【作者】 张岩；

【导师】 郝久玉；

【作者基本信息】 天津大学 ， 通信与信息系统， 2004， 硕士

【摘要】 无线移动通信技术为用户提供了良好的空间与时间灵活性。但同时,复杂的无线移动信道特性,有限的无线频谱资源,新业务的不断涌现等对无线传输技术提出了更高要求。调制技术作为无线传输技术的关键组成部分之一,其设计与选择也就具有非常重要的意义。第三代无线通信技术普遍采用的CDMA技术仍无法满足未来视频和多媒体业务的需求。由此第四代无线通信系统倾向于采用多载波调制技术来实现高速、宽带业务。本文的目的在于研究并实现一种新的调制技术——基于小波包变换的多载波调制技术。本文从小波/小波包理论出发,阐明了基于小波包变换的多载波调制技术的性能特点以及相对于OFDM系统的优势。继而详细介绍了了一种新型的、可实现快速算法的小波包调制方案,并给出理论分析,证明了方案的可行性。接下来,本文简要介绍了TMS320C6701结构及功能特性。在此基础上提出了基于小波包变换的多载波调制技术的软件实现方案及流程。并详细分析了实现过程中需注意的问题。同时,本文在综合考虑了算法的性能及效率的基础上,讨论了算法的优化及数据读取。最后在TI公司TMS320C6701 DSP EVM板上实现该算法和与该算法配合的信道编码。理论分析与实验结果表明,本文提出的快速小波包调制方案作为一种新的调制技术,在功能及性能方面基本能够完成实时调制及解调任务,在提高通信系统性能方面具有独特的优势和潜力,值得进一步研究与探讨。更多还原

【Abstract】 Wireless mobile communication provides a more efficient way of messagetransmission for moving subscribers, with flexibility in both time and space. However,the complex wireless channels and limited frequency spectrum source put forwardstricter requirement to the wireless transmission. The select and design of wirelessmodulation/demodulation plays an important role in bettering wireless mobilecommunication performances. CDMA, widely employed in the third generationwireless communication system, however, could not meet the increasing needs ofhigh-quality video and multimedia services. The forth generation prefers to usingmulticarrier modulation technique in order to provide the wide-band, high-speed rateservices. As a result, multicarrier modulation technique became a hotspot in theseyears.The purpose of this paper lies on researching a new modulation technique—WPT-MCM (Wavelet Packet Transform-based MultiCarrier Modulation). First of all,based on the wavelet/wavelet packet theory, the performance and the superiority over theOFDM are presented. At the same time, a new modulation approach, which can beimplemented by fast algorithm, is discussed and analyzed. This paper also proves thepossibility of this new method.Then the structural and the functional features of TMS320C6701 are presentedin detail. Based on it, the software approach and the procedure of WPT-MCM areprovided. Meanwhile, some main techniques in the software design are discussed.After that, under the consideration of the tradeoffs between processing speedand system performance, optimized solutions of some parts are provided. At last,algorithm and some channel coding are implemented on TI’s TMS320C6701 EVM.The analysis of the experiment results indicates that the softwareimplementation scheme of this system is qualified to accomplish the task ofWPT-MCM. It also proves the WPT-MCM has unique advantage and great potentialand worth of further researching.更多还原