Sökning: "low-density codes"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden low-density codes.

1. 1. Low-density parity-check codes : unequal error protection and reduction of clipping effects

   Författare :Sara Sandberg; David Declercq; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; Signal Processing;

   Sammanfattning : The invention of low-density parity-check (LDPC) codes made reliable communication possible at transmission rates very close to the theoretical limit predicted by Shannon. However, communication close to the Shannon limit requires very long codes and results in long delay and high encoder and decoder complexity. LÄS MER

3. 2. 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

4. 3. Codes on Graphs and More

   Författare :Florian Hug; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; convolutional codes; woven graph codes; Low-density parity-check LDPC codes; tailbiting codes; bit error probability; MacWilliams Identity;

   Sammanfattning : Modern communication systems strive to achieve reliable and efficient information transmission and storage with affordable complexity. Hence, efficient low-complexity channel codes providing low probabilities for erroneous receptions are needed. LÄS MER

5. 4. Iteratively Decodable Convolutional Codes: Analysis and Implementation Aspects

   Författare :Alberto Jimenez Feltström; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; systems theory; Informatics; Intersymbol Interference; BPSK; Product Codes; Braided Codes; Low-Density Parity-Check Codes; Convolutional Codes; Iterative Decoding; Informatik; systemteori; Systems engineering; computer technology; Data- och systemvetenskap;

   Sammanfattning : This thesis addresses the theory and implementation aspects of iteratively decodable codes. Iteratively decodable codes include, in particular, Gallager's regular low-density parity-check (LDPC) codes, Tanner's generalized LDPC (GLDPC) codes, turbo codes due to Berrou et. al. and expander codes. LÄS MER

7. 5. Sparse Codes on Graphs with Convolutional Code Constraints

   Författare :Muhammad Umar Farooq; Kommunikationsteknologi; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Braided codes; Density evolution; Serially concatenated codes; Spatially coupled codes; Generalized LDPC codes; threshold saturation; Turbo codes;

   Sammanfattning : Modern coding theory is based on the foundation of the sparse codes on graphs, such as the low-density parity-check (LDPC) codes, and the turbo-like codes (TCs) with component convolutional codes. The success of the LDPC codes and the TCs lies in their ability to perform low-complexity iterative message passing decoding procedures. LÄS MER