Cyclic position codes
AssigneeSilverbrook Research Pty Ltd
InventorsPaul Lapstun, Kia Silverbrook
Life of this patent
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Abstract
A method of determining an offset, modulo n, of at least one point with respect to a sequence 50 of at least n symbols, the sequence consisting of a repeating codeword of a cyclic position code, the cyclic position code having length n and minimum distance dmin, the method including: obtaining, from the sequence 50 and at a position corresponding to the at least one point, a subsequence 52 of length w symbols, where w≧n−dmin+1; mapping the subsequence 52 to a codeword 58 of the cyclic position code most likely to match the subsequence in the presence of symbol errors 60, 62 in the subsequence; and determining an offset 54, in the sequence 50, of the codeword 58 thus obtained, and thereby determining the offset of the at least one point.
Claims44
A method of determining a first offset, modulo n, of at least one point with respect to a first sequence of at least n symbols, the first sequence consisting of a repeating first codeword of a first cyclic position code, the first cyclic position code having length n and minimum distance dmin, the method including:
- obtaining, from the first sequence and at a position corresponding to the at least one point, a first subsequence of length w symbols, wherein w≧n−dmin+1;
- mapping the first subsequence to a codeword of the first cyclic position code;
- and
- determining an offset, in the first sequence, of the codeword thus obtained, and thereby determining the first offset.
A method of determining a first coordinate value of at least one point with respect to a plurality of first sequences, each of the first sequences consisting of a repeating first codeword of a first cyclic position code, the first cyclic position code having length n1 and minimum distance, dmin 1 the method including:
- obtaining, from each of h1 the first sequences and at a position corresponding to the at least one point, a respective first subsequence of length w1 symbols, where h1≧2 and w1≧n1−dmin1;
- mapping each of the first subsequences to a respective codeword of the first cyclic position code;
- determining an offset, in the corresponding first sequence, of each codeword thus obtained, and thereby determining a respective one of a plurality of first offsets of the at least one point;
- deriving, for each of h1−1 pairs of the first sequences, a difference between the corresponding pair of first offsets, and thereby deriving a respective one of a plurality of first differences;
- and
- deriving, from the plurality of first differences, the first coordinate value.
A method of determining a first offset of at least one point with respect to a first sequence of at least n symbols, the first sequence consisting of a repeating first codeword of a first cyclic position code, the first cyclic position code having length n, the method substantially as herein described with reference to the drawings.
Dependencies are inferred from the claim text.