Spelling suggestions: "subject:"multihop transmission"" "subject:"multiihop transmission""
1 |
Multi-hop Transmission in Millimeter Wave WPAN with Directional AntennaQiao, Jian January 2010 (has links)
Millimeter-wave (mmWave) communications is a promising enabling technology for high rate (Giga-bit) multimedia applications. However, because oxygen absorption peaks at 60 GHz, mmWave signal power degrades significantly over long distances. Therefore, a traffic flow transmitting over multiple short hops is preferred to improve the flow throughput. In this thesis, we first design a hop selection metric for the piconet controller (PNC) to select appropriate relay hops for a traffic flow, aiming to improve the flow throughput and balance the traffic loads across the network. We then propose a multi-hop concurrent transmission (MHCT) scheme to exploit the spatial diversity of the mmWave WPAN by allowing multiple communication links to transmit simultaneously. By deriving the probability that two links can transmit simultaneously as a function of link length, the MHCT scheme is capable of improving spatial multiplexing gain in comparison with the single hop concurrent transmission (SHCT) scheme. We theoretically demonstrate that by properly breaking a single long hop into multiple short hops, the time resource can be utilized more efficiently, thus supporting more traffic flows in the network within the same time interval. In addition, the per-flow throughput is obtained analytically. Extensive simulations are conducted to validate the analysis and demonstrate that the proposed MHCT scheme can significantly improve the average traffic flow throughput.
|
2 |
Multi-hop Transmission in Millimeter Wave WPAN with Directional AntennaQiao, Jian January 2010 (has links)
Millimeter-wave (mmWave) communications is a promising enabling technology for high rate (Giga-bit) multimedia applications. However, because oxygen absorption peaks at 60 GHz, mmWave signal power degrades significantly over long distances. Therefore, a traffic flow transmitting over multiple short hops is preferred to improve the flow throughput. In this thesis, we first design a hop selection metric for the piconet controller (PNC) to select appropriate relay hops for a traffic flow, aiming to improve the flow throughput and balance the traffic loads across the network. We then propose a multi-hop concurrent transmission (MHCT) scheme to exploit the spatial diversity of the mmWave WPAN by allowing multiple communication links to transmit simultaneously. By deriving the probability that two links can transmit simultaneously as a function of link length, the MHCT scheme is capable of improving spatial multiplexing gain in comparison with the single hop concurrent transmission (SHCT) scheme. We theoretically demonstrate that by properly breaking a single long hop into multiple short hops, the time resource can be utilized more efficiently, thus supporting more traffic flows in the network within the same time interval. In addition, the per-flow throughput is obtained analytically. Extensive simulations are conducted to validate the analysis and demonstrate that the proposed MHCT scheme can significantly improve the average traffic flow throughput.
|
3 |
Wide-area broadband private wireless communication system / 広域広帯域自営無線通信システムMakino, Kiminobu 25 March 2024 (has links)
付記する学位プログラム名: 社会を駆動するプラットフォーム学卓越大学院プログラム / 京都大学 / 新制・課程博士 / 博士(情報学) / 甲第25442号 / 情博第880号 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 原田 博司, 教授 大木 英司, 教授 梅野 健, 教授 中村 公人 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
|
4 |
Relay-Assisted Free-Space Optical CommunicationsSafari, Majid 04 January 2011 (has links)
The atmospheric lightwave propagation is considerably influenced by
the random variations in the refractive index of air pockets due to
turbulence. This undesired effect significantly degrades the
performance of free-space optical (FSO) communication systems.
Interestingly, the severity of such random degradations is highly
related to the range of atmospheric propagation. In this thesis, we
introduce relay-assisted FSO communications as a very promising
technique to combat the degradation effects of atmospheric
turbulence. Considering different configurations of the relays, we
quantify the outage behavior of the relay-assisted system and
identify the optimum relaying scheme. We further optimize the
performance of the relay-assisted FSO system subject to some power
constraints and provide optimal power control strategies for
different scenarios under consideration. Moreover, an application of
FSO relaying technique in quantum communications is investigated.
The results demonstrate impressive performance improvements for the
proposed relay-assisted FSO systems with respect to the conventional
direct transmission whether applied in a classical or a quantum communication channel.
|
5 |
Relay-Assisted Free-Space Optical CommunicationsSafari, Majid 04 January 2011 (has links)
The atmospheric lightwave propagation is considerably influenced by
the random variations in the refractive index of air pockets due to
turbulence. This undesired effect significantly degrades the
performance of free-space optical (FSO) communication systems.
Interestingly, the severity of such random degradations is highly
related to the range of atmospheric propagation. In this thesis, we
introduce relay-assisted FSO communications as a very promising
technique to combat the degradation effects of atmospheric
turbulence. Considering different configurations of the relays, we
quantify the outage behavior of the relay-assisted system and
identify the optimum relaying scheme. We further optimize the
performance of the relay-assisted FSO system subject to some power
constraints and provide optimal power control strategies for
different scenarios under consideration. Moreover, an application of
FSO relaying technique in quantum communications is investigated.
The results demonstrate impressive performance improvements for the
proposed relay-assisted FSO systems with respect to the conventional
direct transmission whether applied in a classical or a quantum communication channel.
|
Page generated in 0.0812 seconds