In this thesis we study Low Density Parity Check (LDPC) and LDPC like codes over
non-binary fields. We extend the concepts used for non-binary LDPC codes to generalize
Product Accumulate (PA) codes to non-binary fields. We present simulation results that
show that PA codes over GF(4) performs considerably better than binary PA codes at
smaller block lengths and slightly better at large block lengths. We also propose a trellis
based decoding algorithm to decode PA codes and show that its complexity is
considerably lower than the message-passing algorithm.
In the second part of the thesis we study the convergence properties of non-binary PA
codes and non-binary LDPC codes. We use EXIT-charts to study the convergence
properties of non-binary LDPC codes with different mean column weights and show why
certain irregularities are better. Although the convergence threshold predicted by EXIT-charts
on non-binary LDPC codes is quite optimistic we can still use EXIT-charts for
comparison between non-binary LDPC codes with different mean column weights.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/67 |
| Date | 30 September 2004 |
| Creators | Gilra, Deepak |
| Contributors | Narayanan, K. R. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 379855 bytes, 73851 bytes, electronic, application/pdf, text/plain, born digital |
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