Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2005-09-30
2010-02-23
Chaudry, M. Mujtaba K (Department: 2112)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S794000, C714S792000, C375S341000
Reexamination Certificate
active
07669110
ABSTRACT:
Methods and apparatus are provided for determining survivor paths in a Viterbi detector, using a trace-ahead algorithm. A trellis memory is maintained having a depth L that stores L trellis stages, each of the L stages having a plurality, N, of trellis states; and a status memory is maintained for each of the N states of the trellis, wherein each entry in the status memory identifies a least recent trellis state stored in the trellis memory of a survivor path that begins at a given state on a side of the trellis associated with most recent states. A bit sequence of one or more of the survivor paths in the trellis is determined in an order that the bits are received by examining least and most recent trellis stages of the trellis and the status memory. One or fork memories maintain an indicator of whether a given fork is active; a list of active forks; a trellis position of active forks in the trellis; and a fork type of one or more forks in the trellis.
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Agere Systems Inc.
Ahmed Enam
Chaudry M. Mujtaba K
Ryan & Mason & Lewis, LLP
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