FDD-TDD系统数字基带技术研究

发布时间：2018-04-03 09:30

本文选题：FDD　切入点：数字基带系统　出处：《电子科技大学》2014年硕士论文

【摘要】：随着LTE标准的广泛应用,全球范围内已有多家通信厂商研制出了近百款可以同时支持FDD和TDD的终端。如此看来,FDD-TDD通信系统在未来将得到更大规模的应用。本课题的目的是设计一个能同时支持FDD和TDD模式的高速通信系统。FDD模式采用高阶(64/256)正交幅度(QAM)调制方式,TDD模式调制方式为QPSK。本文主要介绍了FDD模式下的数字基带系统实现。系统设计的难点在于高阶QAM信号数字信号处理算法的设计与FPGA实现。除此以外,FPGA还要与DSP、ADC/DAC进行通信。本文在阐述算法功能和原理的基础上,详细说明各算法功能模块的实现以及优化方法,然后对适用于高阶QAM的盲均衡算法做了深入而详细的研究:考虑到高阶QAM信号模值不恒定的特性,采用恒模算法(CMA)结合多模算法(DAMA)的CADAMA算法;针对相位偏移的问题,改进为MCADAMA算法;为了获得更快的收敛速度和更低的稳态误差,采用T/4的分数间隔结构;并且使用预测判决反馈结构保证均衡器在干扰严重的情况下仍能正常工作。对均衡器用SIMULINK进行仿真,说明其相比其他均衡器在性能上的优势。在文章的最后,进行系统测试以及分析,验证了系统的正确性。
[Abstract]:With the wide application of LTE standard, many telecom manufacturers have developed nearly 100 terminals that can support both FDD and TDD.So it seems that FDD-TDD communication system will be used on a larger scale in the future.The purpose of this paper is to design a high speed communication system. FDD mode can support both FDD and TDD mode.This paper mainly introduces the realization of digital baseband system in FDD mode.The difficulty of system design lies in the design of high-order QAM signal digital signal processing algorithm and FPGA implementation.In addition, FPGA communicates with the DSP ADC / DAC.On the basis of expounding the function and principle of the algorithm, this paper explains the realization and optimization method of each arithmetic function module in detail.Then, the blind equalization algorithm suitable for high order QAM is studied in detail: considering the unsteady mode value of high order QAM signal, the CADAMA algorithm of constant modulus algorithm (CMA) and multimode algorithm (MMA) is used to solve the problem of phase shift.The equalizer is simulated by SIMULINK, and its performance is proved to be superior to that of other equalizers.At the end of the article, the system is tested and analyzed to verify the correctness of the system.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.5

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