LLR-Based Decode-and-Forward Protocol for Relay Networks and Closed-Form BER Expressions

Ho Van KHUONG; Hyung Yun KONG

doi:10.1093/ietfec/e89-a.6.1832

LLR-Based Decode-and-Forward Protocol for Relay Networks and Closed-Form BER Expressions

Ho Van KHUONG, Hyung Yun KONG

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Decode-and-forward cooperative communications protocol (DFP) allows single-antenna users in wireless medium to obtain the powerful benefits of multi-antenna systems without physical antenna arrays. So far, only signal-to-noise ratio (SNR) or square amplitude of path gain has been used to evaluate the reliability of received signals for relays to decide whether to forward the decoded data so as to prevent unsuccessful detection at the relays. In this paper, we propose using log-likelihood ratio (LLR) as an alternative to SNR in the conventional DFP. Closed-form BER expressions for different versions of DFP are also derived and verified by Monte-Carlo simulations. A variety of numerical results reveal the significant superiority of LLR-based DFP to SNR-based DFP regardless of threshold level and relay position under flat Rayleigh fading channel plus additive white Gaussian noise (AWGN).

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E89-A No.6 pp.1832-1841

Publication Date: 2006/06/01

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Online ISSN: 1745-1337

DOI: 10.1093/ietfec/e89-a.6.1832

Type of Manuscript: PAPER

Category: Communication Theory and Signals

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Ho Van KHUONG, Hyung Yun KONG, "LLR-Based Decode-and-Forward Protocol for Relay Networks and Closed-Form BER Expressions" in IEICE TRANSACTIONS on Fundamentals, vol. E89-A, no. 6, pp. 1832-1841, June 2006, doi: 10.1093/ietfec/e89-a.6.1832.
Abstract: Decode-and-forward cooperative communications protocol (DFP) allows single-antenna users in wireless medium to obtain the powerful benefits of multi-antenna systems without physical antenna arrays. So far, only signal-to-noise ratio (SNR) or square amplitude of path gain has been used to evaluate the reliability of received signals for relays to decide whether to forward the decoded data so as to prevent unsuccessful detection at the relays. In this paper, we propose using log-likelihood ratio (LLR) as an alternative to SNR in the conventional DFP. Closed-form BER expressions for different versions of DFP are also derived and verified by Monte-Carlo simulations. A variety of numerical results reveal the significant superiority of LLR-based DFP to SNR-based DFP regardless of threshold level and relay position under flat Rayleigh fading channel plus additive white Gaussian noise (AWGN).
URL: https://global.ieice.org/en_transactions/fundamentals/10.1093/ietfec/e89-a.6.1832/_p

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@ARTICLE{e89-a_6_1832,
author={Ho Van KHUONG, Hyung Yun KONG, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={LLR-Based Decode-and-Forward Protocol for Relay Networks and Closed-Form BER Expressions},
year={2006},
volume={E89-A},
number={6},
pages={1832-1841},
abstract={Decode-and-forward cooperative communications protocol (DFP) allows single-antenna users in wireless medium to obtain the powerful benefits of multi-antenna systems without physical antenna arrays. So far, only signal-to-noise ratio (SNR) or square amplitude of path gain has been used to evaluate the reliability of received signals for relays to decide whether to forward the decoded data so as to prevent unsuccessful detection at the relays. In this paper, we propose using log-likelihood ratio (LLR) as an alternative to SNR in the conventional DFP. Closed-form BER expressions for different versions of DFP are also derived and verified by Monte-Carlo simulations. A variety of numerical results reveal the significant superiority of LLR-based DFP to SNR-based DFP regardless of threshold level and relay position under flat Rayleigh fading channel plus additive white Gaussian noise (AWGN).},
keywords={},
doi={10.1093/ietfec/e89-a.6.1832},
ISSN={1745-1337},
month={June},}

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TY - JOUR
TI - LLR-Based Decode-and-Forward Protocol for Relay Networks and Closed-Form BER Expressions
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1832
EP - 1841
AU - Ho Van KHUONG
AU - Hyung Yun KONG
PY - 2006
DO - 10.1093/ietfec/e89-a.6.1832
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E89-A
IS - 6
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - June 2006
AB - Decode-and-forward cooperative communications protocol (DFP) allows single-antenna users in wireless medium to obtain the powerful benefits of multi-antenna systems without physical antenna arrays. So far, only signal-to-noise ratio (SNR) or square amplitude of path gain has been used to evaluate the reliability of received signals for relays to decide whether to forward the decoded data so as to prevent unsuccessful detection at the relays. In this paper, we propose using log-likelihood ratio (LLR) as an alternative to SNR in the conventional DFP. Closed-form BER expressions for different versions of DFP are also derived and verified by Monte-Carlo simulations. A variety of numerical results reveal the significant superiority of LLR-based DFP to SNR-based DFP regardless of threshold level and relay position under flat Rayleigh fading channel plus additive white Gaussian noise (AWGN).
ER -