【作者】 谭红伟；

【导师】 郭见兵；

【作者基本信息】 武汉邮电科学研究院 ， 通信与信息系统， 2012， 硕士

【摘要】 GSM移动通信系统在我国经过长期的发展，目前已经成为运用最广泛的移动通信系统。虽然3G通信系统已经在我国商用，但由于其成本及技术等方面的限制，在未来几年内，运营商仍将投入大量的财力对GSM移动通信网络进行维护和优化。在实际工程中，架设GSM直放站无疑成为解决基站覆盖盲区的最佳方式。近几年来随着模拟直放站被数字直放站取代，大量的GSM数字直放站运用于GSM网络中，在实现小容量大覆盖的目标时也对整个GSM网络造成了负面影响。本论文正是基于上述背景，在传统的GRRU（GSM数字射频拉远）系统中加入广播信道解调模块。通过对GSM下行广播信道的解调提取出GSM小区跳频信息，预期实现GRRU与基站的同步跳频，以此来提高GRRU的工作性能，降低GRRU对GSM网络的负面影响。本论文第一章介绍了GSM移动通信系统的发展现状以及本课题的研究背景和研究意义，并对文章的组织结构进行了总结；第二章详细介绍了GSM通信系统基带相关的理论知识；第三章讨论了GMSK调制技术及系统中所采用的同步算法，并利用MATLAB对GMSK调制过程和同步算法进行了仿真。第四章对整个GSM广播信道解调系统进行了详细介绍，重点介绍了GMSK解调和信道译码模块的实现方式；第五章用FPGA实现了各个模块的逻辑功能，并在基于软件无线电的数字信号处理平台上进行调试。最后对全文进行了总结，提出了前期工作的改进点和后续工作安排。更多还原

【Abstract】 With its long-term development history in China, GSM mobile communicationsystem has become the most widely used communication system in the present days. The3G communication system has been used in business. However, due to the restrictions of3Gs cost and technology, operators still have to pay much for the maintenance andoptimization of GSM in the next few years. Building repeaters is the best solution toenhance network coverage in actual construction. In recent years, with the traditionalanalog repeater being replaced by digital repeater, a large number of GSM digital repeatershave been used in GSM network. The GSM digital repeater has achieved the goal ofnetwork coverage with a small capacity, but it makes adverse impact on GSM network aswell.Based on the above background, this paper brings broadcast channel demodulationmodule into traditional GRRU (GSM digital remote radio unit) system. The system isexpected to make the frequency-hopping synchronized with base station by abstractingfrequency-hopping information of GSM cell from demodulating GSM downlink broadcastchannel. This will help to improve GRRU work performance and reduce its adverse impacton GSM network.In this paper, Chapter1includes the development status of GSM communicationsystem, the significance and background of the research project, and a summary of theorganizational structure of the present research. Chapter2details the GSM communicationsystem with the theoretical knowledge of baseband. Chapter3discusses the technique ofGMSK modulation and the synchronization algorithm in system, and simulates GMSKmodulation and synchronization algorithm by MATLAB. Chapter4introduces the GSMbroadcast channel demodulation system in detail and focuses on the implementation ofGMSK demodulation and channel decoding module. In Chapter5, each module’s logicfunction is implemented by FPGA and debugged on the digital signal processing platformbased on software radio. The research ends up with a summary of the thesis and deficiencies of previous work which gives directions for future work.更多还原