| Project/Area Number |
09450154
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
情報通信工学
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| Research Institution | Osaka University |
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Principal Investigator |
KOMAKI Shozo Graduate School of Engineering, Osaka University, Professor, 大学院・工学研究科, 教授 (10243164)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Minoru Graduate School of Engineering, Osaka University, Research Assistant, 大学院・工学研究科, 助手 (10252587)
TSUKAMOTO Katsutoshi Graduate School of Engineering, Osaka University, Associate Professor, 大学院・工学研究科, 助教授 (10207342)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,600,000 (Direct Cost: ¥13,600,000)
Fiscal Year 1999: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1998: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 1997: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Keywords | Wireless Agent Techniques / Open Frequency Intelligent Wireless Communication Network / Virtual Radio Free Space Networking / OFDM / Hierarchical Modulation / Microwave Photonics / Photonic CDMA / Macro Diversity / 光ファイバ無線 / 移動通信 / 無線ハイウェー / 高度道路交通システム / 光フィード偏在アンテナ / 帯域自然標本化 / オーバラップセル / 非線形ひずみ補償 / ニューラルネットワーク / 無線ハイウェイ |
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| Research Abstract |
In this research, we have studied Radio Agents Technologies and Virtual Radio Free Space Photonic Networks provided by Ultra High Speed Signal Processing Techniques using Combined Photonic & Radio-wave Technologies in order to realize Open Frequency Intelligent Wireless Networks (OFINe) providing Flexible Spectrum Operation and Air Interfaces Adaptation to users according to their demands and environments.
Wireless Agents Techniques : First, we have newly proposed the Hierarchical Modulation scheme to adaptively control modualation formats according to the importance of frequency components in a picture or a video and the wireless link quality. Computer simulations have shown its graceful degradation characteristics and PSNR quality improvement. As an expanded scheme, furthermore, we have proposed the Hierarchical Modulation Agent System. In order to maximize the degree of users' satisfaction, this novel system chooses an optimum signal format by considering both the requested QoS and t
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he importance of requested information contents. Computer simulations have clarified that the proposed agent system can realize the compatibility between the transferring delay and the received quality keeping the spectral effciency maximal. Regarding orthogonal multi-carrier modulations, we have proposed a new type of nonlinear compensation schemes, frequency acquisition schemes using the guard time and the pre-DFT spatial diversity scheme, which can realize Spatial Division Multiple Access in the same frequency channel.
Virtual Radio Free Space Photonic Networks : Radio signal use photonic bandwidth as their free spaces in Virtual Radio Free Space Photonic Networks. First, to realize the university of this network for various type of air-interfaces, that is multi-carrier wireless services, we have newly proposed the photonic chirp multiplexing transforming systems and the photonic radio packet asynchronous transferring scheme. Theoretical analyses have clarified its good quality of transferred radio signals. Second, we have newly proposed Direct Optical Switching CDMA system where photonic code spaces can realize the virtual radio free space in optical fibers, and proposed a novel higher order bandpass sampling scheme to improve the process gain of DOS-CDMA. Third, we have theoretically and experimentally examine the spectral aliasing distortion occurring when we use the code period not equal to the bandpass sampling period to improve the transparency of DOS-CDMA for various radio signal formats. The results show the required chip rates to reduce the required distortion power. Moreover, we have also proposed an novel aliasing canceller. Less
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