Publications – Details

 

Breaking Cycles with Dummy Bits: Improved Rate-Compatible LDPC Codes with Short Block Lengths

Authors:

Moritz Beermann and Peter Vary

Book Title:

Proceedings of International ITG Conference on Systems, Communications and Coding (SCC)

Venue:

München

Event Date:

21.-24.1.2013

Organization:

ITG

Publisher:

IEEE

Date:

Jan. 2013

ISBN:

978-3-80073-482-5

Language:

English

Abstract

It is well-known that the presence of cycles in a factor graph degrades the performance of message-passing algorithms due to the violation of the assumption of statistical independence of messages. While finding and counting all cycles in a graph is a very hard problem, efficient algorithms have been proposed recently to find all short cycles up to some maximum length. For the message-passing decoding of Low-Density Parity-Check (LDPC) codes, these short cycles are the main cause for the existing performance gap to optimal Maximum Likelihood (ML) decoding. In this paper, we exploit this observation in the proposed novel method of realizing rate-compatible (RC) LDPC codes with short block lengths by inserting known dummy bits into the information bit sequence before encoding. This technique can be seen as a special case of traditional code shortening and allows to achieve lower code rates using one fixed rate mother code. The novelty of the proposed method lies in the selection of the specific dummy bit positions in a way that "breaks" a significant number of short cycles in the mother code's graph which, thus, no longer degrade the decoding performance.

Download of Publication

Copyright Notice

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

The following notice applies to all IEEE publications:
© IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

File