Digital Communications: Fundamentals and Applications, 3rd Edition

8.2 Low-Density Parity Check (LDPC) Codes

8.2.1 Background and Overview

Claude Shannon’s noisy channel coding theorem [18, 19], made public in 1948, sparked the richest time of coding research in the 20 years that followed and provided the motivation for finding good codes (i.e., codes that approach the ultimate capacity limitation imposed by the theorem). A communication channel can be characterized by a number called capacity, typically measured in bits/s or information bits per channel symbol. Shannon proved that there exist channel codes that can achieve arbitrarily small error probability up to some maximum data rate (less than the capacity of the given channel). He taught us that reliable transmission is possible for rates up to the ...