Patent ID: 6377539
Filing Date: 2002-04-23
Classification: H04J

Abstract:
A method for generating quasi-orthogonal codes of length 22m in a mobile communication system using Walsh codes and said quasi-orthogonal codes, comprising the steps of:generating an m-sequence of length 22m where length 22m is determined for a variable m selected from the group of numbers (1, 2, 3, . . . ) and selecting sub-sequences having a period of 2mâˆ’1 by selecting elements at intervals of 2m+1; generating a sequence of length 22m by adding â€œ0â€  at the first position of the sequence of length 22mâˆ’1; generating 2mâˆ’1 sequences by connecting said sub-sequences, and column-permuting said generated sequences by a column permutation function; adding said Walsh codes to said column-permuted sequences to generate quasi-orthogonal candidate sequences having a full correlation value between said Walsh codes and other quasi-orthogonal codes that is smaller than a lowest full correlation value threshold; and selecting, from said quasi-orthogonal candidate sequences, quasi-orthogonal codes having a partial correlation value with said Walsh codes that satisfies said partial correlation value at a variable data rate.