Nokia Solutions and Networks, 54-130 Wrocław, Poland.
Institute of Communications Systems, Faculty of Electronics, Military University of Technology, 00-908 Warsaw, Poland.
Sensors (Basel). 2021 Jan 16;21(2):597. doi: 10.3390/s21020597.
Multi-beam antenna systems are the basic technology used in developing fifth-generation (5G) mobile communication systems. In practical implementations of 5G networks, different approaches are used to enable a massive multiple-input-multiple-output (mMIMO) technique, including a grid of beams, zero-forcing, or eigen-based beamforming. All of these methods aim to ensure sufficient angular separation between multiple beams that serve different users. Therefore, ensuring the accurate performance evaluation of a realistic 5G network is essential. It is particularly crucial from the perspective of mMIMO implementation feasibility in given radio channel conditions at the stage of network planning and optimization before commercial deployment begins. This paper presents a novel approach to assessing the impact of a multi-beam antenna system on an intra-cell interference level in a downlink, which is important for the accurate modeling and efficient usage of mMIMO in 5G cells. The presented analysis is based on geometric channel models that allow the trajectories of propagation paths to be mapped and, as a result, the angular power distribution of received signals. A multi-elliptical propagation model (MPM) is used and compared with simulation results obtained for a statistical channel model developed by the 3rd Generation Partnership Project (3GPP). Transmission characteristics of propagation environments such as power delay profile and antenna beam patterns define the geometric structure of the MPM. These characteristics were adopted based on the 3GPP standard. The obtained results show the possibility of using the presented novel MPM-based approach to model the required minimum separation angle between co-channel beams under line-of-sight (LOS) and non-LOS conditions, which allows mMIMO performance in 5G cells to be assessed. This statement is justified because for 80% of simulated samples of intra-cell signal-to-interference ratio (SIR), the difference between results obtained by the MPM and commonly used 3GPP channel model was within 2 dB or less for LOS conditions. Additionally, the MPM only needs a single instance of simulation, whereas the 3GPP channel model requires a time-consuming and computational power-consuming Monte Carlo simulation method. Simulation results of intra-cell SIR obtained this way by the MPM approach can be the basis for spectral efficiency maximization in mMIMO cells in 5G systems.
多波束天线系统是开发第五代（5G）移动通信系统的基础技术。在 5G 网络的实际实现中，使用了不同的方法来实现大规模多输入多输出（mMIMO）技术，包括波束网格、迫零或基于特征的波束形成。所有这些方法的目的都是确保为不同用户服务的多个波束之间有足够的角分离。因此，确保对现实 5G 网络的精确性能评估至关重要。从在商业部署开始之前的网络规划和优化阶段，在给定的无线电信道条件下实现 mMIMO 的可行性的角度来看，这一点尤为关键。本文提出了一种评估多波束天线系统对下行链路小区内干扰水平影响的新方法，这对于在 5G 小区中对 mMIMO 进行精确建模和有效利用非常重要。所提出的分析基于几何信道模型，该模型允许映射传播路径的轨迹，从而可以得到接收信号的角功率分布。使用了多椭圆传播模型（MPM），并将其与由第三代合作伙伴计划（3GPP）开发的统计信道模型的仿真结果进行了比较。传播环境的传输特性，如功率延迟分布和天线波束模式，定义了 MPM 的几何结构。这些特性是根据 3GPP 标准采用的。得到的结果表明，可以使用所提出的基于新型 MPM 的方法来模拟视距（LoS）和非视距（NLOS）条件下同信道波束之间所需的最小分离角，从而可以评估 5G 小区中的 mMIMO 性能。这一说法是合理的，因为在 80%的模拟小区内信号干扰比（SIR）样本中，MPM 和常用的 3GPP 信道模型的结果之间的差异在 LOS 条件下不超过 2dB。此外，MPM 只需要一次模拟，而 3GPP 信道模型需要使用耗时且计算量大的蒙特卡罗仿真方法。通过 MPM 方法获得的这种小区内 SIR 的仿真结果可以成为 5G 系统中 mMIMO 小区中频谱效率最大化的基础。
