Patent ID: 7092457

Claim:
A system for estimating inputs and outputs of a digital transmission system, comprising: a receiver front-end configured to receive a digital signal in the digital transmission system as an observed digital signal; a forward recursion element adapted to receive the observed digital signal, and generate a first sequence of soft information by performing a forward recursion; at least one forward channel estimator adapted to receive the observed digital signal and said first sequence of soft information, said at least one forward channel estimator operating to estimate forward channel parameters using said first sequence of soft information; a backward recursion element adapted to receive the observed digital signal, and generate a second sequence of soft information by performing a backward recursion; at least one backward channel estimator adapted to receive the observed digital signal and said second sequence of soft information, said at least one backward channel estimator operating to estimate backward channel parameters using said second sequence of soft information; and a combiner configured to compute a transitional information that binds the forward channel parameter estimates with the backward channel parameter estimates, said combiner operating to generate soft information for the digital transmission system by combining said first and second sequences of soft information and said transitional information.