Patent ID: 7254160

Claim:
A radio receiver in a radio mobile communication system using a code division multiple access (CDMA) communication method, comprising: means for calculating a first correlation between a received signal and a plurality of Walsh codes, each Walsh code having a code length of “a”, where a Walsh code having a code length of “m” is expressed as the Kronecker product of a Walsh code having a code length of “a” and a Walsh code having a code length of “b”, and “a” and “b” satisfy log 2 m=log 2 a+log 2 b; means for determining a first Walsh code having a code length “a” based on results of absolute-value additions of the first correlations for all Walsh numbers of the Walsh codes; means for further calculating a second correlation between the first correlations that corresponds to a Walsh number of the first Walsh code and a plurality of Walsh codes having a code length of “b”, to determine a first Walsh code having a code length of “b,” and for determining a Walsh code having a code length of “m” based on the first Walsh code having a code length of “a” and the first Walsh code having a code length of “b”.