[Article] Soft-input soft-output modules for the construction and distributed iterative decoding of code networks

Soft input soft output building blocks modules are presented to construct and iteratively decode in a distributed fashion code networks a new concept that includes and generalizes various forms of concatenated coding schemes Among the modules a central role is played by the SISO module and the underlying algorithm it consists of a four port device performing a processing of the sequences of two input probability distributions by constraining them to the code trellis structure The SISO and other soft input soft output modules are employed to con struct and decode a variety of code networks including turbo codes and serially concatenated codes with interleavers