With the massive data service requirements brought by the mobile Internet and the Internet of things

spectrum resources gradually become saturated

and the high-frequency millimeter wave available spectrum resources are abundant

which can effectively alleviate a shortage of spectrum resources and meet a requirement of a 5G mobile communications system for large capacity and high rate transmission. The industry is highly concerned about this

and starts to accelerate the research and application of the high-frequency millimeter wave in the 5G system. In this paper

the millimeter wave communication technology of 5G system is introduced. The advantage is that the bandwidth is great

the disadvantage is the line of sight propagation. Then

the indoor application scenario of millimeter wave is discussed thought the simulation results of indoor link budget.