Joint viterbi decoder and decision feedback equalizer

A method for use in a Viterbi decoder for decoding a stream of signal points corrupted by intersymbol interference, the method comprising the steps of

• a) generating in response to each received signal point a plurality of equalized signal points, each equalized signal point being generated as a function of a respective estimate of the intersymbol interference component of said each received signal point, each estimate being a function of a respective present surviving path of said Viterbi decoder,
• b) generating updated surviving paths for said Viterbi decoder as a function of the set of equalized signal points, and
• c) forming a decision as to a particular one of the signal points of said stream as a function at least of a particular one of the updated surviving paths,
• a first plurality of said signal points having been generated using a particular trellis code and a second plurality of said signal points having been generated elsewise.

A method for decoding a stream of signal points, a first plurality of said signal points having been generated using a predetermined trellis code defined by a state transition diagram, a second plurality of said signal points having been generated not using said predetermined code, said method comprising the steps of

• maintaining a path metric associated with each of a plurality of surviving paths through the code trellis, each of said surviving paths terminating on a respective state of the code,
• responsive to a received one of said signal points, generating an updated path metric for each of a plurality of candidate paths, each candidate path comprising a respective one of the surviving paths extended from the respective terminating state a) along a branch of said state transition diagram, if said received signal point is one of said first plurality signal point, or b) to that same state, if said received signal point is one of said second plurality signal points,
• identifying new surviving paths from the candidate paths as a function of the updated path metrics, and
• forming a decision as to the value of a previously received one of said signal points as a function of at least one of said new surviving paths.