Soft Combining for Hybrid ARQ

Document type: Journal Articles
Article type: Original article
Peer reviewed: Yes
Author(s): Ian Holland, Hans-Jürgen Zepernick, Manora Caldera
Title: Soft Combining for Hybrid ARQ
Journal: Electronics Letters
Year: 2005
Volume: 41
Issue: 22
Pagination: 1230-1231
ISSN: 0013-5194
Publisher: IEE
Organization: Blekinge Institute of Technology
Department: School of Engineering - Dept. of Signal Processing (Sektionen för teknik – avd. för signalbehandling)
School of Engineering S- 372 25 Ronneby
+46 455 38 50 00
Authors e-mail:,,
Language: English
Abstract: A soft combining approach utilising symbol-by-symbol maximum a posteriori probability decoding is proposed for hybrid automatic repeat request schemes. In comparison to an existing soft combining approach, significant reductions in post-decoding bit error rate can be obtained without sacrificing the throughput efficiency. This is achieved with the proposed method by accumulating the signal-to-noise ratio at the channel output on each additional retransmission, for use in calculating extrinsic log-likelihood ratios on subsequent decoding attempts.
Subject: Telecommunications\Coding Theory