Distributed joint source-channel code design for GMAC using irregular LDPC codes

Simple item page
dc.contributor.authorShahid, Iqbal
dc.contributor.authorYahampath, Pradeepa
dc.date.accessioned2014-01-17T08:03:27Z
dc.date.available2014-01-17T08:03:27Z
dc.date.issued2014-01-09
dc.date.updated2014-01-17T08:03:28Z
dc.description.abstractAbstract Separate source and channel coding is known to be sub-optimal for communicating correlated sources over a Gaussian multiple access channel (GMAC). This paper presents an approach to designing distributed joint source-channel (DJSC) codes for encoding correlated binary sources over a two-user GMAC, using systematic irregular low-density parity check (LDPC) codes. The degree profile defining the LDPC code is optimized for the joint source probabilities using extrinsic information transfer (EXIT) analysis and linear programming. A key issue addressed is the Gaussian modeling of log-likelihood ratios (LLRs) generated by nodes representing the joint source probabilities in the combined factor graph of the two LDPC codes, referred to as source-channel factor (SCF) nodes. It is shown that the analytical expressions based on additive combining of incoming LLRs, as done in variable nodes and parity check nodes of the graph of a single LDPC code, cannot be used with SCF nodes. To this end, we propose a numerical approach based on Monte-Carlo simulations to fit a Gaussian density to outgoing LLRs from the SCF nodes, which makes the EXIT analysis of the joint decoder tractable. Experimental results are presented which show that LDPC codes designed with the proposed approach outperforms previously reported DJSC codes for GMAC. Furthermore, they demonstrate that when the sources are strongly dependent, the proposed DJSC codes can achieve code rates higher than the theoretical upper-bound for separate source and channel coding.
dc.description.versionPeer Reviewed
dc.identifier.citationEURASIP Journal on Wireless Communications and Networking. 2014 Jan 09;2014(1):3
dc.identifier.doihttp://dx.doi.org/10.1186/1687-1499-2014-3
dc.identifier.urihttp://hdl.handle.net/1993/23269
dc.language.rfc3066en
dc.rightsopen accessen_US
dc.rights.holderIqbal Shahid et al.; licensee BioMed Central Ltd.
dc.titleDistributed joint source-channel code design for GMAC using irregular LDPC codes
dc.typeJournal Article
Files
Original bundle
Now showing 1 - 2 of 2
Thumbnail Image
Name:
1687-1499-2014-3.xml
Size:
231.43 KB
Format:
Extensible Markup Language
Description:
Download
Thumbnail Image
Name:
1687-1499-2014-3.pdf
Size:
1.3 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
2.17 KB
Format:
Item-specific license agreed to upon submission
Description:
Download
Collections
University of Manitoba Scholarship
Price Faculty of Engineering Scholarly Works