Periodic Reporting for period 1 - DELIGHT (Device-Centric Low-Complexity High-Frequency Networks)
Période du rapport: 2020-07-01 au 2022-06-30
For the device-level perspective, we mainly considered fully digital massive MIMO architectures with low-resolution analog-to-digital/digital-to-analog converters (ADCs/DACs) as a means to reduce the hardware power consumption and complexity at the base station when operating at high frequencies. Hybrid analog-digital arrays do not scale well beyond the low mmWave spectrum due to the need for complex analog circuitry and resource-consuming beam management schemes. Few-bit or 1-bit fully digital massive MIMO can outperform its hybrid analog-digital counterpart in terms of beamforming flexibility and spectral/energy efficiency. 1-bit ADCs/DACs are particularly attractive as they minimize the complexity and power consumption of the data conversion, although the 1-bit quantization inevitably deteriorates the spectral efficiency. Hence, we provided new analytical studies on the channel estimation, data detection, and spectral efficiency of massive MIMO systems with 1-bit and few-bit ADCs/DACs. In addition, we considered fully digital unquantized massive MIMO and devised innovative methods to boost the spectral efficiency, i.e. by means of statistical beamforming at the user-side for highly overlapping user equipments, and the data detection performance, i.e. via low-complexity detection algorithms based on variational Bayesian inference.
For the integration of network- and device-level perspectives, to guarantee the necessary physical-layer paradigm shift with respect to the current 5G systems, the increase in the operating frequencies must go hand in hand with the introduction of flexible device-centric mechanisms. In this respect, there is a plethora of interconnected design parameters at the network and device level that need to be considered jointly in order to satisfy application-specific quality-of-service requirements. Hence, we aimed at determining a unified view of the infrastructure, spectrum, and protocols/algorithms that are necessary to accommodate specific wireless applications in future 6G systems. In addition, we analyzed multi-antenna multicasting aided by device-to-device communications to accommodate safety-critical applications under different channel state information assumptions.