基于混沌理论的MC-CDMA通信系统研究

发布时间：2018-03-11 01:38

本文选题：混沌　切入点：混沌序列　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：多载波码分多址是未来移动通信领域一项重要的基础技术,随着移动通信系统中用户数量的不断增加,通信系统对于扩频码数量有了越来越高的要求。而混沌映射系统可以生成数量众多且相关性好的码序列,能够很好的克服传统伪随机码本身所存在的数量有限的局限性并应用于多载波码分多址通信系统之中,为通信系统性能的提升提供了新的研究方向。本文首先对混沌的基本理论及其系统进行了分析,其次研究了基于混沌系统的扩频码序列及其性能,通过对四种经典的离散型混沌映射(Logistic映射、改进型Logistic映射、Tent映射和Chebyshev映射)所产生的混沌序列进行分析与仿真研究,最后提出了一种具备数量丰富的迭代初值且能够自适应对混沌系统分型参数进行随机选取的新混沌序列产生方法。仿真分析表明,这种新的混沌序列与m序列和Gold序列相比在初值敏感性、平衡性和相关特性等方面具有良好的性能表现。基于MTLAB仿真平台通过蒙特卡罗仿真方法将新提出的混沌序列应用于多载波码分多址通信系统中进行不同用户条件下的性能仿真,结果表明:提出的新混沌序列对系统的用户容量、抗多径、抗多址干扰和系统的误码率性能具有较好的提升作用,各序列在多载波码分多址通信系统中随着信噪比的增加,新混沌序列具有更加优良的误码率特性,可以实现比m序列和Gold序列更好的通信性能。
[Abstract]:Multicarrier code division multiple access is an important basic technology in the future mobile communication field. With the increasing number of users in mobile communication system, The communication system has more and more requirements for the number of spread spectrum codes, and the chaotic mapping system can generate a large number of code sequences with good correlation. It can overcome the limitation of the traditional pseudorandom code itself and be used in the multicarrier code division multiple access communication system. It provides a new research direction for improving the performance of communication system. Firstly, the basic theory of chaos and its system are analyzed in this paper. Secondly, the spread spectrum sequence based on chaotic system and its performance are studied. The chaotic sequences generated by four classical discrete chaotic maps, such as Logistic map, modified Logistic map and Chebyshev map, are analyzed and simulated. Finally, a new chaotic sequence generation method with abundant iterative initial values and adaptive random selection of the classification parameters of chaotic system is proposed. The simulation results show that, Compared with m sequence and Gold sequence, this new chaotic sequence is sensitive to initial value. Based on the MTLAB simulation platform, the proposed chaotic sequence is applied to the multi-carrier code division multiple access communication system under different user conditions through Monte Carlo simulation. The results show that the proposed new chaotic sequences can improve the user capacity, anti-multipath, anti-multiple access interference and BER performance of the system, and each sequence increases with the increase of signal-to-noise ratio (SNR) in the multi-carrier CDMA communication system. The new chaotic sequence has better BER characteristics and can achieve better communication performance than m sequence and Gold sequence.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN914;O415.5

【参考文献】