中文摘要：

文中提出了一种新的多码多载波CDMA（MC-MC-CDMA）系统，并对此系统在频率选择性衰落信道的性能做了分析。相似于多载波调制，传输的高数据率数据首先进行串一并转换，再对变换后的低数据流用一组正交序列进行扩频调制，然后对各支路的扩频信号分别用L个正交的载波进行调制．MC-MC-CDMA系统中每个用户使用多个正交的码可以实现多数据率的传送并且在时域上进行扩时，满足下一代通信标准的要求．

英文摘要：

In this paper, a new multi-code multicarrier code division multiple access （MC-MC-CDMA） system is proposed and analyzed in a frequency selective fading channel. Similar to multicarrier modulation, the high rate input data to be transmitted is first serial-to-parallel converted, and the low rate data streams are spread-spectrum modulated by a set of orthogonal sequence, then they are transmitted by using L orthogonal carriers. By allowing each user to transmit multiple orthogonal codes, the proposed MC-MC-CDMA system can support various data rates, as required by next generation standards, and achieve spreading gain in the time domain.