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en:group:seminars:20051117 [2009/04/07 11:17]
127.0.0.1 external edit
en:group:seminars:20051117 [2009/04/07 12:32]
admin
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 ==== abstract ==== ==== abstract ====
 Error-correcting codes which employ iterative decoding algorithms are now  Error-correcting codes which employ iterative decoding algorithms are now 
 +considered state of the art in communications. ​ There is now a large
 +collection of code families which achieve a small gap to capacity with
 +feasible decoding complexity. ​ Examples are low-density parity-check (LDPC)
 +codes, irregular repeat-accumulate (IRA) codes, and Raptor codes. For each
 +of these code families, one can construct code sequences which provably
 +achieve capacity on the binary erasure channel (BEC). ​ In each case,
 +however, the decoding complexity becomes unbounded as the gap to capacity
 +vanishes. This talk will focus on recently constructed code families whose
 +complexity remains bounded as the gap to capacity vanishes. Assuming only
 +basic knowledge of LDPC codes, three closely related ensembles will be
 +described: IRA codes, accumulate-repeat-accumulate (ARA) codes, and
 +accumulate-LDPC (ALDPC) codes. ​ Using the duality between these ensembles
 +and simplified approach to density evolution, we will construct a variety
 +of codes which achieve capacity with bounded complexity. This is joint work
 +with Igal Sason and Ruediger Urbanke.