LDPC Decoding: VLSI Architectures and Implementations

κ
Check Node Unit (CNU) Design
( i)
mn
The above equation (2) can be reformulated as the following set of
equations.
( i)
M1m
= min
n′∈ Ν
( i)
( m)
( m)
( i −1)
Q mn ′
( i −1)
M 2m
= 2nd min Q
n′∈ Ν mn ′
• Simplifies the number of comparisons required as well as the memory
needed to store CNU outputs.
• Additional possible improvements: The correction has to be applied to only two
values instead of distinct values. Need to apply 2’s complement to only 1 or 2 values
instead of values at the output of CNU.
Flash Memory Summit 2013
Santa Clara, CA 10
10
(6)
(7)
k = Min1Index
(8)
( i) ( i)
mn
M1
κ = , ∀ n ∈ Ν( m) \ k
m
( )
( i − )
= R = min Q
n′∈ Ν m \ n n ′ m
( i) 1
mn
( )
= M 2 i m
, n = k
(9)
(2)