大频偏环境下异步DS-CDMA频偏估计算法研究
发布时间：2019-04-23 17:56
【摘要】：异步DS-CDMA通信方式拥有诸多优点使得很多通信系统采用这种通信方式。WCDMA移动通信系统本质上是一种异步DS-CDMA系统。当移动用户处于高速移动状态时,WCDMA通信系统缺乏快速有效的频偏补偿技术,尤其在移动用户发起随机接入请求时WCDMA系统的频偏估计技术亟需提高。本文从这一问题切入,首先介绍了无线信道理论,然后对WCDMA上行链路随机接入信道接收理论进行研究,重点探讨了上行链路随机接入过程和帧结构。针对大频偏环境下的WCDMA随机接入信道的频偏估计,重点研究了几种估计算法。本文在对多普勒频偏的产生机理及对接收性能的影响进行分析研究的基础上,介绍了当前的WCDMA上行链路预置频偏补偿算法,研究了预置频偏算法的改进算法即能量插值算法,分析了这两种算法的不足。然后根据已有的基于子空间的频偏估计算法,提出了一种适合大频偏环境下异步DS-CDMA通信方式的频偏估计算法并对算法原理进行了阐述与分析。然后本文就算法中的一些参数对算法性能的影响进行了仿真。并且在WCDMA上行链路随机接入信道环境下,针对算法在低信噪比以及用户数增多时估计性能下降的情况,做出了一些改进并测试了改进算法的估计性能。最后本文讨论了改进算法的DSP实现。从算法的基本步骤开始,介绍了选择TMS320DM6437的原因以及CCS5.5.0开发环境。然后介绍了改进算法的程序流程。最后分析了算法的DSP实现后的性能。从测试结果来看,提出的改进算法在大频偏环境依然有很好的估计性能,具有很强的实际应用价值。
[Abstract]:Asynchronous DS-CDMA communication mode has many advantages which make many communication systems adopt this kind of communication mode. WCDMA mobile communication system is an asynchronous DS-CDMA system in essence. When the mobile user is in the high-speed mobile state, the WCDMA communication system lacks the fast and effective frequency offset compensation technology, especially when the mobile user initiates the random access request, the frequency offset estimation technology of the WCDMA system needs to be improved urgently. In this paper, we first introduce the theory of wireless channel, then study the receiving theory of WCDMA uplink random access channel, and focus on the uplink random access process and frame structure. Aiming at the frequency offset estimation of WCDMA random access channel in large frequency offset environment, several estimation algorithms are studied in this paper. Based on the analysis of the generation mechanism of Doppler frequency offset and the influence of Doppler frequency offset on reception performance, this paper introduces the current WCDMA uplink pre-set frequency offset compensation algorithm, and studies the improved algorithm, that is, the energy interpolation algorithm, of the preset frequency offset algorithm, which is based on the analysis of the generation mechanism of Doppler frequency offset and the influence on reception performance. The shortcomings of these two algorithms are analyzed. Then, according to the existing subspace-based frequency offset estimation algorithm, a frequency offset estimation algorithm suitable for asynchronous DS-CDMA communication in large frequency offset environment is proposed, and the principle of the algorithm is described and analyzed. Then the influence of some parameters in the algorithm on the performance of the algorithm is simulated. In the environment of WCDMA uplink random access channel, some improvements are made and the performance of the improved algorithm is tested to reduce the estimation performance when the SNR is low and the number of users is increased. Finally, the DSP implementation of the improved algorithm is discussed. Starting from the basic steps of the algorithm, this paper introduces the reason of choosing TMS320DM6437 and the development environment of CCS5.5.0. Then the program flow of the improved algorithm is introduced. Finally, the performance of the algorithm after the implementation of DSP is analyzed. From the test results, the proposed improved algorithm still has a good estimation performance in the large frequency offset environment, and has a strong practical application value.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53
本文编号：2463672
[Abstract]:Asynchronous DS-CDMA communication mode has many advantages which make many communication systems adopt this kind of communication mode. WCDMA mobile communication system is an asynchronous DS-CDMA system in essence. When the mobile user is in the high-speed mobile state, the WCDMA communication system lacks the fast and effective frequency offset compensation technology, especially when the mobile user initiates the random access request, the frequency offset estimation technology of the WCDMA system needs to be improved urgently. In this paper, we first introduce the theory of wireless channel, then study the receiving theory of WCDMA uplink random access channel, and focus on the uplink random access process and frame structure. Aiming at the frequency offset estimation of WCDMA random access channel in large frequency offset environment, several estimation algorithms are studied in this paper. Based on the analysis of the generation mechanism of Doppler frequency offset and the influence of Doppler frequency offset on reception performance, this paper introduces the current WCDMA uplink pre-set frequency offset compensation algorithm, and studies the improved algorithm, that is, the energy interpolation algorithm, of the preset frequency offset algorithm, which is based on the analysis of the generation mechanism of Doppler frequency offset and the influence on reception performance. The shortcomings of these two algorithms are analyzed. Then, according to the existing subspace-based frequency offset estimation algorithm, a frequency offset estimation algorithm suitable for asynchronous DS-CDMA communication in large frequency offset environment is proposed, and the principle of the algorithm is described and analyzed. Then the influence of some parameters in the algorithm on the performance of the algorithm is simulated. In the environment of WCDMA uplink random access channel, some improvements are made and the performance of the improved algorithm is tested to reduce the estimation performance when the SNR is low and the number of users is increased. Finally, the DSP implementation of the improved algorithm is discussed. Starting from the basic steps of the algorithm, this paper introduces the reason of choosing TMS320DM6437 and the development environment of CCS5.5.0. Then the program flow of the improved algorithm is introduced. Finally, the performance of the algorithm after the implementation of DSP is analyzed. From the test results, the proposed improved algorithm still has a good estimation performance in the large frequency offset environment, and has a strong practical application value.
【学位授予单位】：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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