| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable even a multirate user to have high transmission quality by selecting one of row vectors in a matrix having a different number of dimensions as a spread series according to the peak of the transmission rate of transmit data. SOLUTION: Transmit data of each user are modulated by a data modulator 1 to generate a narrow-band modulated signal. Spread modulation on the modulated signal is performed with a short-cycle spread series selected by a short- cycle spread series generating circuit 2 to obtain a broadband signal, which is added by an adder 3; and the resulting signal is spread with a long-cycle spread series which is generated by a long-cycle spread series generating circuit 4 and has longer cycles than the short-cycle spread series generated, and outputted. In this case, when the spread series is selected, a matrix having a small number of dimensions is used according to a certain rule to generate matrixes of large degree (2N×2N elements, N integer equal to or larger than 1) having mutually orthogonal row vectors in sequence, and one of row vectors of the matrixes differing in the number of dimensions is selected as a spread series according to the peak of the transmission rate of transmit data.</p> |
