On the SOVA for Extremely High Code Rates over Partial Response Channels

  • Ghrayeb, Ali (Department of Electrical and Computer Engineering, Concordia University)
  • 발행 : 2003.03.01

초록

In this paper, we extend the derivation of the iterative soft-output Viterbi algorithm (SOVA) for partial response (PR) channels, and modify its decoding process such that it works consistently for arbitrary high code rates, e.g., rate 64/65. We show that the modified SOVA always outperforms the conventional SOVA that appears in the literature with a significant difference for high code rates. It also offers a significant cut down in the trace-back computations. We further examine its performance for parallel and serial concatenated codes on a precoded Class IC partial response (PR4) channel. Code rates of the form $\frac{k_0}{k_0+1}$($k_0$ = 4, 8, and 64) are considered. Our simulations indicate that the loss suffered by the modified SOVA, relative to the APP algorithm, is consistent for all code rates and is at most 1.2 dB for parallel concatenations and at most 1.6 dB for serial concatenations at $P_b$ = $10^{-5}$.

키워드

참고문헌

  1. W. Ryan,'Performance of high rate turbo codes on a PR4-equa1ized mag-netic recording channel,' in Proc. lEEEIm. Conf. Commun., vol. 2, June1998, pp.947-951
  2. W. Ryan, L. McPheters, and S. McLauphlin, 'Combined turbo coding andturbo decoding for PR4-equa1ized Lorentzian channels,' in Proc. Conf.Information Sciences and Systems, Mar. 1998, PP. 489-493
  3. L. McPheters, S. McLaughlin and E. Hirsh,'Turbo Codes for PR4 andEPR4 Magnetic Recording,' in Proc. the 32nd Asitomar Conf. Sienats,Systems, and Computers, vol. 2, Nov. 1999, PP. 1778-1782
  4. L. McPheters, S. McLaughlin, and K. Narayanan, 'Precoded PRML, serialconcatenation, and iterative (turbo) decoding for digital magnetic record-ing,' IEEE Trans. Mag., vol. 35, PP. 2325-2327, Sept. 1999 https://doi.org/10.1109/20.800814
  5. T. Souvignier et al., 'Tm-bo Decoding for PR4: Parallel Versus Serial Con-catenation,' in Proc. 1999 Int. Conf. Commun., vol. 3, June 1999, PP.1638-1642
  6. A. Ghrayeb and W. Ryan, 'Concatenated system design for storage systems,' IEEEJ. Setect. Areas Commun., vol. 19, no. 4, PP. 709-718, Apr.2001 https://doi.org/10.1109/49.920179
  7. P. Kobertson, H,. Villebrun, and P. Hoeher, 'A comparison of optimal andsub-optimal MAP decoding algorithms operating in the log domain,' in Proc. 1995 Int. Conf. Commun., PP. 1009-1013
  8. L. Gong, W. Xiaofu, and Y. Xiaoxin, 'On SOVA for nonbinary codes,'IEEE Commun. Lett., vol. 3, issue 12, PP. 335-337, Dec. 1999 https://doi.org/10.1109/4234.809527
  9. J. Hagenauer, E. Offer, and L. Papke, 'Iterative decoding of binary blockand convolutional codes,' IEEE Trans. Infomatwn Theory, vol. 42, no. 2,pp. 429-445, Mar. 1996 https://doi.org/10.1109/18.485714
  10. J. Hagenauer, and P. Hoeher, 'A Viterbi Algorithm with soft-decision out-puts and its applications,' in Proc. GL0BEC0M'89, pp. 1680-1686
  11. J. Hagenauer, 'Source-controIled channel decoding,' IEEE Trans. Comm.vol. 43, issue 9, PP. 2449-2457, Sept. 1995 https://doi.org/10.1109/26.412719
  12. L. R. Bahl, J. Cocke, F. Jelinelc, and J. Raviv, 'Optimal decoding of linearcodes for minimizing symbol error rate,' IEEE Trans. Infom. Theorv, Mar.1974
  13. W. E. Ryan, 'Concatenated codes for class IV partial response channels,'lEEETrans. Commun., pp. 445-454, Apr. 2001
  14. D. Divsalar and F. Pollara, 'Multiple turbo codes for deep-space communications,' JPL TDA Progress Report 42-121, May 1995
  15. S. Shamai, L. H. Ozarow, and A. D. Wyner, 'Information rates for adiscrete-time Gaussian channel with intersymbol interference and station-ary inputs,' IEEE Trans. Infom. theory, vol. 37, PP. 1527-1539, Nov.1991 https://doi.org/10.1109/18.104314
  16. H. D. Pfister, J. B. Soriaga and Paul H. Siegel, 'On the achievable information rates of finite state ISI channel,' in Proc. GL0BEC0M'2001, pp.2992-2996
  17. D. Amold and H. Loeliger, 'On the information rate of binary input chan-nels with memory,' in Proc. Int. Conf. Commun., vol. 9, June 2001, pp.2692-2695
  18. V. Sharma and S. K. Singh, 'Entropy and channel capacity in the regenera-tive setup with applications to Markov channel,' in Proc. Int. Symp. Infom.Theory, P. 283, June 2001
  19. O. Acikel and W. E. Ryan, 'Punctured turbo codes for BPSK/QPSK chan-nels,' IEEE Trans. Commun., pp. 1315-1323, Sept. 1999
  20. A. Ghrayeb and W. Ryan, 'Performance of high rate turbo codes employ-ing the soft output Viterbi algoiithm (SOVA),' in Proc. the 33rd Asitomar Conf. Signats, Systems, and Computers, vol. 2, Nov. 1999, pp. 1665-1669