Fast convergencealgorithm forLDPC Codes
Norbert Wehn
Abstract
Low-Density Parity-Check (LDPC)codesareone ofthemostpowerful codesknowntoday. Theyaredecoded iteratively bya messagepassing algorithm. Thereexist many different update schemes oftheexchanged messages. Themajor difference ofallupdate schemes istheconvergence speed, i.e. the achieved communications performance foralimited numberof iterations. Thispaperpresents anewdecoding algorithm whichefficiently utilizes theencoder property oflinear encodable LDPC codes. Thebasic ideaistointerpret theLDPC encoder asanencoder withpuncturing unitwhichopensaswellthedoorforhybrid ARQ schemes. Thepresented newdecoding algorithm showsa faster convergence behavior thanstate ofartdecoding schemes anditresults inalowererrorfloor.