Millimeter wave (mmWave) communications have recently attracted large interest of research society, since the enormous available bandwidth can potentially lead to the excesive transmission rates per second per end-user. Due to its potential for multi-gigabit and low latency wireless links, millimeter wave (mmWave) technology is expected to play a central role in 5th Generation (5G) cellular systems. While there has been considerable progress in understanding the mmWave physical layer, innovations will be required at all layers of the protocol stack, in both the access and the core network. As the discrete-event network simulation is essential way for end-to-end, crosslayer research and development, this paper provides insights on our contribution to the recently-developed full-stack mmWave module for the Network Simulator 3. The module is interfaced with the core network of the NS3 LTE module (LENA) for full-stack simulations of end-to-end connectivity. We propose an NYUSIM model enhancement to obtain more accurate results in communication scenarios dealing with the building attenuation. Simulation data confirms that our modifications significantly affect the results and model more precisely the NLOS conditions of big obstacles like concrete office blocks. © 2017 IEEE.