TY - JOUR
T1 - Analysis and Design of Binary Message-Passing Decoders
AU - Lechner, Gottfried
AU - Pedersen, Troels
AU - Kramer, Gerhard
PY - 2012/3/9
Y1 - 2012/3/9
N2 - Binary message-passing decoders for low-density parity-check (LDPC) codes are studied by using extrinsic information transfer (EXIT) charts. The channel delivers hard or soft decisions and the variable node decoder performs all computations in the L-value domain. A hard decision channel results in the well-know Gallager B algorithm, and increasing the output alphabet from hard decisions to two bits yields a gain of more than 1.0 dB in the required signal to noise ratio when using optimized codes. The code optimization requires adapting the mixing property of EXIT functions to the case of binary message-passing decoders. Finally, it is shown that errors on cycles consisting only of degree two and three variable nodes cannot be corrected and a necessary and sufficient condition for the existence of a cycle-free subgraph is derived.
AB - Binary message-passing decoders for low-density parity-check (LDPC) codes are studied by using extrinsic information transfer (EXIT) charts. The channel delivers hard or soft decisions and the variable node decoder performs all computations in the L-value domain. A hard decision channel results in the well-know Gallager B algorithm, and increasing the output alphabet from hard decisions to two bits yields a gain of more than 1.0 dB in the required signal to noise ratio when using optimized codes. The code optimization requires adapting the mixing property of EXIT functions to the case of binary message-passing decoders. Finally, it is shown that errors on cycles consisting only of degree two and three variable nodes cannot be corrected and a necessary and sufficient condition for the existence of a cycle-free subgraph is derived.
UR - http://www.scopus.com/inward/record.url?scp=84858337000&partnerID=8YFLogxK
U2 - 10.1109/TCOMM.2011.122111.100212
DO - 10.1109/TCOMM.2011.122111.100212
M3 - Journal article
SN - 0090-6778
VL - 60
SP - 601
EP - 607
JO - IEEE Transactions on Communications
JF - IEEE Transactions on Communications
IS - 3
ER -