Maximum Spectral Efficiency Through Parallelized Multiple-Input-Multiple-Output (MIMO) Transmission Using High-Resolution 3D Antenna Topologies

随着移动数据流量的快速增长和网络的进一步致密化，设计出高效、灵活、具有可行实用外形的无线前端/回程终端，对于提供5G网络所要求的高数据速率、低时延和低能耗至关重要。Maximum MIMO项目的第一阶段研究重点是基于高度并行化的系统结构和多单元天线阵列的高吞吐量毫米波视距MIMO系统。提出了一种基于空间复用和波束形成增益的分层MIMO收发信机结构，并推导了确定性LOS信道下的最优天线布置。我们的研究表明，所提出的无线回程解决方案具有实际可行性，能够在点对点链路中实现100 Gb/S及以上的吞吐量和高能量效率。为了获得更高的吞吐量并支持回程网络中的多个终端，需要开发适用于多路径和多方向场景的3D MIMO系统。出现了一些相关的科学挑战，这些挑战可视为第一项目阶段所做研究工作的自然延伸。在Maximum MIMO的第二阶段中考虑的方法有两个方向，即多路径的毫米波3D MIMO和点到多点的毫米波LOS MIMO，以获得更高的吞吐量和效率。申请者在第二阶段考虑的目标系统参数与欧洲5G网络倡议中定义的关键性能指标非常一致。与依赖于点对点LOS MIMO链路的最优布置的天线的第一阶段相比，第二阶段专注于具有多个确定性路径的基于毫米波的通信，利用3D MIMO布置支持来自多个方向的多个终端。研究主题将涵盖可重新配置的3D MIMO天线拓扑结构、具有低复杂性混合信号处理的收发机架构、宽带和稀疏信道估计、毫米波频段的均衡和信道特性、同步和射频损伤缓解技术、用于低分辨率量化和功率消耗的系统设计、基于自适应波束形成的用户检测和调度方案，以及用于高带宽和低延迟的多用户3D MIMO基带架构。建议的概念将在现实环境中使用定制的MIMO硬件演示器进行验证。Maximum MIMO项目的第二阶段解决了DFG优先项目SPP1655感兴趣的几个研究课题，即：实现100 GB/S及以上吞吐量的系统架构、用于低复杂度高能效的混合信号处理、用于高带宽的基带处理算法以及组合PHY/MAC协议设计。

With the rapid increase of mobile data traffic and further network densification, the design of efficient and flexible wireless front-/backhaul terminals with a feasible practical form factor is essential for providing high data rates, low latency and low energy consumption as e.g. required by 5G networks. The first phase of the research project maximumMIMO is focused on mmWave line-of-sight MIMO systems with high throughput based on highly parallelized system architectures and many-element antenna arrays. A hierarchical MIMO transceiver architecture relying on spatial multiplexing and beamforming gain is proposed and the optimal antenna arrangements are derived for deterministic LoS channels. Our investigations have shown the practical feasibility of the proposed wireless backhaul solutions that are capable of achieving throughput of 100 Gb/s and beyond with high energy efficiency in point-to-point links. In order to achieve even higher throughputs and to support multiple terminals inside the backhaul networks, the development of 3D MIMO systems for multipath and multi-directional scenarios is required. A number of related scientific challenges arise that can be considered as a natural extension to the research work done in the first project phase. The approach considered in the second phase of maximumMIMO takes two directions, namely mmWave 3D MIMO with multipath and point-to-multipoint mmWave LoS MIMO for higher throughput and efficiency. The target system parameters considered by the applicants in the second phase are well aligned to the key performance indicators defined in the European 5G networks initiative. In contrast to the first phase that relies on optimally arranged antennas for point-to-point LoS MIMO links, the second phase focuses on mmWave-based communications with multiple deterministic paths, supporting multiple terminals from multiple directions with 3D MIMO arrangements. The research topics will cover reconfigurable 3D MIMO antenna topologies, transceiver architectures with hybrid signal processing of low complexity, broadband as well as sparse channel estimation, equalization and channel characterization at mmWave bands, synchronization and RF impairment mitigation techniques, system design for low resolution quantization and power consumption, adaptive beamforming-based user detection and scheduling schemes, and multi-user 3D MIMO baseband architectures for high bandwidths and low latency. The validation of the proposed concepts will be performed using a custom built MIMO hardware demonstrator setup in a realistic environment. The second phase of the project maximumMIMO addresses several research topics of interest of the DFG priority program SPP1655, namely: system architectures achieving throughput of 100 Gb/s and beyond, hybrid signal processing for high energy efficiency with low complexity, baseband processing algorithms for high bandwidths, as well as combined PHY/MAC protocol design.