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US 12,009,919 B2Granted
Error-tolerant forward error correction ordered set message decoder
AssigneeKandou Labs, S.A.
InventorsFilippo Borlenghi, David Stauffer
Life of this patent
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Abstract
Methods are described for identifying and acting upon predetermined message patterns during reception of a data stream structured as USB message frames. A first embodiment performs pattern matching between received message bits and one or more predetermined sequences, identifying unscrambled ordered set messages. A second embodiment applies a descrambling operation and performs comparable pattern matching between descrambled received message bits and one or more additional predetermined sequences, identifying scrambled ordered set messages.
Claims20
A method comprising:
- receiving a data frame including a set of super symbols, a set of sync bits and a received forward error correction (FEC) parity word and calculating a local FEC parity word based on the received frame;
- identifying an unscrambled ordered set (UOS) candidate in the set of super symbols by comparing portions of each super symbol to corresponding portions of one or more known UOS values;
- responsive to the identification of the UOS candidate, halting advancement of a descrambler operation for a predetermined number of bit intervals associated with a length of the super symbol;
- comparing the received FEC parity word to the local FEC parity word and determining at least one bit error occurred in the data frame, and responsively determining the UOS candidate is a true UOS;
- and
- descrambling scrambled super symbols received in a subsequent data frame to identify scrambled ordered sets.
3 more elements
A method comprising:
- receiving a sequence of data frames, each data frame including a set of super symbols, a set of sync bits and a received forward error correction (FEC) parity word, and calculating a local FEC parity word based on the received frame;
- identifying unscrambled ordered set (UOS) candidates in the set of super symbols by comparing portions of each super symbol to corresponding portions of one or more known UOS values;
- comparing the local FEC parity word to the received FEC parity word to determine a successful FEC comparison indicating no bit errors are present in the data frame or a failed FEC comparison indicating at least one bit error is present in the data frame;
- responsive to the identification of a UOS candidate in each data frame of the sequence of data frames, halting advancement of a descrambler operation for a length of a super symbol;
- determining whether the UOS candidate in each data frame is a true UOS or a false UOS, wherein:
- a true UOS is determined responsive to (i) the successful FEC comparison and a corresponding sync bit in the set of sync bits is asserted, or (ii) the failed FEC comparison;
- and
- a false UOS corresponds to (i) the successful FEC comparison and a corresponding sync bit in the set of sync bits is de-asserted;
- and
- advancing the descrambling operation responsive to identification of each false UOS.
7 more elements
Dependencies are inferred from the claim text.