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Hybrid-ARQ-aided short fountain codes designed for block-fading channels

Hybrid-ARQ-aided short fountain codes designed for block-fading channels
Hybrid-ARQ-aided short fountain codes designed for block-fading channels
As a benefit of their inherent rateless nature, fountain codes constitute a favourable choice for protecting packetbased transmissions in the physical layer for wireless channels having varying quality. However, previous research revealed that the performance of fountain codes substantially degrades, as their block-length is reduced. Three structural phenomena of the Tanner graph were identified by Mackay in the hard decoding of fountain codes on Binary Erasure Channels (BECs) [1], which may be referred to as having ‘no degree-one check nodes’, ‘no emerging degree-one check nodes’ and ‘uncovered variable nodes’. In this paper, we explicitly analyzed how these structural phenomena influence their soft decoding algorithm. Furthermore, these phenomena are shown to be responsible for the high error floors, when fountain codes are transmitted over noisy fading channels, especially for the transmissions of short blocks. In order to eliminate the influence of these structural phenomena, we conceived a technique of generating a few specifically encoded bits, with the aid of the associated Tanner graph. Simulation results have demonstrated that our improved Raptor codes significantly reduce the Packet Loss Ratio (PLR) of conventional fountain codes, despite imposing a reduced low complexity. Finally, we conceive a novel adaptive Hybrid Automatic Repeat reQuest (HARQ) scheme based on a Look-Up Table (LUT) aided technique, which may adapt its coding rate for each transmission. Our simulation results demonstrated that the proposed IRaptor HARQ achieves a similar performance to the Long Term Evolution (LTE) turbo coded HARQ scheme, or even outperforms the LTE arrangement for block-length in excess of 1000 bits.
0018-9545
5701-5712
Chen, Hong
0f30c1b9-7831-4010-a81c-c6825f78af16
Maunder, Robert G.
76099323-7d58-4732-a98f-22a662ccba6c
Ma, Yi
65e7c32b-f381-4134-abb0-f6c4bb3e98e9
Tafazolli, Rahim
a6cb9da0-d823-449a-a400-c438084c7fa3
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Chen, Hong
0f30c1b9-7831-4010-a81c-c6825f78af16
Maunder, Robert G.
76099323-7d58-4732-a98f-22a662ccba6c
Ma, Yi
65e7c32b-f381-4134-abb0-f6c4bb3e98e9
Tafazolli, Rahim
a6cb9da0-d823-449a-a400-c438084c7fa3
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1

Chen, Hong, Maunder, Robert G., Ma, Yi, Tafazolli, Rahim and Hanzo, Lajos (2015) Hybrid-ARQ-aided short fountain codes designed for block-fading channels IEEE Transactions on Vehicular Technology, 64, (12), pp. 5701-5712.

Record type: Article

Abstract

As a benefit of their inherent rateless nature, fountain codes constitute a favourable choice for protecting packetbased transmissions in the physical layer for wireless channels having varying quality. However, previous research revealed that the performance of fountain codes substantially degrades, as their block-length is reduced. Three structural phenomena of the Tanner graph were identified by Mackay in the hard decoding of fountain codes on Binary Erasure Channels (BECs) [1], which may be referred to as having ‘no degree-one check nodes’, ‘no emerging degree-one check nodes’ and ‘uncovered variable nodes’. In this paper, we explicitly analyzed how these structural phenomena influence their soft decoding algorithm. Furthermore, these phenomena are shown to be responsible for the high error floors, when fountain codes are transmitted over noisy fading channels, especially for the transmissions of short blocks. In order to eliminate the influence of these structural phenomena, we conceived a technique of generating a few specifically encoded bits, with the aid of the associated Tanner graph. Simulation results have demonstrated that our improved Raptor codes significantly reduce the Packet Loss Ratio (PLR) of conventional fountain codes, despite imposing a reduced low complexity. Finally, we conceive a novel adaptive Hybrid Automatic Repeat reQuest (HARQ) scheme based on a Look-Up Table (LUT) aided technique, which may adapt its coding rate for each transmission. Our simulation results demonstrated that the proposed IRaptor HARQ achieves a similar performance to the Long Term Evolution (LTE) turbo coded HARQ scheme, or even outperforms the LTE arrangement for block-length in excess of 1000 bits.

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e-pub ahead of print date: 7 January 2015
Published date: December 2015

Identifiers

Local EPrints ID: 373999
URI: http://eprints.soton.ac.uk/id/eprint/373999
ISSN: 0018-9545
PURE UUID: 181e1c31-8d13-42cc-aa03-2aa87d5a5999
ORCID for Robert G. Maunder: ORCID iD orcid.org/0000-0002-7944-2615
ORCID for Lajos Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 03 Feb 2015 14:55
Last modified: 10 Nov 2017 01:02

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Contributors

Author: Hong Chen
Author: Robert G. Maunder ORCID iD
Author: Yi Ma
Author: Rahim Tafazolli
Author: Lajos Hanzo ORCID iD

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