On the trade-off between uncertainty and delay in UWB and 5G localization

Location-aware technologies in combination with emerging wireless communication systems\ua0have revolutionized many aspects of our daily lives by means of applications within\ua0the commercial, public and military sectors. Ultra-wideband (UWB) and 5G stand\ua0out as emerging radio frequency (RF) based technologies that tackle the limitations of\ua0Global Positioning System solutions. The thrive in search for better accuracy involves\ua0improved ranging algorithms, higher transmission powers, network densification, larger\ua0bandwidths, and the use of cooperation among nodes in the network. However, practical\ua0implementations introduce communication related constraints. In this thesis, we study\ua0the trade-off between localization accuracy and communication constraints in terms of\ua0delay. This trade-off is investigated and quantified for two of the most rapidly growing\ua0RF technologies for high precision positioning: UWB and 5G.In UWB, we investigate the trade-off between medium access control (MAC) delay and\ua0accuracy based on a two-way-ranging and a spatial time division multiple access scheme.\ua0We quantify this relationship by deriving lower bounds on localization accuracy and MAC\ua0delay during the measurements phase, which is often neglected in the analyses. We find\ua0that the traditional means to improve accuracy such as increased number of anchors,\ua0increased communication range, and cooperation among nodes, come at a significant cost\ua0in terms of delay, which can be mitigated by means of techniques such as selective ranging\ua0and eavesdropping. We summarize and generalize our findings by characterizing the\ua0position error and delay lower bounds by deriving asymptotic scaling laws. These scaling\ua0laws are presented for dense noncooperative and cooperative networks in combination\ua0with delay mitigation techniques. Moreover, we introduce a delay/accuracy trade-off\ua0parameter, which can uniquely quantify the trade-off as a function of the agent and\ua0anchor density. Finally, we consider the problem of fast link scheduling and propose an\ua0optimization strategy to perform robust ranging scheduling with localization constraints.\ua0We propose two MAC-aware link selection heuristic approximation approaches which\ua0show similar performance as the optimal solution, but alleviate the problem complexity.In 5G, we analyze the interplay between communication and positioning within the initial\ua0access procedure between a transmitter and a receiver in a millimeter-wave multipleinput\ua0multiple-output system. We exploit the ability of the receiver to determine its\ua0location during the beam selection process and thus, improve the subsequent selection\ua0of beams within initial access. First, assuming that only the transmitter has beamforming\ua0capabilities, we propose an in-band position-aided transmitter beam selection\ua0protocol for scenarios with direct line-of-sight and scattering. Then, we extend the work\ua0and propose an in-band position-aided beam selection protocol where we also allow for\ua0the receiver to perform beamforming in scenarios with line-of-sight, reflected paths, and\ua0possible beam alignment errors. Both protocols show similar performance compared to\ua0their conventional counterparts in terms of final achieved signal-to-noise ratio, but they\ua0are significantly faster and can additionally provide the position and orientation of the\ua0devices in an accurate manner