【作者】 李虎；

【导师】 杨鸿文；

【作者基本信息】 北京邮电大学 ， 电子与通信工程（专业学位）， 2022， 硕士

【摘要】 在各种新增业务需求的推动下,移动通信网络迫切需要向新的一代不断演进,毫米波通信、大规模多输入多输出(Massive MIMO)、波束赋形和透镜天线阵列等技术的融合成为了无线通信领域的研究热点。Massive MIMO在传统MIMO的基础上,扩大了天线阵列的规模,这导致全数字波束赋形方案硬件复杂度极高,能量消耗极高,在实际通信系统中不可能实现。模拟波束赋形虽然降低了系统能耗,但缺少了信号的数字域处理过程,导致通信系统的灵活性很低,只能实现单数据流传输,影响了系统性能。目前毫米波Massive MIMO通信系统中主要采用混合波束赋形方案,但现有的混合波束赋形架构中大多使用大量高精度移相器进行信号相位的调节,系统的硬件开销和能耗仍然较高。为了进一步降低混合波束赋形架构的硬件成本和能量消耗,很多技术和设计应运而生。最近相关研究提出了将透镜天线阵列引入毫米波Massive MIMO通信系统中,利用电磁透镜可以在不同位置产生不同的相移特性,将空间中以不同到达角入射的电磁信号聚集在不同的天线阵元上,在波束赋形架构中使用自适应开关结构来替代移相器进行波束选择,很大程度降低了系统的硬件成本和能量消耗。本文重点研究了毫米波Massive MIMO系统引入透镜阵列后的波束赋形方案设计问题,本文工作主要有如下两个创新点:一是提出了窄带情况下单用户系统中基于自适应开关结构的透镜天线阵列波束赋形方案。基于透镜阵列自身所具有的移相特性,使用开关结构代替移相器进行模拟波束赋形,从而简化波束选择结构降低能耗。所提出的自适应开关结构在天线选择上具有更高的灵活度,根据信道情况自适应给每根射频链路分配天线子集,并且通过遗传算法实现数字波束赋形。同时结合块对角化迫零算法,将所提出的混合波束赋形方案推广到多用户通信系统。二是针对宽带情况下多用户通信系统中应用透镜天线阵列存在的功率泄露,波束斜视以及多用户干扰等问题。给出了优化系统和速率的波束赋形方案。同时给出了对应的通信系统模型,建立了合适的信道模型和能耗模型,设计了联合子载波波束选择(JS-BS)算法,给出了对应的数学推导。更多还原

【Abstract】 Driven by various new service requirements,mobile communication networks urgently need to evolve to a new generation.The integration of millimeter-wave communication,Massive Multiple Input Multiple Output(Massive MIMO),beamforming,and lens antenna arrays has become a research hotspot in the field of wireless communication.On the basis of traditional MIMO,Massive MIMO expands the scale of the antenna array,which leads to extremely high hardware complexity and high energy consumption of the all-digital beamforming solution,which is impossible to implement in actual communication systems.Although analog beamforming reduces the energy consumption of the system,it lacks the digital domain processing process of the signal,resulting in low flexibility of the communication system,and only single data stream transmission can be realized,which affects the system performance.At present,the hybrid beamforming scheme is mainly used in the millimeter-wave Massive MIMO communication system,but most of the existing hybrid beamforming architectures use a large number of high-precision phase shifters to adjust the signal phase,and the hardware overhead and energy consumption of the system are still high.To further reduce the hardware cost and energy consumption of hybrid beamforming architectures,many technologies and designs have emerged.Recent related studies have proposed to introduce lens antenna arrays into millimeter-wave Massive MIMO communication systems.Using electromagnetic lenses,different phase shift characteristics can be generated at different positions,and electromagnetic signals incident at different angles of arrival in space can be concentrated on different antenna array elements.In the above,the adaptive switch structure is used in the beamforming architecture to replace the phase shifter for beam selection,which greatly reduces the hardware cost and energy consumption of the system.This paper focuses on the design of the beamforming scheme after the lens array is introduced into the millimeterwave Massive MIMO system.The work in this paper mainly has the following two innovations:First,a beamforming scheme of lens-antenna array based on adaptive switching structure in single-user system in narrow-band situation is proposed.Based on the phase shift characteristics of the lens array itself,the switch structure is used instead of the phase shifter to perform analog beamforming,thereby simplifying the beam selection structure and reducing energy consumption.The proposed adaptive switch structure has higher flexibility in antenna selection,adaptively allocates antenna subsets to each RF link according to channel conditions,and realizes digital beamforming by genetic algorithm.At the same time,combined with the block-diagonal zero-forcing algorithm,the proposed hybrid beamforming scheme is extended to multi-user communication systems.The second is to address the problems of power leakage,beam squint and multi-user interference in the application of lens antenna arrays in multi-user communication systems under broadband conditions.The beamforming scheme to optimize the system and rate is given.At the same time,the corresponding communication system model is given,the appropriate channel model and energy consumption model are established,the joint subcarrier beam selection(JS-BS)algorithm is designed,and the corresponding mathematical derivation is given.更多还原