无线通信系统中XPIC及载波同步实现技术研究

发布时间：2018-07-03 02:16

  本文选题：交叉极化干扰抵消器 + 载波同步　； 参考：《电子科技大学》2014年硕士论文

【摘要】：随着无线通信业务的需求日益增加,无线移动通信技术得到迅猛的发展,但是却始终面临着频谱短缺这一严重问题。无线通信系统中,提高频谱利用率是研究重点之一。提高频谱利用率,除了可以采用QAM调制技术,也可以采用极化波复用技术。采用极化波复用技术时,涉及到在信道中造成的交叉干扰,抵消交叉干扰会用到交叉极化干扰抵消器,本文讨论了交叉极化干扰抵消器的结构以及相关算法;采用QAM调制技术时,解调一般采用相干解调技方式,而载波同步环路是相干解调不可或缺的环路之一。首先,本文介绍了交叉极化干扰抵消器的结构与算法。本文主要介绍了三种算法,包括LMS算法、DD-LMS算法和CMA算法。基于DD-LMS和CMA算法各自的优点,讨论了DD-LMS和CMA的切换算法。根据算法的数学推导,用Simulink分别对DD-LMS、CMA和切换算法进行建模,在信道中设定一定的交叉极化干扰,分析比较算法的性能。仿真后,用Verilog实现DD-LMS算法的交叉干扰抵消器,并在FPGA板上进行了功能仿真和板级仿真,调试结果正确。其次,介绍了载波同步环路的原理以及算法。本文主要讨论了载波同步环路的DD算法、极性判决法及二者的切换算法。根据算法的数学推导,用Simulink分别对DD算法、极性判决法和切换算法进行建模,在信道中设定一定的频偏,分析比较算法的性能。仿真结果说明,采用DD算法的载波同步环路收敛速度慢,但收敛后,相位误差抖动小,捕获的频偏稳定;采用极性判决法的载波同步环路收敛速度快,但是收敛后相位误差抖动大,捕获的频偏抖动也大;而切换算法具备二者的优点。之后,用Verilog实现切换算法的载波同步环路,对载波同步环路单个模块在FPGA板上进行功能仿真和板级仿真,证明了采用切换算法的载波同步环路可以达到很好的纠正频偏的效果。并对载波同步环路进行系统联合调试,调试结果正确。
[Abstract]:With the increasing demand of wireless communication services, the wireless mobile communication technology has been developing rapidly, but it is always faced with the serious problem of spectrum shortage. In wireless communication system, improving spectrum efficiency is one of the key research points. In order to improve spectral efficiency, not only QAM modulation technology can be used, but also polarization multiplexing technology can be used. When using polarization multiplexing technology, the cross-interference caused by the channel is involved, and the cross-polarization interference canceller is used to cancel the cross-polarization interference. In this paper, the structure of the cross-polarization interference canceller and the related algorithms are discussed. When QAM modulation technology is adopted, coherent demodulation is generally adopted, and carrier synchronization loop is one of the indispensable loops for coherent demodulation. Firstly, the structure and algorithm of cross polarization interference canceller are introduced. This paper mainly introduces three algorithms, including LMS algorithm, DD-LMS algorithm and CMA algorithm. Based on the advantages of DD-LMS and CMA, the switching algorithms of DD-LMS and CMA are discussed. According to the mathematical derivation of the algorithm, the DD-LMSCMA and the handoff algorithm are modeled by Simulink, and the cross-polarization interference is set up in the channel, and the performance of the algorithm is analyzed and compared. After simulation, the cross interference canceller of DD-LMS algorithm is realized by Verilog, and the functional simulation and board level simulation are carried out on the FPGA board, and the debugging results are correct. Secondly, the principle and algorithm of carrier synchronization loop are introduced. This paper mainly discusses DD algorithm, polarity decision method and switching algorithm of carrier synchronous loop. According to the mathematical derivation of the algorithm, the DD algorithm, the polarity decision method and the switching algorithm are modeled by Simulink, and a certain frequency offset is set up in the channel to analyze and compare the performance of the algorithm. The simulation results show that the convergence speed of the carrier synchronization loop using DD algorithm is slow, but after convergence, the phase error jitter is small, and the frequency offset of the acquisition is stable. However, the phase error jitter after convergence is large, and the frequency offset jitter captured is also large, and the switching algorithm has the advantages of both. After that, the carrier synchronization loop of the switching algorithm is implemented by Verilog, and the single module of the carrier synchronization loop is simulated on the FPGA board. It is proved that the carrier synchronization loop with the switching algorithm can correct the frequency offset very well. And carry on the system joint debugging to the carrier synchronous loop, the debugging result is correct.
【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】：TN92
，

本文编号：2091938