Method and System For Cyclic Redundancy Check
AssigneeResearch In Motion Limited
InventorMartin Kosakowski
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Abstract
The present disclosure describes a method, performed by a data processor comprising a cyclic redundancy check (CRC) module configured for calculating CRC remainders for encoded data and a comparator comprising a shift register, for making a cyclic redundancy check of an encoded data record of bit length L, in which at least A bits of the record represent content data and at least B bits represent check data. A system for performing a cyclic redundancy check is also described.
Claims5
A method, performed by a data processor comprising a cyclic redundancy check (CRC) module configured for calculating CRC remainders for encoded data and a comparator comprising a shift register, for making a cyclic redundancy check of an encoded data record of bit length L, in which at least A bits of the record represent content data and at least B bits represent check data, the method comprising:
- over A clock cycles, using the CRC module to calculate a CRC remainder for the A content bits of the data record;
- during the same A clock cycles, comparing the calculated CRC remainder to the B bits of check data using a shift register;
- determining, using the comparison of the calculated CRC remainder and the B bits of check data, whether the A bits of content data are corrupt;
- if the A bits of content data are determined to be corrupt, preparing a command signal to request resending of the data record.
A system for processing electromagnetic signals representing convolutionally encoded data streams, the system comprising:
- a survivor memory unit configured to provide output signals representing convolutionally decoded data records of bit length L;
- a cyclic redundancy check module configured to make cyclic redundancy checks of the first A bits of a decoded data record;
- a comparator to compare the outputs of the cyclic redundancy check module and final B bits of the decoded data record provided by the survivor memory unit.
Dependencies are inferred from the claim text.