| Project/Area Number |
59850056
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
電子通信系統工学
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥8,400,000 (Direct Cost: ¥8,400,000)
Fiscal Year 1985: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1984: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | radio communication / mobile communication / portable communication / propagation in urban area / multipath propagation / fading / diversity reception / 指向性アンテナ |
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| Research Abstract |
High speed digital mobile radio is widely required for the increasing demands of various kinds of new services, such as local and nation-wide communications on speech signal, digital data and visual information. The purpose of this research is to confirm the reduction of multipath fading and the improvement in transmission bandwidth performance achieved by a prototype system using an antenna pattern diversity reception (APDR), which has been developed in this research.
As the results of the field tests conducted in urban areas, the fading reduction by the prototype system has been found to be close to that by an ideal four-branch selection diversity reception system. However, the improvement in transmission bandwidth performance was not so good as expected before the tests. Then, the improvement in transmission bandwidth of a four-direction antenna by itself was evaluated experimentally and was found to be alwawys obtainable if the antenna pattern of the best transmission bandwidth performance can be selected by a proper branch-switching algorithm. A computer simulation of APDR with a branch-switching algorithm directly observing the flatness of the signal strength within the transmission band shows that a flatness below 1.5 dB within 100 kHz bandwidth is obtainable with 95 % of cumulative probability.
The results of this research show that APDR system can reduce the fading and the distortion due to frequency-selective fading which causes serious bit errors in digital mobile radio, and that it expands the applicable area of anti-multipath modulation/demodulation system, thus resulting in a possibility of high speed digital mobile radio.
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