| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
In this investigation, we have proposed the new type of information platforms, where mobile communication systems and digital terrestrial broadcasting systems are effectively fused. The digital terrestrial broadcasting media using UHF band from 470 to 770 MHz is applied to the download link to achieve broadband transmissions. To realize the proposed platforms, we have focused on the ratio propagation characteristics in the UHF band, and the high effective data distribution method on the platforms in this investigation.
The UHF band radio propagation characteristics have been investigated based on the measurement. In the outdoor measurement, we utilized the measurement systems using GPS and UHF band receiver configured on the vehicle. By use of this measurement system, we can simultaneously measure the received level and the positioning data. And from the derived these data, we can configure the received level contour map around Hiroshima city. Evaluating the received level contour map combined with the terrain LOS area, it is found that the received level in UHF band has a high correlation to the terrain LOS area. On the other hand, from the results of indoor measurement, using the radio wave enters from outside to inside, it is clarified that there are many multi-path of radio wave at the receiver. The multi-path waves cause the large fading in the received level. To solve this problem, we have applied the diversity technique to the reception of the radio wave, and clarified that the diversity technique can largely improve the level fading.
Moreover, in the investigation of the data distribution method, we have proposed the wireless multicast method that can deliver the data to many users using radio waves. And it is found that the proposed method can improve distribution efficiency controlling the link capacity even if the unicast service coexists on the same networks.
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