  We study the distribution of the interference power in a millimeter wave
(mmWave) cellular network. Such interference is random and highly dependent on
the employed transmission technique, as well as the varying channel conditions
and the varying association between users and base stations. Traditional
networks at lower frequencies usually employ omnidirectional transmission which
creates an (almost) equal amount of interference in any direction. MmWave
networks, however, must employ directional beamforming transmission in order to
compensate for the high path loss in mmWave frequency bands. These directional
transmissions drastically change the network interference structure. We examine
the interference power distributions in an mmWave network employing beamforming
transmission under different user association schemes, and contrast with those
under omnidirectional transmission. Numerical results using an analytical
mmWave channel model and a measurement-based channel generator, NYUSIM, show
that beamforming not only reduces the amount of strong interference and hence
significantly enhances network throughput, but also user association can
considerably alter network interference and throughput structures.
