【摘要】：隨著用戶業(yè)務(wù)需求的不斷增加,高速率、大容量的通信需求與有限的帶寬資源之間的矛盾,推動(dòng)著通信理念和ICT不斷向前發(fā)展,MIMO-OFDM技術(shù)的出現(xiàn)為解決上述矛盾提供了新的途徑。TD-LTE系統(tǒng)在國內(nèi)大規(guī)模商用之后,通信速率和系統(tǒng)容量有了明顯提升,其下行鏈路就采用了MIMO-OFDM技術(shù)。然而因其布網(wǎng)時(shí)頻率復(fù)用因子趨近于1,小區(qū)內(nèi)和小區(qū)間的同頻干擾問題已成為影響通信質(zhì)量、速率以及系統(tǒng)容量的重要因素。TD-LTE系統(tǒng)小區(qū)內(nèi)的用戶受到來自同頻小區(qū)的干擾以及小區(qū)內(nèi)同頻中繼節(jié)點(diǎn)的干擾,小區(qū)邊緣的用戶受到其他同頻小區(qū)的基站干擾,針對(duì)這些場(chǎng)景下的干擾問題,本文在對(duì)比已有的干擾處理方法的基礎(chǔ)上,采用了干擾對(duì)齊技術(shù),并搭建了基于FPGA的干擾對(duì)齊技術(shù)驗(yàn)證模型,研究了干擾對(duì)齊算法對(duì)系統(tǒng)性能提升的影響,得出了相應(yīng)的結(jié)論。論文主要工作如下:1.對(duì)TD-LTE系統(tǒng)中的同頻干擾的典型場(chǎng)景進(jìn)行分析總結(jié),結(jié)合干擾對(duì)齊的相關(guān)理論知識(shí),選用了一種易于在FPGA上實(shí)現(xiàn)的干擾對(duì)齊算法,使之能用于TD-LTE系統(tǒng)中,改善典型干擾場(chǎng)景下的通信質(zhì)量,提升系統(tǒng)容量;對(duì)設(shè)計(jì)的算法用Matlab進(jìn)行了仿真,與不采用IA技術(shù)的MIMO-OFDM信道進(jìn)行對(duì)比,指出其在系統(tǒng)誤碼率和容量方面隨著信噪比的增大而帶來的增益;2.搭建了基于Xilinx FPGA ML605的干擾對(duì)齊算法驗(yàn)證硬件平臺(tái),在IA算法的FPGA實(shí)現(xiàn)過程中,優(yōu)化了預(yù)編碼矩陣V和解碼矩陣U的求解過程;通過簡化FPGA中矩陣求逆運(yùn)算以及乘法運(yùn)算,解決了硬件上實(shí)現(xiàn)算法時(shí)復(fù)雜度高而消耗資源過大,系統(tǒng)時(shí)延過高的問題;3.提出了一種解決預(yù)編碼之后待發(fā)送數(shù)據(jù)峰均比過大問題的方法,通過構(gòu)造調(diào)整因子來自適應(yīng)的對(duì)預(yù)編碼后的數(shù)據(jù)進(jìn)行調(diào)整,降低峰均比;通過觀察板上液晶屏顯示以及上位機(jī)星座圖,驗(yàn)證了采用干擾對(duì)齊算法前后的效果,實(shí)測(cè)表明,干擾對(duì)齊技術(shù)的應(yīng)用可以給TD-LTE系統(tǒng)帶來實(shí)際的增益和性能的改善;4.在上述工作的基礎(chǔ)上,進(jìn)行系統(tǒng)射頻部分的開發(fā),以便模擬真實(shí)的信道環(huán)境來驗(yàn)證干擾對(duì)齊技術(shù)的效能;運(yùn)用μSDR420軟件無線電平臺(tái)進(jìn)行TD-LTE系統(tǒng)MIMO-OFDM下行鏈路信道環(huán)境的開發(fā),最后成功的實(shí)現(xiàn)了MIMO-OFDM信道的構(gòu)建,為以后IA技術(shù)在真實(shí)無線信道環(huán)境下的性能驗(yàn)證提供了條件。本文的研究成果為干擾對(duì)齊技術(shù)在FPGA上的實(shí)現(xiàn)提供了可行方案,為干擾對(duì)齊技術(shù)在面向未來移動(dòng)通信演進(jìn)中的應(yīng)用提供了參考,為TD-LTE系統(tǒng)的干擾問題提供了一種解決方案,具有現(xiàn)實(shí)指導(dǎo)意義。
[Abstract]:With the increasing demand of user service, the contradiction between high speed, large capacity communication demand and limited bandwidth resources promotes the development of communication concept and ICT. The emergence of MIMO-OFDM technology provides a new way to solve the above contradiction. After the large-scale commercial use of TD-LTE system, the communication rate and system capacity have been obviously improved, and MIMO-OFDM technology has been adopted in the downlink of TD-LTE system. However, because the frequency multiplexing factor is approaching 1, the co-frequency interference between the cell and the cell has become a problem affecting the communication quality. The users in the TD-LTE system are interfered by the same frequency cell and the same frequency relay node in the cell, and the users in the edge of the cell are interfered by the base station of other same frequency cell. Aiming at the interference problem in these scenarios, this paper compares the existing interference processing methods, adopts the interference alignment technology, and builds a verification model of interference alignment technology based on FPGA. The effect of interference alignment algorithm on system performance improvement is studied, and the corresponding conclusions are obtained. The main work of this paper is as follows: 1. This paper analyzes and summarizes the typical scenes of the same frequency interference in TD-LTE system, and combines the relevant theoretical knowledge of interference alignment, selects a kind of interference alignment algorithm which is easy to realize on FPGA, so that it can be used in TD-LTE system. Improve the communication quality in the typical jamming scene and enhance the system capacity; The algorithm is simulated by Matlab and compared with the MIMO-OFDM channel without IA technology. The gain of the proposed algorithm is pointed out with the increase of signal-to-noise ratio (SNR) in the system bit error rate (BER) and capacity. 2. The hardware platform of interference alignment algorithm based on Xilinx FPGA ML605 is built. In the FPGA implementation of IA algorithm, the solving process of precoding matrix V and decoding matrix U is optimized. By simplifying matrix inversion and multiplication in FPGA, the problem of high complexity, excessive consumption of resources and high system delay in hardware implementation is solved. 3. A method is proposed to solve the problem that the PAPR of the data to be transmitted after precoding is too large. The PAPR is reduced by constructing the adjustment factor to adjust the precoded data. The results before and after the interference alignment algorithm are verified by the LCD display on the board and the upper computer constellation diagram. The experimental results show that the application of the interference alignment technology can bring the actual gain and performance improvement to the TD-LTE system; 4. Based on the above work, the RF part of the system is developed to simulate the real channel environment to verify the effectiveness of the interference alignment technology. The 渭 SDR420 software radio platform is used to develop the MIMO-OFDM downlink channel environment of TD-LTE system. Finally, the construction of MIMO-OFDM channel is successfully realized, which provides the condition for the future performance verification of IA technology in the real wireless channel environment. The research results of this paper provide a feasible scheme for the implementation of interference alignment technology on FPGA, provide a reference for the application of interference alignment technology in the evolution of mobile communication facing the future, and provide a solution to the interference problem of TD-LTE system. It is of practical significance.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.5

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本文編號(hào)：2379717