Patent ID: 7000175

Claim:
A method for processing a signal received from a dispersive channel using a reduced-state sequence estimation technique, said channel having a channel impulse response, said method comprising the steps of: precomputing intersymbol interference estimates based on a combination of (i) speculative partial intersymbol interference estimates for a first postcursor tap of said channel impulse response, wherein said speculative partial intersyinbol interference estimates are based on each possible value for a data symbol, and (ii) a combination of partial intersymbol interference estimates for each subsequent postcursor tap of said channel impulse response, wherein at least one of said partial intersymbol interference estimates for said subsequent postcursor taps is based on a first past decision from a corresponding state; precomputing branch metrics based on said precomputed intersymbol interference estimates; selecting one of said precomputed branch metrics based on a second past decision from a corresponding state; computing a new path metric for a path extension from a corresponding state based on said selected branch metrics; and determining a best survivor path into a state by selecting a path having a best new path metric among said corresponding computed new path metrics.