- Theoretical and experimental analyses of radio propagation and development of field prediction for wireless radio systems, with special reference to MIMO-DAS solutions;
The research activity on radio propagation has been mainly devoted to the development of field prediction models, both statistical and deterministic. With reference to the deterministic approach, a relevant contribution concerns the diffuse scattering modeling, and therefore the embedding of scattering models into ray tracing (RT) tools. Moreover, database simplification techniques aiming at the reduction of the computation time have been developed and tested. These activities have been carried out also in cooperation with the Helsinki University of Technology, now Aalto University.
The possibility of evaluating the spatial dispersion of the radio channel provided by the RT prediction model is for instance used for the evaluation of the performance of MIMO systems. This analysis has been started in the context of the European project ICT-ALPHA and in collaboration with CommScope Italy s.r.l.; in particular, “Interleaved-MIMO with distributed antennas” solutions have been proposed, where the different MIMO branches are interleaved over different Remote Antenna Units (RAU), and each RAU is equipped with a single antenna element corresponding to a single MIMO branch.
- Characterization of indoor and outdoor propagation at millimeter wave, with special reference to MIMO-beamforming solutions;
In view of the advent of future-generation wireless communication standards (i.e: 5th Generation) multi-Gigabit wireless communication at mm-wave frequencies has recently gained great attention. The relatively small size of mm-wave antennas and devices allows in theory the adoption of compact, very high-order MIMO arrays and therefore of narrow-beam, high-performance beam-forming schemes.
Advanced beam-forming might allow the exploitation of multipath propagation for spatial reuse and multiplexing to achieve high throughput density. Moreover, it allows the implementation of spatial-spectrum management strategies to dynamically “choose” the best paths for transmission, thus overcoming line of sight (LOS) obstruction problems and improving the signal to interference-plus-noise ratio (SINR). This potential however can really be exploited if mm-wave propagation in real environment actually offers independent, spatially separated pathways for multiple concurrent communication links. Unfortunately, the presence of a strong distributed multi-path component (DMC) due to surface-roughness scattering and other phenomena might put into question the actual performance of advanced beam-forming techniques. Therefore a thorough propagation characterization and modelling study addressing time-domain, angle-domain and polarization-domain dispersion characteristics of the mm-wave radio channel in realistic environment is necessary and has been for instance carefully addressed
- Performance assessment of NLoS point-to-point microwave link for mobile back-hauling applications;
In order to cope with increasing traffic demand, future 5G wireless network will likely exploit both macro-cellular and micro-cellular coverage layout. In this framework, the back-hauling system will include poin-to-point radio link between the micro-cellular base station (BS) placed below the rooftop level and the macr-cellular BSs instead locate above that level. In order to allow the transport of a great amount of data, such links will likely work at millimeter frequencies (30 or 60 GHz) not always in Line of Sight, and this aspect may affect the performance to an extent that must be investigated.
- Study of planning and deployment strategies for 5G systems;
The incoming 5G systems will have to meet rather demanding requirement, e.g. in terms of system throughput, latency and overall system efficiency. These technical constraints will require specific solutions like fully dynamic resource management, space division multiple access (beam-forming), etc. which will affect the deployment and planning strategies to an extent that needs to be investigated.
