Equalization method with adjustable equalizer span

An equalization method, receiving a received sample to generate an equalizer output, comprising:

• providing a channel profile comprising a main path and a plurality of echoes distributed in time domain, wherein echoes anterior to the main path are precursors, and echoes posterior to the main path are postcursors;
• filtering the received sample with a linear equalizer (LE) comprising a plurality of taps to generate an LE output;
• slicing the equalizer output to generate a sliced sample;
• filtering the sliced sample with a decision feedback equalizer (DFE) comprising a plurality of taps to generate a DFE output;
• determining an equalizer span based on the channel profile;
• and
• combining the LE output and the DFE output to generate the equalizer output having the equalizer span;
• categorizing the echoes into a plurality of groups based on their path loss, with group distances of each group recorded;
• wherein a group distance represents distance between the main path and the farthest echo of a group;
• providing a lookup table storing the span factors of each group, applicable for the linear equalizer to reduce the echoes of each group to a predetermined level;
• consulting up the lookup table to obtain the span factors of each group;
• calculating tap requirements from multiplications of the span factors and corresponding group distances;
• and
• allocating an ith tap in the linear equalizer as a main tap based on the tap requirements;
• wherein the equalizer span consists of the former i linear equalizer taps and a total of DFE filter taps.