459 research outputs found
Impact of an Interfering Node on Unmanned Aerial Vehicle Communications
Unlike terrestrial communications, unmanned aerial vehicle (UAV)
communications have some advantages such as the line-of-sight (LoS) environment
and flexible mobility. However, the interference will be still inevitable. In
this paper, we analyze the effect of an interfering node on the UAV
communications by considering the LoS probability and different channel fading
for LoS and non-line-of-sight (NLoS) links, which are affected by the elevation
angle of the communication link. We then derive a closed-form outage
probability in the presence of an interfering node for all the possible
scenarios and environments of main and interference links. After discussing the
impacts of transmitting and interfering node parameters on the outage
probability, we show the existence of the optimal height of the UAV that
minimize the outage probability. We also show the NLoS environment can be
better than the LoS environment if the average received power of the
interference is more dominant than that of the transmitting signal on UAV
communications. Finally, we analyze the outage probability for the case of
multiple interfering nodes using stochastic geometry and the outage probability
of the single interfering node case, and show the effect of the interfering
node density on the optimal height of the UAV.Comment: 12 pages, 10 figures, this paper has been submitted in IEEE
Transactions on Vehicular Technology. arXiv admin note: substantial text
overlap with arXiv:1806.0984
Using macroscopic entanglement to close the detection loophole in Bell inequality
We consider a Bell-like inequality performed using various instances of
multi-photon entangled states to demonstrate that losses occurring after the
unitary transformations used in the nonlocality test can be counteracted by
enhancing the "size" of such entangled states. In turn, this feature can be
used to overcome detection inefficiencies affecting the test itself: a slight
increase in the size of such states, pushing them towards a more "macroscopic"
form of entanglement, significantly improves the state robustness against
detection inefficiency, thus easing the closing of the detection loophole.
Differently, losses before the unitary transformations cause decoherence
effects that cannot be compensated using macroscroscopic entanglement.Comment: 5 pages, 5 figures, to be published in Phys. Rev.
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