US 8,291,284 B2 · Method and device for decoding LDPC codes and communication apparatus including such device

Abstract

A device and method for the iterative decoding of a received word represented by signal values according to a parity control matrix code of the type for passing messages between variable nodes and control nodes of a two-part graph related to the matrix. The method includes at least the following steps: setting up at least one message of a variable node, according to the values, by an information representative of the ratio between the probability of having the most likely symbol at a position corresponding to the variable node and the probability of having the current symbol at the position; determining at least one message, relating to a determined symbol, of a control node to a determined variable node, as the selected minimal value, among the symbol sequences corresponding to the control node equation using the determined symbol at the determined variable node, by the maximal value of the messages received at the control node from variable nodes different from the determined variable node and each relating to the symbol associated with the different variable node in the sequence corresponding to the equation; and determining the messages of a variable node to a control node that relate to the whole set of symbols so that the minimal value of said messages is equal to zero.

Claims17

Dependent claims

A method of iterative decoding of a received word, represented by values of a signal, according to a parity check matrix code, of the type using passage of messages between variable nodes and control nodes of a bipartite graph associated with the matrix, the method comprising at least one of the following steps:

initializing at least one message from a variable node, as a function of the values, by information representing the ratio between the probability of having the most probable symbol at the position corresponding to the variable node and the probability of having the current symbol at the position;
determining at least one message, relating to a particular symbol a, from a control node m to a particular variable node n, as the minimum value taken, among the sequences of symbols ak satisfying an equation
(
⊕
k
=
1
d
⁢
h
m
,
n
k
⊗
a
k
)
⊕
(
h
m
,
n
⊗
a
)
=
0
where hm,nk is the element at line m and column nk of the parity matriz, hm,n is the element at line m and column n of the parity matrix and nk defines variable nodes, other than particular variable node n, by the maximal value of the messages received at the control node m from variable nodes nk other than the particular variable node n and each relating to the symbol ak associated with the other variable node in the sequence satisfying the equation;
or
determining the messages from a variable node to a control node which relate to all the symbols so that the minimal value of the messages is null.

29 more elements

A device for iterative decoding of a received word, represented by values of a signal, according to a parity check matrix code, of the type using passage of messages between variable nodes and control nodes of a bipartite graph associated with the matrix, the device comprising at least one of:

means for initializing at least one message from a variable node, as a function of the values, by information representing the ratio between the probability of having the most probable symbol at the position corresponding to the variable node and the probability of having the current symbol at said position;
means for determining at least one message, relating to a particular symbol a, from a control node m to a particular variable node n, as the minimum value taken, among the sequences of symbols ak satisfying an equation
(
⊕
k
=
1
d
⁢
h
m
,
n
k
⊗
a
k
)
⊕
(
h
m
,
n
⊗
a
)
=
0
where hm,nk is the element at line m and column nk of the parity matriz, hm,n is the element at line m and column n of the parity matrix and nk defines variable nodes, other than particular variable node n, by the maximal value of the messages received at the control node m from variable nodes nk other than the particular variable node n and each relating to the symbol ak associated with the other variable node nk in the sequence satisfying the equation;
or
means for determining the messages from a variable node to a control node which relate to the set of symbols so that the minimal value of the messages is null.

29 more elements

Dependencies are inferred from the claim text.

Method and device for decoding LDPC codes and communication apparatus including such device

Life of this patent

Method and device for decoding LDPC codes and communication apparatus including such device

Life of this patent

Abstract

Claims17