Sökning: "turbo codes"

Visar resultat 6 - 10 av 28 avhandlingar innehållade orden turbo codes.

1. 6. 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

3. 7. Synchronization in Turbo Coded Systems

   Författare :Bartosz Mielczarek; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; timing offset; Turbo codes; synchronization; maximum a-posteriori estimation; phase offset; BCJR algorithm.; maximum likelihood estimation;

   Sammanfattning : Turbo codes and their unusual properties have attracted significant attentionof the information theory community. There already exist many articlesand papers devoted to the theory of these codes. This thesis, however,focuses on practical implementation issues of turbo codes, with synchronizationproblems as the main topic. LÄS MER

4. 8. Analysis of Some Convolutional Coding Constructions

   Författare :Karin Engdahl; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbo-codes; low-density parity-check convolutional codes; low-density codes; PSK; PAM; QAM; coded modulation; multilevel coding; convolutional codes; multilevel modulation; iterative decoding; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : This thesis focuses on different convolutional coding constructions for digital communication systems, and on methods to analyze these constructions. The work presented in the thesis can be divided into three main areas; error probability bounds for convolutional codes, analysis of multilevel modulation, and investigation of low-density parity-check convolutional codes. LÄS MER

5. 9. Spatially Coupled Turbo-Like Codes

   Författare :Saeedeh Moloudi; Kommunikationsteknologi; []
   Nyckelord :;

   Sammanfattning : The focus of this thesis is on proposing and analyzing a powerful class of codes on graphs---with trellis constraints---that can simultaneously approach capacity and achieve very low error floor. In particular, we propose the concept of spatial coupling for turbo-like code (SC-TC) ensembles and investigate the impact of coupling on the performance of these codes. LÄS MER

7. 10. On the Construction and Analysis of Iteratively Decodable Codes

   Författare :Dmitri Truhachev; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computer science; minimum distance; cycles; asymptotic performance; turbo codes; iterative decoding; low-density parity-check codes; numerical analysis; systems; control; Datalogi; numerisk analys; system; kontroll;

   Sammanfattning : Iterative decoding methods allow efficient decoding of long codes that are composed of smaller component codes. As a result reliable communication can be achieved with low decoding complexity even for rates close to Shannon capacity. This makes iteratively decodable codes a very attractive object of study in modern coding theory. LÄS MER