System and method for descrambling data
AssigneeFreescale Semiconductor, Inc.
InventorsSACHIN KUMAR GOLECHHA, Devesh Kunwar
Life of this patent
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Abstract
A method and system for negating a series of packed data bytes simultaneously based on conditional flags is used to descramble the data, as opposed to negating each byte with respect to each conditional flag bit. Sets of scrambled binary values are received. A descrambling code that corresponds to a flag bit sequence used to scramble the sets of binary values is generated. Then the sets of scrambled binary values are descrambled using the descrambling code. The method is particularly suitable for use in a wireless base band receiver.
Claims19
A method for descrambling data, wherein the data includes one or more sets of scrambled binary values, the method comprising:
- receiving a first predetermined number of sets of scrambled binary values that were scrambled using a predefined flag bit sequence;
- generating at least one descrambling code by repeating each bit of the predefined flag bit sequence for a second predetermined number that is equal to the bit length of a set of the scrambled binary values;
- and
- calculating a first predetermined number of sets of descrambled binary values corresponding to the first predetermined number of sets of scrambled binary values using the at least one descrambling code and a predefined value, wherein the predefined value is calculated using the first predetermined number and the bit length of a set of scrambled binary values.
A method for descrambling one or more sets of scrambled binary values using a lookup table, the lookup table comprising a plurality of descrambling codes and a plurality of binary combinations, the method comprising:
- receiving a first predetermined number of sets of scrambled binary values to be descrambled simultaneously, wherein the first predetermined number of sets of scrambled binary values are scrambled using a predefined flag bit sequence;
- accessing at least one descrambling code from the lookup table corresponding to a binary combination, wherein the binary combination is identical to the predefined flag bit sequence;
- and
- calculating the first predetermined number of sets of descrambled binary values corresponding to the first predetermined number of sets of scrambled binary values by using the at least one descrambling code and a predefined value, wherein the predefined value is calculated using the first predetermined number and the bit length of a set of scrambled binary values.
A method for descrambling one or more sets of scrambled binary values using a lookup table, the lookup table comprising a plurality of descrambling codes and a plurality of binary combinations, comprising:
- receiving a first predetermined number of sets of scrambled binary values to be descrambled simultaneously, wherein the first predetermined number of sets of scrambled binary values are scrambled using a predefined flag bit sequence;
- accessing at least one descrambling code from the lookup table corresponding to a binary combination, wherein the binary combination is identical to the predefined flag bit sequence;
- calculating a first intermediate value by performing a bitwise logical AND operation on the at least one descrambling code and a predefined value, wherein the predefined value is calculated using the first predetermined number and the bit length of a set of scrambled binary values;
- calculating a second intermediate value by performing a bitwise logical XOR operation on the first predetermined number of sets of scrambled binary values and the at least one descrambling code;
- and
- adding the first intermediate value to the second intermediate value to obtain the first predetermined number of sets of descrambled binary values corresponding to the first predetermined number of sets of scrambled binary values.
Dependencies are inferred from the claim text.