【摘要】：異步DS-CDMA通信方式擁有諸多優(yōu)點使得很多通信系統(tǒng)采用這種通信方式。WCDMA移動通信系統(tǒng)本質(zhì)上是一種異步DS-CDMA系統(tǒng)。當(dāng)移動用戶處于高速移動狀態(tài)時,WCDMA通信系統(tǒng)缺乏快速有效的頻偏補償技術(shù),尤其在移動用戶發(fā)起隨機接入請求時WCDMA系統(tǒng)的頻偏估計技術(shù)亟需提高。本文從這一問題切入,首先介紹了無線信道理論,然后對WCDMA上行鏈路隨機接入信道接收理論進行研究,重點探討了上行鏈路隨機接入過程和幀結(jié)構(gòu)。針對大頻偏環(huán)境下的WCDMA隨機接入信道的頻偏估計,重點研究了幾種估計算法。本文在對多普勒頻偏的產(chǎn)生機理及對接收性能的影響進行分析研究的基礎(chǔ)上,介紹了當(dāng)前的WCDMA上行鏈路預(yù)置頻偏補償算法,研究了預(yù)置頻偏算法的改進算法即能量插值算法,分析了這兩種算法的不足。然后根據(jù)已有的基于子空間的頻偏估計算法,提出了一種適合大頻偏環(huán)境下異步DS-CDMA通信方式的頻偏估計算法并對算法原理進行了闡述與分析。然后本文就算法中的一些參數(shù)對算法性能的影響進行了仿真。并且在WCDMA上行鏈路隨機接入信道環(huán)境下,針對算法在低信噪比以及用戶數(shù)增多時估計性能下降的情況,做出了一些改進并測試了改進算法的估計性能。最后本文討論了改進算法的DSP實現(xiàn)。從算法的基本步驟開始,介紹了選擇TMS320DM6437的原因以及CCS5.5.0開發(fā)環(huán)境。然后介紹了改進算法的程序流程。最后分析了算法的DSP實現(xiàn)后的性能。從測試結(jié)果來看,提出的改進算法在大頻偏環(huán)境依然有很好的估計性能,具有很強的實際應(yīng)用價值。
[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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.53

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本文編號：2463672