Sökning: "fading"

Visar resultat 21 - 25 av 205 avhandlingar innehållade ordet fading.

1. 21. Constellation Design under Channel Uncertainty

   Författare :Jochen Giese; Mikael Skoglund; Bertrand Hochwald; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Constellation design; diversity; fading channels; frequency-selective channels; joint channel estimation and data detection; multiple antennas; partial channel state information; wireless communication; Telecommunication; Telekommunikation;

   Sammanfattning : The topic of this thesis is signaling design for data transmission through wireless channels between a transmitter and a receiver that can both be equipped with one or more antennas. In particular, the focus is on channels where the propagation coefficients between each transmitter--receiver antenna pair are only partially known or completetly unknown to the receiver and unknown to the transmitter. LÄS MER

3. 22. Channel Related Optimization of Wireless Communication Systems

   Författare :Fredrik Tufvesson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; time division duplex; multicarrier; Radio communication; orthogonal frequency division multiplex; channel estimation; pilot symbol assisted modulation; sub-channel spacing; sub-channel bandwidth; interchannel interference; cyclic prefix; intersymbol interference; Rayleigh fading; precoding; pre-compensation;

   Sammanfattning : This thesis deals with different optimization problems in the design of wireless communication systems. It is mainly directed to the design of systems based on multicarrier techniques and orthogonal frequency division multiplex, OFDM, but some of the problems apply to single carrier systems as well. LÄS MER

4. 23. Multirate Codes and Multicarrier Modulation for Future Communication Systems

   Författare :Pål Frenger; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; channel estimation; code-spread CDMA; DS-CDMA; convolutional codes; interference cancellation; nested convolutional codes; multicarrier modulation; optimum distance spectrum ODS ; rate-compatible punctured convolutional codes RCPC-codes ; OFDM; turbo decoding; rate matching; parallel combinatory signaling; Rayleigh fading;

   Sammanfattning : In this thesis, new detection and modulation methods for multicarrier systems are presented. The proposed multicarrier detectors are based on feedback of previously detected symbols and the idea is to exploit the correlation, both in time between consecutive symbols, and in frequency between neighboring sub-carriers. LÄS MER

5. 24. On Soft Decoding and Robust Vector Quantization

   Författare :Mikael Skoglund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; speech and image coding; intersymbol interference; Rayleigh fading; soft decoding; CDMA; index assignment; Hadamard transform; channel optimized VQ; robust VQ; combined source-channel coding; vector quantization VQ ; noisy channels;

   Sammanfattning : This thesis considers vector quantization for noisy channels. Vector quantization (VQ) is an important technique for block-based source coding, with applications in, e.g., speech and image coding. LÄS MER

7. 25. Morphological characterization of primary austenite in cast iron

   Författare :Juan Carlos Hernando; Attila Diószegi; Jönköping University; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lamellar Graphite Iron; Solidification; Primary Austenite; Microstructure Evolution; Dendritic coarsening; Compacted Graphite Iron; Magnesium Fading; Nodularity;

   Sammanfattning : Automotive industry products portfolio includes a wide variety of complex‐shaped cast iron products, such as truck engine components, that need to withstand a constant trend of higher demands, especially urged by stricter environmental regulations on emissions. Combined with this continued demand on properties improvement, cast iron industry faces a process problem related to the lack of understanding of solidification and mechanisms behind defect formation. LÄS MER