| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio transmission apparatus employing an OFDM-CDMA (orthogonal frequency division multiplex-code division multiple access) system and a CDMA system for making both of frequency utilization efficiency and an error rate characteristic compatible. <P>SOLUTION: In the OFDM-CDMA transmission apparatus, selecting sections B1-B5 select a multiplex number for each symbol. In adders C1-C5, spread signals of the number selected by the sections B1-B5 are multiplexed. In this way, since intercode interference in transmitting code division multiplexed signals can be selected for each symbol, the suitability of the error rate characteristic can be selected for each symbol. As the result, the error rate characteristic is improved without sharply reducing the frequency characteristic by reducing the multiplex number and selecting a symbol improving the error rate characteristic. <P>COPYRIGHT: (C)2004,JPO |
