Title: A Practical Optimization Framework for the Degree Distribution in LT Codes
Authors: Chen, Chih-Ming
Chen, Ying-Ping
Shen, Tzu-Ching
Zao, John K.
Department of Computer Science
Keywords: LT codes;degree distribution;forward error correction;evolutionary algorithms;digital fountain
Issue Date: 1-Nov-2013
Abstract: LT codes are the first practical rateless codes whose reception overhead totally depends on the degree distribution adopted. The capability of LT codes with a particular degree distribution named robust soliton has been theoretically analyzed; it asymptotically approaches the optimum when the message length approaches infinity. However, real applications making use of LT codes have finite number of input symbols. It is quite important to refine degree distributions because there are distributions whose performance can exceed that of the robust soliton distribution for short message length. In this work, a practical framework that employs evolutionary algorithms is proposed to search for better degree distributions. Our experiments empirically prove that the proposed framework is robust and can customize degree distributions for LT codes with different message length. The decoding error probabilities of the distributions found in the experiments compare well with those of robust soliton distributions. The significant improvement of LT codes with the optimized degree distributions is demonstrated in the paper.
URI: http://dx.doi.org/10.1587/transcom.E96.B.2807
ISSN: 0916-8516
DOI: 10.1587/transcom.E96.B.2807
Volume: E96B
Issue: 11
Begin Page: 2807
End Page: 2815
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