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  本文選題：干擾對齊　切入點：OFDM　出處：《西安電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：在無線通信系統(tǒng)中,干擾廣泛存在,隨著用戶數(shù)的日益增加,多用戶之間的干擾嚴重限制了通信系統(tǒng)容量,干擾已成為未來無線通信的主要問題之一。傳統(tǒng)管理干擾的方法應用于當前密集多用戶系統(tǒng)時,單用戶頻譜效率較低。干擾對齊(Interference Alignment,IA)從干擾重疊這一全新角度來處理多用戶之間的干擾,通過預編碼技術使干擾在接收端處于有用信號的零空間,徹底消除干擾對期望信號的影響,它是一種有效的干擾管理方法。由于干擾對齊技術需要獲知全局信道信息,因此工程實現(xiàn)中必須找到一種降低信道信息反饋量的方法。本文依托國家自然科學基金重點項目“無線網絡的干擾管理與容量研究”,在TD-LTE的背景下,提出了干擾對齊鏈路控制協(xié)議以及降低信道信息反饋量的方法,并從工程實現(xiàn)的角度,基于現(xiàn)場可編程門陣列(FPGA),設計與實現(xiàn)了線性干擾對齊OFDM通信系統(tǒng)。首先,通過平衡信道估計準確度與系統(tǒng)傳輸性能,提出了干擾對齊鏈路控制協(xié)議,并在其中使用了一種降低信道信息反饋量的方法。依據(jù)此協(xié)議,終端在每一個無線幀開頭進行一次頻域信道估計,然后將頻域信道估計值轉換到時域進行反饋,以降低信道信息反饋量�；緩V播收到的全局信道估計信息,同時利用該信道信息,求出干擾對齊預編碼矩陣,并對當前幀后續(xù)發(fā)送的有效數(shù)據(jù)進行預編碼處理。終端利用基站廣播的全局信道信息求出解碼矩陣,對當前幀的有效數(shù)據(jù)部分解碼處理,實現(xiàn)干擾對齊。其次,在理論驗證正確的情況下,利用FPGA技術實現(xiàn)了包含線性干擾對齊技術的OFDM基帶系統(tǒng)收發(fā)模塊的設計與編碼。通信系統(tǒng)平臺采用自頂向下的設計方法,首先設計出系統(tǒng)模塊的整體架構圖,然后使用Xilinx公司的開發(fā)套件ISE14.6和ModelSim仿真軟件,通過Verilog硬件描述語言完成各個模塊的設計與編碼工作。文中重點描述加擾與解擾模塊、映射與解映射模塊、參考序列分配模塊、信道估計及反饋模塊、FFT/IFFT模塊及外圍接口模塊的設計思路和實現(xiàn)方法。仿真與運行結果表明,本文設計的包含IA技術的OFDM基帶系統(tǒng)的各編解碼模塊基本滿足要求,仿真與硬件測試顯示各模塊正常工作,整個通信系統(tǒng)基本可以實現(xiàn)3對用戶同時通信,驗證了本文提出的IA鏈路交互協(xié)議和降低信道信息反饋量方法的可行性。最后對平臺的性能進行分析與評估,結果表明平臺使用IA技術的吞吐量約為使用傳統(tǒng)復用技術的2倍。
[Abstract]:In wireless communication system, interference exists widely. With the increasing number of users, interference between multiple users seriously limits the capacity of communication system. Interference has become one of the main problems in future wireless communication. Single user spectrum efficiency is relatively low. Interference alignment interference alignment (IIA) deals with interference between multiple users from a completely new perspective of interference overlap, making interference in the zero space of a useful signal at the receiving end through precoding techniques. It is an effective interference management method to eliminate the influence of interference on the desired signal completely. Because the interference alignment technology needs to know the global channel information, Therefore, it is necessary to find a way to reduce the channel information feedback in engineering implementation. This paper relies on the key project of National Natural Science Foundation, "interference Management and capacity Research of Wireless Network", under the background of TD-LTE. An interference alignment link control protocol and a method to reduce the channel information feedback are proposed. Based on the field programmable gate array (FPGA), a linear interference aligned OFDM communication system is designed and implemented from the point of view of engineering implementation. By balancing channel estimation accuracy with system transmission performance, an interference alignment link control protocol is proposed, and a method to reduce channel information feedback is used. The terminal performs a frequency domain channel estimation at the beginning of each radio frame, and then converts the frequency domain channel estimation value to time domain for feedback, so as to reduce the channel information feedback.; the base station broadcasts the received global channel estimation information. At the same time, the interference alignment precoding matrix is obtained by using the channel information, and the effective data transmitted by the current frame is precoded. The terminal uses the global channel information broadcast by the base station to obtain the decoding matrix. The effective data part of the current frame is decoded to achieve interference alignment. Secondly, if the theory is correct, The design and coding of the transceiver module of the OFDM baseband system including linear interference alignment technology is realized by using FPGA technology. The communication system platform adopts the top-down design method, and the overall architecture diagram of the system module is designed at first. Then, using ISE14.6 and ModelSim simulation software of Xilinx Company, the design and coding of each module are accomplished by Verilog hardware description language. The scrambling and descrambling module, mapping and descrambling module, reference sequence allocation module are described in this paper. The channel estimation and feedback module FFT / Ifft module and peripheral interface module are designed and implemented. The simulation and operation results show that the OFDM baseband system including IA technology designed in this paper basically meets the requirements of the coding and decoding modules. Simulation and hardware test show that each module works normally, and the whole communication system can basically realize 3 pairs of users to communicate at the same time. Finally, the performance of the platform is analyzed and evaluated. The results show that the throughput of the platform using IA technology is about twice as high as that of traditional multiplexing technology.
【學位授予單位】：西安電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5;TN972

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本文編號：1591048