Sökning: "turbo codes"

Visar resultat 26 - 28 av 28 avhandlingar innehållade orden turbo codes.

1. 26. Some results on fast correlation attacks

   Författare :Fredrik Jönsson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Technological sciences; stream ciphers; linear feedback shift registers; cryptology; correlation attacks; cryptanalysis; Teknik; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : This thesis presents new results on fast correlation attacks on stream ciphers. In particular, fast correlation attacks on stream ciphers containing linear shift registers with an arbitrary number of taps, are considered. A general introduction to stream ciphers and correlation attacks is given. LÄS MER

3. 27. Iterative Detection, Decoding and Channel Parameter Estimation for Orthogonally Modulated DS-CDMA Systems

   Författare :Pei Xiao; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : In this thesis, we study iterative detection, decoding and channel parameter estimation algorithms for asynchronous direct-sequence code division multiple access (DS-CDMA) systems employing orthogonal signalling formats and long scrambling codes. Multiuser detection techniques are widely used to combat the detrimental effects of multipath fading and multiple access interference (MAI), which are the major impairments in CDMA communication systems. LÄS MER

4. 28. On Bit-interleaved Coded Modulation with QAM Constellations

   Författare :Alex Alvarado; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Bit-interleaved coded modulation (BICM) is a flexible modulation/coding scheme which allows the designer to choose a modulation constellation independently of the coding rate. This is because the output of the channel encoder and the input to the modulator are separated by a bit-level interleaver. LÄS MER