Fountain codes and their typical application in wireless standards like edge

dc.contributor.advisorOlivier, Jan Corneen
dc.contributor.emailtrienkog@gmail.comen
dc.contributor.postgraduateGrobler, Trienko Lupsen
dc.date.accessioned2013-09-06T21:05:56Z
dc.date.available2009-04-09en
dc.date.available2013-09-06T21:05:56Z
dc.date.created2008-09-02en
dc.date.issued2008en
dc.date.submitted2009-01-26en
dc.descriptionDissertation (MEng)--University of Pretoria, 2008.en
dc.description.abstractOne 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: <ol> <li>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).</li> <li> The successful decoding of systematic LT codes were verified.</li> <li>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).</li></ol> 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.availabilityunrestricteden
dc.description.degreeMEng
dc.description.departmentElectrical, Electronic and Computer Engineeringen
dc.identifier.citationGrobler, TL 2008, Fountain codes and their typical application in wireless standards like edge, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/25381>en
dc.identifier.otherE1204/gmen
dc.identifier.upetdurlhttp://upetd.up.ac.za/thesis/available/etd-01262009-171258/en
dc.identifier.urihttp://hdl.handle.net/2263/25381
dc.language.isoen
dc.publisherUniversity of Pretoriaen_ZA
dc.rights©University of Pretoria 2008 E1204/en
dc.subjectTornado codesen
dc.subjectBelief propagationen
dc.subjectNoisy decodingen
dc.subjectLdpcen
dc.subjectLten
dc.subjectLow-density parity-check codesen
dc.subjectLuby-transform codesen
dc.subjectFountain codeen
dc.subjectIncremental redundancyen
dc.subjectFactor graphen
dc.subjectEdgeen
dc.subjectEnhanced data rates for gsm evolutionen
dc.subjectArticulation principleen
dc.subjectSparse graphen
dc.subjectRaptor codesen
dc.subjectUCTDen_US
dc.titleFountain codes and their typical application in wireless standards like edgeen
dc.typeDissertationen

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