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 145 for “"Channel Model"”.
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MIMO channel model
… the capacity capability of the geometric channel model by using the one-ring and two-ring channel model and attempting to explain the differences and similarities between these two models.Simulations were performed on one-ring and two-ring channel models by using mat-lab code programming. …
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Nerva-derived reactor coolant channel model for Mars mission applications
NERVA-Derived Reactor Coolant Channel Model for Mars Mission Applications presents the results of a computational fluid dynamics (CFD) study of a 1.3m NERVA-Derived Reactor (NDR) coolant channel; The CFD code FLOW-3D was used to model the flow of gaseous hydrogen through the core of a NDR. Hydrogen …
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An Underwater Channel Model and Chirp Slope Keying Modulation Scheme Performance
… allow us to accurately generate a laboratory model for the channel of interest.
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The Applicability of the Tap-Delay Line Channel Model to Ultra Wideband
… bandwidth of UWB signals, we need to revisit UWB channel modeling. Specifically we need to verify whether or not the traditional tap-line delay channel model is still applicable to UWB. One essential task involved in channel modeling is deconvolving the channel impulse response from the …
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A channel model and coding for vehicle to vehicle communication based on a developed V-SCME
… in order to evaluate and validate the proposed model, these simulations are considered inexpensive compared to the real world (hardware) tests.<br/><br/>The development of a more realistic simulation environment for VANET is critical in ensuring high performance. Any environment required for …
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A statistical ultra wideband indoor channel model and the effects of antenna directivity on multipath delay spread and path loss in ultra wideband indoor channels
Ultra-wideband (UWB) indoor frequency domain channel measurements have been performed in the 2 GHz to 6 GHz frequency band using three different transmitter/receiver (Tx/Rx) antenna combination pairs. The effects of antenna directivity on path loss and multipath propagation in the channel were …
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An improved code rate search scheme for adaptive multicode CDMA
… joint rate and power adaptation with perfect channel information in a multicode CDMA system. By specifying suitable boundary conditions and adaptively searching the optimal rate vectors, the search range can be narrowed down thereby significantly improving search complexity. We also build a …
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Iterative algorithms for lossy source coding
… the double-erasure information embedding channel model. We develop capacity-achieving codes for the double-erasure channel model. Furthermore, we show that our codes can be efficiently encoded and decoded using belief propagation techniques. We also discuss a generalization of the …
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Simulation and Estimation Techniques for Wideband High-Frequency Communication Channels
A technique for estimating the channel multipath parameters for wideband high frequency (WBHF) communication systems is analyzed. To explore the technique, a WBHF communication system is simulated in software using three new channel models. One channel model is based on a simulation of wave …
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Ultra-Wideband Channel Modeling using Singularity Expansion Method
… in excess of 100 Mbps. However, the wireless channel distorts the transmitted signal by dispersing the signal energy over time. This degrades the output signal-to-noise ratio (SNR) of a correlation based matched-filter receiver, limiting the achievable data-rate and user capacity. Most …
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Coding Techniques for Linear Block Codes With Applications to Fault Identification
When channel reliability information is available, soft-decision decoding becomes attractive for many applications, since maximum-likelihood (ML) soft-decision decoding offers (roughly) 3 dB additional gain over algebraic decoding. Since ML soft-decision decoding is an NP-hard problem, we …
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Ultrawideband Channel Sounding Studies in Outdoor and Outdoor-Indoor Environments
… the parameters needed in order to develop a channel model for such cases. The channel model would then play an important role in determining physical layer (PHY) solutions to optimally exploit these characteristics. The measurements carried out on the Virginia Tech campus are used to compute …
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Smart Antennas at Handsets for the 3G Wideband CDMA Systems and Adaptive Low-Power Rake Combining Schemes
… to exploit the advantages of the two schemes. To model dual antenna signals, we consider three channel models: loosely correlated fading channel model (LCFCM), spatially correlated fading channel model (SCFCM), and envelope correlated fading channel model (ECFCM). Each antenna signal is assumed to …
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Harvesting time-frequency-space diversity with coded modulation for underwater acoustic communications
… system with robust performance under various channel conditions. The need for robust performance emerges because underwater acoustic (UWA) channels have time-varying statistics, thus a coded modulation scheme optimally designed for a specific channel model will be suboptimal when the channel …
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Blind Comprehension of Waveforms through Statistical Observations
… a blind receiver in the presence of time varying channels, which is built from the work done on cumulants in static channels currently in the literature. Results show the classification accuracy is on the order or better than current methods in use in static channels that do not vary over an …
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Simulation of adaptive equalization in two-ray, SIRCIM, and SMRCIM mobile radio channels
… better performances. A two-ray Rayleigh fading channel model is used to simulate the mobile channels. The results show that adaptive equalization can significantly improve the performance of mobile communications if the channel does not change too fast. The simulation shows that if the delay (T) …
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Performance investigation of spatial modulation systems under realistic channel models
… threedimensional (3D) geometry based stochastic model (GBSM) for V2V MIMO channels is investigated by both theoretical analysis and system simulations. The impacts of vehicle tra c density (VTD), Doppler effect, and 3D feature on the BER performance of SM systems are thoroughly studied. In …
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Non-linear saturation of vertically propagating Rossby waves
… abstract context, through a variety of simple model studies. We thus consider the cases of a topographically forced barotropic beta plane channel model, of vertical propagation through a three-dimensional beta plane channel model, and of a polar coordinate model with realistic basic state and …
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An Electrophysiological Study of Noisy Channel Sentence Comprehension.
… letter by post (insertion error). Based on noisy Channel model propositions, language processing system acts as a rational comprehender and follows Bayesian size principle, which posits deletions are more likely to occur than insertions. This assumption would be held true if, comprehenders show …
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A POMDP framework for antenna selection and user scheduling in multi-user massive MIMO systems
… a limited number of RF chains. Considering that channels evolve according to a Markov process and that only partial CSI is available, we use a POMDP framework for antenna selection with the aim to maximize the expected long-term data rate. To avoid the high computational complexity of the value …
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