LTE下行鏈路信道估計技術(shù)研究
發(fā)布時間：2018-11-13 15:49
【摘要】：LTE-Advanced系統(tǒng)是當前國際上公認的第四代移動通信(即4G)系統(tǒng)。LTE-Advanced數(shù)據(jù)傳輸速率更快,系統(tǒng)容量進一步提高,峰值速率顯著增加,系統(tǒng)的頻譜利用率更高。LTE-Advanced系統(tǒng)采用的關(guān)鍵技術(shù)有正交頻分復用(OFDM)、多輸入多輸出(MIMO)等技術(shù)。 高速移動環(huán)境下,LTE-Advanced系統(tǒng)信道在短時間內(nèi)會發(fā)生快速的變化,精確的信道估計技術(shù)對于接收端準確恢復發(fā)送信號必不可少。 本文首先分析信道估計技術(shù)的國內(nèi)外研究現(xiàn)狀,介紹了LTE下行鏈路物理信道的結(jié)構(gòu)、LTE下行鏈路基帶信號的處理流程以及關(guān)鍵技術(shù)。在對高速移動場景下的衰落信道特性進行分析的基礎(chǔ)上,研究基擴展擬合時頻雙選信道模型,介紹復指數(shù)基、離散余弦變換基、多項式基、離散卡-洛基函數(shù)、橢圓基函數(shù)以及結(jié)合過采樣技術(shù)的修正復指數(shù)基等常見的基擴展模型,仿真分析各個基擴展模型歸一化均方誤差以及擬合實際信道的性能。 隨后,搭建LTE下行鏈路基帶系統(tǒng)信道估計仿真平臺,介紹了LTE系統(tǒng)無線幀結(jié)構(gòu),導頻結(jié)構(gòu)及導頻序列生成,LTE下行信號處理流程的發(fā)射系統(tǒng)模塊、物理信道與LTE下行鏈路接收系統(tǒng)模塊,仿真驗證平臺的準確性。 其次,在LTE下行鏈路仿真平臺上分別仿真分析了不同發(fā)送接收天線、不同MIMO檢測算法、不同調(diào)制方式、不同信道模型場景下以及不同終端移動速度下,基于導頻的LS、LMMSE、SVD-MMSE和簡化SVD信道估計算法性能,仿真分析得到LS信道估計算法的估計性能最差,LMMSE估計算法和簡化SVD算法性能最優(yōu)。 最后,研究高速移動環(huán)境下的信道估計算法性能仿真,仿真結(jié)果表明在高速移動場景下,多天線多徑LTE下行鏈路中基擴展模型可以更好的擬信道,信道估計算法性能比LS算法更優(yōu)。特別在分析研究120km/h和350km/h兩種不同終端移動速度下,基擴展信道估計性能的變化,發(fā)現(xiàn)終端移動速度的變化對估計性能有很大的影響。
[Abstract]:LTE-Advanced system is currently recognized as the fourth generation mobile communication (4G) system in the world. The data transmission rate of LTE-Advanced is faster, the system capacity is further increased, and the peak rate is increased significantly. The key techniques used in LTE-Advanced system include orthogonal Frequency Division Multiplexing (OFDM),) multiple input multiple output (MIMO) and so on. In high speed mobile environment, the channel of LTE-Advanced system will change rapidly in a short time, and accurate channel estimation technology is essential for the receiver to recover the transmitted signal accurately. In this paper, firstly, the research status of channel estimation technology at home and abroad is analyzed, and the structure of LTE downlink physical channel, the processing flow of LTE downlink baseband signal and the key technology are introduced. Based on the analysis of fading channel characteristics in high-speed mobile scene, the time-frequency double-selective channel model based on extended basis fitting is studied, and the complex exponential basis, discrete cosine transform basis, polynomial basis, discrete card-Lowe function are introduced. The elliptic basis function and the modified complex exponential basis based on over-sampling technique are used to simulate and analyze the normalized mean square error of each base expansion model and the performance of fitting the actual channel. Then, the channel estimation simulation platform of LTE downlink baseband system is built, and the wireless frame structure, pilot structure and pilot sequence generation of LTE system, the transmitting system module of LTE downlink signal processing flow are introduced. Physical channel and LTE downlink receiving system module, simulation verify the accuracy of the platform. Secondly, different transmit and receive antennas, different MIMO detection algorithms, different modulation methods, different channel model scenarios and different terminal moving speeds are simulated on the LTE downlink simulation platform, and the LS,LMMSE, based on pilot frequency is analyzed respectively. The performance of SVD-MMSE and simplified SVD channel estimation algorithms is the worst, and that of LMMSE estimation algorithm and simplified SVD algorithm is the best. Finally, the performance simulation of channel estimation algorithm in high-speed mobile environment is studied. The simulation results show that the base expansion model in multi-antenna multipath LTE downlink is better for quasi-channel under high-speed mobile environment. The performance of channel estimation algorithm is better than that of LS algorithm. Especially, the performance changes of base spread channel estimation are analyzed and studied under two different terminal moving speeds of 120km/h and 350km/h. It is found that the change of terminal moving speed has a great influence on the estimation performance.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5
本文編號：2329601
[Abstract]:LTE-Advanced system is currently recognized as the fourth generation mobile communication (4G) system in the world. The data transmission rate of LTE-Advanced is faster, the system capacity is further increased, and the peak rate is increased significantly. The key techniques used in LTE-Advanced system include orthogonal Frequency Division Multiplexing (OFDM),) multiple input multiple output (MIMO) and so on. In high speed mobile environment, the channel of LTE-Advanced system will change rapidly in a short time, and accurate channel estimation technology is essential for the receiver to recover the transmitted signal accurately. In this paper, firstly, the research status of channel estimation technology at home and abroad is analyzed, and the structure of LTE downlink physical channel, the processing flow of LTE downlink baseband signal and the key technology are introduced. Based on the analysis of fading channel characteristics in high-speed mobile scene, the time-frequency double-selective channel model based on extended basis fitting is studied, and the complex exponential basis, discrete cosine transform basis, polynomial basis, discrete card-Lowe function are introduced. The elliptic basis function and the modified complex exponential basis based on over-sampling technique are used to simulate and analyze the normalized mean square error of each base expansion model and the performance of fitting the actual channel. Then, the channel estimation simulation platform of LTE downlink baseband system is built, and the wireless frame structure, pilot structure and pilot sequence generation of LTE system, the transmitting system module of LTE downlink signal processing flow are introduced. Physical channel and LTE downlink receiving system module, simulation verify the accuracy of the platform. Secondly, different transmit and receive antennas, different MIMO detection algorithms, different modulation methods, different channel model scenarios and different terminal moving speeds are simulated on the LTE downlink simulation platform, and the LS,LMMSE, based on pilot frequency is analyzed respectively. The performance of SVD-MMSE and simplified SVD channel estimation algorithms is the worst, and that of LMMSE estimation algorithm and simplified SVD algorithm is the best. Finally, the performance simulation of channel estimation algorithm in high-speed mobile environment is studied. The simulation results show that the base expansion model in multi-antenna multipath LTE downlink is better for quasi-channel under high-speed mobile environment. The performance of channel estimation algorithm is better than that of LS algorithm. Especially, the performance changes of base spread channel estimation are analyzed and studied under two different terminal moving speeds of 120km/h and 350km/h. It is found that the change of terminal moving speed has a great influence on the estimation performance.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5
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