基于随机共振的CDMA波束成形技术研究
发布时间：2019-05-08 23:03
【摘要】：波束成形作为智能天线中的关键技术,可以有效地解决频谱资源匮乏的问题。它在通信系统中引入了空时处理的自由度,利用用户信号到达方向的不同,采用空分多址,将同时、同频、同码的信号区分开了,大幅度地提高了频谱利用率,扩展了系统容量。然而波束成形的精度会受到噪声的干扰,在低信噪比下,阵列的性能和输出信噪比会大幅度下降,阵列天线形成的波束已经不能准确地对准期望用户的方向,波束成形就失去了在空域上分离用户,并且抑制干扰的作用。因此,在低信噪比下提高波束成形的准确度就成为一个值得研究的课题。针对以上问题,本论文将研究基于随机共振波束成形结构和算法。在提出的结构中,接收信号先经过随机共振系统的处理,将淹没在强噪声背景中的微弱信号提取出来,然后进行自适应的波束成形算法。针对随机共振系统对采样率较高的要求,本文主要研究在高频段(3~30M)的波束成形问题。本文的主要内容为以下几个方面:1本文先详细介绍了基于朗之万方程的随机共振系统模型,并对随机共振的理论分析做了详细介绍。2由于绝热近似理论下的非线性随机共振系统(参数a=1 b=1)在检测微弱信号时受小频率参数的约束,给实际应用带来很大困难。针对这一情况,提出二次采样方法和调整系数法来检测任意大频率的微弱信号。以调节参数双稳态系统的基础上,研究了双稳态系统参数和信号频率之间的相互关系。对于淹没在噪声中的不同频率的输入信号,提出一种自适应调节参数的方法,使输入信号频率和双稳态系统达到最佳共振效果。3本文详细介绍了自适应波束成形的概念、算法准则和常用算法。重点介绍并推导了两种CDMA系统中的多目标自适应解扩重扩波束成形算法。4在以上研究的基础上,本文提出了一种自适应的阵列天线信号处理结构,将自适应随机共振应用在多目标自适应解扩重扩波束成形算法中,通过仿真在极低信噪比下使算法性能得到大幅度提高。
[Abstract]:Beamforming, as the key technology of smart antenna, can effectively solve the problem of lack of spectrum resources. It introduces the degree of freedom of space-time processing in the communication system, makes use of the different direction of arrival of the user signal, adopts the space division multiple access, distinguishes the signals of the same frequency and the same code at the same time, and greatly improves the spectrum utilization. The system capacity is expanded. However, the precision of beamforming will be interfered by noise. At low SNR, the performance and output signal-to-noise ratio (SNR) of the array will be greatly reduced, and the beam formed by the array antenna will no longer be able to accurately target the direction of the desired user. Beamforming loses the role of separating users in spatial space and suppressing interference. Therefore, improving the accuracy of beamforming at low signal-to-noise ratio becomes a subject worth studying. In order to solve the above problems, this paper will study the structure and algorithm based on stochastic resonance beamforming. In the proposed structure, the received signal is processed by stochastic resonance system, and the weak signal submerged in the strong noise background is extracted, and then an adaptive beamforming algorithm is carried out. In order to meet the requirement of high sampling rate for stochastic resonance system, the beamforming problem in high frequency band (3 鈮，
本文编号：2472292
[Abstract]:Beamforming, as the key technology of smart antenna, can effectively solve the problem of lack of spectrum resources. It introduces the degree of freedom of space-time processing in the communication system, makes use of the different direction of arrival of the user signal, adopts the space division multiple access, distinguishes the signals of the same frequency and the same code at the same time, and greatly improves the spectrum utilization. The system capacity is expanded. However, the precision of beamforming will be interfered by noise. At low SNR, the performance and output signal-to-noise ratio (SNR) of the array will be greatly reduced, and the beam formed by the array antenna will no longer be able to accurately target the direction of the desired user. Beamforming loses the role of separating users in spatial space and suppressing interference. Therefore, improving the accuracy of beamforming at low signal-to-noise ratio becomes a subject worth studying. In order to solve the above problems, this paper will study the structure and algorithm based on stochastic resonance beamforming. In the proposed structure, the received signal is processed by stochastic resonance system, and the weak signal submerged in the strong noise background is extracted, and then an adaptive beamforming algorithm is carried out. In order to meet the requirement of high sampling rate for stochastic resonance system, the beamforming problem in high frequency band (3 鈮，
本文编号：2472292
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