LLR calculation for iterative decoding on fading channels using Padé approximation

Gou Hosoya, Mikio Hasegawa, Hiroyuki Yashima

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In this paper, approximate calculation of channel log likelihood ratio (LLR) for wireless channels using Padé approximation is devised. Due to the lack of knowledge of the channel state information of a wireless fading channel, such as uncorrelated flat Rayleigh fading channels, calculation of exact LLR for these channels is quite complicated for a practical implementation. The previous work, LLR calculation using the Taylor approximation, quickly becomes inaccurate as the channel output leaves some derivative point. To overcome this problem, we devise a new LLR approximation using Padé approximation, which expresses the original function by rational form of two polynomials with the same total number of coefficients of the Taylor series, accelerates the Taylor approximation, is devised. By applying the proposed approximation to the iterative decoding and the low-density parity-check codes, we show the effectiveness of the proposed methods by simulation results and analysis based on the density evolution.

Original languageEnglish
Title of host publication2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012
DOIs
Publication statusPublished - 2012
Externally publishedYes
Event2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012 - Huangshan, China
Duration: 2012 Oct 252012 Oct 27

Publication series

Name2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012

Conference

Conference2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012
CountryChina
CityHuangshan
Period12/10/2512/10/27

Keywords

  • BP decoding
  • LDPC code
  • LLR approximation
  • Log-likelihood ratio
  • padé approximation
  • uncorrelated flat Rayleigh fading channel

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Signal Processing

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  • Cite this

    Hosoya, G., Hasegawa, M., & Yashima, H. (2012). LLR calculation for iterative decoding on fading channels using Padé approximation. In 2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012 [6542931] (2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012). https://doi.org/10.1109/WCSP.2012.6542931