差分混沌键控通信系统的改进与分析

发布时间：2018-03-10 06:25

本文选题：差分混沌键控　切入点：多径衰落　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：混沌通信是一种将混沌现象应用于实际通信的全新技术,它的发展历史较为短暂,但有着很好的通信质量和性能。混沌是一种伪随机现象,它具有对初始条件的极端敏感性、貌似随机的行为、连续宽带功率谱以及良好的自相关和低互相关特性等特点,目前研究表明,利用混沌可以实现高质量和高性能的通信。另外,混沌可以通过简单电路产生,如此又可降低发送端与接收端的成本,所以混沌在通信领域具有广阔的应用前景。本文首先介绍了混沌及混沌通信的发展历史、国内外的研究及应用现状以及研究中主要存在的问题。之后对混沌的理论基础作了阐述,包括混沌的定义及特征、混沌的产生、几种常见混沌映射的模型及特性。然后对比了各种键控类通信系统的优缺点,着重分析了在混沌通信系统中占重要地位的DCSK在高斯白噪声下的误码性能。最后在借鉴分集接收技术和反相对称调制法这两种思路的前提下,对原DCSK通信系统进行了改进,提出一种DCSK的分集接收反相解调方案,并在瑞利和莱斯衰落信道下对其做了理论分析及性能仿真。该方案将发射信号做适当延时以形成多路信号,将各路信号相加后进行反相相关运算,接收端对运算后的结果做出门限判决。理论分析和仿真结果均表明,和原DCSK通信系统相比,使用了改进的DCSK方案后的系统误码率性能有所改善。此外,该方案也可有效抑制噪声的影响。
[Abstract]:Chaotic communication is a new technology which applies chaos phenomenon to actual communication. Its development history is short, but it has good communication quality and performance. Chaos is a pseudorandom phenomenon, and it is extremely sensitive to initial conditions. The characteristics of seemingly random behavior, continuous wideband power spectrum and good autocorrelation and low cross-correlation characteristics have shown that high quality and high performance communication can be achieved by using chaos. In addition, chaos can be generated by simple circuits. In this way, the cost of transmitter and receiver can be reduced, so chaos has a broad application prospect in the field of communication. Firstly, this paper introduces the history of chaos and chaotic communication. The research and application status at home and abroad as well as the main problems in the study. Then the theoretical basis of chaos is expounded, including the definition and characteristics of chaos, the emergence of chaos, The models and characteristics of several common chaotic maps are compared, and the advantages and disadvantages of various keying communication systems are compared. The error performance of DCSK, which plays an important role in chaotic communication system, under Gao Si white noise is analyzed emphatically. Finally, the original DCSK communication system is improved on the premise of using diversity receiving technology and inverse phase symmetric modulation method for reference. A diversity receiver inverse demodulation scheme for DCSK is proposed, and its theoretical analysis and performance simulation are performed in Rayleigh and Rice fading channels. After adding each signal together, the inverse phase correlation operation is carried out, and the receiver determines the threshold of the result. The theoretical analysis and simulation results show that, compared with the original DCSK communication system, After using the improved DCSK scheme, the BER performance of the system is improved. In addition, the proposed scheme can effectively suppress the influence of noise.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918;O415.5

【共引文献】