基于DFT-SV-OFDM的自适应多速率DFT加扰矢量码分多址系统研究

摘要

Multipath interference would degrade the performance of multi-rate systems based on OFDM and CDMA, which spectrum efficiency was also lower relatively. To improve the performance and spectrum efficiency, a novel adap-tive multi-rate DFT scrambling vector multi-carrier CDMA (AMR-DFT-VMC-CDMA) was proposed based on the theory of matrix permutation and r-cyclical matrix decomposition characteristics. Meanwhile, by theoretical analysis, the para-meters of the system could be adaptively adjusted to ensure frame length long enough to break the restriction between channel bit error rate and data frame length on a certain channel utilization condition. The simulation results show that compared with the traditional multi-rate, multi-subcarrier and spreading system, the new system could achieve multi-rate and multi-user information transmission flexibly with better performance and better spectrum efficiency in fading chan-nels. Moreover, it can satisfy the requirement of frame length under certain channel utilization by adjusting the parame-ters.%为解决多速率多载波扩频多址系统存在的信道衰落条件下性能下降以及频谱效率相对较低的问题,利用矩阵置换原理和r循环信道矩阵的分解特性,提出一种自适应多速率DFT加扰矢量多载波码分多址接入(AMR-DFT-VMC-CDMA)系统模型.在理论分析的基础上,综合考虑一定信道利用率条件下,信道误码率与发送信号帧长的相互制约关系,提出自适应参数调整算法以确保足够长的传输帧长.仿真结果表明,该系统在衰落信道下相比传统的多速率多载波扩频系统具有更好的性能,且通过调整参数,既满足了一定信道利用率下对帧长的要求,保证了频谱效率提高,又可以灵活完成多速率多用户的信息传输.