Software Radio Theory And Application In Digital Microwave Transceiver

The term "Software Radio" stands for "radio functionalities defined by software", it refers to configurate an opened, modularized, standardized and reused hardware platform, realize almost all of the functions of transceiver by software such as working frequency, modulation and demodulation, data format, encryption and decryption, communication protocol and so on, and use over-the-air (OTA) download. The software radio communication system is based on modern communication theory, digital signal processing and micro-electronics technologies.Compared the software radio to the old radio communication system, most of the function should be realized by digital and software, so we face new technical challenges not only on micro-electronics technology but also on radio communication system architecture theory and digital signal processing technologies. Therefore, software radio is mainly studied on three aspects: 1) Radio Communication System Architecture Theory—the ideal software radio cannot be realized with present technique advancement, the realized structure is studied which has high performance, low power, high-integration, and satisfy as much requirement of software radio as possible; 2) Digital Signal Processing Theory—software radio is one kind of digital signal processing system, which greatly expand the areas of digital signal processing; 3) Application of Software Radio—software radio originates form the development of military radio, but now its application in the 3rd generation mobile communication has been a research hot spot.In this report, we have a try on software radio theory of architecture and digital signal processing, which consists of six parts. Section Ⅰ is preface, which introduces the concept of software radio and its development. Section Ⅱ discusses three software radio architectures, compares the structures of IF receiver, and gives a new kind architectures of low IF receiver for digital image-rejection. Section Ⅲ discusses the key techniques of software radio—ADC, DSP and FPGA. Our analysis of ADC shows that the sigma-delta converter is a more perfect fit to the application in software radio. Section IV' studies some digital signal processing algorithm of software radio, which includes multirate signal processing, digital channelizer, carrier synchronization and timing recovery, modulation and demodulation, and channel error monitoring. In this section we stress on a kind of time-variable CIC filter based on CIC filter for fraction radio sample rate conversion, a timing error detection algorithm for all digital receivers, and a bit error rate detection algorithm base on re-encode of forward error correction. Section Vdescribes the scheme of digital microwave transceiver which has some characteristic of software radio; Section VI is conclusion of this dissertation.