基于小波包变换的多载波调制系统性能分析
发布时间：2018-07-31 11:07
【摘要】：小波包多载波调制系统(WPDM),就是小波包变换应用于多载波调制系统而产生的一种新的多载波调制技术。具有时频域都正交特点的小波包函数结合具有内在的抗多径衰落优点的多载波调制技术,使得WPDM系统具有频率利用率高和良好的抗衰落、抗干扰,以及易于实现多速率传输的特点,相比于传统的OFDM系统有一定的优势。本文的主要目的在于WPDM系统的最优小波基的选择,分析了不同系的小波的时频特性,根据最优小波的选取原则,以及仿真结果的验证,选取出最适合本文WPDM系统的小波基。同时结合小波分析在信号去噪方面的应用,对基于小波去噪的信道估计算法进行了仿真研究,重点分析了小波去噪阈值选择和小波去噪小波基的选择对信道估计性能的影响,通过对比小波去噪信道估计和常见的几种信道估计算法,体现出小波去噪信道估计的优越性。最后通过MATLAB实现信道建模与仿真,分析比较WPDM系统和OFDM系统的多方面性能。通过理论分析和实验结果可知,综合各方面因素,通过选用Db4作为最优小波基可以使WPDM系统的性能能够改善明显,而且能够使用等效滤波器算法实现。信道估计算法方面,基于小波去噪的信道估计算法不仅减少了运算量,也大大的提高了系统的性能,是一种有效的信道估计算法。
[Abstract]:Wavelet packet multicarrier modulation system (WPDM),) is a new multicarrier modulation technique which is generated by wavelet packet transform applied to multi-carrier modulation system. The wavelet packet function with orthogonal time-frequency domain combined with the multi-carrier modulation technology which has the inherent advantages of anti-multipath fading makes the WPDM system with high frequency utilization and good anti-fading and anti-interference. Compared with the traditional OFDM system, it has some advantages. The main purpose of this paper is to select the optimal wavelet basis of WPDM system. The time-frequency characteristics of different wavelets are analyzed. According to the principle of optimal wavelet selection and the verification of simulation results, the wavelet bases that are most suitable for this WPDM system are selected. At the same time, combining the application of wavelet analysis in signal denoising, the channel estimation algorithm based on wavelet denoising is simulated, and the influence of wavelet denoising threshold selection and wavelet base selection on channel estimation performance is analyzed. By comparing wavelet denoising channel estimation with some common channel estimation algorithms, the superiority of wavelet de-noising channel estimation is demonstrated. Finally, channel modeling and simulation are realized by MATLAB, and the performance of WPDM system and OFDM system is analyzed and compared. The theoretical analysis and experimental results show that the performance of WPDM system can be improved obviously by using Db4 as the optimal wavelet basis, and the equivalent filter algorithm can be used to realize it. In the aspect of channel estimation algorithm, the channel estimation algorithm based on wavelet denoising not only reduces the computation, but also greatly improves the performance of the system. It is an effective channel estimation algorithm.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761
本文编号：2155393
[Abstract]:Wavelet packet multicarrier modulation system (WPDM),) is a new multicarrier modulation technique which is generated by wavelet packet transform applied to multi-carrier modulation system. The wavelet packet function with orthogonal time-frequency domain combined with the multi-carrier modulation technology which has the inherent advantages of anti-multipath fading makes the WPDM system with high frequency utilization and good anti-fading and anti-interference. Compared with the traditional OFDM system, it has some advantages. The main purpose of this paper is to select the optimal wavelet basis of WPDM system. The time-frequency characteristics of different wavelets are analyzed. According to the principle of optimal wavelet selection and the verification of simulation results, the wavelet bases that are most suitable for this WPDM system are selected. At the same time, combining the application of wavelet analysis in signal denoising, the channel estimation algorithm based on wavelet denoising is simulated, and the influence of wavelet denoising threshold selection and wavelet base selection on channel estimation performance is analyzed. By comparing wavelet denoising channel estimation with some common channel estimation algorithms, the superiority of wavelet de-noising channel estimation is demonstrated. Finally, channel modeling and simulation are realized by MATLAB, and the performance of WPDM system and OFDM system is analyzed and compared. The theoretical analysis and experimental results show that the performance of WPDM system can be improved obviously by using Db4 as the optimal wavelet basis, and the equivalent filter algorithm can be used to realize it. In the aspect of channel estimation algorithm, the channel estimation algorithm based on wavelet denoising not only reduces the computation, but also greatly improves the performance of the system. It is an effective channel estimation algorithm.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761
【参考文献】
相关期刊论文 前2条
1 郝久玉;王小梅;齐振豪;李惠敏;;小波包多载波调制算法及DSP实现[J];天津大学学报;2006年03期
2 杨慰民,毕光国;基于小波包变换的多址通信[J];通信学报;1999年03期
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