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Visar resultat 1 - 5 av 258 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Channel Estimation in Wireless Communication Systems Employing Multiple Antennas

   Författare :Mikael Coldrey; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multiple antennas; capacity; channel estimation; non-parametric estimation; training; distributed sources; MIMO; Wireless communications; superimposed pilots; performance bounds;

   Sammanfattning : Antennas that are able to adaptively direct the transmitted (and received) energy are of great interest in future wireless communication systems. The directivity implies reduced transmit power and interference, and also a potential for increased capacity. LÄS MER

3. 2. Multiple Antenna Terminals in Realistic Environments - A Composite Channel Modeling Approach

   Författare :Fredrik Harrysson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Channel model; MIMO; multiple antennas terminal; propagation; user interaction; vehicular channel; diversity; spatial multiplexing; channel measurement;

   Sammanfattning : For evaluation of specific antenna arrangements in wireless communication systems we need physical channel models that take into account also the directional domain of the propagation channel. In this thesis we investigate, validate and propose a practical approach to wireless channel modeling and, particularly, to mobile communication systems. LÄS MER

4. 3. Influence of Fiber Nonlinearity on the Capacity of Optical Channel Models

   Författare :Kamran Keykhosravi; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinearity mitigation; Fiber optics; information theory; channel capacity; perturbation; achievable rate;

   Sammanfattning : The majority of today’s global Internet traffic is conveyed through optical fibers. The ever-increasing data demands has pushed the optical systems to evolve from using regenerators and direct-direction receivers to a coherent multi-wavelength network. LÄS MER

5. 4. Prediction of Mobile Radio Channels : Modeling and Design

   Författare :Torbjörn Ekman; Rodney Vaughan; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systemteknik; mobile radio channel; fading; channel model; channel estimation; channel prediction; power prediction; Systemteknik; Systems engineering; Systemteknik; Signal Processing; signalbehandling;

   Sammanfattning : Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation and fast link adaptation. This thesis deals with linear prediction of the complex impulse response of a channel and unbiased quadratic prediction of the power. LÄS MER

7. 5. Baseband Processing for 5G and Beyond: Algorithms, VLSI Architectures, and Co-design

   Författare :Mojtaba Mahdavi; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VLSI Implementation; Hardware architectures; ASIC implementation; FPGA implementation; CMOS Technology; Baseband Processing; Massive MIMO; 5G New Radio; Beyond 5G; Co-Design; FFT processor; OFDM modulation; wireless communications; Massive MIMO Detection; Angular domain processing; Zero forcing; Systolic array; Non-linear detector; Channel Sparsity; Channel compression; Linear detector; Channel coding; Spatial coupling; Turbo-like codes; Spatially coupled serially concatenated codes; Threshold analysis; Decoder architecture; BCJR algorithm; MAP algorithm; Coupling memory; Window decoding; Complexity analysis; Performance Evaluation; Throughput; Decoding Latency; Silicon area; Design tradeoffs; Interleaver architecture; Memory requirements; Matrix multiplication; Channel state information CSI ; Cholesky decomposition; Tanner graph; Trellis codes; Convolutional encoder; Code design; Puncturing; Reordering circuit; wireless communication system; digital electronic;

   Sammanfattning : In recent years the number of connected devices and the demand for high data-rates have been significantly increased. This enormous growth is more pronounced by the introduction of the Internet of things (IoT) in which several devices are interconnected to exchange data for various applications like smart homes and smart cities. LÄS MER