ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
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27.16
Displaying 1-15 of 15 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    Pages Cover1-
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_Cover1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    Pages Toc1-
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_Toc1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Prediction and Validation of Path Loss in Urban Non-Line-of-Sight Micro-cell Environment by using Ray Tracing Simulation
    Satoshi Nagata, Jun-ichi Takada, Takeshi Toda, Houtao Zhut
    Article type: Article
    Pages 1-4
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_1
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Spatio and temporal (ST) processing can provide great improvement of capacity and transmission quality in high data rate mobile wireless communications. A ST equalizer using adaptive array antenna and maximum likelihood sequence estimator has been prototyped and evaluated in field [1][2]. Such prototype development and field trial, however, need large cost and time. Use of a Ray tracing simulation proposed in Ref [3] is one of solutions in order to evaluate the ST processing for real ST propagation scenario. In this paper, the results of the Ray-Tracing simulation presented in Refs. [3][4] are compared with those of field test with respect to the path loss in urban micro-cell environment, to show the validation and the limitation of the simulator.
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  • On the analysis of the ferrite-loaded small loop antenna by using electromagnetic field simulator
    Hiroaki SATO, Jun-ichi TAKADA
    Article type: Article
    Pages 5-8
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_5
    CONFERENCE PROCEEDINGS FREE ACCESS
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    The mainstream of the wave signal used as a standard of time and frequency in recent years is shifting from HF analog modulation to LF digital modulation. The radio control clock which automatically adjust the time by using standard-frequency and time-signal is getting popular on the market. The ferrite-loaded small loop antenna has been mainly used as a built-in antenna for reception of LF and MF waves including standard-frequency and time-signal because the size is very small compared with wavelength. In this study the numerical analysis of the antenna characteristic using the electromagnetic field simulator is considered solenoid coil placed over the uniform AC magnetic field as the size of antenna is much smaller than wavelength.ferrite-loaded small loop antenna
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  • Strip Antenna with Three-Frequency Bands Printed on the Dielectric Substrate
    Yusuke UKAWA, Hiroyasu Matsui, Toshio WAKABAYASHI
    Article type: Article
    Pages 9-12
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_9
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Mobile and satellite communication is used in various frequency bands. It is important to obtain characteristics of planar antennas such as microstrip and patch antennas for the mobile communications. And so, we have designed an antenna which has several resonance frequencies. In this paper, we analyze characteristics of the antenna printed on dielectric substrate by using the FDTD method. The characteristics of the antenna such as return loss far field patterns and electromagnetic field are shown in figures. The analytical results are coincident with experimental results.
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  • Design and Analysis of Two-arm Multiloop Printed Antennas
    Sanjeev Singh Kathayat, Naoki Yoshida, Yusuke Ukawa, Toshio Wakabayahi
    Article type: Article
    Pages 13-16
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_13
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Two-arm multiloop antennas printed on a dielectric substrate is analyzed by using the Finite Difference Time Domain (FDTD) method. These antennas are fed at the center of the two arms. The antenna characteristics, including the input impedance, far field patterns, electric field and current distribution are obtained by using the FDTD method. From the analysis results, it is clear that these antennas have multi resonance at different frequencies. The gain of these antennas is around 2 dBi and the antenna shows the omni directional radiation pattern very similar to that of a dipole antenna. Since multi frequency operation is revealed as the functions of number of loops, this antenna can be used in multi frequency operation in different applications such as multimedia wireless communication, GPS receiver etc.
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  • A Study on OFDM Adaptive Array by the Multiple Control with Pre-and Post-FFT
    Youhei Yamamoto, Takeo Fujii, Yasuo Suzuki
    Article type: Article
    Pages 17-20
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_17
    CONFERENCE PROCEEDINGS FREE ACCESS
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    In OFDM transmission systems, the delayed waves beyond the guard interval and the co-channel interference waves cause Inter-Symbol Interference (ISI) and Co-channel Interference (CCI) respectively. These waves degrade the transmission performance. The Post-FFT array can constrain the interference wave in the guard interval, and multipath waves with the high correlation between the antenna. However, when it is going to obtain a diversity profit by extending an element interval, the delayed waves beyond the guard interval and interference waves receives with different symbol timing become low correlation waves. As a result, the system requires increasing the number of elements . In this paper, the proposed system divides an element of the Post-FFT array with a large element interval into the subarray which consists of two or more elements with a still narrower element interval. The proposed system can obtain the diversity gain using the compound control, and can remove a long delayed waves and an asynchronous interference waves. In order to clarify the validity of the proposal system, the basic characteristic was analyzed by the computer simulation.
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  • Fading Tracking Improvement of Adaptive Array Antenna by Cooperation with Diversity Combining
    Kaoru USUKU, Takeo FUJII, Yasuo SUZUKI
    Article type: Article
    Pages 21-24
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_21
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Recently, in mobile communications systems, the research of an adaptive array antenna has attracted attention as one of the interference suppression technology. If the antenna element space increases in multipath fading environment the correlation of the received signal of each element becomes low. When MMSE algorithm is used for optimal weight decision of adaptive array antenna with wide element space, it is known that a diversity gain will be obtained as well as interference suppressing [l]. However, the adaptive array antenna with wide element space tends to be influenced by fading, and the tracking of the desired signal becomes difficult under the mobile communications environment where fading speed is high. Therefore this paper proposes the layered adaptive array antenna which can also obtains a diversity gain by tracking the fluctuation of fading
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  • A Study on Data Spread OFDM using Transmit Diversity
    Mamoru Minehara, Yoshiaki Owaki, Makoto Itami, Hiroki Ohta, Kohji Itoh
    Article type: Article
    Pages 25-28
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_25
    CONFERENCE PROCEEDINGS FREE ACCESS
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    In OFDM transmission, it is difficult to improve preformance by equalization it influence of multipath is severe become of frequency dips. A data spread OFDM scheme is effective for this degradative. However, characteristics data spreading scheme in Rayleigh fading is not always good. Because its influence is distributed to all carriers. In this paper, characteristics of Alamouti scheme (two-branch transmit diversity) in Rayleigh fading is analyzed. In order to eliminate influence of frequency dips and improve system performance. Moreover, by combining data spread OFDM with transmit diversity better performance of frequency dips and improve system performance is confirmed.
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  • The ICI Canceller based on MMSE in OFDM
    Mitsuru Nakamura, Makoto Itami, Kohji Itoh
    Article type: Article
    Pages 29-32
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_29
    CONFERENCE PROCEEDINGS FREE ACCESS
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    During an OFDM transmission, a loss of sub-carrier orthogonality due to Doppler-spread of the channel leads to inter-carrier interference (ICI). This problem is especially bad in mobile reception environments. ICI causes significant degradation of the bit error rate characteristics and its influence becomes larger as the carrier frequency or velocity of the receiver increases. We have proposed a method to reduce the ICI caused by the Doppler spread of the channel. The transmission channel is modeled by a combination of multiple Doppler shifted propagation paths, and their parameters such as attenuation, relative delay and Doppler-shift are estimated using scattered pilot symbols. The ICI is canceled by multiplying the inverse matrix of the estimated channel matrix with the received OFDM symbol vector. However, the ICI canceller emphasizes a noise component, so it can't improve the bit error rate characteristics sufficiently. In this paper, we propose the ICI canceller based on MMSE which does not emphasize a noise component. Computer simulation confirmed that the ICI canceller based on MMSE can reduce the bit error rate more than ICI canceller based on zero-forcing under the Doppler-spread channel.
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  • A Study on Data Spread OFDM using LDPC Codes
    Koji Kyomen, Yoshiaki Owaki, Makoto Itami, Kohji Itoh
    Article type: Article
    Pages 33-36
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_33
    CONFERENCE PROCEEDINGS FREE ACCESS
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    In the communication systems using OFDM, it is necessary to compensate influence of frequency selective fading caused by multi-path. An error correcting code is one of the effective methods and it is adopted in many systems using OFDM. The method that spreads data symbols in frequency domain is one of the effective methods. In the OFDM signal generated by this procedure, the original data symbols are spread over the whole carriers, coded data spread OFDM scheme. By spreading data symbols over whole carriers, it is possible to recover data symbols even if some carriers are lost under severe frequency selective fading. Though data spread OFDM itself is very effective scheme to improve characteristics under frequency selective fading without loss of data transmission rate, it is possible to improve bit error rate characteristic further by using the LDPC code.
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  • A study of pseudo loss-less transmission using fiber Raman amplifier
    Takahiro FUJIED, MASANORI HANAWA, Miho TAKAHARA
    Article type: Article
    Pages 37-40
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_37
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Loss-less optical fiber transmission is expected for its advantages, i.e. reduction of the nonlinear effects, energy saving and so on. In this paper, a pseudo loss-less transmission system based on the fiber Raman amplifier with the effective core area management is evaluated via computer simulations. The system aims minimizing signal power variation in transmission to reduce nonlinear effects. Our computer simulation results show that the pseudo loss-less transmission system with the effective core area management is good to reduce nonlinear effects and it is better than the system with simple fiber Raman amplifiers.
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  • A Study of All-Optical Multi-Wavelength 3R Regenerator
    Tetsushi YAMADA, Masanori HANAWA, Mikio TAKAHARA
    Article type: Article
    Pages 41-44
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_41
    CONFERENCE PROCEEDINGS FREE ACCESS
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    All-optical regenerators have been studied actively. Most of the conventional regenerators, however, have not aimed to handle WDM signals. In this paper, a novel all-optical 3R regenerator based on four wave mixing which has the ability to handle WDM signals is proposed. Based on the computer simulation results, the transmission characteristics of 1R(EDFA only), 2R(MZI-SOA type), and the proposed 3R regenerators were evaluated for single wavelength signals. In such situation, the proposed 3R regenerator is superior to other systems and is possible to transmit lOGbit/s signals over 3,000km of DSF with eye opening penalty under 1dB.
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  • [title in Japanese]
    Article type: Appendix
    Pages App1-
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_App1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Appendix
    Pages App2-
    Published: February 28, 2003
    Released on J-STAGE: September 20, 2017
    DOIhttps://doi.org/10.11485/itetr.27.16.0_App2
    CONFERENCE PROCEEDINGS FREE ACCESS
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