LTE下行链路信号幅度控制技术研究
发布时间：2019-03-09 17:38
【摘要】：作为第四代通信标准,长期演进(Long Term Evolution,LTE)引入了正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)和高阶正交幅度调制(Quadrature Amplitude Modulation,QAM)技术。相比之前的第二代和第三代通信标准,LTE提供了更高的频谱利用率和更强的抗多径衰落能力。但OFDM技术和QAM高阶调制技术的引入会造成LTE信号的包络波动性较高。信号包络波动较大会使LTE信号峰值容易进入功率放大器非线性区域,从而引起严重的带内信号畸变和频谱扩展,造成了通信系统性能的恶化。现在广泛采用两种度量方式来描述多载波信号幅度变化大小,一种是峰均功率比,另一种是立方度量。本文通过分析多载波信号幅度的变化,提出了两种抑制信号幅度变化大小的方法,分别用于降低信号的峰均功率比和立方度量。本项课题研究的创新如下:第一,基于不确定原理提出了一种降低LTE信号峰均功率比的方法。我们从理论上分析了利用不确定原理降低信号峰均功率比的可行性,并据此提出了一种高效的迭代算法,该算法可以有效降低LTE信号的峰均功率比,同时又保持了良好的误码率性能。仿真结果表明:在互补累积分布函数(Complementary Cumulative Distribution Function,CCDF)为10-3时,该算法可使LTE信号的峰均功率比降低4.7dB,而矢量幅度误差(Error Vector Magnitude,EVM)为0.028。第二,提出了一种基于凸优化的抑制立方度量的方法。我们首先建立了一个和立方度量、邻道泄漏以及EVM有关的非凸优化模型,在将其转化为一个凸优化问题之后,我们给出了求解该问题的一个高效的内点法解决方案。该方案在满足立方度量和邻道泄露的约束条件下,可以实现EVM的最小化,同时该方案也具有良好的收敛性,只需3次迭代即可实现收敛。仿真结果表明:在3CCDF 10-?时,该方法经过3次迭代可使信号的立方度量降低4.12dB,同时EVM也达到了最小。本文提出的两种方法都能够在符合第三代合作伙伴计划(3rd Generation Partnership Project,3GPP)协议条件下有效控制LTE下行链路信号的幅度变化大小,因此这两种方法具有广泛的适用性。
[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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.5
本文编号：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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.5
【参考文献】
相关硕士学位论文 前1条
1 盛山锋;基于IDMA在OFDM系统中的应用研究[D];浙江工商大学;2010年
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