are optical wireless communications and
LED communications.
Shinichiro Haruyama is a professor at Department of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama,
Japan. He received an M.S. in engineering science from University of California at Berkeley in 1983 and a Ph.D. in computer
science from the University of Texas at Austin in 1990. He worked for Bell Laboratories of AT{&}T and Lucent Technologies,
U.S.A from 1991 to 1996, and for Sony Computer Science Laboratories, Inc. from 1998 to 2002. His research interests include
reconfigurable system, system design automation, wireless communication, and visible light communication.
Masao Nakagawa was born in Tokyo, Japan in 1946. He received the B.E., M.E. and Ph.D. degrees in electrical engineering from Keio University,
Yokohama, Japan, in 1969, 1971 and 1974 respectively. Since 1973, he has been with the Department of Electrical Engineering,
Keio University, where he is now a Professor. His research interests are in CDMA, consumer Communications, Mobile communications,
ITS (Intelligent Transport Systems), Wireless Home Networks, and Visible light Communication. He received 1989 IEEE Consumer
Electronics Society Paper Award, 1999-Fall Best Paper Award in IEEE VTC, IEICE Achievement Award in 2000, IEICE Fellow Award
in 2001. He was the executive committee chairman on International Symposium on Spread Spectrum Techniques and Applications
in 1992 and the technical program committee chairman of ISITA (International Symposium on Spread Spectrum Techniques and Applications)
in 1994. He is an editor of Wireless Personal Communications and was a guest editor of the special issues on “CDMA Networks
I, II, III and IV” published in IEEE JSAC in 1994 (I and II) and 1996 (III and IV). He chairs the Wireless Home Link sub-committee
in MMAC (Multimedia Mobile Access Communication Promotion Committee). 相似文献
92.
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94.
Microhardness measurements have been performed on untreated (virgin) and electrically stressed, solvent‐cast laboratory‐prepared samples of pure poly(phenylene oxide) (PPO), pure polystyrene (PS), and PPO : PS polyblends with different weight proportions. Results of such measurement on untreated polyblend sample show that microhardness (Hv) increases with increase in the content of PS up to 10 wt %, which attributed to the existence of homogeneous phase morphology. However, this feature is not observable in samples containing higher content of PS. Electrical stress is found to modify considerably the mechanical property of polymer. The effect of electric field on the microhardness of such samples (PPO : PS :: 90 : 10) has been characterized by the existence of a peak. Trapping of charge carriers in electrically stressed samples imparts hardening to the polyblend up to an applied step field of 190 kV/cm. However, the excessive charging beyond this step field value destroys this characteristic. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
95.
SDH光通信设备工程测试 总被引:1,自引:0,他引:1
结合实际介绍了SDH光通信设备工程测试项目和测试方法,及相关的技术指标,包括平均发送光功率测试、接收机灵敏度测试、接收机过载功率测试、误码测试、抖动和漂移测试、定时同步测试、保护倒换测试、开销和维护信号测试、网管功能测试等。 相似文献
96.
文章依据FBG温度传感的原理以及LPG滤波技术,提出了一种新的光纤光栅温度报警模型.用MATLAB对系统所采用的方法进行了模拟,结果表明该系统能满足温度报警的要求. 相似文献
97.
OPGW应用问题的探讨 总被引:2,自引:1,他引:1
根据多年的光纤复合架空地线(0PGW)应用经验与实践,从0PGW结构及组成、光纤余长、线路配合、金具配套、0PGW安装等方面,对0PGW应用中的若干问题进行详细的探讨。 相似文献
98.
Collinear magnetooptic interaction with magnetostatic surface waves (MSSW) can be used for wavelength‐selective switches, wavelength filters, and frequency shifters in wavelength‐division‐multiplexed (WDM) photonic networks and optical processing systems. The switching efficiency can be improved with a multilayer waveguide structure. To investigate the dynamic switching characteristics, the FDTD method was employed. The mode conversion between TE and TM mode was successfully demonstrated with FDTD simulation. The filtering characteristics were also evaluated. The FDTD results were compared with the result from the coupled mode theory, and good agreement was obtained. Switching of an optical pulse was also demonstrated by the FDTD method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 40–47, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20501 相似文献
99.
激光束偏转法检测金属表面层的缺陷 总被引:3,自引:0,他引:3
本文编程计算了由激光光热应产业的金属表面的温度分布和泵浦光的调制频率、金属层厚度等的关系,预言检测浓度缺陷的能力。用激光光束偏转法检测到表面下不同深处的缺陷,并把面扫描幅值信号以三维象和灰度象显示。 相似文献
100.