中文摘要：

该文提出了一种改进的MC-CDMA方案，该方案取发射的符号周期为切普周期的整数倍，允许各子载波经历多径衰落信道，消除了原方案对切普周期和符号周期的限制，并在接收端可对多径信号进行分离。推导出了在多径衰落信道下改进方案的误码率（BER）表达式，并通过计算机仿真进行了验证。与典型的MC-CDMA方案相比，改进的方案不但又获得了多径分集增益，还使系统的性能得到了显著的改善。

英文摘要：

In this paper, a reformed MC-CDMA scheme is proposed, which choose the symbol period transmitted multiple the chip period. This allows each subcarrier undergoes frequency selective fading channel and avoids the limitation on the chip rate and symbol rates of the former scheme, and furthermore it guarantees the multipath signals can be separated effectively. The Bit Error Rate （BER） expression is derived in a multipath fading channel, which is verified through simulations. Compared with the typical MC-CDMA scheme the BER performance of the proposed system is improved significantly because of the extra path gain.