Maximum Spectral Efficiency Through Parallelised Multiple-Input-Multiple-Output Transmission Using High-Resolution 3D Antenna Topologies, Second Phase

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 parallelised 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 set up 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.