Abstract
We describe a family of instanton-based optimization methods developed recently for the analysis of the error floors of low-density parity-check (LDPC) codes. Instantons are the most probable configurations of the channel noise which result in decoding failures. We show that the general idea and the respective optimization technique are applicable broadly to a variety of channels, discrete or continuous, and variety of sub-optimal decoders. Specifically, we consider: iterative belief propagation (BP) decoders, Gallager type decoders, and linear programming (LP) decoders performing over the additive white Gaussian noise channel (AWGNC) and the binary symmetric channel (BSC). The instanton analysis suggests that the underlying topological structures of the most probable instanton of the same code but different channels and decoders are related to each other. Armed with this understanding of the graphical structure of the instanton and its relation to the decoding failures, we suggest a method to construct codes whose Tanner graphs are free of these structures, and thus have less significant error floors.
Original language | English (US) |
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Article number | 5174515 |
Pages (from-to) | 855-865 |
Number of pages | 11 |
Journal | IEEE Journal on Selected Areas in Communications |
Volume | 27 |
Issue number | 6 |
DOIs | |
State | Published - Aug 1 2009 |
Keywords
- Error Floor
- Instantons
- Iterative Decoding
- Linear Programming Decoding
- Low-density parity-check codes
- Pseudo-Codewords
- Trapping Sets
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering