Patent ID: 8090003

Claim:
An apparatus for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses (N−1) data channels (N is an integer larger than two) and a control channel, the apparatus comprising: a channel coding unit that encodes the source data to generate (N−1) data parts and a control part, wherein the data parts are allocated to the data channels and the control part is allocated to the control channel; a code generator that generates spreading codes to be allocated to the channels, wherein each of the spreading codes is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on the same point or symmetrical with respect to a zero point on a phase domain; and a spreader that spreads the control part and the data part by using the spreading codes to thereby generate the channel-modulated signal, wherein: the spreading codes correspond to an orthogonal variable spreading factor (OVSF) code, the spreading code allocated to the control channel is represented by C 256,0 , where 256 denotes the spreading factor and 0 the code number, the spreading codes allocated to first and second data channels are represented by C 4, 1 ={1, 1, −1, −1}, when there are more than two data channels, the spreading codes allocated to a third data channel and, when present, a fourth data channel are represented by C 4, 3 ={1, −1, −1, 1}, and when there are more than four data channels, the spreading codes allocated to a fifth data channel and, when present, a sixth data channel are represented by C 4, 2 ={1, −1, 1, −1}.