  Internet of things (IoT) is one of main paradigms for 5G wireless systems.
Due to high connection density, interference from other sources is a key
problem in IoT networks. Especially, it is more difficult to find a solution to
manage interference in uncoordinated networks than coordinated system. In this
work, we consider 3D topology of uncoordinated IoT network and propose
interference mitigation scheme with respect to 3D antenna radiation pattern. In
2D topology network, the radiation pattern of dipole antenna can be assumed as
onmi-directional. We show the variance of antenna gain on dipole antenna in 3D
topology, consider the simultaneous use of three orthogonal dipole antennas,
and compare the system performance depending on different antenna
configurations. Our simulation results show that proper altitude of IoT devices
can extensively improve the system performance.
