Fine-Granularity Loading Schemes Using Adaptive Reed-Solomon Coding for xDSL-DMT Systems

  • Saswat Panigrahi
  • Tho Le-Ngoc
Open Access
Research Article
Part of the following topical collections:
  1. Advanced Signal Processing for Digital Subscriber Lines


While most existing loading algorithms for xDSL-DMT systems strive for the optimal energy distribution to maximize their rate, the amounts of bits loaded to subcarriers are constrained to be integers and the associated granularity losses can represent a significant percentage of the achievable data rate, especially in the presence of the peak-power constraint. To recover these losses, we propose a fine-granularity loading scheme using joint optimization of adaptive modulation and flexible coding parameters based on programmable Reed-Solomon (RS) codes and bit-error probability criterion. Illustrative examples of applications to VDSL-DMT systems indicate that the proposed scheme can offer a rate increase of about Open image in new window in most cases as compared to various existing integer-bit-loading algorithms. This improvement is in good agreement with the theoretical estimates developed to quantify the granularity loss.


Information Technology Data Rate Rate Increase Energy Distribution Quantum Information 


  1. 1.
    Cioffi JM: A Multicarrier Primer. ANSI T1E1.4 Committee Contribution, pp. 91–157, November, 1991Google Scholar
  2. 2.
    Asymmetric Digital Subscriber Line (ADSL) Metallic Interface ANSI Std. T1.413-1998, 1998Google Scholar
  3. 3.
    Very-high Speed Digital Subscriber Lines (VDSL) Metallic Interface ANSI Std. T1E1.4/2003-210R5, 2003Google Scholar
  4. 4.
    Gallager RG: Information Theory and Reliable Communication. John Wiley & Sons, New York, NY, USA; 1968.zbMATHGoogle Scholar
  5. 5.
    Chow PS: Bandwidth optimized digital transmission techniques for spectrally shaped channels with impulse noise, Ph.D. dissertation. Stanford University, Stanford, Calif, USA; 1993.Google Scholar
  6. 6.
    Leke A, Cioffi JM: A maximum rate loading algorithm for discrete multitone modulation systems. Proceedings of IEEE Global Telecommunications Conference (GLOBECOM '97), November 1997, Phoenix, Ariz, USA 3: 1514–1518.CrossRefGoogle Scholar
  7. 7.
    Baccarelli E, Fasano A, Biagi M: Novel efficient bit-loading algorithms for peak-energy-limited ADSL-type multicarrier systems. IEEE Transactions on Signal Processing 2002, 50(5):1237–1247. 10.1109/78.995090CrossRefGoogle Scholar
  8. 8.
    Spectrum Management for Loop Transmission Systems ANSI Std. T1.417-2001, January 2001Google Scholar
  9. 9.
    Hughes-Hartogs D: Ensemble modem structure for imperfect transmission media. U.S. Patents nos. 4,679,227 (July 1987), 4,731,816 (March 1988) and 4,833,706 (May 1989)Google Scholar
  10. 10.
    Krongold BS, Ramchandran K, Jones DL: Computationally efficient optimal power allocation algorithms for multicarrier communication systems. IEEE Transactions on Communications 2000, 48(1):23–27. 10.1109/26.818869CrossRefGoogle Scholar
  11. 11.
    Baccarelli E, Biagi M: Optimal integer bit-loading for multicarrier ADSL systems subject to spectral-compatibility limits. Signal Processing 2004, 84(4):729–741. 10.1016/j.sigpro.2003.12.004CrossRefGoogle Scholar
  12. 12.
    Jang J, Lee KB, Lee Y-H: Transmit power and bit allocations for OFDM systems in a fading channel. Proceedings of IEEE Global Telecommunications Conference (GLOBECOM '03), December 2003, San Francisco, Calif, USA 2: 858–862.CrossRefGoogle Scholar
  13. 13.
    Chow PS, Cioffi JM, Bingham JAC: A practical discrete multitone transceiver loading algorithm for data transmission over spectrally shaped channels. IEEE Transactions on Communications 1995, 43(234):773–775.CrossRefGoogle Scholar
  14. 14.
    Oppenheim AV, Schafer RW, Buck JR: Discrete-Time Signal Processing. 2nd edition. Prentice-Hall, Englewood Cliffs, NJ, USA; 1998. (Sec. 4.8.3. Analysis of Quantization Errors)Google Scholar
  15. 15.
    Moroles-Zaragoza RH: The Art of Error Control Coding. John Wiley & Sons, New York, NY, USA; 2000.Google Scholar
  16. 16.
    Zhang L, Gao C, Cao Z: Exact analysis of bit error rate of maximum-distance-separable codes. Proceedings of IEEE Global Telecommunications Conference (GLOBECOM '00), November–December 2000, San Francisco, Calif, USA 2: 816–819.CrossRefGoogle Scholar
  17. 17.
    Telcordia Technologies : Proposed Bit Rates for Spectral Compatibility with VDSL. ANSI T1E1.4 Committee Contribution, T1E1.4/2002-159R2, August 2002Google Scholar
  18. 18.
    Hasan MA, Bhargava VK: Architecture for a low complexity rate-adaptive Reed-Solomon encoder. IEEE Transactions on Computers 1995, 44(7):938–942. 10.1109/12.392853CrossRefGoogle Scholar
  19. 19.
    Shayan YR, Le-Ngoc T: A cellular structure for a versatile Reed-Solomon decoder. IEEE Transactions on Computers 1997, 46(1):80–85. 10.1109/12.559805CrossRefGoogle Scholar
  20. 20.
    Smith JG: Odd-bit quadrature amplitude-shift keying. IEEE Transactions on Communications 1975, 23(3):385–389. 10.1109/TCOM.1975.1092806CrossRefGoogle Scholar
  21. 21.
    Cho K, Yoon D: On the general BER expression of one- and two-dimensional amplitude modulations. IEEE Transactions on Communications 2002, 50(7):1074–1080. 10.1109/TCOMM.2002.800818CrossRefGoogle Scholar
  22. 22.
    VDSL Test Specification for VDSL Olympics ANSI T1E1.4 Contribution, T1E1.4/2003-036R4, February 2003Google Scholar
  23. 23.
    Lauer JP, Cioffi JM: A turbo trellis coded discrete multitone transmission system. Proceedings of IEEE Global Telecommunications Conference (GLOBECOM '99), December 1999, Rio de Janeireo, Brazil 5: 2581–2585.Google Scholar
  24. 24.
    Kerpez KJ, Waring DL, Galli S, Dixon J, Madon P: Advanced DSL management. IEEE Communications Magazine 2003, 41(9):116–123. 10.1109/MCOM.2003.1232246CrossRefGoogle Scholar
  25. 25.
    Song KB, Chung ST, Ginis G, Cioffi JM: Dynamic spectrum management for next-generation DSL systems. IEEE Communications Magazine 2002, 40(10):101–109. 10.1109/MCOM.2002.1039864CrossRefGoogle Scholar
  26. 26.
    Cendrillon R, Yu W, Moonen M, Verlinden J, Bostoen T: Optimal multi-user spectrum management for digital subscriber lines. to appear in IEEE Transactions on Communications, to appear in IEEE Transactions on Communications,
  27. 27.
    Yu W, Ginis G, Cioffi JM: Distributed multiuser power control for digital subscriber lines. IEEE Journal on Selected Areas in Communications 2002, 20(5):1105–1115. 10.1109/JSAC.2002.1007390CrossRefGoogle Scholar

Copyright information

© Panigrahi and Le-Ngoc 2006

Authors and Affiliations

  • Saswat Panigrahi
    • 1
  • Tho Le-Ngoc
    • 1
  1. 1.Department of Electrical and Computer EngineeringMcGill UniversityMontréalCanada

Personalised recommendations