LTE下行鏈路信號幅度控制技術(shù)研究
發(fā)布時間：2019-03-09 17:38
【摘要】：作為第四代通信標準,長期演進(Long Term Evolution,LTE)引入了正交頻分復(fù)用(Orthogonal Frequency Division Multiplexing,OFDM)和高階正交幅度調(diào)制(Quadrature Amplitude Modulation,QAM)技術(shù)。相比之前的第二代和第三代通信標準,LTE提供了更高的頻譜利用率和更強的抗多徑衰落能力。但OFDM技術(shù)和QAM高階調(diào)制技術(shù)的引入會造成LTE信號的包絡(luò)波動性較高。信號包絡(luò)波動較大會使LTE信號峰值容易進入功率放大器非線性區(qū)域,從而引起嚴重的帶內(nèi)信號畸變和頻譜擴展,造成了通信系統(tǒng)性能的惡化�，F(xiàn)在廣泛采用兩種度量方式來描述多載波信號幅度變化大小,一種是峰均功率比,另一種是立方度量。本文通過分析多載波信號幅度的變化,提出了兩種抑制信號幅度變化大小的方法,分別用于降低信號的峰均功率比和立方度量。本項課題研究的創(chuàng)新如下:第一,基于不確定原理提出了一種降低LTE信號峰均功率比的方法。我們從理論上分析了利用不確定原理降低信號峰均功率比的可行性,并據(jù)此提出了一種高效的迭代算法,該算法可以有效降低LTE信號的峰均功率比,同時又保持了良好的誤碼率性能。仿真結(jié)果表明:在互補累積分布函數(shù)(Complementary Cumulative Distribution Function,CCDF)為10-3時,該算法可使LTE信號的峰均功率比降低4.7dB,而矢量幅度誤差(Error Vector Magnitude,EVM)為0.028。第二,提出了一種基于凸優(yōu)化的抑制立方度量的方法。我們首先建立了一個和立方度量、鄰道泄漏以及EVM有關(guān)的非凸優(yōu)化模型,在將其轉(zhuǎn)化為一個凸優(yōu)化問題之后,我們給出了求解該問題的一個高效的內(nèi)點法解決方案。該方案在滿足立方度量和鄰道泄露的約束條件下,可以實現(xiàn)EVM的最小化,同時該方案也具有良好的收斂性,只需3次迭代即可實現(xiàn)收斂。仿真結(jié)果表明:在3CCDF 10-?時,該方法經(jīng)過3次迭代可使信號的立方度量降低4.12dB,同時EVM也達到了最小。本文提出的兩種方法都能夠在符合第三代合作伙伴計劃(3rd Generation Partnership Project,3GPP)協(xié)議條件下有效控制LTE下行鏈路信號的幅度變化大小,因此這兩種方法具有廣泛的適用性。
[Abstract]:As the fourth generation communication standard, long-term Evolution (Long Term Evolution,LTE) introduces orthogonal Frequency Division Multiplexing (Orthogonal Frequency Division Multiplexing,OFDM) and High-order orthogonal amplitude Modulation (Quadrature Amplitude Modulation,QAM). Compared with previous second-generation and third-generation communication standards, LTE provides higher spectrum efficiency and stronger anti-multipath fading capability. However, the introduction of OFDM technology and QAM high-order modulation technology will result in high envelope volatility of LTE signals. The fluctuation of the signal envelope makes the peak value of the LTE signal easily enter the nonlinear region of the power amplifier, resulting in serious in-band signal distortion and spectrum spread, resulting in the deterioration of the performance of the communication system. At present, two measures are widely used to describe the amplitude variation of multi-carrier signal, one is peak-to-average power ratio, the other is cubic measurement. By analyzing the amplitude variation of the multi-carrier signal, two methods to suppress the amplitude variation of the signal are proposed, which are used to reduce the peak-to-average power ratio and cubic measurement of the signal, respectively. The innovations of this project are as follows: firstly, based on the uncertainty principle, a method to reduce the peak-to-average power ratio (PAPR) of LTE signal is proposed. In this paper, we theoretically analyze the feasibility of reducing the peak-to-average power ratio (PAPR) by using the uncertainty principle, and propose an efficient iterative algorithm, which can effectively reduce the peak-to-average power ratio (PAPR) of the LTE signal. At the same time, it maintains a good bit error rate performance. The simulation results show that when the complementary cumulative distribution function (Complementary Cumulative Distribution Function,CCDF) is 10-3, the peak-to-average power ratio of the LTE signal can be reduced by 4.7 dB, while the vector amplitude error (Error Vector Magnitude,EVM) is 0.028. Secondly, a method based on convex optimization to suppress cubic metric is proposed. In this paper, we first establish a nonconvex optimization model related to cubic metric, adjacent channel leakage and EVM. After transforming it into a convex optimization problem, we give an efficient interior point method solution to solve the problem. Under the constraint of cubic metric and adjacent channel leakage, the scheme can minimize the EVM. At the same time, the scheme also has good convergence, and only three iterations are needed to realize the convergence. The simulation results show that: in 3CCDF 10? After three iterations, the cubic metric of the signal can be reduced by 4.12 dB, and the EVM is also minimized. The two methods proposed in this paper can effectively control the amplitude variation of LTE downlink signals in accordance with the third Generation partner Program (3rd Generation Partnership Project,3GPP) protocol, so the two methods have wide applicability.
【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】：2016
【分類號】：TN929.5
本文編號：2437705
[Abstract]:As the fourth generation communication standard, long-term Evolution (Long Term Evolution,LTE) introduces orthogonal Frequency Division Multiplexing (Orthogonal Frequency Division Multiplexing,OFDM) and High-order orthogonal amplitude Modulation (Quadrature Amplitude Modulation,QAM). Compared with previous second-generation and third-generation communication standards, LTE provides higher spectrum efficiency and stronger anti-multipath fading capability. However, the introduction of OFDM technology and QAM high-order modulation technology will result in high envelope volatility of LTE signals. The fluctuation of the signal envelope makes the peak value of the LTE signal easily enter the nonlinear region of the power amplifier, resulting in serious in-band signal distortion and spectrum spread, resulting in the deterioration of the performance of the communication system. At present, two measures are widely used to describe the amplitude variation of multi-carrier signal, one is peak-to-average power ratio, the other is cubic measurement. By analyzing the amplitude variation of the multi-carrier signal, two methods to suppress the amplitude variation of the signal are proposed, which are used to reduce the peak-to-average power ratio and cubic measurement of the signal, respectively. The innovations of this project are as follows: firstly, based on the uncertainty principle, a method to reduce the peak-to-average power ratio (PAPR) of LTE signal is proposed. In this paper, we theoretically analyze the feasibility of reducing the peak-to-average power ratio (PAPR) by using the uncertainty principle, and propose an efficient iterative algorithm, which can effectively reduce the peak-to-average power ratio (PAPR) of the LTE signal. At the same time, it maintains a good bit error rate performance. The simulation results show that when the complementary cumulative distribution function (Complementary Cumulative Distribution Function,CCDF) is 10-3, the peak-to-average power ratio of the LTE signal can be reduced by 4.7 dB, while the vector amplitude error (Error Vector Magnitude,EVM) is 0.028. Secondly, a method based on convex optimization to suppress cubic metric is proposed. In this paper, we first establish a nonconvex optimization model related to cubic metric, adjacent channel leakage and EVM. After transforming it into a convex optimization problem, we give an efficient interior point method solution to solve the problem. Under the constraint of cubic metric and adjacent channel leakage, the scheme can minimize the EVM. At the same time, the scheme also has good convergence, and only three iterations are needed to realize the convergence. The simulation results show that: in 3CCDF 10? After three iterations, the cubic metric of the signal can be reduced by 4.12 dB, and the EVM is also minimized. The two methods proposed in this paper can effectively control the amplitude variation of LTE downlink signals in accordance with the third Generation partner Program (3rd Generation Partnership Project,3GPP) protocol, so the two methods have wide applicability.
【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】：2016
【分類號】：TN929.5
【參考文獻】
相關(guān)碩士學(xué)位論文 前1條
1 盛山鋒;基于IDMA在OFDM系統(tǒng)中的應(yīng)用研究[D];浙江工商大學(xué);2010年
，本文編號：2437705
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