| 摘要 |
PROBLEM TO BE SOLVED: To allow the same user to more efficiently send various service and media data and digital signal different in transmission conditions through plural channels at the same frequency band. SOLUTION: The modulation multi-level numbers of a data multi-value modulator 115 and a spread spectral multi-value modulator 117 are changed for every plural channels through which multiplexed data are transmitted by the same user receptively in transmission sections (A) 110a, (B) 110b in accordance with the transmission condition of transmission data. Then reception sections (A) 210a, (B) 210b identify the modulation multi-level number of the received data and the modulation multi-level number of a data multi-level demodulator 212 and an inverse spread spectral multi-level demodulator 216 is individually changed for every plural channels through which multiplexed data are transmitted from the same user. |
