id: 06130527 dt: j an: au: Aloupis, Greg; Damian, Mirela; Flatland, Robin; Korman, Matias; Özkan, Özgür; Rappaport, David; Wuhrer, Stefanie ti: Establishing strong connectivity using optimal radius half-disk antennas. so: Comput. Geom. 46, No. 3, 328-339 (2013). py: 2013 pu: Elsevier Science B.V. (North-Holland), Amsterdam la: EN cc: 68R10 90B10 94A12 ut: ad-hoc network; directional antennas; minimum spanning tree; radii and orientation assignment ci: li: doi:10.1016/j.comgeo.2012.09.008 ab: Summary: Given a set $S$ of points in the plane representing wireless devices, each point equipped with a directional antenna of radius $r$ and aperture angle $α\geqslant 180^\circ$, our goal is to find orientations and a minimum $r$ for these antennas such that the induced communication graph is strongly connected. We show that $r=\sqrt{3}$ if $α\in [180^\circ, 240^\circ), r=\sqrt{2}$ if $α\in [240^\circ ,270^\circ)$, $r=2\sin(36^\circ)$ if $α\in [270^\circ ,288^\circ$), and $r=1$ if $α\geqslant 288^\circ $ suffices to establish strong connectivity, assuming that the longest edge in the Euclidean minimum spanning tree of $S$ is 1. These results are worst-case optimal and match the lower bounds presented in [{\it I. Caragiannis}, {\it C. Kaklamanis}, {\it E. Kranakis}, {\it D. Krizanc} and {\it A. Wiese}, “Communication in wireless networks with directional antennae", in: SPAA ’08. Proceedings of the twentieth annual symposium on Parallelism in algorithms and architectures. New York: ACM, 344‒351 (2008)]. In contrast, $r=2$ is sometimes necessary when $α<180^\circ $. rv: