Patent ID: 7017104

Claim:
In a detector for detecting block codewords contained in a received signal, the detector including a metric calculator to calculate a branch metric for a branch emanating from a state in a trellis diagram, the metric calculator comprising: a first filter set to estimate intersymbol interference (ISI A ) based on previously block codewords and a channel impulse response and to subtract the estimated ISI A from a received symbol in a block codeword; a second filter set to estimate intersymbol interference (ISI B ) based on a surviving path in the trellis diagram and the channel impulse response and subtract the estimated ISI B from output of the first filter set; and a third filter set to estimate an intersymbol interference (ISI C ) and a received symbol candidate based on symbols associated with a branch and the channel impulse response and to subtract the estimated ISI C and the received symbol candidate from the output of the second filter set, and calculate a distance measurement between the received symbol and received symbol candidate and an estimated overall ISI in order to provide the branch metric.