University of Oulu

J. He, I. Hussain, Y. Li, M. Juntti and T. Matsumoto, "Distributed LT Codes With Improved Error Floor Performance," in IEEE Access, vol. 7, pp. 8102-8110, 2019. doi: 10.1109/ACCESS.2018.2890452

Distributed LT codes with improved error floor performance

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Author: He, Jiguang1; Hussain, Iqbal2; Li, Yong3;
Organizations: 1Centre for Wireless Communications, University of Oulu, Oulu 90014, Finland
2Ericsson, 16483 Stockholm, Sweden
3College of Computer Science, Chongqing University, Chongqing 400044, China
4Japan Advanced Institute of Science and Technology, Ishikawa 923-1292, Japan
Format: article
Version: updated version
Access: open
Online Access: PDF Full Text (PDF, 10.7 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2019
Publish Date: 2019-04-16


Distributed Luby transform (DLT) codes achieve a significant performance improvement in multi-source relay networks compared with the individual Luby transform (LT) code designed for each source. Since the DLT codes preserve the properties of the LT codes, the error floor is dominated by the low variable-node degrees in the bipartite graph, developed for iterative message passing decoding. Therefore, we analyze the error floor of the DLT codes for a multi-source, single relay, and a single destination network over additive white Gaussian noise (AWGN) channels. We modify the encoding process at the sources and propose a new relay combining scheme at the relay. The encoding process at the sources and the combining scheme at the relay are coordinated with the aim of improving the error floor performance of the proposed DLT codes. We derive a lower bound of the bit error probability of the DLT codes over AWGN channels. Furthermore, we optimize the relay degree distribution in terms of the overhead by using the framework of extrinsic information transfer chart analysis. The numerical results confirm that the proposed DLT coding scheme significantly outperforms the conventional scheme, especially in the error floor region.

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Series: IEEE access
ISSN: 2169-3536
ISSN-E: 2169-3536
ISSN-L: 2169-3536
Volume: 7
Pages: 8102 - 8110
DOI: 10.1109/ACCESS.2018.2890452
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported in part by the China NSF under Grant 61771081.
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