本文關(guān)鍵詞：LTE-A鏈路級仿真及關(guān)鍵技術(shù)研究　出處：《東南大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： LTE/LTE-A DFT-S-OFDM 波束賦形

【摘要】：從2G到3G,到3.9G,即：LTE,到現(xiàn)在的4G,即LTE-A,無線通信技術(shù)一直在理論到應(yīng)用的路上不斷發(fā)展與成熟,這個過程中,通過仿真對通信技術(shù)從理論上進(jìn)行正確性證明以及發(fā)展是不可或缺的部分。本文對LTE-A系統(tǒng)在鏈路層進(jìn)行仿真,并對其關(guān)鍵技術(shù)進(jìn)行了研究與改進(jìn)。本文首先對LTE/LTE-A的發(fā)展進(jìn)程進(jìn)行了簡單介紹,針對鏈路仿真特性,研究了LTE/LTE-A關(guān)鍵技術(shù),即MIMO技術(shù)、OFD M技術(shù)、物理層上行鏈路、物理層下行鏈路設(shè)計原理。針對仿真中采用開環(huán)方案,文中重點研究了通信系統(tǒng)中的常用信道模型,對比不同信道特性,給出了鏈路仿真中使用的信道模型方案。本文給出了一種基于STR算法的抑制DFT-S-OFDM信號峰均功率比的改進(jìn)算法。物理層上行鏈路中使用的SC-FDMA技術(shù)使得單載波具有與多載波類似的正交性,能滿足多用戶的需求,并且使得上下行傳輸可以共用很多參數(shù)。DFT-S-OFDM技術(shù)是SC-FDMA信號的頻域生成方式,通過簡單的DFT變換生成SC-FDMA信號,降低了系統(tǒng)的實現(xiàn)復(fù)雜性,但是DFT-S-OFDM技術(shù)使得信號峰均功率比顯著增加,從而降低了終端的功放效率,針對此問題,文中給出了可以有效的抑制DFT-S-OFDM信號峰均功率比的STR改進(jìn)算法,通過軟件仿真驗證了該改進(jìn)算法的性能,并將此改進(jìn)算法應(yīng)用于物理層上行鏈路傳輸?shù)姆抡嫫脚_,該平臺使用MATLAB仿真軟件搭建,其信號處理流程遵循3GPP協(xié)議規(guī)定。文中基于上述平臺,在不同的信道場景下(包括AWGN、EPA信道)對優(yōu)化后的DFT-S-OFDM技術(shù)對調(diào)制編碼方式(Modulation and Coding Scheme, MCS)的性能表現(xiàn)進(jìn)行研究。本文研究了最能體現(xiàn)TD-LTE系統(tǒng)特性的幀結(jié)構(gòu),給出了一種TD-LTE系統(tǒng)下行傳輸?shù)逆溌芳壏抡娣桨�。FDD-LTE系統(tǒng)和TD-LTE系統(tǒng)的上行鏈路處理流程是一樣的,均是基于SC-FDN MA技術(shù),而下行則是不同的,FDD-LTE系統(tǒng)的下行鏈路根據(jù)碼本對發(fā)射信號進(jìn)行預(yù)編碼,而TD-LTE的下行使用的預(yù)編碼方案是波束賦形。文中給出的仿真方案模擬TD-LTE系統(tǒng),對上行、下行數(shù)據(jù)使用半雙工方式傳輸,使用仿真軟件MATLAB搭建了該物理層鏈路傳輸?shù)姆抡嫫脚_,研究了TD-LTE系統(tǒng)中的波束賦形技術(shù)在AWGN和EPA信道場景下對調(diào)制編碼方式(MCS)的性能表現(xiàn)。本文改進(jìn)了基于RBIR算法的物理層抽象技術(shù)(L2S方法),減小了L2S方法對BLER的預(yù)測誤差。經(jīng)典的RBIR算法的做法是計算出平均的RBIR后反查詢SINR-RBIR映射表,得到有效信噪比,再查詢AWGN信道的SINR-BLER參考曲線來預(yù)測系統(tǒng)級的BLER,改進(jìn)方案將上述的兩步合為一步,以減少由查詢步驟產(chǎn)生的插值誤差,大量的仿真驗證了上述改進(jìn)算法相比原算法的性能提高。最后,鏈路仿真結(jié)果使用上述改進(jìn)的L2S方法進(jìn)行分析,從而驗證了L2S算法的有效性與正確性,即,運用L2S接口技術(shù),僅進(jìn)行鏈路級仿真就可以預(yù)測系統(tǒng)級的BLER性能。
[Abstract]:From 2G to 3G, to 3.9G, that is to say, to the current 4G, that is LTE-A, wireless communication technology has been developing and maturing in the process of theory and application. It is an indispensable part to prove the correctness and development of communication technology in theory by simulation. This paper simulates the LTE-A system in link layer. And the key technology is studied and improved. Firstly, the development process of LTE/LTE-A is briefly introduced, and the key technology of LTE/LTE-A is studied according to the characteristics of link simulation. That is, MIMO technology, physical layer uplink, physical layer downlink design principle. In view of the simulation of open-loop scheme, this paper focuses on the common channel model in communication system. Compare different channel characteristics. The channel model scheme used in link simulation is given. An improved algorithm for suppressing PAPR of DFT-S-OFDM signal based on STR algorithm is presented. S used in uplink in physical layer. C-FDMA technology makes single carrier have the same orthogonality as multi-carrier. It can meet the needs of multiple users, and make the uplink and downlink transmission can share many parameters. DFT-S-OFDM technology is the frequency domain generation of SC-FDMA signal. The complexity of the system is reduced by the simple DFT transform to generate the SC-FDMA signal, but the PAPR of the signal is significantly increased by the DFT-S-OFDM technology. In order to reduce the power amplifier efficiency of the terminal, this paper presents an improved STR algorithm which can effectively suppress the PAPR of DFT-S-OFDM signal. The performance of the improved algorithm is verified by software simulation, and the improved algorithm is applied to the simulation platform of physical layer uplink transmission. The platform is built with MATLAB simulation software. The signal processing flow follows the 3GPP protocol. Based on the above platform, this paper is based on different channel scenarios (including AWGN). EPA channel) Modulation and Coding Scheme with optimized DFT-S-OFDM technique. The performance of MCSs is studied. The frame structure which can best reflect the characteristics of TD-LTE system is studied in this paper. This paper presents a link-level simulation scheme for downlink transmission of TD-LTE system. The uplink processing flow of FDD-LTE system and TD-LTE system is the same. All of them are based on SC-FDN MA technology, but downlink is the downlink of different FDD-LTE systems, which precode the transmitted signal according to the codebook. The pre-coding scheme used in the downlink of TD-LTE is beamforming. The simulation scheme presented in this paper simulates the TD-LTE system. The uplink and downlink data are transmitted in half duplex mode. The simulation platform of the physical layer link transmission is built by using the simulation software MATLAB. The beamforming technique in TD-LTE system is studied in AWGN and EPA channel scenarios. In this paper, the physical layer abstraction technique based on RBIR algorithm is improved. The prediction error of L2S method to BLER is reduced. The classical RBIR algorithm is to calculate the average RBIR backward query SINR-RBIR map table and obtain the effective signal-to-noise ratio (SNR). Then the SINR-BLER reference curve of the AWGN channel is queried to predict the system level BLER.The improved scheme combines the above two steps into one step to reduce the interpolation error generated by the query step. A large number of simulations verify the performance of the improved algorithm compared with the original algorithm. Finally, the link simulation results are analyzed using the improved L2S method, which verifies the validity and correctness of the L2S algorithm. That is, using L2S interface technology, only link level simulation can predict system level BLER performance.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TN929.5

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