| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve signal transmission efficiency in a communication system utilizing the orthogonal frequency division multiplex-code division multiplex (OFDM-CDM) transmission system. <P>SOLUTION: A spread modulator 1 applies spread processing to a signal sequence. A sub-carrier modulator 2 uses an output of the spread modulator 1 to apply frequency modulation to a plurality of sub-carriers with different frequencies. An adder 3 compounds the modulated sub-carriers. A guard interval control section 23 determines a length of a guard interval depending on a maximum transmission delay difference of a path between a transmission apparatus and a receiving apparatus. A guard interval insert unit 21 inserts a guard interval to the signal sequence by each symbol period according to the control by the guard interval control section 23. A gain adjustment unit 22 multiplies a gain factor corresponding to the inserted guard interval with a transmission signal. <P>COPYRIGHT: (C)2010,JPO&INPIT |
