681 research outputs found
Production of entanglement with highly-mixed states
We study production of entanglement with highly-mixed states. We find that
entanglement between highly mixed states can be generated via a direct unitary
interaction even when both states have purities arbitrarily close to zero. This
indicates that purity of a subsystem is not required for entanglement
generation. Our result is in contrast to previous studies where the importance
of the subsystem purity was emphasized.Comment: 4 pages, 5 figure
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
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