| Project/Area Number |
15300020
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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 |
Computer system/Network
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| Research Institution | Osaka Seikei University (2004)
Osaka City University (2003) |
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Principal Investigator |
FUJIWARA Chikato Osaka Seikei Univ., Fac.of Modern Management Information, Prof., 現代経営情報学部, 教授 (70047190)
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| Co-Investigator(Kenkyū-buntansha) |
OKA Ikuo Osaka City Univ., Graduate School of Eng., Prof., 大学院・工学研究科, 教授 (80160646)
ATA Shingo Osaka City Univ., Graduate School of Eng., Lecturer, 大学院・工学研究科, 講師 (30326251)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 2004: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2003: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | distributed Queuing networks / subnetwork / bridge network / suppression of slot discards / loophack retransmission / reliable multicast / modulation identification / peak power reduction / 位相回転 / DQDB / ループバック再送方式 / 廃棄抑圧 / 無線ネットワーク / OFDM |
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| Research Abstract |
In exhibition sites, the booth layout is changed for each exhibition and the network configuration is required to be changed according to it. For those situations the terminals at booths are added and removed frequently. We investigate the network with flexible characteristics for network change and capable of giving both fair and prioritized bandwidth allocation for the terminals. The proposed network is composed of the subnetworks connecting the terminals at each booth and global bridge network connecting subnetworks. The proposed network has a loopback retransmission mechanism in order to eliminate the packet loss even when the buffer memory at the bridge overflows. In the proposed system, the slot has a loopback bit in its header. If the buffer of the bridge overflows, the received slot at the bridge is relayed to the next bridge with the loopback bit set to 1. If the slot terminator receives a slot with the loopback bit set to 1, it retransmits the received slot with the loopback
… More
reset on the reverse channel. By repeating the loophacks the slot discarding does not occur both in subnetworks and bridgenetwork if the buffer memoriy overflow occurs at the bridge.
We also propose a loopback retransmission between routers for reliable multicast communication network. The proposed system can reduce the delay compared with the conventional systems in which the receivers request retransmission whenever detecting message loss.
In a radio network, various modulations are employed to transmit multimedia information, and it is important to identify the modulations. We propose a modulation identification method based on joint moments of a received signal, and analyze the modulation identification error probability.
An orthogonal frequency division multiplexing (OFDM) is attractive to realize high speed communications and to obtain a high QoS in the radio network. However the OFDM has a high peak power and it causes an inefficient amplification. To reduce the peak power, we propose the phase rotation method and show the peak power suppression effects by the phase rotation. Less
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