METHOD FOR ITERATIVE AND NON-ITERATIVE DATA DETECTION USING REDUCED-STATE SOFT-INPUT/SOFT-OUTPUT ALGORITHMS FOR COMPLEXITY REDUCTION

摘要

A digital information processing including a model of a finite state machine (FSM) receiving a plurality of FSM inputs and producing a plurality of FSM outputs is represented by a reduced-state trellis and where the FSM inputs are defined on a base closed set of symbols (42, 44, 46, 48, 50, 52, 54, 56, 58). A method for updating soft decision information on the FSM inputs into higher confidence information by a) inputting the soft decision information into a first index set, b) a forward recursion is processed on the input soft decision information based on the reduced-state trellis representation to produce forward state metrics, c) a backward recursion is processed on the input soft decision information based on the reduced-state trellis representation to produce backward state metrics, and d) the forward metrics and the backward state metrics are operated on to produce the higher confidence information.