非线性OFDM接收机脉冲干扰抑制方法与性能的研究

发布时间：2018-03-25 10:17

本文选题：正交频分复用　切入点：脉冲熄灭　出处：《中国民航大学》2017年硕士论文

【摘要】：现代通信系统中,常用的一种调制方法是正交频分复用(OFDM),其为多载波调制方法。然而在实际应用中,OFDM系统经常存在脉冲干扰,由于系统中脉冲干扰的统计特性与高斯白噪声(AWGN)的统计特性差异较大,导致OFDM系统中符号差错概率(SER)性能显著恶化,因此在OFDM系统的接收机中需要消除脉冲干扰。针对此问题,论文在OFDM系统中开展脉冲干扰抑制方法与性能的研究。论文主要工作如下:第一,为定量分析非线性脉冲干扰抑制方法对OFDM接收机链路传输可靠性的影响,本文首先将脉冲干扰建模为伯努利~复高斯模型,在频率选择性衰落信道下,理论分析给出了峰值脉冲熄灭、峰值脉冲限幅OFDM接收机解调器输出信噪比(SNR)的计算过程。然后,以此为基础定量解析给出非线性OFDM接收机在瑞利衰落信道与莱斯衰落信道下,采用多进制相移键控(MPSK)调制方式和多进制正交幅度调制(MQAM)调制方式的SER计算公式。最后,搭建了非线性OFDM接收机差错性能仿真平台,验证了理论推导的准确性,研究结论如下:1)OFDM系统中每个子信道具有同样的SER性能;2)在相同条件下,基于峰值脉冲熄灭的OFDM接收机性能优于峰值脉冲限幅的OFDM接收机性能。第二,为了解决非线性OFDM接收机在瑞利衰落信道下脉冲熄灭门限的最优设置问题,论文提出基于信干噪比(SINR)最大化标准准则的最优脉冲熄灭门限设置方法。首先,论文给出通用的非线性OFDM接收机输出SINR的闭合公式。然后,以此为基础提出基于SINR最大化标准准则的脉冲熄灭最优门限计算方法。最后,进一步给出基于最优门限的OFDM接收机SER计算过程,同时在频率选择性瑞利衰落信道下搭建了系统仿真平台,仿真结果验证了所提出方法的正确性。
[Abstract]:In modern communication systems, one of the common modulation methods is orthogonal Frequency Division Multiplexing (OFDM), which is a multicarrier modulation method. Because the statistical characteristics of pulse interference in OFDM system are different from those of Gao Si white noise system, the performance of symbol error probability in OFDM system is obviously deteriorated, so it is necessary to eliminate the pulse interference in the receiver of OFDM system. The main work of this paper is as follows: first, to quantitatively analyze the effect of nonlinear pulse interference suppression on the link transmission reliability of OFDM receiver. In this paper, the pulse interference is modeled as Bernoulli complex Gao Si model. In frequency selective fading channel, the calculation process of peak pulse quenching and output SNR of peak pulse limiting OFDM receiver demodulator is given. On this basis, the formulas for calculating the SER of nonlinear OFDM receiver in Rayleigh fading channel and Rice fading channel are given, which adopt the modulation mode of multi-ary phase shift keying keying (MPSKK) and the modulation of multi-ary quadrature amplitude modulation (MQAM). A nonlinear OFDM receiver error performance simulation platform is built to verify the accuracy of the theoretical derivation. The research results are as follows: each sub-channel in the OFDM system has the same SER performance under the same conditions. The performance of OFDM receiver based on peak pulse quenching is better than that of OFDM receiver with peak pulse limiting. Secondly, in order to solve the problem of optimal setting of pulse extinction threshold for nonlinear OFDM receiver in Rayleigh fading channel, In this paper, an optimal pulse quenching threshold setting method based on the SINR maximization criterion is proposed. Firstly, a general closed formula for the output SINR of a nonlinear OFDM receiver is presented. Based on this, an optimal threshold calculation method for pulse quenching based on SINR maximization criterion is proposed. Finally, the SER calculation process of OFDM receiver based on optimal threshold is further presented. At the same time, the system simulation platform is built in frequency-selective Rayleigh fading channel, and the simulation results verify the correctness of the proposed method.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.53

【相似文献】