  To fully exploit the millimeter-wave bands for the fifth generation cellular
systems, an accurate understanding of the channel propagation characteristics
is required, and hence extensive measurement campaigns in different
environments are needed. In this paper, we use a rotated directional
antenna-based channel sounder for measurements at 28 GHz in large indoor
environments at a library setting. We present models for power angular-delay
profile and large-scale path loss based on the measurements over distances
ranging from 10 m to 50 m. In total, nineteen different line-of-sight (LOS) and
non-line-of-sight (NLOS) scenarios are considered, including the cases where
the transmitter and the receiver are placed on different floors. Results show
that the close-in free space reference distance and the floating intercept path
loss models both perform well in fitting the empirical data. The path loss
exponent obtained for the LOS scenarios is found to be very close to that of
the free space path loss model.
