Modified Max-Log-MAP turbo decoding algorithm using optimized scaling factor

The Max-Log-MAP is a Soft Input Soft Output (SISO) algorithm, which determines the probability of most likely path through the trellis and hence it gives sub optimal performance compared to Log-MAP algorithm. A simple but effective technique to improve the performance of Max-Log-MAP (MLMAP) algorith...

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Veröffentlicht in:2013 International Conference on Recent Trends in Information Technology (ICRTIT) S. 19 - 25
Hauptverfasser: Krishnamoorthy, R., Pradeep, N. S.
Format: Tagungsbericht
Sprache:Englisch
Veröffentlicht: IEEE 01.07.2013
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Zusammenfassung:The Max-Log-MAP is a Soft Input Soft Output (SISO) algorithm, which determines the probability of most likely path through the trellis and hence it gives sub optimal performance compared to Log-MAP algorithm. A simple but effective technique to improve the performance of Max-Log-MAP (MLMAP) algorithm is to scale the extrinsic information exchanged between two decoders using appropriate Scaling Factor (SF). Modified Max-Log-MAP (M-MLMAP) algorithm is achieved by fixing an arbitrary SF for inner decoder S 2 and an optimized SF for the outer decoder S 1 . This paper presents the performance of the Modified Max-Log-MAP decoding algorithm by reducing the over estimation of reliability values to achieve low Bit Error Rate (BER). Appropriate mathematical relationship between SF and E b /N 0 is also proposed. The numerical results show that M-MLMAP algorithm improved the performance of turbo decoding over Additive White Gaussian Noise (AWGN) and Rayleigh fading channels. The proposed M-MLMAP algorithm showed a gain of 0.75dB over MLMAP algorithm at BER of 2×10 -5 for Rayleigh fading channel.
DOI:10.1109/ICRTIT.2013.6844174