无线通信中轨道角动量传输特性建模研究

发布时间：2018-01-22 03:34

本文关键词： 轨道角动量传输特性建模大气湍流　出处：《宁夏大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着通信技术的日益发展,当今无线通信系统正向着更高速率和更高带宽的目标迈进。容量需求和频谱资源短缺的矛盾在这个智能终端以及互联网飞速发展的时代显得尤为突出,因此,解决这一问题成为5G无线通信技术中迫在眉睫的事情。轨道角动量(orbital angular momentum,OAM)技术能够在不增加带宽的条件下,极大地提高系统容量,这就让它在无线通信领域里的研究以及应用日渐成为一个热点。目前把轨道角动量技术应用到无线通信系统中只是探索阶段,还有很多技术难关需要攻克。本课题以轨道角动量的基本性质为理论基础,提出无线通信中轨道角动量的模型,并且对电磁涡旋波的传输特性进行研究和分析。在传播过程中,电磁涡旋波会受到大气湍流等因素的影响,使相位的扭转角度发生改变,从而破坏电磁涡旋波最初的波形。本课题为容量需求和频谱资源短缺的问题提供一定的理论支持,从而加快智能终端的普及和互联网的发展。本文主要工作内容如下:(1)文章提出了无线通信系统里轨道角动量的模型,本文将光子轨道角动量的模型应用于低频,建立类似于拉盖尔高斯光束的电磁涡旋波模型,并且通过Labview软件对30GHz的OAM波束进行仿真,这为本文后续的研究工作打下了基础。(2)本文通过Labview仿真软件研究无线通信中电磁涡旋波在理想信道中的传输特性。携带轨道角动量的电磁涡旋波在理想信道中传输后,电场分布发散,出现波束展宽现象,能量产生损耗;相位发生随机畸变,等相位线弯曲。之后研究了距离、波长以及束腰半径等参数对轨道角动量传输特性的影响,随着轨道角动量在理想信道中传输距离的增大,电磁涡旋波波形变化逐渐严重;当传输距离为0时,电磁涡旋波的相位分布仅由OAM模态值的大小和正负决定。(3)本文研究了无线通信系统中大气湍流对电磁涡旋波传输特性产生的影响。传输距离相同时,电磁涡旋波在大气湍流里传播明显比在理想信道里传播波形损失严重;电磁涡旋波携带的OAM模态值绝对值越大,它受到大气湍流的影响就越大;当模态值大小相同、符号相反时,电磁涡旋波受到大气湍流的影响基本相同,只因为大气湍流的随机性有微小的差异。之后文章研究了不同传输距离和大气湍流强度对轨道角动量产生的影响。最后采用发射空间分集技术来抑制大气湍流对轨道角动量传输特性的影响,并且发现不考虑空间、成本等限制时,发射天线数量越多,抑制大气湍流对轨道角动量影响的效果越好。
[Abstract]:With the development of communication technology. Nowadays, the wireless communication system is moving towards the goal of higher rate and higher bandwidth. The contradiction between the capacity demand and the shortage of spectrum resources is particularly prominent in this era of intelligent terminals and the rapid development of the Internet. Solving this problem has become an urgent matter in 5G wireless communication technology. Orbital angular momentum angular momentum. OAM) technology can greatly improve system capacity without increasing bandwidth. This makes its research and application in the field of wireless communication increasingly become a hot spot. At present, the application of orbital angular momentum technology to wireless communication systems is only a phase of exploration. There are still many technical difficulties to overcome. Based on the basic properties of orbital angular momentum, a model of orbital angular momentum in wireless communication is proposed in this paper. And the transmission characteristics of electromagnetic vortex wave are studied and analyzed. In the process of propagation, the electromagnetic vortex wave will be affected by atmospheric turbulence and other factors, making the phase torsional angle change. In order to destroy the initial waveform of electromagnetic vortex wave, this paper provides some theoretical support for the problem of capacity demand and the shortage of spectrum resources. In order to speed up the popularity of intelligent terminals and the development of the Internet. The main work of this paper is as follows: 1) the paper puts forward the model of orbital angular momentum in wireless communication system. In this paper, the photon orbital angular momentum model is applied to the low frequency, and the electromagnetic vortex wave model similar to the Laguerre Gao Si beam is established, and the 30GHz OAM beam is simulated by Labview software. This will lay a foundation for further research work in this paper. In this paper, Labview simulation software is used to study the transmission characteristics of electromagnetic vortex wave in the ideal channel in wireless communication. After the electromagnetic vortex wave with orbital angular momentum is transmitted in the ideal channel. The distribution of electric field diverges and the beam widens and the energy is lost. The influence of the parameters such as distance, wavelength and beam waist radius on the transmission characteristics of orbital angular momentum is studied, with the increase of orbital angular momentum transmission distance in ideal channel. The change of electromagnetic vortex wave waveform is serious. When the transmission distance is 0:00. The phase distribution of electromagnetic vortex wave is determined only by the magnitude of OAM mode value and the positive and negative value.) in this paper, the influence of atmospheric turbulence on electromagnetic vortex wave propagation characteristics in wireless communication system is studied. The electromagnetic vortex wave propagates more seriously in the atmospheric turbulence than in the ideal channel. The larger the absolute value of OAM mode carried by electromagnetic vortex wave is, the greater it will be affected by atmospheric turbulence. When the modal value is the same and the symbol is opposite, the electromagnetic vortex wave is affected by the atmospheric turbulence basically the same. It is only because of the slight difference in the randomness of atmospheric turbulence. Then the influence of different transmission distance and atmospheric turbulence intensity on orbital angular momentum is studied. Finally, emission space diversity technique is used to suppress atmospheric turbulence. The influence of orbital angular momentum transmission characteristics. It is also found that the more the number of transmitting antennas is, the better the effect of suppressing atmospheric turbulence on orbital angular momentum is when space and cost are not taken into account.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92

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