4 research outputs found
5G Downlink Multi-Beam Signal Design for LOS Positioning
In this work, we study optimal transmit strategies for minimizing the
positioning error bound in a line-of-sight scenario, under different levels of
prior knowledge of the channel parameters. For the case of perfect prior
knowledge, we prove that two beams are optimal, and determine their beam
directions and optimal power allocation. For the imperfect prior knowledge
case, we compute the optimal power allocation among the beams of a codebook for
two different robustness-related objectives, namely average or maximum squared
position error bound minimization. Our numerical results show that our
low-complexity approach can outperform existing methods that entail higher
signaling and computational overhead.Comment: accepted for publication at IEEE GLOBECOM 201
Collaborative Indoor Positioning Systems: A Systematic Review
Research and development in Collaborative Indoor Positioning Systems (CIPSs) is growing
steadily due to their potential to improve on the performance of their non-collaborative counterparts.
In contrast to the outdoors scenario, where Global Navigation Satellite System is widely adopted, in
(collaborative) indoor positioning systems a large variety of technologies, techniques, and methods is
being used. Moreover, the diversity of evaluation procedures and scenarios hinders a direct comparison. This paper presents a systematic review that gives a general view of the current CIPSs. A total of
84 works, published between 2006 and 2020, have been identified. These articles were analyzed and
classified according to the described system’s architecture, infrastructure, technologies, techniques,
methods, and evaluation. The results indicate a growing interest in collaborative positioning, and
the trend tend to be towards the use of distributed architectures and infrastructure-less systems.
Moreover, the most used technologies to determine the collaborative positioning between users are
wireless communication technologies (Wi-Fi, Ultra-WideBand, and Bluetooth). The predominant collaborative positioning techniques are Received Signal Strength Indication, Fingerprinting, and Time
of Arrival/Flight, and the collaborative methods are particle filters, Belief Propagation, Extended
Kalman Filter, and Least Squares. Simulations are used as the main evaluation procedure. On the
basis of the analysis and results, several promising future research avenues and gaps in research
were identified