Abstract
In this paper, we propose a simple remedy for the exaggerated extrinsic information produced by the soft-output Viterbi algorithm (SOVA). We argue that what leads to these optimistic extrinsic values is the inherent strong correlation between the intrinsic information (input to the SOVA) and extrinsic information (output of the SOVA). The proposed remedy involves employing two attenuators, one applied to the immediate output of the SOVA and another applied to the extrinsic information before it is passed to the other decoder (assuming iterative decoding). We examine the modified SOVA (MSOVA) on additive white Gaussian noise (AWGN) and fading channels for serial concatenated codes (SCCs). We show that the MSOVA provides substantial performance improvements over both channels. For example, it provides improvements of about 0.8 to 1.0 dB at P b = 10-5 in AWGN, and about 1.4 to 2.0 dB at Pb = 10-5 on fading channels, all relative to the SOVA. We extend the proposed modifications to the aposteriori probability (APP) algorithm with favorable results. We demonstrate that the modified APP (MAPP) provides performance improvements between 0.3 to 0.6 dB at Pb = 10 -5 relative to the APP.
| Original language | English |
|---|---|
| Title of host publication | GLOBECOM'04 - IEEE Global Telecommunications Conference |
| Pages | 189-193 |
| Number of pages | 5 |
| Volume | 1 |
| Publication status | Published - 2004 |
| Externally published | Yes |
| Event | GLOBECOM'04 - IEEE Global Telecommunications Conference - Dallas, TX, United States Duration: 29 Nov 2004 → 3 Dec 2004 |
Other
| Other | GLOBECOM'04 - IEEE Global Telecommunications Conference |
|---|---|
| Country | United States |
| City | Dallas, TX |
| Period | 29/11/04 → 3/12/04 |
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ASJC Scopus subject areas
- Engineering(all)
Cite this
Improved SOVA and APP decoding algorithms for serial concatenated codes. / Huang, Chuan Xiu; Ghrayeb, Ali.
GLOBECOM'04 - IEEE Global Telecommunications Conference. Vol. 1 2004. p. 189-193.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Improved SOVA and APP decoding algorithms for serial concatenated codes
AU - Huang, Chuan Xiu
AU - Ghrayeb, Ali
PY - 2004
Y1 - 2004
N2 - In this paper, we propose a simple remedy for the exaggerated extrinsic information produced by the soft-output Viterbi algorithm (SOVA). We argue that what leads to these optimistic extrinsic values is the inherent strong correlation between the intrinsic information (input to the SOVA) and extrinsic information (output of the SOVA). The proposed remedy involves employing two attenuators, one applied to the immediate output of the SOVA and another applied to the extrinsic information before it is passed to the other decoder (assuming iterative decoding). We examine the modified SOVA (MSOVA) on additive white Gaussian noise (AWGN) and fading channels for serial concatenated codes (SCCs). We show that the MSOVA provides substantial performance improvements over both channels. For example, it provides improvements of about 0.8 to 1.0 dB at P b = 10-5 in AWGN, and about 1.4 to 2.0 dB at Pb = 10-5 on fading channels, all relative to the SOVA. We extend the proposed modifications to the aposteriori probability (APP) algorithm with favorable results. We demonstrate that the modified APP (MAPP) provides performance improvements between 0.3 to 0.6 dB at Pb = 10 -5 relative to the APP.
AB - In this paper, we propose a simple remedy for the exaggerated extrinsic information produced by the soft-output Viterbi algorithm (SOVA). We argue that what leads to these optimistic extrinsic values is the inherent strong correlation between the intrinsic information (input to the SOVA) and extrinsic information (output of the SOVA). The proposed remedy involves employing two attenuators, one applied to the immediate output of the SOVA and another applied to the extrinsic information before it is passed to the other decoder (assuming iterative decoding). We examine the modified SOVA (MSOVA) on additive white Gaussian noise (AWGN) and fading channels for serial concatenated codes (SCCs). We show that the MSOVA provides substantial performance improvements over both channels. For example, it provides improvements of about 0.8 to 1.0 dB at P b = 10-5 in AWGN, and about 1.4 to 2.0 dB at Pb = 10-5 on fading channels, all relative to the SOVA. We extend the proposed modifications to the aposteriori probability (APP) algorithm with favorable results. We demonstrate that the modified APP (MAPP) provides performance improvements between 0.3 to 0.6 dB at Pb = 10 -5 relative to the APP.
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UR - http://www.scopus.com/inward/citedby.url?scp=18144363231&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:18144363231
VL - 1
SP - 189
EP - 193
BT - GLOBECOM'04 - IEEE Global Telecommunications Conference
ER -