软件无线电中几项DSP实现技术的研究

【作者】 黎照明；

【导师】 李晓峰；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2001， 硕士

【摘要】 软件无线电作为一种新的无线通信概念和体制近年来浮出水面，日益受到国内外相关通信厂商的重视。它使得通信体制具有很好的通用性、灵活性和可配置性，并使系统互联和升级变得容易。虽然，真正意义上应用软件无线电技术的“全球统一”终端的出现还会有一段时日，但软件无线电思想对传统通信体制和结构的影响却是不言而喻的。本文首先论述了软件无线电的概念和关键技术；然后，针对它在第三代移动通信WCDMA系统中基带信号处理部分的应用，文章讨论了相关的调制解调、信道编码、滤波器设计和语音编码等技术，强调了软件无线电思想在这些技术中与DSP编程的结合运用；最后，论文以一个电力载波专用Modem的软件实现为例，说明了软件无线电的通用和灵活配置性在有线通信领域中的应用。 论文各部分内容的安排为：第一章是绪论；第二章综述软件无线电的概念；第三章介绍了移动通信系统中相关的调制和信道编码技术，其中Turbo码是最近提出来的一种接近Shannon性能限的信道编码；考虑到成形滤波器在无码间干扰数据通信中的重要作用，我们在第四章里详细论述了根升余弦FIR滤波器的设计，并给出了满足3GPP要求的实验结果；第五章则集中介绍了AMR声码器中VAD（语音激活检测）算法的原理与实现；第六章里我们谈了一个电力载波专用Modem软件实现的例子，借以表明在有线通信领域，软件无线电的思想也有其应用的场所。在附录中，我们列举了一些相关的实验和仿真图表，以备参考。更多还原

【Abstract】 Software radio has emerged from obscurity to be heralded by some in the personal communications and other related industries as offering a potential solution to man抯 historical inability to achieve common global standards. It introduces the generality, flexibility and reconfigurability into the radio communication systems, and will make the interoperation among different systems better and help to easily upgrade the system. Although the advent of the true software-reconfigurable 搖niversal handset?may lie beyond the launch date of third-generation systems, the concepts of software radio will have profound impact on both technologies and industrial structures. This thesis first offers its concept and key techniques. As an important facet of its today implementation, the paper then illustrates some applications on base-band processing in WCDMA mobile communication systems (3GPP). These include modulation-demodulation, channel coding, filter designing and speech codec, etc. Finally, a software modem design and implementation are selected as an example. The aim is to extend software radio抯 idea in other communication fields. Chapters are arranged as following: Chapter 1 demonstrates system-level views and describes the whole framework of this paper. Chapter 2 discusses software radio抯 background, concepts, key techniques and potential applications. Chapter 3 provides implementation schemes of GMSK, QPSK modem and Turbo code. Turbo code, which has novel structures and amazing performance, ~vas believed to be mostly close to Shannon抯 Coding Theory. Data transmission over bandlimited channels requires pulse shaping to eliminate or control intersymbol interference (ISI). A shaping filter is needed, which fits Nyquist rule and can provide ISJ-free transmission. In Chapter 4, we discuss the design methods for this kind of filter in WCDMA applications and present our experiment results. VAD (Voice Activity Detection) is an important characteristic introduced by speech codec of mobile communications. Chapter 5 provides a design and implementation plan of VAD algorithm (AMR speech codec) in WCDMA systems. In fact, software radio抯 idea of flexibility and reconfigurability could also be introduced into other communication fields. Chapter 6 provides a further-explaining example, a special modem for Electric Power transmission. Appendices, which enumerate related experiment graphs and tables, provide some details for those interested in solving practical soft~vare radio-application problems in base-band signal processing using DSPs.更多还原