相位噪声对60GHz通信系统的影响分析与校正

发布时间：2018-03-18 17:32

本文选题：60GHz　切入点：单载波频域均衡(SC-FDE)　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着全球无线通信技术的高速发展,60GHz通信技术凭借其拥有的巨大带宽、高传输速率、强大的安全性和抗干扰能力等诸多优势在众多无线传输方案中脱颖而出。然而由于其所在频段的特殊性,60GHz通信技术在备受瞩目的同时也面临着诸多挑战,射频非线性的影响就是其中不可忽略的一环。高频特性使得60GHz通信技术与低频段相比更容易受到射频非线性因素的影响,且由于器件制作工艺的限制,在基带选取低复杂度的、简单易行的抑制方案对系统性能的提升具有重要意义。本论文针对射频非线性的主要影响之一——相位噪声(Phase Noise, PN)展开研究分析,在此基础上提出了基于K-L展开的相噪自相关矩阵正交基重构补偿方案,并针对基于IEEE 802.11 ad的标准信道进行了整体链路预算和容量分析,最终验证了对射频非线性影响进行补偿后能够达到吉比特每秒的传输需求。本论文的研究工作基于单载波频域均衡(Single-Carrier with Frequency Domain Equalization, SC-FDE)体制下的60GHz通信系统,所采用模型均基于IEEE 802.11 ad标准。现将全文结构简介如下：首先,对60GHz通信的发展现状及射频非线性影响进行概述,在此基础上分别给出了基于IEEE 802.11ad标准下的系统模型、调制体制和信道模型,模型的建立是接下来研究工作的基础。其次,对引入射频非线性影响的60GHz SC-FDE系统进行链路预算和容量分析,包括功放(Power Amplifier, PA)非线性、相位噪声和IQ不平衡的模型建立及简单补偿仿真、不同信道环境下的容量分析,验证了在现有工艺水准和抑制方案下射频非线性影响不会给系统容量带来太大损失。最后,对本论文的主体——相位噪声影响分析与校正展开了深入研究：常用的公共相位误差(Common Phase Error, CPE)补偿方案仅在低相噪水平和低阶调制下有较好的效果,并不适用于高阶调制在大相噪水平下的补偿应用。针对此种情况,本论文提出了基于K-L展开的时域相噪自相关矩阵正交基相噪补偿方案：通过对指数相噪自相关矩阵的特征值分解获得最大特征值对应的特征向量构造正交基对相位噪声进行重构,正交基的维数可以根据补偿精度需要自行调整。为了提高补偿效果,算法中还引入了判决反馈迭代更新,并选取收敛时的结果作为最终的解调数据。本算法相对于经典的CPE补偿算法在高阶调制和大相噪水平下具有明显的补偿效果提升。根据仿真结果显示,本论文的算法比单纯的CPE补偿对系统性能有多达4dB以上的改善,与经典的自适应最小均方(Least Mean Square, LMS)判决反馈相噪补偿算法相比也有约1dB的性能提升。
[Abstract]:With the rapid development of global wireless communication technology, the 60GHz communication technology has a huge bandwidth and high transmission rate. Many advantages, such as strong security and anti-jamming ability, stand out in many wireless transmission schemes. However, due to the particularity of its frequency band, 60GHz communication technology is facing many challenges while it is attracting much attention. The influence of RF nonlinearity is not to be ignored. The high frequency characteristic makes 60GHz communication technology more vulnerable to the influence of RF nonlinear factors than the low frequency band, and because of the limitation of device fabrication technology, low complexity is selected in the baseband. The simple and easy suppression scheme is of great significance to the improvement of system performance. In this paper, phase noise phase Noise (PNs), one of the main effects of RF nonlinearity, is studied and analyzed. Based on this, a phase noise autocorrelation matrix orthogonal basis reconstruction compensation scheme based on K-L expansion is proposed, and the overall link budget and capacity of the standard channel based on IEEE 802.11ad are analyzed. Finally, it is verified that the compensation of RF nonlinear influence can meet the transmission demand of gigabits per second. The research work in this thesis is based on single-carrier frequency domain equalization single-carrier with Frequency Domain equalization (SC-FDE) based on 60GHz communication system. All the models are based on IEEE 802.11ad standard. The structure of this paper is summarized as follows: firstly, the development of 60GHz communication and the influence of RF nonlinearity are summarized, and then the system models based on IEEE 802.11ad are given. The establishment of modulation system and channel model is the basis of the next research work. Secondly, the link budget and capacity of 60GHz SC-FDE system with RF nonlinear effect are analyzed, including power amplifier power amplifier (PAA) nonlinearity. The modeling and simple compensation simulation of phase noise and IQ imbalance, and capacity analysis under different channel environments, verify that the nonlinear effect of RF on the existing process level and suppression scheme will not bring much loss to the system capacity. In this paper, the influence analysis and correction of the main body phase noise are deeply studied. The common phase error Phase error (CPE) compensation scheme is only effective at low phase noise level and low order modulation. It is not suitable for the compensation application of high order modulation at large phase noise level. In this paper, we propose a phase noise compensation scheme for time domain phase noise autocorrelation matrix based on K-L expansion. By decomposing the eigenvalue of exponential phase noise autocorrelation matrix, we construct orthogonal basis phase by eigenvector corresponding to the largest eigenvalue. Bit noise is reconstructed, The dimension of orthogonal basis can be adjusted according to the accuracy of compensation. In order to improve the compensation effect, the iterative updating of decision feedback is also introduced in the algorithm. The result of convergence is chosen as the final demodulation data. Compared with the classical CPE compensation algorithm, this algorithm has obvious compensation effect at high order modulation and large phase noise level. The simulation results show that, The proposed algorithm can improve the performance of the system by more than 4dB compared with the simple CPE compensation, and has a performance improvement of about 1 dB compared with the classical adaptive least mean square least square squared (LMS-LMS) decision feedback phase noise compensation algorithm.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN914

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