The R&I efforts are structured around Work Packages (WPs) 1-3 and are carried out through researcher secondments and sharing of knowledge and skills. The work performed from the beginning of the project to the end of the first reporting period has achieved the following results.
WP1 studies indoor 3D MIMO channel measurement, characterization, and modeling, which form the foundation of the theoretical analysis, design, simulation, and evaluation for indoor 3D MIMO small-cell (SC) networking. We have completed Task 1.1 on indoor 3D ray launching channel simulation incorporating elevation sub-path generation, where the mechanisms of sub-path generation have been studied for indoor environments. We have carried out Task 1.2 on 3D MIMO channel characterization. The 3D MIMO channel path parameters and sub-path parameters have been obtained from extensive 3D MIMO channel simulations using the 3D ray launching based channel model established in Task 1.1 and theoretical analysis based on the sub-path model.
WP2 develops new over-the-air (OTA) characterization methods and performance metrics of 3D MIMO antennas. We have carried out Task 2.1 on optimization of array antennas for 3D spatial multiplexing (SMX) and 3D beamforming, where the initial design of a 3D MIMO antenna system based on a millimeter-wave ultra-wideband antenna has been completed. We have also carried out Task 2.2 on OTA characterization of array antennas and have devised an OTA characterization methodology that can properly evaluate the performance of 3D MIMO array antennas.
WP3 focuses on the planning and optimization of 3D indoor deployment of small-cell access points (APs) equipped with 3D MIMO array antennas. We have carried out Task 3.1 on deriving fundamental performance limits of 3D MIMO small-cell (SC) networks in 3D indoor environments and have completed the interference modeling for a single-floor densely deployed indoor SC network with randomly located interior walls under a stochastic-geometry based framework. The coverage probability of a typical user equipment (UE) has been derived and validated by Monte Carlo simulations. We have also carried out Task 3.2 on analyzing the spectral efficiency (SE) achievable from the dense deployment of 3D MIMO small cells in indoor environments. The analytical expressions for three performance metrics, including the coverage probability, SE, and area spectral efficiency (ASE), have been derived and verified by Monte Carlo simulations.