Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Subchannels"”.
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Creating subchannels to improve throughput in wireless communication
… a single communciation channel into two separate subchannels. One subchannel is used to send large packets, and the other sends small packets. This split allows for the spectrum to be used more efficiently. Large throughput gains are possible, even with different mixes of traffic patterns. The …
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Sum-rate maximization for two-way active channel with unequal subchannel noise powers
… destination through a set of parallel orthogonal subchannels. In such channels, the transmitted signals undergo path loss, phase shift, and can also be affected by multi-path propagation effects. In conventional wireless channel models, there is no control over the gain of each individual …
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On sounding in wideband channels
… upper bound and a lower bound on the number of subchannels that should be probed for capacity maximization in terms of the available transmission energy, the available bandwidth and the fading characteristics of the channel. Moreover, the two bounds are so close to each other that they may well …
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Distributed Multiple Access for OFDMA Femtocells
… over the frequency domain by switching subchannels randomly after each collision. However, this comes at the expense of expanded time scale, or larger slot size due to lower channel rates. We showed that when the network is lightly loaded, the reduction in the collision rate outweighs …
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Sum-rate maximization for two-way active channels.
… channel where by injecting power into the subchannels, somewhere between a transmitter and a receiver, the gain of the subchannels are adjusted. We herein study the problem of joint power allocation and channel design over a reciprocal two-way active channel. Assuming the channel is …
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Resource allocation and physical layer security in wireless communication systems
… simultaneously over a number of parallel subchannels, two fairness-aware resource allocation problems are investigated in the sense that certain QoS constraints are considered. Typically, this kind of problems fall within the NP class because of the integer nature of the involved user …
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Computational fluid dynamic investigations of flow through an aged CANDU pressure tube
… bypasses the fuel. The reduced flow within the subchannels of the fuel bundles impacts the coolability of the fuel.
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New Techniques for Multicarrier Communication Systems
… can be obtained using active (data-carrying) subchannels where outer constellation points are dynamically moved, within margin-preserving constraints, to reduce the peak magnitude. This scheme, known as active constellation extension (ACE), simultaneously decreases the bit error rate slightly …
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Physical layer DSP design of a wireless gigabit/s indoor LAN
… that establish session links and allocate subchannels among devices in an optimal way. Finally, a custom-written software simulation is used to estimate the bit error rate (BER) network performance under different channel conditions.
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Capactiy of single-hop communication links in wireless ad hoc networks
… single frequency channel into equally sized subchannels.
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Investigation of velocity gradient as driving force of flow pulsation in fuel assemblies
… as the difference in bulk velocities of adjacent subchannels. A threshold value of [delta]vbulk was seen close to 0.4 m/s, below which very little crossflow mixing was observed. Using these results, an analytical relationship between inter-subchannel velocity gradient and crossflow mixing could be …
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A methodology for session monitoring on broadband bus/tree local area networks
… to ensure load balance over the broadband subchannels, and the capability to monitor specific nodes for accounting, performance and security purposes. This thesis presents the design considerations for a session level passive hardware monitor on a broadband local area network having a …
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Channel Estimation for OFDM Systems With Transmitter Diversity
… channel that can cause deep fades in some subchannels. The combination of the two techniques, OFDM and transmitter diversity, can further enhance the data rates in a frequency-selective fading environment. However, this enhancement requires accurate and computationally efficient channel …
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Implementation of a non-linear eddy viscosity turbulence model into Hydra-TH for fuel related applications
… flow profile that develops in nuclear reactor subchannels. This thesis concludes with a rigorous sensitivity study of the triangular fuel rod array simulations, whereby guidelines and best practices for the quadratic model's use for nuclear fuel related applications are derived.
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Assessment of helical-cruciform fuel rods for high power density LWRs
… a need to increase the flow area of the edge subchannels was demonstrated. This prompted a slight re-design of the HC fuel rod cross-section in order to make room for small spacer protrusions at the duct wall, to increase flow to peripheral subchannels. The modification was accomplished by …
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ARQ Techniques for MIMO Communication Systems
… is converted into a set of parallel independent subchannels. The performance of the type-I hybrid-ARQ error control is presented. Simulation results show the throughput gain of using an ARQ scheme in MIMO communication systems. When the channel state information is unknown to the transmitter, …
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A search for the Higgs boson in H->WW->lvlv with 8.2 fb-1
… in addition to the base analysis. We include subchannels searching for Higgs production in events with low dilepton invariant mass and in events having final states with either same-sign dileptons or trileptons With the combination of the separate analyses, we observed a 95% C.L. upper …
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Antifragile Communications
… a block of spectrum and selectively jams active subchannels. To aid in analysis, we introduce a generalized model for reactive jamming, applicable to both repeater-based and sensing-based jamming behaviors. Despite being limited to electronic warfare scenarios, we hope that this work can pave the …
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