# Fountain codes and their typical application in wireless standards like edge

 dc.contributor.advisor Olivier, Jan Corne en dc.contributor.postgraduate Grobler, Trienko Lups en dc.date.accessioned 2013-09-06T21:05:56Z dc.date.available 2009-04-09 en dc.date.available 2013-09-06T21:05:56Z dc.date.created 2008-09-02 en dc.date.issued 2008 en dc.date.submitted 2009-01-26 en dc.description Dissertation (MEng)--University of Pretoria, 2008. en dc.description.abstract One of the most important technologies used in modern communication systems is channel coding. Channel coding dates back to a paper published by Shannon in 1948 [1] entitled “A Mathematical Theory of Communication”. The basic idea behind channel coding is to send redundant information (parity) together with a message to make the transmission more error resistant. There are different types of codes that can be used to generate the parity required, including block, convolutional and concatenated codes. A special subclass of codes consisting of the codes mentioned in the previous paragraph, is sparse graph codes. The structure of sparse graph codes can be depicted via a graphical representation: the factor graph which has sparse connections between its elements. Codes belonging to this subclass include Low-Density-Parity-Check (LDPC) codes, Repeat Accumulate (RA), Turbo and fountain codes. These codes can be decoded by using the belief propagation algorithm, an iterative algorithm where probabilistic information is passed to the nodes of the graph. This dissertation focuses on noisy decoding of fountain codes using belief propagation decoding. Fountain codes were originally developed for erasure channels, but since any factor graph can be decoded using belief propagation, noisy decoding of fountain codes can easily be accomplished. Three fountain codes namely Tornado, Luby Transform (LT) and Raptor codes were investigated during this dissertation. The following results were obtained:
1. The Tornado graph structure is unsuitable for noisy decoding since the code structure protects the first layer of parity instead of the original message bits (a Tornado graph consists of more than one layer).
2. The successful decoding of systematic LT codes were verified.
3. A systematic Raptor code was introduced and successfully decoded. The simulation results show that the Raptor graph structure can improve on its constituent codes (a Raptor code consists of more than one code).
Lastly an LT code was used to replace the convolutional incremental redundancy scheme used by the 2G mobile standard Enhanced Data Rates for GSM Evolution (EDGE). The results show that a fountain incremental redundancy scheme outperforms a convolutional approach if the frame lengths are long enough. For the EDGE platform the results also showed that the fountain incremental redundancy scheme outperforms the convolutional approach after the second transmission is received. Although EDGE is an older technology, it still remains a good platform for testing different incremental redundancy schemes, since it was one of the first platforms to use incremental redundancy. en dc.description.availability unrestricted en dc.description.degree MEng dc.description.department Electrical, Electronic and Computer Engineering en dc.identifier.citation Grobler, TL 2008, Fountain codes and their typical application in wireless standards like edge, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd en dc.identifier.other E1204/gm en dc.identifier.upetdurl http://upetd.up.ac.za/thesis/available/etd-01262009-171258/ en dc.identifier.uri http://hdl.handle.net/2263/25381 dc.language.iso en dc.publisher University of Pretoria en_ZA dc.rights ©University of Pretoria 2008 E1204/ en dc.subject Tornado codes en dc.subject Belief propagation en dc.subject Noisy decoding en dc.subject Ldpc en dc.subject Lt en dc.subject Low-density parity-check codes en dc.subject Luby-transform codes en dc.subject Fountain code en dc.subject Incremental redundancy en dc.subject Factor graph en dc.subject Edge en dc.subject Enhanced data rates for gsm evolution en dc.subject Articulation principle en dc.subject Sparse graph en dc.subject Raptor codes en dc.subject UCTD en_US dc.title Fountain codes and their typical application in wireless standards like edge en dc.type Dissertation en
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