Fast linear feedback shift register engine
AssigneeAnalog Devices, Inc.
InventorWei An
Life of this patent
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Abstract
A method of generating a pseudo-noise sequence without masking a linear feedback shift register (LFSR) generator is provided. An offset pseudo-noise sequence is generated at a desired offset from a reference psuedo-noise sequence by determining a corresponding initial state vector of the LFSR based on an arbitrary mask.
Claims65
A method of generating an offset sequence for use as a pseudo-random number (PN) code in a wireless communication, the method comprising acts of:
- generating a reference sequence;
- determining an initial state vector based at least in part on a mask associated with a first offset from the reference sequence, the initial state vector operating initially as a current state vector;
- and
- generating the offset sequence beginning at the initial state vector, the offset sequence offset from the reference sequence by the first offset, wherein generating the offset sequence includes generating a plurality of bits of the offset sequence on each of a plurality of iterations, each of the plurality of iterations comprising acts of:
- providing i bits of the current state vector as a portion of the offset sequence, i having a value greater than 1;
- and
- computing a subsequent state vector advanced at least i states from the current state vector, the subsequent state vector operating as the current state vector for a next iteration of the plurality of iterations.
A computer readable medium encoded with instructions for execution on at least one processor, the instructions, when executed on the at least one processor, performing a method of generating an offset sequence for use as a pseudo-random number (PN) code in a wireless communication, the method comprising acts of:
- determining an initial state vector based at least in part on a mask associated with a first offset from the reference sequence, the initial state vector operating initially as a current state vector;
- and
- generating the offset sequence beginning at the initial state vector, the offset sequence offset from the reference sequence by the first offset, wherein generating the offset sequence includes generating a plurality of bits of the offset sequence on each of a plurality of iterations, each of the plurality of iterations comprising acts of:
- providing i bits of the current state vector as a first portion of the offset sequence, i having a value greater than 1;
- and
- computing a subsequent state vector advanced at least i states from the current state vector, the subsequent state vector operating as the current state vector for a next iteration of the plurality of iterations.
A computer readable medium encoded with instructions for execution on at least one processor, the instructions, when executed on the at least one processor, performing a method for use with a sequence generator having a plurality of states adapted to produce an offset sequence for use as a pseudo-random number (PN) code in a wireless communication, the method comprising acts of:
- receiving an input including a mask associated with a first offset of a reference sequence of the sequence generator;
- and
- determining a first state of the plurality of states based on the input, the first state operating initially as a current state of the sequence generator, wherein when the first state is applied to the sequence generator, the offset sequence at the first offset from the reference sequence is provided, and wherein a plurality of bits of the offset sequence are generated on each of a plurality of iterations, each of the plurality of iterations including:
- providing i bits of the current state of the sequence generator as a first portion of the offset sequence, i having a value greater than 1;
- and
- computing a next state of the sequence generator advanced at least i states from the current state, the next state operating as the current state of the sequence generator on a next iteration of the plurality of iterations.
A sequence generator implemented in software stored on at least one computer readable medium, the sequence generator configured to generate an offset sequence for use as a pseudo-random number (PN) code in a wireless communication, the sequence generator comprising:
- a first software component having a plurality of states, the first software component configured to generate a reference sequence and the offset sequence;
- and
- a second software component adapted to receive at least one mask associated with an offset from the reference sequence, the second software component configured to determine an initial state from the plurality of states based at least in part on the at least one mask, the initial state operating initially as a current state of the sequence generator, wherein when the first software component is operated from the initial state, the first software component generates the offset sequence offset from the reference sequence by the offset,
- wherein the first software component is adapted to simultaneously provide at least two bits of the current state associated with the reference sequence as a portion of the offset sequence on each of a plurality of iterations of the sequence generator, and wherein the second software component is further adapted to compute a next state advanced from the current state by at least two of the plurality of states on each of the plurality of iterations, the next state operating as the current state in a next iteration of the plurality of iterations.
Dependencies are inferred from the claim text.