本文選題：LTE + 探測參考信號��； 參考：《電子科技大學(xué)》2014年碩士論文

【摘要】：隨著數(shù)據(jù)通信和多媒體業(yè)務(wù)的飛速發(fā)展,現(xiàn)有的移動通信系統(tǒng)已越來越不能滿足人們的需求。因此,3GPP提出了3G的長期演進(jìn)計劃(Long Term Evolution,LTE),意在提供更高的傳輸速率和更大的系統(tǒng)帶寬。作為新一代移動通信的發(fā)展方向,LTE受到了全球研究人員和通信業(yè)界的廣泛關(guān)注。LTE系統(tǒng)以O(shè)FDM和MIMO作為其物理層關(guān)鍵技術(shù),同時采用了許多新的通信技術(shù),其中一個重要技術(shù)就是在系統(tǒng)上行鏈路定義了兩種重要的參考信號:解調(diào)參考信號(DeModulation Reference Signal,DMRS)和探測參考信號(Sounding Reference Signal,SRS)。本文主要對SRS進(jìn)行了研究。本文首先對LTE系統(tǒng)的上行物理層進(jìn)行了概述,包括無線幀結(jié)構(gòu)、時頻資源、子載波映射方式等。簡要介紹了LTE的上行多址方式SC-FDMA。接著根據(jù)3GPP協(xié)議的定義,詳細(xì)分析了SRS序列的生成方式、序列的循環(huán)自相關(guān)特性、SRS帶寬分配以及時頻資源配置等。本文重點研究了基于SRS的信噪比估計算法和定時同步算法。在信噪比估計方面:首先給出了SRS的傳輸方式和信噪比估計的系統(tǒng)模型;然后簡要介紹了三種常用的信噪比估計算法,并針對其各自的缺點,提出了兩種改進(jìn)的算法:改進(jìn)的DFT算法和改進(jìn)的DASS算法。改進(jìn)的DFT算法通過在時域上修正噪聲的估計區(qū)間,減小了高信噪比時有用信號能量泄露對噪聲估計的影響,從而獲得更準(zhǔn)確的信噪比估計。仿真結(jié)果表明,在高信噪比區(qū)域,新算法的平均估計性能比Boumard算法和DFT算法提高了約6dB左右;改進(jìn)的DASS算法通過重新定義子載波的計算方式,減小了噪聲估計的誤差,使得高信噪比時的性能有了明顯提高,并且復(fù)雜度僅為原DASS方法的1/3。在定時估計方面:本文首先從理論上對定時誤差對系統(tǒng)帶來的影響進(jìn)行了詳細(xì)分析。然后在現(xiàn)有的兩種定時估計算法基礎(chǔ)上,提出了一種適用于SRS的改進(jìn)的后向搜索算法。該方法通過重新定義門限值,根據(jù)定時度量函數(shù)和新的搜索判決技術(shù)來確定多徑環(huán)境中的第1徑的位置,進(jìn)而得到正確的定時點位置。仿真結(jié)果表明該算法能有效地消除判決過程中的旁瓣的影響,系統(tǒng)的正確定時概率有明顯提高。最后,本文對多用戶條件下的SRS進(jìn)行了研究,重點研究了碼分復(fù)用情形下的SRS信噪比估計算法。分別從多用戶的信道估計和噪聲估計兩方面展開了研究,給出了一種消除其他用戶干擾的方法,將本文所提的兩種改進(jìn)的信噪比估計算法推廣到了多用戶環(huán)境,并通過計算機仿真驗證了算法的有效性。
[Abstract]:With the rapid development of data communication and multimedia services, the existing mobile communication systems have become more and more unable to meet the needs of people. Therefore, 3GPP proposed the long-term evolution plan of 3G (Long Term Evolution, LTE), intended to provide higher transmission rate and larger system band width. As the development direction of the new generation of mobile communications, LTE suffers. The widespread concern of the global researchers and communications industry is the key technology of the.LTE system with OFDM and MIMO, and many new communication technologies are adopted. One of the important technologies is to define two important reference signals in the uplink of the system: the demodulation reference number (DeModulation Reference Signal, DMRS) and the detection. The reference signal (Sounding Reference Signal, SRS). This paper mainly studies SRS. This paper first summarizes the uplink physical layer of LTE system, including wireless frame structure, time frequency resources, subcarrier mapping mode and so on. This paper briefly introduces LTE's uplink multiple access mode SC-FDMA. then according to the definition of 3GPP protocol, analyzes the SRS sequence in detail. Generation mode, cyclic autocorrelation of sequence, SRS bandwidth allocation and time frequency resource allocation. This paper focuses on SRS based SNR estimation algorithm and timing synchronization algorithm. In signal-to-noise ratio estimation, the transmission mode of SRS and the system model of signal to noise ratio estimation are given first, and then three kinds of commonly used letters are briefly introduced. Two improved algorithms, the improved DFT algorithm and the improved DASS algorithm, are proposed for the noise ratio estimation algorithm. The improved DFT algorithm reduces the effect of the signal energy leakage on the noise estimation by modifying the estimation interval of the noise in the time domain, thus obtaining a more accurate estimation of the signal to noise ratio. The real results show that the average estimation performance of the new algorithm is about 6dB around the Boumard algorithm and the DFT algorithm in the high signal to noise ratio region. The improved DASS algorithm reduces the noise estimation error by redefining the calculation method of the subcarrier, and makes the performance of the high signal to noise ratio improved obviously, and the complexity is only 1/ of the original DASS method. 3. in timing estimation, this paper first analyzes the effect of timing error on the system in detail. Then, on the basis of two existing timing estimation algorithms, an improved backward search algorithm for SRS is proposed. By redefining the threshold value, the method is based on the timing measure function and the new search judgment. In order to determine the position of the first path in the multipath environment and get the correct position of the timing point, the simulation results show that the algorithm can effectively eliminate the effect of the sidelobe in the decision process, and the correct timing probability of the system is obviously improved. Finally, this paper studies the SRS under the multi user condition and focuses on the code division multiplexing situation. The SRS signal-to-noise ratio estimation algorithm is studied from two aspects of the multiuser channel estimation and noise estimation, and a method to eliminate other user interference is given. The two improved signal to noise ratio estimation algorithm proposed in this paper is extended to the multi user environment, and the effectiveness of the algorithm is verified by computer simulation.
【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】：TN929.5

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 邵道炯;TD-LTE上行鏈路中參考信號技術(shù)的研究與DSP實現(xiàn)[D];電子科技大學(xué);2011年

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本文編號：2074118