  This paper provides an overview of the features of fifth generation (5G)
wireless communication systems now being developed for use in the millimeter
wave (mmWave) frequency bands. Early results and key concepts of 5G networks
are presented, and the channel modeling efforts of many international groups
for both licensed and unlicensed applications are described here. Propagation
parameters and channel models for understanding mmWave propagation, such as
line-of-sight (LOS) probabilities, large-scale path loss, and building
penetration loss, as modeled by various standardization bodies, are compared
over the 0.5-100 GHz range.
