【作者】 王小梅；

【导师】 郝久玉；

【作者基本信息】 天津大学 ， 通信与信息系统， 2006， 硕士

【摘要】 未来视频和多媒体业务日益增长的需求使得多载波调制成为第四代无线通信系统的关键技术。多载波调制大大提高了无线频谱利用率,具有广阔的发展空间。基于小波包变换的多载波调制(简称小波包调制)结合了多载波调制和小波包函数的特点,使得这种调制方式具有较高的频谱利用率和良好的抗衰落抗干扰的性能。本文内容一共分为两部分。第一部分主要集中于小波包调制通信系统的DSP实现。以往的国内外研究主要在小波包调制的算法研究。在这部分中,则提出了一个完整的小波包调制通信系统方案,介绍了基带部分各模块,给出了原理以及DSP实现算法。在软件开发环境CCS下,仿真了整个系统,并且在TMS320C6701 EVM板上进行了大量数据的传送接收,测试了整个系统的性能。结果表明,小波包调制通信系统可以达到理论上的研究性能。本文的另外一部分内容是关于小波包调制系统的符号同步的研究。首先总结了数字通信系统中定时恢复的估计算法、插值算法和插值控制方式,进而阐述了定时偏差对小波包调制系统的影响,仿真表明小波包调制比OFDM具有更优良的抗符号间干扰性能,并且比较了不同的小波包函数在定时偏差下的性能。最后讨论了一种面向判决的最大似然估计(MLDD)符号同步方法,结合MATLAB编程仿真了这种同步方法在小波包调制系统中的性能。理论分析和仿真结果表明,小波包调制作为一种较新的多载波调制方式,其独特的优势使其具备良好的发展前景和研究价值。更多还原

【Abstract】 Multi-carrier modulation has become an important technique with the increasing needs of high-quality video and multimedia services in 4G wireless mobile communication. It provides higher frequency efficiency and has potential prospect. Wavelet packet based multi-carrier modulation is a technique combining wavelet analysis theory and multi-carrier modulation perfectly. It provides high frequency efficiency, better immunity against inter-symbol interference and inter-carrier interference.In the first part , we mainly concentrate on the DSP implementation of wavelet packet based multi-carrier modulation communication system. Research at home and abroad mostly lies in algorithm . However ,this paper presents a whole system scheme. Principles and DSP implementation algorithm of the base-band function modules are explained . The system is simulated in CCS environment and BER is tested on the TMS320C6701 EVM board. The results indicate the system can reach theoretical performance.In the second part symbol synchronization of the system is studied. The estimate algorithm, interpolation algorithm and control methods are discussed. Then system performance under timing error effects is set forth. Simulation results show that the system has better immunity against inter-symbol interference than OFDM. At the same time we compare several different wavelet packet function under timing error effects. At last we present a Maximum Likelihood Decision-Directed symbol synchronization scheme and simulate it in the system.The theoretical analysis and simulation results indicate that wavelet packet based multi-carrier modulation has a promising prospect as a kind of new technique.更多还原