Speaker: Karen Marie Webster

Advisor: Dr. Jon Hamkins, NASA JPL

Place/Time: EERC 226, 1:05pm, 11/14/2002

All NASA deep space missions use error-correcting codes to protect digital data during transmission. Reed-Solomon codes have been widely used for error correction on missions such as Cassini, Mars Pathfinder, and Galileo. This research project at the Jet Propulsion Laboratory focused on improving the error correcting capabilities of Reed-Solomon decoders. Improved decoders would benefit missions in several ways: reducing cost and required power, and increasing data received.

Techniques were developed for decoding Reed-Solomon codes. Reed-Solomon codes can be treated as binary codes and decoded using belief propagation algorithms. These algorithms depend on a matrix that describes the code. Several such matrices were constructed. Error correcting capabilities of the matrices were determined from computer simulations of a communication system using these decoders. Techniques were also developed to modify the matrices to improve the properties of these decoders.

The decoder simulations did not perform well for the NASA standard Reed-Solomon codes, however, there are promising results for smaller Reed-Solomon codes. Further research will go into understanding the distinctive properties of small Reed-Solomon codes and eventually extend the understanding to larger codes.