Search for dissertations about: "Oversampling"

Showing result 11 - 15 of 21 swedish dissertations containing the word Oversampling.

2. 11. Massive MIMO with Low-Resolution Data Converters: Algorithm Design and Performance Evaluation

   Author : Sven Jacobsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : Massive multiuser multiple-input multiple-output (MIMO) is foreseen to be a key technology in next-generation (5G) cellular communication systems, due to huge potential gains in spectral efficiency and energy efficiency. In this thesis, we investigate the performance of massive MIMO systems, which operate over a Rayleigh-fading channel, for the case when the base station (BS) is equipped with low-resolution data converters. READ MORE

4. 12. Numerical Methods for Aeroacoustic Analysis of Turbomachines

   Author : Daniel Lindblad; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stability Analysis; Acoustic Analogy; Tonal Noise; Nonreflecting Boundary Conditions; Duct Modes; Turbomachinery; Harmonic Balance; Ffowcs Williams - Hawkings; Time Sampling; Aliasing;

   Abstract : Numerical simulations are important tools for developing new aircraft that can meet future needs. When numerical simulations are used to compute aircraft noise, a two-step procedure is often employed. In the first step, the noise sources are determined using, e.g. READ MORE

5. 13. Localised Radial Basis Function Methods for Partial Differential Equations

   Author : Victor Shcherbakov; Elisabeth Larsson; Grady B. Wright; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Radial basis function; Partition of unity; Computational finance; Option pricing; Credit default swap; Glaciology; Fluid dynamics; Non-Newtonian flow; Anisotropic RBF; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Abstract : Radial basis function methods exhibit several very attractive properties such as a high order convergence of the approximated solution and flexibility to the domain geometry. However the method in its classical formulation becomes impractical for problems with relatively large numbers of degrees of freedom due to the ill-conditioning and dense structure of coefficient matrix. READ MORE

6. 14. Complexity and Power Reduction in Digital Delta-Sigma Modulators

   Author : Nadeem Afzal; Jacob Wikner; Oscar Gustafsson; Mark Vesterbacka; Michael Peter Kennedy; Linköpings universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : A number of state-of-the-art low power consuming digital delta-sigma modulator (ΔΣ) architectures for digital-to-analog converters (DAC) are presented in this thesis. In an oversampling ΔΣ DAC, the primary job of the modulator is to reduce the word length of the digital control signal to the DAC and spectrally shape the resulting quantization noise. READ MORE

7. 15. Massive Multi-Antenna Communications with Low-Resolution Data Converters

   Author : Sven Jacobsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; orthogonal frequency-division multiplexing; channel estimation; quantization; linear precoding; convex optimization; nonlinear precoding; linear combing; hardware impairments; analog-to-digital converter; beamforming; Massive multi-user multiple-input multiple-output; digital-to-analog converter;

   Abstract : Massive multi-user (MU) multiple-input multiple-output (MIMO) will be a core technology in future cellular communication systems. In massive MU-MIMO systems, the number of antennas at the base station (BS) is scaled up by several orders of magnitude compared to traditional multi-antenna systems with the goals of enabling large gains in capacity and energy efficiency. READ MORE