Thomas Mittelholzer


Thomas Mittelholzer received his diploma in mathematics, his Ph.D., also in mathematics, and his diploma in computer science from the Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, in 1981, 1987, and 1988, respectively.

From 1989 to 1993, he was a Research Associate with the Signal and Information Processing Laboratory at the Swiss Federal Institute of Technology. He spent the year 1994 as Visiting Post-Graduate Research Scientist at the Center for Magnetic Recording Research at the University of California in San Diego. After working three years as a consultant for security and cryptography, he joined the IBM Zurich Research Laboratory in 1999, where he has focused on coding for hard disk and tape recording as well as on phase change memory and flash memory technology. Currently, he is a lecturer at HSR Hochschule für Technik Rapperswil.

Dr. Mittelholzer holds 50+ granted US and European patents in the areas of magnetic recording for hard disk/tape drives and solid state memory technology and received the IBM Master Inventor Award.

He is a senior member of the IEEE Information Theory Society and Chair of the IEEE Switzerland Chapter on Digital Communication Systems.

Research Interests

  • Coding and communication theory, 
    including signal processing for data storage based on magnetic recording, flash and phase change memory
  • Sequence design for multi-user spread-spectrum systems
  • Cryptography and digital watermarking
  • Machine learning

Classes taught at ETH-Zurich and EPF-Lausanne

  • ETHZ 91-101, Linear Algebra (Winter 1986/87)
  • EPFL A2, Théorie de l'information (Summer 1988)
  • EPFL 4813, Algebraic Methods in Communications (Winter 1991/92)
  • ETHZ 35-417, Applied Digital Information Theory I (Winter 1998/99)
  • ETHZ 35-418, Applied Digital Information Theory II (Summer 1998 and 2002)
  • ETHZ 227-0104, Information Transfer (Summer 2006)


Recent Publications

can be viewed on his Google Scholar profile.


  1. Communications and Cryptography: Two Sides of One Tapestry, Eds. R.E. Blahut, D.J. Costello, Jr., U. Maurer, T. Mittelholzer, Kluwer 1994.

Papers in Books

  1. J.L. Massey and T. Mittelholzer, ``Welch's Bound and Sequence Sets for Code-Division Multiple-Access Systems,'' published in Sequences II (1991: Positano, Italy), Eds. R. Capocelli, A. De Santis and U. Vaccaro, pp. 63 - 78, Springer 1993.
  2. T. Mittelholzer, ``Minimal Encoders for Convolutional Codes over Rings,'' published in Communications Theory and Applications, Eds. B. Honary, M. Darnell and P.G. Farrell, pp. 30 -- 36, HW Comm. Ldt., 1993.
  3. T. Mittelholzer, `Construction and Decoding of Optimal Group Codes from Finite Reflection Groups,' published in Communications and Cryptography: Two Sides of One Tapestry, Eds. R.E. Blahut, D.J. Costello, Jr., U. Maurer, T. Mittelholzer, Kluwer 1994, pp. 297--306.
  4. T. Mittelholzer, ``An Information-Theoretic Approach to Steganography and Watermarking,'' in Information Hiding: 3rd Intnl. Workshop IH '99, Dresden, Germany, Sep/Oct 1999, Proceedings, Ed. A. Pfitzmann, Springer LNCS 1768, 2000, pp. 1--16.
  5. T. Mittelholzer, ``Linear Codes and Their Duals over Artinian Rings,'' in Codes, Systems, and Graphical Models, Eds. B. Marcus and J. Rosenthal, Springer, The IMA Volumes in Mathematics and its Applications, Vol. 123, 2001, pp. 361--379.


Journal Publications

  1. H.-A. Loeliger, G.D. Forney, Jr., T. Mittelholzer, M.D. Trott, ``Minimality and Observability of Group Systems,'' Linear Algebra & Appl., vol. 205-206, pp.937--963, July 1994.
  2. Thomas Mittelholzer, Peter A. McEwen, Shirish A. Altekar, and Jack K. Wolf, ``Finite Truncation Depth Trellis Codes for the Dicode Channel,'' IEEE Trans. on Magnetics vol. 31, no. 6, pp. 3027--3029, November 1995.
  3. T. Mittelholzer and J. Lahtonen, ``Group Codes Generated by Finite Reflection Groups,'' IEEE Trans. on Information Theory vol. 42, no. 2, pp. 519 -- 528, March 1996.
  4. H.-A. Loeliger and T. Mittelholzer, ``Convolutional Codes over Groups,'' Special Issue on ``Codes and Complexity'' of the IEEE Trans. on Information Theory, vol. 42, Nov. 1996, pp. 1660 -- 1686.
  5. E. Eleftheriou, T. Mittelholzer, and A. Dholakia, ``Reduced-Complexity Decoding Algorithm for Low-Density Parity-Check Codes, IEE Electron. Lett., Vol. 37, pp. 102--104, Jan. 2001.
  6. T. Mittelholzer, A. Dholakia, and E. Eleftheriou, ``Reduced-Complexity Decoding of Low-Density Parity-Check Codes for Generalized Partial Response Channels,'' IEEE Trans. on Magnetics vol. 37, no. 2, pp. 721--728, March 2001.
  7. Xiao-Yu Hu, T. Mittelholzer, ``A Sorting-Based Approximation of the Sum-Product Algorithm,'' Journal Brazilian Telecommunications Society, Vol. 18, No. 1, June 2003, pp. 54 -- 60.
  8. A. Dholakia, E. Eleftheriou, M. Fossorier, T. Mittelholzer, ``Capacity-Approaching Codes: Can They Be Applied to the Magnetic Recording Channel?,'' IEEE Communications Magazine, Vol. 42, No. 2, February 2004, pp. 122 - 130.
  9. M. Blaum, R. D. Cideciyan, E. Eleftheriou, R. Galbraith, K. Lakovic, T. Mittelholzer, T. Oenning, B. Wilson, ”High-Rate Modulation Codes for Reverse Concatenation,” IEEE Transactions on Magnetics, Vol. 43, No. 2, Feb. 2007, pp. 740–743.
  10. A. J. Argumedo, D. Berman, R. G. Biskeborn, G. Cherubini, R. D. Cideciyan, E. Eleftheriou, W. Haeberle, D.J. Hellman, R. Hutchins, W. Imaino, J. Jelitto, K. Judd, P.-O. Jubert, M. A. Lantz, G. M. McClelland, T. Mittelholzer, C. Narayan, S. Oelcer, P. J. Seger, “Scaling tape-recording areal densities to 100 Gb/in2”, IBM Journal of Research and Development, Vol. 5, Issue 4.5, 2008, pp. 513 – 527.
  11. M. Franceschini, L.A. Lastras-Montano, T. Mittelholzer, M. Sharma, “The Role of Feedback in Rewritable Storage Channels,” IEEE Signal Processing Mag., Vol. 26(6), Nov 2009, pp. 190–194.
  12. L.A. Lastras-Montano, M. Franceschini, T. Mittelholzer, M. Sharma, “On the Capacity of Memoryless Rewritable Storage Channels”, IEEE Trans. on Information Theory, Vol. 60(6), June 2014, pp. 3178–3195.


Conference Publications and Presentations

  1. J.L. Massey and T. Mittelholzer, ``Convolutional Codes over Rings,'' Proc. of Fourth Joint Swedish--USSR Int. Workshop on Information Th., 27 Aug -- 1 Sep, 1989, Gotland, Sweden, pp. 14--18.
  2. T. Mittelholzer and J.L. Massey, ``Convolutional Codes and Cohomological Invariants,'' Abstracts of papers Workshop on Applications of Algebraic Geometry, Jan 8 -- 12, 1990, Univ. of Puerto Rico, Puerto Rico.
  3. J.L. Massey, T. Mittelholzer, T. Riedel and M. Vollenweider, ``Ring Convolutional Codes for Phase Modulation,'' Proc. IEEE Int. Symp. on Information Th., San Diego, USA, Jan 1990, p. 176.
  4. T. Mittelholzer and J.L. Massey, ``Convolutional Codes over Rings,'' Book of abstracts U.R.S.I., General Assembly, Prag, Czechoslovakia, 28 Aug -- 5 Sep, 1990, p. 428.
  5. J.L. Massey and T. Mittelholzer,``Systematicity and Rotational Invariance of Convolutional Codes over Rings,'' Proc. 2nd Int. Workshop on Algebraic and Combinatorial Coding Th., Leningrad, Sep 16 -- 22, 1990, pp. 154--158.
  6. H.-A. Loeliger and T. Mittelholzer, ``Linear Codes over Groups and New Slepian-Type Signal Sets,'' Proc. IEEE Int. Symp. on Information Th., Budapest, Hungary, June 24 -- 28, 1991, p. 241.
  7. T. Mittelholzer, ``Minimality Criteria for Convolutional Encoders,'' Abstracts of papers Workshop on Coding and Information Th., Essen, Germany, Dec 16 -- 17, 1991, p. 22.
  8. T. Mittelholzer, ``Convolutional Codes over Groups,'' Abstracts of papers Workshop on Information Th., Oberwolfach, Germany, April 5 -- 11, 1992, p. 10.
  9. H.-A. Loeliger and T. Mittelholzer, ``Convolutional Codes over Groups: Facts and Hopes,'' Abstracts of papers IEEE Information Th. Workshop, San Salvador, Brazil, June 21 -- 26, 1992, p. 30.
  10. T. Mittelholzer and H.-A. Loeliger, ``On Minimality Conditions for Linear Systems and Convolutional Codes,'' Proc. IEEE Int. Symp. on Information Th., San Antonio, USA, Jan 17 -- 22, 1993, p. 182.
  11. T. Mittelholzer, ``Decomposition and Construction of Group Codes,'' Proc. IEEE Int. Symp. on Information Th., Trondheim, Norway, June 27 -- July 1, 1994, p. 481.
  12. T. Mittelholzer, ``Minimality Tests for Rational Encoders over Rings,'' Proc. IEEE Int. Symp. on Information Th., Whistler, B.C. Canada, 17 -- 22 Sep, 1995, p. 305.
  13. T. Mittelholzer, ``Convolutional Codes over Groups: A Pragmatic Approach,'' Proc. of 33rd Annual Allerton Conference on Communication, Control, and Computing, Monticello, Illinois, USA, October 4-6, 1995, pp. 380 -- 381.
  14. T. Mittelholzer, ``Fast Maximum-Likelihood Decoding of Group Codes from Finite Reflection Groups,'' Abstract of Papers of the Math. Research Inst., Oberwolfach, Germany, 18-24 February, 1996.
  15. T. Mittelholzer, ``Minimal-Trellis Decoding Versus Permutation Decoding of Permutation Modulation Codes,'' Proc. of the 1st INTAS Intern. Seminar on Coding Th. and Combinatorics, Thahkadzor, Armenia, Oct 6 -- 11, 1996, pp. 116 --121.
  16. T. Mittelholzer, ``Convolutional Codes over Rings and the Two Chain Conditions,'' Proc. IEEE Int. Symp. on Information Th., Ulm, Germany, June 29 -- July 4, 1997, p. 285.
  17. T. Mittelholzer, X. Lin, J.L. Massey, ``Multilevel Turbo Codes for M-ary Quadrature and Amplitude Modulation,'' Proc. of the Intern. Symp. on Turbo Codes & Related Topics, Brest, France, 3 -- 5 Sep, 1997, pp. 127 --134.
  18. X. Lin, J.L. Massey, T. Mittelholzer, B. Rimoldi, ``Hard-Decision-Aided Turbo Decoding,'' Proc. of the Intern. Symp. on Turbo Codes & Related Topics, Brest, France, 3 -- 5 Sep, 1997, pp. 235 -- 238.
  19. T. Mittelholzer, ``Subcode Graphs of Linear Block Codes, Proc. IEEE Int. Symp. on Information Th., Sorrento, Italy, 25 -- 30 June, 2000, p. 116.
  20. A. Dholakia, E. Eleftheriou, and T. Mittelholzer, ``Iterative Detection/Decoding Techniques for the Magnetic Recording Channel,'' Digests of the Magnetic Recording Conference, TMRC 2000, Aug. 14--16, 2000, Santa Clara, CA, USA, pp. D6.
  21. A. Dholakia, E. Eleftheriou, and T. Mittelholzer, ``On Iterative Decoding for Magnetic Recording Channels,'' Proc. of the 2nd Intern. Symp. on Turbo Codes & Related Topics, Brest, France, 4--7 Sep., 2000, pp. 219--226.
  22. T. Mittelholzer, ``Efficient Encoding and Minimum Distance Bounds of Reed-Solomon-Type Array Codes,'' IEEE Proc. Intl. Symposium on Information Theory 2002, Lausanne, Switzerland, June 30 -- July 5, 2002, p. 282.
  23. T. Mittelholzer, ``Channel Precoding and Low-Density Parity-Check Codes for Magnetic Recording, '' IEEE Proc. Intl. Symposium on Information Theory 2003, Yokohama, Japan, June 29 -- July 4, 2003, p. 47.
  24. R.C. Cideciyan, T. Mittelholzer, ``Average Transition Density Constraints for Mitigating Transition Noise in Magnetic Recording,'' IEEE Proc. Intl. Symposium on Information Theory 2004, Chicago, USA, June 27 -- July 2, 2004, p. 265.
  25. M. Blaum, R.D. Cideciyan, E. Eleftheriou, R. Galbraith, K. Lakovic, T. Mittelholzer, T.  Oenning, B. Wilson, “Enumerative encoding with non-uniform modulation constraints,” Proc. Intl. Symposium on Information Theory 2007, Nice, France, 24-29 June 2007, pp. 1831–1835.
  26. T. Mittelholzer, E. Eleftheriou, “Reverse Concatenation of Product and Modulation Codes,” Proc. IEEE International Conf. on Communications (ICC ’08), Beijing, China, 19-23 May 2008 , pp. 1991– 1995.
  27. L.A. Lastras-Montano, M. Franceschini, T. Mittelholzer, M. Sharma, ”Rewritable Storage Channels,” Proc. IEEE Int’l Symp. on Information Theory and Its Applications (ISITA 2008), Auckland, New Zealand, Dec 2008, pp 1–6.
  28. L.A. Lastras-Montano, M. Franceschini, T. Mittelholzer, J. Karidis, M. Wegman, ”On the Lifetime of Multilevel Memories,” Proc. IEEE Int’l Symp. on Information Theory (ISIT 2009), Seoul, South Korea, July 2009, pp. 1224–1228.
  29. T. Mittelholzer, M. Franceschini, L. Lastras-Montano, I. Elfadel, M. Sharma, ”Rewriteable Storage Channels with Data-Dependent Noise,” Proc. IEEE Int’l Conf. on Communications (ICC 2009), Dresden, Germany, 14-18 June, 2009, session SAC-02, pp. 1–6.
  30. T. Mittelholzer, “Enumerative Maximum-Transition-Run Codes,” Proc. IEEE Int’l Symp. on Information Theory (ISIT 2009), Seoul, South Korea, July 2009, pp. 1549-1553.
  31. T. Mittelholzer, “Enumerative Encoding of Maximum-Transition-Run Codes,” Proc. 10th Int’l Symp. on Communication Theory and Applications (ISCTA ’09), Ambleside, UK, July 2009, (CD).
  32. L.-A. Lastras-Montano, T. Mittelholzer, M. Franceschini, “Superposition coding in rewritable channels,” Proc. IEEE Information Theory and Applications Workshop (ITA 2010), San Diego CA, USA, Jan 2010, (invited).
  33. L.A. Lastras-Montano, M. Franceschini, T. Mittelholzer, “The Capacity of the Uniform Noise Rewritable Channel with Average Cost,” Proc. IEEE Int’l Symp. on Information Theory (ISIT 2010), Austin, TX, USA, June 2010, pp. 201-205.
  34. T. Mittelholzer, L.A. Lastras-Montano, M. Sharma, M. Franceschini, “Rewritable Storage Channels with Limited Number of Rewrite Iterations,” Proc. IEEE Int’l Symp. on Information Theory (ISIT 2010), Austin, TX, USA, June 2010, pp. 973-977.
  35. H. Pozidis, N. Papandreou, A. Sebastian, A. Pantazi, T. Mittelholzer, GF Close, E. Eleftheriou, “Enabling Technologies for Multilevel Phase-Change Memory,” European Symp. on Phase Change and Ovonics (EPCOS 2011), Zurich, Switzerland, 4 - 6 Sept, 2011, SESSION-8 PCRAM (invited talk, 8 pages).
  36. N. Papandreou, H. Pozidis, T. Mittelholzer, G.F. Close, M. Breitwisch, C. Lam, E. Eleftheriou, “IBM Scientists Demonstrate Memory Breakthrough Drift-tolerant Multilevel Phase-Change Memory,” Database and Network Journal, vol. 41(4), Aug 2011, (White paper)
  37. N. Papandreou, H. Pozidis, T. Mittelholzer, G.F. Close, M. Breitwischy, C. Lamy and E. Eleftheriou, ”Drift-Tolerant Multilevel Phase-Change Memory,”Proc. 3rd IEEE International Memory Workshop (IMW 2011), 22 - 25 May, 2011, Monterey CA, USA, pp. 1–4.
  38. H. Pozidis, N. Papandreou, A. Sebastian, T. Mittelholzer, M. BrightSky, C. Lam, E. Eleftheriou, “A Framework for Reliability Assessment in Multilevel Phase-Change Memory,” Proc. 4th IEEE International Memory Workshop (IMW), 2012, Milano, Italy, 20-23 May 2012, pp. 1– 4.
  39. H. Pozidis, N. Papandreou, A. Sebastian, T. Mittelholzer, M. BrightSky, C. Lam, E. Eleftheriou, “Reliable MLC Data Storage and Retention in Phase-Change Memory after Endurance Cycling,” Proc. 5th IEEE International Memory Workshop (IMW), 2013, Monterey, CA, USA, May 2013, pp. 100–103.
  40. T. Mittelholzer, R.D. Cideciyan, “Enumerative Modulation Codes Based on Sliding-Window Substitutions,” Proc. IEEE Intíl Symp. on Information Theory (ISIT 2014), Honolulu, HI, USA, June 2014, pp. 251 – 255.
  41. N. Papandreou, T. Parnell, H. Pozidis, T. Mittelholzer, E. Eleftheriou, C. Camp, T. Griffin, G. Tressler, A. Walls, “Using adaptive read voltage thresholds to enhance the reliability of MLC NAND flash memory systems,” Proc. 24th ACM Great Lakes Symp. on VLSI (GLSVLSI 2014), Houston, TX, USA, May 2014, pp. 151 – 156.
  42. H. Pozidis, T. Mittelholzer, N. Papandreou, T. Parnell, M. Stanislavjlevic, “Phase Change Memory Reliability: A Signal Processing and Coding Perspective,” Proc. 25th The Magnetic Recording Conference (TMRC 2014), Aug 11-13, 2014, F3 pp. 81–82.
  43. T. Parnell, N. Papandreou, T. Mittelholzer, H. Pozidis, “Modelling of the threshold voltage distributions of sub-20nm nand flash memory,” IEEE Global Communications Conference (GLOBECOM 2014), Austin, TX, USA, Dec 2014, pp. 2351 – 2356.
  44. R.D. Cideciyan, , R. Hutchins, T. Mittelholzer, & S. Oelcer, “Partial reverse concatenation for data storage,” Proc. IEEE Asia-Pacific Signal and Information Processing Association (APSIPA 2014), Dec 2014, pp. 1–9.