Salamander Error Correction

                 Home     About Us     Products     Research     Contact Us     News     Tutorials     Applications     Industries


Reed-Solomon

Viterbi

Concatenated RS/ Viterbi

Turbo

Turbo Product

LDPC

BCH

Interleavers

Channel Simulators

 

CCSDS

WiMAX (802.16)

3GPP (WCDMA)

3GPP2 (CDMA2000)

DOCSIS

GPON

 

Press

Design Services

Device Selector

 

Quality

Integrity

Service

 

 

Research at Salamander

 

                                                                                                                                                         

In addition to standard products, Salamander Error Correction is currently conducting primary research in select areas of error correction and coding and the behavior of signals in a noisy channel. Some of our projects are listed below.

Current Projects

Soft decision and "pseudo-soft" decision decoding of Reed-Solomon codes

Despite revolutionary developments in capacity-approaching codes in recent years, Reed-Solomon (RS) codes remain very relevant today, especially for high rate systems with relatively small packets. RS codes are straightforward to decode and have excellent burst correction capability. Soft decision RS coders are still notoriously complex, however. Development work is currently underway on practical systematic soft decision RS decoders using the Koetter-Vardy variation of the Guruswami-Sudan algorithm.

High speed Turbo codes

Parallel concatenated "turbo" codes are often mischaracterized in the literature as being not inherently parallelizable, unlike, for example, LDPC codes. Actually, the constituent convolutional codes that make up turbo codes can easily be decoded using a graphical strategy and recognizing that the constituent codes have memory limited to about 5 x (constraint length) of the code.

Resources

There are many excellent web resources for the coding enthusiast. We won't attempt to provide a comprehensive list here, just a few of our favorites:

A most remarkable and readable book on "modern" error control theory can be found here. Buy this book and read every page, you will be very glad you did. You'll want to check out the rest of David J.C. MacKay's interesting and informative site as well.

Basic papers in coding theory

This is a short list of what are arguably the most important technical and scientific papers in coding theory. Warning: many of these references are not for the novice!

1. Shannon, C. E., "A Mathematical Theory of Communication," Bell Sys. Tech. J., 27, 379-423, 623-656 (1948).

2. Reed, I. S., and G. Solomon, "Polynomial Codes over Certain Finite Fields," J. SIAM, 8, 300-304 (1960)

3. Viterbi, A. J., "Error Bounds for Convolutional Codes and an Asymptotically Optimum Decoding Algorithm," IEEE Trans. Inf. Theory, IT-13, 260-269 (1967).

4. Bose, R. C., and D. K. Ray-Chaudhuri, "On a Class of Error Correcting Binary Group Codes," Inf. Control, 3, 68-79 (1960).

5. Hocquenghem, A., "Codes correcteurs d'erreurs," Chiffres, 2, 147-156 (1959).

6. C. Berrou, A. Glavieux, and P. Thitimajshima, "Near Shannon limit error-correcting coding and decoding: Turbo-codes," Proc. IEEE Int. Conf. on Commun. (Geneva, Switzerland) 1064-1070, May 1993.

7. R. M. Pyndiah, "Near-optimum decoding of product codes: block turbo codes," IEEE Transactions on Communications, vol. 46, August, 1998, pp. 1003-1010.
 

8. L.R. Bahl, J. Cocke, F. Jelinek , J. Raviv.  "Optimal Decoding of Linear Codes for Minimizing Symbol Error Rate."  IEEE Transactions on Information Theory,
IT-20, pp. 284-287, March 1974

 

Basic texts in coding theory

There are quite a few significant and excellent textbooks on coding theory. We list a few of the most important here.

S. Lin and D. J. Costello, Error Control Coding. Englewood Cliffs, NJ: Prentice Hall, 1982.

A. M. Michelson and A. H. Levesque, Error Control Techniques for Digital Communication. New York: John Wiley & Sons, 1985.

W. W. Peterson and E. J. Weldon, Jr., Error Correcting Codes, 2 nd ed. Cambridge, MA: The MIT Press, 1972.

V. Pless, Introduction to the Theory of Error-Correcting Codes, 3rd ed. New York: John Wiley & Sons, 1998.

C. Schlegel and L. Perez, Trellis Coding. Piscataway, NJ: IEEE Press, 1997

S. B. Wicker, Error Control Systems for Digital Communication and Storage . Englewood Cliffs, NJ: Prentice Hall, 1995.
 

Other references:

Other papers are:

G. D. Forney, Jr., "Convolutional Codes II: Maximum-Likelihood Decoding," Information Control, vol. 25, June, 1974, pp. 222-226.

K. S. Gilhousen et. al., "Coding Systems Study for High Data Rate Telemetry Links," Final Contract Report, N71-27786, Contract No. NAS2-6024, Linkabit Corporation, La Jolla, CA, 1971.

J. A. Heller and I. M. Jacobs, Viterbi Decoding for Satellite and Space Communications," IEEE Transactions on Communication Technology, vol. COM-19, October, 1971, pp. 835-848.

K. J. Larsen, "Short Convolutional Codes with Maximal Free Distance for Rates 1/2, 1/3, and 1/4," IEEE Transactions on Information Theory, vol. IT-19, May, 1973, pp. 371-372.

J. P. Odenwalder, "Optimum Decoding of Convolutional Codes," Ph. D. Dissertation, Department of Systems Sciences, School of Engineering and Applied Sciences, University of California at Los Angeles, 1970.

C. Gumas, "Turbo codes rev up error-correcting performance," (Part 1), PE&IN, January, 1998, pp. 61-66.

C. Gumas, "Turbo codes build on classic error-correcting codes and boost performance," (Part 2), PE&IN, February, 1998, pp. 54-63.

C. Gumas, "Turbo Codes propel new concepts for superior codes," (Part 3), PE&IN, March, 1998, pp. 65-70.

C. Gumas, "Win, place, or show, Turbo Codes enter the race for next generation error-correcting systems," (Part 4), PE&IN, April, 1998, pp. 54-62.

A. Burr, "Turbo-codes:  the ultimate error control codes?"  Electronics and Communication Engineering Journal, August, 2001, pp. 155-165.

C. Berrou, "Some clinical aspects of turbo codes," International Symposium on Turbo Codes, September, 1997, pp. 26-31.

S. Benedetto and G. Montorsi, "Design of parallel concatenated convolutional codes," IEEE Transactions on Communications, vol. 44, May, 1996.

S. Benedetto, D. Divsalar, G. Montorsi, and F. Pollara, "Algorithm for continuous decoding of turbo codes," Electronic Letters, vol. 32 no. 4, February, 1996.

 

link1

link2

link3

link4

link5

link6 

link7
 
link8  

Visit the Viterbi Algorithm Workshop and try it out.

Dr. Robert H. Morelos-Zaragoza, currently at the University of Tokyo, has a comprehensive page listing links to source code for error-control coding programs in C and links to other pages with more information on error-control coding. Reed-Solomon, convolutional/Viterbi, BCH, and Golay codes and Galois-field calculators are among the topics covered.

Phil Karn, KA9Q, has published the source code for his Reed-Solomon, Viterbi, and Fano decoders.  His main FEC code page is here .  Phil recently released the source code for Viterbi and Reed-Solomon decoders designed to take advantage of the Intel® SIMD instruction sets.  His Viterbi decoder reaches speeds of 14 Mbps running on a 1.8 GHz Intel® Pentium® 4 Processor.  Phil also has a descriptive page on convolutional code decoders for amateur radio. Includes the Fano sequential decoding algorithm as well as the Viterbi algorithm.

There is a very useful web page on turbo codes at this JPL site maintained by Fabrizio Pollara and Dariush Divsalar. It contains detailed information about turbo codes with emphasis on deep-space applications, and contains a good bibliography on turbo codes as well as links to other turbo coding research sites. They also have links to commercial turbo codec providers.  Another extensive bibliography on turbo coding can be found at this University of Virginia site .

Reed-Solomon, Viterbi, and Turbo Codes. Salamander Error Correction specializes in the design and marketing of Verilog IP modules for Forward Error Correction.

Salamander Error Correction is a division of Komodo Industries, Inc. (c) 2007 Komodo Industries, Inc. All rights reserved.

Salamander Error Correction

5330 Carroll Canyon Rd

San Diego, CA 92121

(858) 373-2112

Fax: (858) 373-1224

sales@salamander-ecc.com

www.salamander-ecc.com