【作者】 孙鹏；

【导师】 毛德祥；

【作者基本信息】 大连理工大学 ， 通信与信息系统， 2006， 硕士

【摘要】 WCDMA是无限传输的一种技术,每个移动终端和每个无线基站都在同一个频谱上工作。为了区分不同的移动终端,每一个移动终端需要有一个唯一的码序列。CDMA基站必须能区分这些不同的码序列,从而区分不同的数据传输。码序列的区分是通过匹配滤波器完成的,通过检测输入数据流中特殊的码序列可以区分不同的移动终端。 WCDMA支持从低速率到高速率的多种数据业务,每种业务都有不同的扩频码。为了防止各种类型速率之间的干扰,扩频码必须具有正交的特性。同时,对于所有速率不等的业务而言,扩频后的带宽是固定的,为了适应信道传输,就必须采用不等长度的正交可变扩频因子码。WCDMA系统的信道扩频采用长度可变的正交码序列,即正交可变扩频因子码作为扩频码。 论文对匹配滤波器和正交可变扩频因子作了研究。第二章对匹配滤波器的基本原理进行分析,先介绍传统的匹配滤波器结构,然后给出改进的并行匹配滤波器和折叠匹配滤波器结构,重点分析了适合FPGA实现的转置形式的滤波器。第三章介绍了XilinxFPGA的硬件资源,给出传统结构匹配滤波器和并行匹配滤波器的硬件描述语言的实现算法,并对传统结构的匹配滤波器进行Matlab仿真,之后对所提出的改进的匹配滤波器结构进行FPGA的仿真。第四章对正交可变扩频因子进行研究,先阐述正交可变扩频因子的生成方法以及它的性质,然后讨论了正交可变扩频因子的单码分配和多码分配的原则,最后给出了其评价的指标。第五章介绍了ALTERA FPGA的特点,对正交可变扩频因子的生成算法给出了FPGA实现的算法,并对此算法进行了仿真,最后给出了FPGA的配置方法。更多还原

【Abstract】 Wideband CDMA is a technique used for wireless data transmission. Every mobile handset and every wireless base station operate on the same frequency spectrum. In order to discriminate one conversation from another, every handset broadcasts a unique code sequence. CDMA base stations must be able to discriminate these different code sequences in order to distinguish one transmission from another. This discrimination is accomplished by means of a matched filter, whose output indicates when a particular code sequence is detected in the input data stream.Wideband CDMA supports many kinds of services. These services have different data rate. Each service has its own spreading code. To prevent the interferences of different services, the spreading code is requested to have the orthogonal specification. Since the wideband after spreading is same to different services, it is necessary to take the orthogonal variable spreading factor (OVSF). Wideband CDMA uses this kind of spreading code.In this dissertation, matched filter and orthogonal variable spreading factor are investigated. In chapter 2, basic principles and architectures of matched fileter are analysised. Parallel matched filter and fold matched filter are put forward. This dissertation puts emphasis on the architecture which is suitable in FPGA. In chapter 3, Xilinx FPGAs are introduced first. Simulators based on FPGA are made, and HDL codes are listed partly. In chapter 4, characteristic of orthogonal variable spreading factor are studied. Distributive principle and estimate performance are analysised. In chapter 5, ALTERA FPGAs are recommended. Simulators based on FPGA for orthogonal variable spreading factor are made. Also ways of configurature of FPGA are discussed.更多还原