OFDM通信系统的APSK调制及信道估计研究

发布时间：2018-03-07 07:56

本文选题：S频段　切入点：APSK调制　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：与地面移动/无线通信系统融合是未来卫星移动通信系统发展的必然趋势,两者的融合是实现个人通信(即实现5W)发展的方式之一。目前,地面无线通信的主流传输技术是OFDM技术,鉴于此,本文设计一个基于OFDM的卫星移动通信系统,该系统工作在S频段。本文首先介绍了OFDM的基本原理,其次研究了适合卫星通信系统的调制方式,再次设计了适合既定信道的信道估计及均衡算法,最后搭建了卫星通信系统仿真平台。本文主要研究内容如下:1.介绍了OFDM的系统模型,每个模块的工作原理及其作用,分析了该系统中的峰均比技术,同步技术,信道估计技术等三种关键技术。2.在非线性卫星信道中,分析了非线性幅度失真,非线性相位失真对QAM,PSK,APSK三种调制方式信号的影响,对比了其信噪比与误码率的性能,得出APSK在非线性卫星信道中有更好的误码性能。设计了两种APSK的星座结构,并研究了其软调制和软解调算法。3.针对系统的信道模型研究并设计了适合该系统的信道估计和均衡算法,该算法是基于导频的信道估计,在LS算法的基础上进行了改进,改进后的算法相对传统的LS算法,不仅能提高3d B的误码性能,还可以估计采样相偏以及残余频偏。4.进行了系统总体方案的设计,包括OFDM帧结构的设计及形成,收发信机和仿真信道的设计,并对仿真结果在比特率,频谱效率和误码率等方面进行了分析。
[Abstract]:Integration with terrestrial mobile / wireless communication system is the inevitable trend of the future satellite mobile communication system. The fusion of the two systems is one of the ways to realize the development of personal communication (that is, to realize 5W). The mainstream transmission technology of terrestrial wireless communication is OFDM technology. In view of this, this paper designs a satellite mobile communication system based on OFDM, which works in S band. Firstly, the basic principle of OFDM is introduced. Secondly, the modulation mode suitable for satellite communication system is studied, and a channel estimation and equalization algorithm suitable for a given channel is designed again. Finally, the simulation platform of satellite communication system is built. The main contents of this paper are as follows: 1. The system model of OFDM, the working principle and function of each module are introduced, and the PAPR technology and synchronization technology are analyzed. In nonlinear satellite channel, the influence of nonlinear amplitude distortion and nonlinear phase distortion on the signal of QAM PSK / APSK modulation mode is analyzed, and the performances of SNR and bit error rate are compared, and the signal to noise ratio (SNR) and bit error rate (BER) of the signal to noise ratio (SNR) and bit error rate (BER) are compared. It is concluded that APSK has better error-code performance in nonlinear satellite channels. Two constellation structures of APSK are designed. And the soft modulation and soft demodulation algorithm. 3. Aiming at the channel model of the system, the channel estimation and equalization algorithm suitable for the system is studied and designed. The algorithm is based on pilot channel estimation, and is improved on the basis of LS algorithm. Compared with the traditional LS algorithm, the improved algorithm can not only improve the error performance of 3D B, but also estimate the sampling phase offset and residual frequency offset. 4. The overall scheme of the system is designed, including the design and formation of OFDM frame structure. The design of transceiver and simulation channel is given. The simulation results are analyzed in bit rate, spectrum efficiency and bit error rate.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53

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