Graduate Student Seminar, 4:30pm March 17, 2003, Hayes-Healy 231


Christine Kelley


Algebraic constructions of LDPC codes


One of the major goals in coding theory is to construct codes which reach the Shannon limit. "Codes on graphs" is a main focus of current research, as existing Shannon-limit approaching codes may all be represented by graphs. The prime examples of codes on graphs are Low Density Parity Check (LDPC)codes. Although they perform well empirically, LDPC codes still lack efficient constructions which can guarantee certain parameters characteristic of good codes. In this talk we will discuss how graph structure relates to code performance. This will include Tanner's bounds on the minimum distance for general codes on graphs based on the eigenvalues of the graph. We will then survey known algebraic constructions of LDPC codes based on incidence structures and Ramanujan graphs.

To volunteer to give a talk, or for any other questions regarding this schedule, contact Wesley Calvert