Patent ID: 6707846
Filing Date: 2004-03-16
Classification: H04B

Abstract:
A radio communication apparatus which subjects each signal series which is described by I-Q orthogonal components and is received via a multi-path and demodulated, to a Hadamard transform at each of fingers, by use of an M-ary quadrature coding scheme, obtains correlation values of codes, combines correlation values output from fingers which obtain valid correlation values, and demodulates a received signal based on a maximum correlation value of combined correlation values, wherein:each finger includes a correlation energy detector so as to obtain the correlation values of the codes, a maximum value selector, and a gate section, said correlation energy detector detecting a magnitude of a correlation between a first signal series (Ii, Qi) described by I-Q orthogonal components and a predetermined second signal series (HJ) when carrying out a despreading in a code division multiple access (CDMA) system, and comprising: correlation computing means for computing correlation values (Iij, Qij) between the first signal series (I, Qi) and the predetermined second signal series (HJ), said first signal series (Ii, Qi) being a spread code; and root computing means for computing {{square root over ( )}(Iij2+Qij2)} as a root value of a sum of squares of the correlation values (Iij, Qij) obtained from the correlation computing means, said maximum value selector selectively outputting a largest {{square root over ( )}(Iij2+Qij2)} value computed by said root computing means belonging to the same finger as said maximum value selector, said gate section outputting the {{square root over ( )}(Iij2+Qij2)} values computed by said root computing means belonging to the same finger as said gate section when the largest {{square root over ( )}(Iij2+Qij2)} value exceeds a threshold value, for use in obtaining the combined values.