|LINSALATA FRANCESCO||Cycle: XXXV |
Tutor: CESANA MATTEO
Advisor: MAGARINI MAURIZIO Major Research topic
:Performance Analysis of Advanced Modulation Formats
for Non-Stationary Flying Ad-Hoc Networks (FANETs)Abstract:
With recent technological progress in the field of electronics, sensors and communication systems, the use of small UAVs (Unmanned Air Vehicles) to guarantee connectivity is reality. UAVs admit several potential applications in wireless systems. A strategic aspect is their ability to deploy on-demand network at specific locations, thanks to their inherent properties of mobility, flexibility and adaptive altitude. Hence, UAVs can be viewed as flying antenna systems that can exploit novel techniques of next-generation network, e.g. massive Multi-Input Multi-Output (MIMO), 3D network and millimetre wave communications. A Flying Ad hoc Network (FANET) is such kind of network that consists of a group of small UAVs connected in ad-hoc manner, which are integrated into a team to achieve high level goals. FANETs could expand the connectivity and extend the communication range at infrastructure-less area. Though on one hand, FANETs mobility can be used to provide a rapidly deployable, flexible, self-configurable and relatively small operating expenses network, on the other hand connecting multiple UAVs in ad-hoc network is a big challenge and mobility itself could generate non-stationary behaviours that need to be addressed. This level of coordination requires an appropriate system design that can be set up on highly dynamic flying nodes in order to establish a reliable and robust communication.One of the purposes of this PhD research is to investigate potentials and performance limits of this new communications system in terms of spectral and energy efficiency considering the non-stationarity of the interference that arises in a scenario with multiple drones and moving users From the perspective of waveforms design, many new solutions have been developed, but they cannot meet in a flexible way all the system requirements of this new Beyond fifth Generation (B5G) system. The current 5G-NR waveform, based on Orthogonal Frequency Division Multiplexing (OFDM), is characterized by low spectral efficiency and high Peak-To-Average Power Ratio (PAPR). Similar to OFDM, Discrete Fourier Transform (DFT) spreaded OFDM (DFT-s-OFDM) also poses challenges in the high mobility (Doppler impairments) scenarios such as, for example, Enhanced Vehicle-to-Everything (eV2X) communications and the FANETs. Hence, there is high interest in the development of new multi-carrier waveforms that are able to overcome the limits of OFDM. With this aim, new tuneable waveforms that are able to support variable and customizable pulse shaping filters, such that the air interface can be optimized to each individual application scenario, is one of the research priorities of this study. New proposals that are investigated in this PhD research are filtered multi-carrier waveforms, as Generalized Frequency Division Multiplexing (GFDM), and Orthogonal Time Frequency Space (OTFS). Pro and cons of both of them will be examined, defining a complete mathematical framework for the performance metrics analysis.