The apparatus includes a first SOVA decoder that generates a first path
reliability value from a channel value, a parity symbol and a first a
priori likelihood value. A first decorrelation unit generates a first
extrinsic symbol reliability value by decorrelating the channel value and
the first a priori likelihood value from the path reliability value. A
first symbol reliability saturation unit saturates the first extrinsic
symbol reliability value to generate a first saturated extrinsic symbol
reliability value. A first interleaver interleaves the first saturated
extrinsic symbol reliability value to generate a second a priori
likelihood value. A second interleaver interleaves the channel value to
generate an interleaved channel value. A second SOVA decoder generates a
second path reliability value from an interleaved parity symbol, the
second a priori likelihood value, and the interleaved channel value. A
second decorrelation unit generates a second extrinsic symbol reliability
value by decorrelating the interleaved channel value and the second a
priori likelihood value from the second path reliability value. A second
symbol reliability saturation unit saturates the second extrinsic symbol
reliability value to generate a second saturated extrinsic symbol
reliability value. A first de-interleaver de-interleaves the second
saturated extrinsic symbol reliability value to generate the first a
priori likelihood value. A second de-interleaver de-interleaves the second
extrinsic symbol reliability value to generate a decoded message.
Additionally, the path reliability value are saturated. Advantages include
simplified hardware implementations having improved BER characteristics
and faster convergence, requiring fewer decoding iterations to generate a
result.