In this thesis, we investigate the basics of Low-Density Parity-Check (LDPC) codes
over binary and non-binary alphabets. We especially focus on the message passing
decoding algorithms, which have different message definitions such as a posteriori
probabilities, log-likelihood ratios and Fourier transforms of probabilities. We
present the simulation results that compare the performances of small block length
binary and non-binary LDPC codes, which have regular and irregular structures
over GF(2),GF(4) and GF(8) alphabets. We observe that choosing non-binary
alphabets improve the performance with careful selection of mean column weight
by comparing LDPC codes with variable node degrees of 3, 2.8 and 2.6, since it is
effective in the order of GF(2), GF(4) and GF(8) performances.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12609072/index.pdf |
| Date | 01 December 2007 |
| Creators | Uzunoglu, Cihan |
| Contributors | Diker Yucel, Melek |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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