Load pull compensation in multi user massive MIMO

多用户大规模 MIMO 中的负载牵引补偿

• 批准号: 1936223
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1936223
• 关键词: Load; pull; compensation; multi; user

The purpose of this research is to determine an algorithm and/or process that lends itself to a practical solution for load pull (mutual coupling), an issue that manifests itself in 'multi user massive multiple in multiple out' (MIMO) systems. Antenna arrays used for beam forming or MIMO require the antenna elements to be physically close to each other. With this arrangement, active antenna elements affect their neighbours and visa versa; modifying the antenna impedance (at a given frequency) and electromagnetic field(s). This causes unwanted shifts in radiated power, RF beam direction and intensity. Digital pre-distortion used to compensate for the non linear nature of power amplifiers has been used extensively and can also be employed to compensate for load pull. With a uniform linear phase difference across antenna elements, such as in conventional beam steering, the digital pre-distortion coefficients can be calculated relatively easily. However, with MIMO, the antenna elements phase and amplitude configuration is irregular and hence the effects of antenna elements on one another cannot be predicted. The dynamic MIMO channel matrix, in conjunction with the power amplifier transfer function and the antenna array characteristics are thus processed by said novel algorithm that calculates the digital pre-distortion coefficients for each element, actively compensating for load pull at each element. This research details the MIMO load pull compensation algorithm and a practical real-time hardware/firmware solution. The resulting algorithm/implementation works within a large frequency range and for any PA/antenna combination. It is also inexpensive, low power and scale-able to ultra massive MIMO.

本研究的目的是确定一个算法和/或过程，适合于一个实际的解决方案，负载拉（互耦合），一个问题，体现在“多用户大规模多输入多输出”（MIMO）系统。用于波束成形或MIMO的天线阵列要求天线元件在物理上彼此靠近。通过这种布置，有源天线元件影响它们的邻居，反之亦然;修改天线阻抗（在给定频率下）和电磁场。这会导致辐射功率、RF波束方向和强度发生不必要的变化。用于补偿功率放大器的非线性特性的数字预失真已经被广泛使用，并且还可以用于补偿负载牵引。利用跨天线元件的均匀线性相位差，诸如在常规波束控制中，可以相对容易地计算数字预失真系数。然而，在MIMO的情况下，天线元件的相位和幅度配置是不规则的，因此天线元件彼此之间的影响无法预测。动态MIMO信道矩阵连同功率放大器传递函数和天线阵列特性因此由所述新颖算法处理，所述新颖算法计算每个元件的数字预失真系数，主动补偿每个元件处的负载牵引。本研究详细介绍了MIMO负载牵引补偿算法和实用的实时硬件/固件解决方案。所得到的算法/实现在大的频率范围内并且对于任何PA/天线组合工作。它也是廉价的，低功耗和可扩展到超大规模MIMO。