The modification of current cellular networks, operating in ultra-high frequency (UHF) bands, to support high data rates with optimum coverage is leading to severe bandwidth congestion. As millimeter waves holding large unoccupied bandwidth are among the solutions, an investigation into the wideband characteristics of millimeter wave propagation is paramount. Results from such an investigation can be used for planning and designing indoor 5G wireless communication networks. The main objective of the paper was therefore to simulate and analyze the propagation characteristics of millimeter wave propagation in an indoor complex environment considering the geometry and motion of objects. Intelligent Ray Tracing (IRT) model was employed to predict wideband parameters that affect the propagation of millimeter waves on the second floor of Building-412 of Haramaya University. Propagation considered in this research was mainly from the direct path, single and two-times reflections, and diffraction from moving objects, walls, and indoor objects. The simulation results demonstrated that human shadows near receiver locations significantly obstructed and affected signal strength. Furthermore, the movement of persons in the corridor of the building caused temporal variations of received power, path loss, and delay spread in NLOS. Results were compared with CI path loss model parameters are derived from measurement and indicated that CI path loss model fits the best in indoor environments when compared to other models. As a result, the CI path loss model is chosen to validate the path loss predicted in this paper. This implies that the geometry and motion of objects impact indoor propagation, and hence indoor geometry and motion of objects need to be considered in planning and designing indoor wireless networks.