Patent ID: 7299398
Filing Date: 2007-11-20
Classification: H03M

Abstract:
1. A method to determine a value of a V-bit variable field so that a CRC value calculated based on a data field including the variable field according to a generator polynomial is equal to a desired CRC value, comprising the steps of: establishing a temporary variable field value; reading from a conversion table all corrective values which correspond to a bit number where a bit value of said temporary variable field value is 1, and exclusive-ORing the read corrective values to calculate a first calculated value, wherein each said corrective value in the conversion table corresponds to a given bit number in the variable field, each said corrective value identifying those bits in the CRC calculated based on the data field whose value is changed when a single bit in the given bit number in the variable field is changed; and determining, when said first calculated value corresponds to the desired CRC value, said temporary variable field value to be a variable field value for obtaining the desired CRC value.