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dc.contributor.supervisor Yahampath, Pradeepa (Electrical and Computer Engineering) en_US
dc.contributor.author Shahid, Iqbal
dc.date.accessioned 2013-08-23T17:20:17Z
dc.date.available 2013-08-23T17:20:17Z
dc.date.issued 2013-08-23
dc.identifier.uri http://hdl.handle.net/1993/22099
dc.description.abstract The efficient and reliable communication of data from multiple sources to a single receiver plays an important role in emerging applications such as wireless sensor networks. The correlation among observations picked-up by spatially distributed sensors in such a network can be exploited to enhance the efficiency and reliability of communication. In particular, information theory shows that optimal communication of information from correlated sources requires distributed joint source-channel (DJSC) coding. This dissertation develops new approaches to designing DJSC codes based on low density parity check (LDPC) codes. The existence of low complexity code optimization algorithms and decoding algorithms make these codes ideal for joint optimization and decoding of multiple codes operating on correlated sources. The well known EXIT analysis-based LDPC code optimization method for channel coding in single-user point-to-point systems is extended to the optimization of two-user LDPC codes for DJSC coding in multi-access channels (MACs) with correlated users. Considering an orthogonal MAC with two correlated binary sources, an asymptotically optimal DJSC code construction capable of achieving any rate-pair in the theoretically-achievable two-user rate-region is presented. A practical approach to realizing this scheme using irregular LDPC codes is then developed. Experimental results are presented which demonstrate that the proposed codes can approach theoretical bounds when the codeword length is increased. For short codeword length and high inter-source correlation, these DJSC codes are shown to significantly outperform separate source and channel codes. Next, the DJSC code design for the transmission of a pair of correlated binary sources over a Gaussian MAC (GMAC) is investigated. The separate source and channel coding is known to be sub-optimal in this case. For the optimization of a pair of irregular LDPC codes, the EXIT analysis for message passing in a joint factor-graph decoder is analyzed, and an approach to modeling the probability density functions of messages associated with graph nodes which represent the inter-source dependence is proposed. Simulation results show that, for sufficiently large codeword lengths and high inter-source correlation, the proposed DJSC codes for GMAC can achieve rates higher than the theoretical upper bound for separate source and channel coding. en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Source Coding en_US
dc.subject Joint Source and Channel Coding en_US
dc.subject LDPC Code Design en_US
dc.subject Multi-user Communication en_US
dc.title Low Density Parity Check Code Designs For Distributed Joint Source-Channel Coding Over Multiple Access Channels en_US
dc.type info:eu-repo/semantics/doctoralThesis
dc.type doctoral thesis en_US
dc.degree.discipline Electrical and Computer Engineering en_US
dc.contributor.examiningcommittee Cai, Jun (Electrical and Computer Engineering) Sepehri, Nariman(Department of Mechanical and Manufacturing Engineering) Saengudomlert, Poompat (Centre of Research in Optoelectronics, Bangkok University) en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note October 2013 en_US


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