Signal combining for relay transmission with rateless codes

  • Authors:

  • Azad Ravanshid;Lutz Lampe;Johannes Huber

  • Affiliations:

  • Lehrstuhl für Informationsübertragung, Universität Erlangen-Nürnberg, Germany;Department of Electrical and Computer Engineering, University of British Columbia, Canada;Lehrstuhl für Informationsübertragung, Universität Erlangen-Nürnberg, Germany

  • Venue:
  • ISIT'09 Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

The invention of practical rateless codes in the form of Luby transform and Raptor codes has facilitated the implementation of decode-and-forward relaying schemes which permit the relay to autonomously switch between listening and collaboration phase. Considering the classical three-node relay network employing such a flexible decode-and-forward mechanism, in this paper we investigate signal combining strategies for the destination node. In particular, we compare information and energy combining considered previously in the literature and introduce a new, so-called mixed combining scheme, which is a hybrid of the two former strategies. Assuming general finite-size signal constellations we show that mixed combining is advantageous over the pure combining schemes in terms of achievable rate given the same total transmit energy. A comparison of the associated constellation-constrained capacities with simulated rates achieved for relay transmission with moderate-length Raptor codes underscores (i) the relevance of the capacity-based analysis and (ii) the suitability of rateless codes for relay transmission.