Convergence prediction for iterative decoding of threefold concatenated systems

We show how to use EXIT charts for convergence prediction of a threefold serially concatenated system. The corresponding chart has three dimensions and allows us to appropriately select system parameters and to find an optimal schedule of decoding iterations between the three decoders of such a system. Convergence thresholds are obtained to determine the minimal signal-to-noise ratios for which convergence is possible. It turns out that threefold concatenated systems do not achieve any additional performance gain compared to suitably designed twofold systems. We conclude that a threefold concatenation should be considered only when the decoders cannot be chosen freely.

[1]  Krishna R. Narayanan.  Effect of precoding on the convergence of turbo equalization for partial response channels , 2001, IEEE J. Sel. Areas Commun..

[2]  Alain Glavieux,et al.  Iterative correction of intersymbol interference: Turbo-equalization , 1995, Eur. Trans. Telecommun..

[3]  Hans-Andrea Loeliger,et al.  On the information rate of binary-input channels with memory , 2001, ICC 2001. IEEE International Conference on Communications. Conference Record (Cat. No.01CH37240).

[4]  Stephan ten Brink,et al.  Code characteristic matching for iterative decoding of serially concatenated codes , 2001, Ann. des Télécommunications.

[5]  S. ten Brink,et al.  Iterative demapping and decoding for multilevel modulation , 1998, IEEE GLOBECOM 1998 (Cat. NO. 98CH36250).

[6]  Dariush Divsalar,et al.  Serial concatenated trellis coded modulation with rate-1 inner code , 2000, Globecom '00 - IEEE. Global Telecommunications Conference. Conference Record (Cat. No.00CH37137).

[7]  Dariush Divsalar,et al.  Serial concatenated trellis coded modulation with iterative decoding , 1997, Proceedings of IEEE International Symposium on Information Theory.

[8]  Michael Tuchler,et al.  EXIT charts of irregular codes , 2002 .

[9]  Sergio Benedetto,et al.  Convergence properties of iterative decoders working at bit and symbol level , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[10]  Stephan ten Brink,et al.  Convergence behavior of iteratively decoded parallel concatenated codes , 2001, IEEE Trans. Commun..

[11]  Inkyu Lee,et al.  The effect of a precoder on serially concatenated coding systems with an ISI channel , 2001, IEEE Trans. Commun..

[12]  Rüdiger L. Urbanke,et al.  The capacity of low-density parity-check codes under message-passing decoding , 2001, IEEE Trans. Inf. Theory.

[13]  William E. Ryan,et al.  Convolutional double accumulate codes (or double turbo DPSK) , 2001, IEEE Commun. Lett..

[14]  Hesham El Gamal,et al.  Analyzing the turbo decoder using the Gaussian approximation , 2001, IEEE Trans. Inf. Theory.

[15]  Stephan ten Brink,et al.  Extrinsic information transfer functions: A model and two properties , 2002 .

[16]  S. ten Brink.  Convergence of multidimensional iterative decoding schemes , 2001, Conference Record of Thirty-Fifth Asilomar Conference on Signals, Systems and Computers (Cat.No.01CH37256).

[17]  Paul D. Alexander,et al.  Iterative detection in code-division multiple-access with error control coding , 1998, Eur. Trans. Telecommun..

[18]  Aleksandar Kavcic,et al.  Deriving performance bounds for ISI channels using Gallager codes , 2001, Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252).

[19]  Andrew C. Singer,et al.  Turbo equalization: principles and new results , 2002, IEEE Trans. Commun..

[20]  John Cocke,et al.  Optimal decoding of linear codes for minimizing symbol error rate (Corresp.) , 1974, IEEE Trans. Inf. Theory.

[21]  Radford M. Neal,et al.  Near Shannon limit performance of low density parity check codes , 1996 .

[22]  Dan Raphaeli,et al.  Combined turbo equalization and turbo decoding , 1998, IEEE Communications Letters.