A system and method are provided for non-causal channel equalization in a communications
system. The method comprises: receiving a non-return to zero (NRZ) data stream
input; establishing thresholds to distinguish a first bit estimate; comparing the
first bit estimate in the NRZ data stream to a second bit value received prior
to the first bit, and a third bit received subsequent to the first bit; in response
to the comparisons, determining the value of the first bit; tracking the NRZ data
stream inputs in response to sequential bit value combinations; maintaining long-term
averages of the tracked NRZ data stream inputs; adjusting the thresholds in response
to the long-term averages; and, offsetting the threshold adjustments to account
for the asymmetric noise distribution. Two methods are used to offset the threshold
adjustments to account for the asymmetric noise distribution: forward error correction
(FEC) decoding and tracking the ratio of bit values.