The Design And Implementation Of CDMA Base Station Simulation System

With the impetuous growth of mobile communication, it brings a rapid increase in mobile communication testing and repair market correspondingly. At the same time, because of the competition of the 3G mobile communication standards and long time's waiting for the 3G network's commercial use, the mobile communication testing market still gives the leading position to 2G productions. The successful commercialization of CDMA(Code Division Multiple Access) mobile communication system in China improved need of maintenance and optimization for the CDMA mobile communication system equipment. But in the area of mobile communication test set, we are far behind of that of overseas, the market expects good mobile communication testing equipments which are made in our country. According to the present status, Wuhan University of Technology and The HuBei ZhongYou Company jointly develop the CDMA Mobile Station Test Set . The research subject in this paper is the important part of CDMA Mobile Station Test Set, it discuss the design of base station simulator and give the realization and emulation of some module.Adopting the modularization design of software radio concept and embedded system, the project in this paper accomplish most module design in programmer device, which makes the system easy to maintain and expand, and it could fulfill the upgrade to 3G test system by software upgrade and small hardware change. After giving an outline of the development of mobile communication system and CDMA mobile communication system, this paper mainly introduces the modularization design scheme of base station simulator system and the implement method of RF module and base band module, and proceeds on emulation experiment of some sub-module.Chapter one introduces the development of mobile communication, and discusses the technology advantages and developing status.Chapter two recommend the CDMA system in three aspects of fundamental, character and offering service, and CDMA air interface standards and radio linkare also described.In chapter three the network structure is given, and the structure and function of CDMA mobile communication system are introduced through three important components (base station subsystem, mobile station and mobile switch subsystem), base on it, the functional architecture and design method of CDMA base station simulator system discussed in this paper are presented.In chapter four, after analyzing the ,RF (radio frequency) qualification, I design the receive scheme of RF and IF (intermediate frequency) parts, and accomplish the choosing of chip and design of peripheric connection of chip.In chapter five, the base band signal process of CDMA base station simulator system is introduced, including channel coding and decoding, interleave and disinterleave, PN sequence generator, orthogonal spread spectrum and quadrature Spreading, scrambling code, power control, digital forming filter, the capture and track of PN code, dispreading and demodulation, etc. Some FPGA design 'graphic and waveform simulation of base band transmitter module is given and realization algorithm of base band receiver is discussed in detail.