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Stability analysis of the turbo decoding algorithm using Max-Log-MAP. (English) Zbl 1073.94526
Blaum, Mario (ed.) et al., Information, coding and mathematics. Proceedings of workshop honoring Professor Bob McEliece on his 60th birthday, Pasadena, CA, USA, May 24–25, 2002. Boston, MA: Kluwer Academic Publishers (ISBN 1-4020-7079-9/hbk). The Kluwer International Series in Engineering and Computer Science 687, 257-277 (2002).
Summary: We investigate analytically the stability and convergence properties of iterative turbo decoding with the Max-Log-MAP algorithm for soft-output generation. With respect to the turbo decoding algorithm (TDA) using Max-Log-MAP, several equivalent forms of the mathematical formulation are derived to facilitate the stability analysis. Based on the derived formulation, we show that the TDA using Max-Log-MAP has at least one fixed point regardless of the choice of constituent codes. By some specially constructed examples, we also show that the TDA using Max-Log-MAP is in general suboptimal for symbol decision and may not even converge. Finally, from the viewpoint of the derived formulation, some conditions are given to guarantee the convergence of iterative turbo decoding.
For the entire collection see [Zbl 1054.94001].
94B35 Decoding
94B60 Other types of codes