混沌和小波包变换应用于多载波码分多址系统研究

In this project, we proposed a new multicarrier(MC) CDMA(code division multiple access)system based on wavelet packet transform(WPT) and give idea of the diversity reception in wavelet packet subspaces. We looked into the performance of the proposed system in the multipath environment and have found that the nature of support in time domain and localization in frequency domain of the wavelet packet function makes the system superior to conventional DFT based syetem. The computer simulation shows that the WPT-CDMA symtem outperforms the.DFTbased MC-CDMA syetemin the channel specified by GSM TU6. In the meantime the.diversity reception with equal combining of different wavelet packet subspace can improve the performance of the proposed remarkably.In this project, Reed-Muller coding scheme is also implemented to reduce the PAPR(Peak Average Power Ratio). Theoretical analysis and simulation result indicate that PAPR can belimited within 3~4dB, certain coding gain can also be achieved as well.

课题拟针对第四代移动通信信道，提出一种基于小波包变换和混沌序列扩谱的宽带多载波CDMA空中接口方案，用小波包变换实现多载波调制，用混沌序列作为扩谱序列，并对宽带移动信道模型、信号波形成形、子信道功率谱的平滑、信道的非线性畸变进行研究。课题将分析所提的性能，并提出相应的分集接收技术和抗MAI技术