Decision feedback equalizer with fractional tap unrolling

• Main Authors: Qian, Haoli, Sun, Junqing (Phil), Cai, Fang, Luo, Tianchen
• Format: Patent
• Language: English
• Published: 21.09.2021
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Decision feedback equalizers and equalization methods may employ fractional tap unrolling and/or probability-based decision threshold placement. One illustrative fractional tap unrolling equalization method embodiment includes: tracking preceding symbol decisions; converting an equalized signal into tentative symbol decisions with a precompensation unit; and selecting from the tentative symbol decisions based on the preceding symbol decisions. The precompensation unit has a decision element for each combination of a first number of speculative preceding symbols, with comparators in each decision element using a first type of symbol decision threshold that accounts for trailing intersymbol interference from the corresponding combination, and with an additional comparator in at least one of the decision elements using a second type of symbol decision threshold that accounts for trailing intersymbol interference from a second number of speculative preceding symbols, the second number being greater than the first.