Sökning: "Gaussian channel"

Visar resultat 21 - 25 av 96 avhandlingar innehållade orden Gaussian channel.

1. 21. On Bit-Wise Decoders for Coded Modulation

   Författare :Mikhail Ivanov; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bit-error probability; L-values; labeling; Gray code; coded modulation; log-likelihood ratio; maximum likelihood decoder; Additive white Gaussian noise; quadrature amplitude modulation.; interleaver; flat fading channel; pairwise error probability;

   Sammanfattning : Coded modulation is a technique that emerged as a response to the growing demand for high data rates. It was devised to achieve high spectral efficiency with high reliability, potentially approaching Shannon’s capacity. The main idea of coded modulation consists in combining error-correcting coding with higher-order modulation. LÄS MER

3. 22. Speech and Video Coding for Unreliable Channels

   Författare :Daniel Persson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; joint source-channel coding; channel-optimized quantization;

   Sammanfattning : Speech and video communications via the Internet and cellular phones have become a part of modern life. This thesis deals with different methods for speech and video transmission over noisy and lossy communication channels. LÄS MER

4. 23. Efficient Digital Communication over the Time Continuous Rayleigh Fading Channel

   Författare :Ulf Hansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Frequency flat, fast Rayleigh fading may be considered the most critical disturbance in a wireless communication system. In its most general form, it is modeled as a multiplicative time continuous random (zero mean complex Gaussian) distortion of the transmitted signal. LÄS MER

5. 24. 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

7. 25. Common-Mode Aided Wireline Communications

   Författare :Thomas Magesacher; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknik; Technological sciences; DSL; multicarrier modulation; DMT; Shannon capacity; channel modelling; common mode; wireline communications; information processing;

   Sammanfattning : Wireline communication is the Internet access technology with the largest number of subscribers worldwide. On physical-layer level, the traditional way to transmit signals at one end of a wire pair and to extract receive signals at the other end is to apply differential-mode signalling: transmit and receive signals correspond to voltage differences between the two wires. LÄS MER