Patent ID: 7002901

Claim:
A method for assigning orthogonal codes used for a first system and a second system in a CDMA (Code Division Multiple Access) system including first system channels having first system signals for spreading with first orthogonal codes corresponding to a first set of orthogonal code numbers in different rows of a set of orthogonal codes arranged in a matrix of m rows and m columns, and second system channels having second system signals for spreading with second orthogonal codes corresponding to a second set of orthogonal code numbers different from said first set of orthogonal code numbers, comprising the steps of: assigning to the first system channels orthogonal codes, each being a Walsh code with a length of m chips, taking as a root at least one of 4-chip Walsh codes of W 0 4 =0000, W 1 4 =0101, W 2 4 =0011, and W 3 4 =0110; and assigning to the second system channels orthogonal codes, each being a Walsh code with a length shorter than m chips, taking as a root remaining 4-chip Walsh codes excepting the 4-chip Walsh codes assigned to the first system channels.