Toward Massive Ray-Based Simulations of mmWave Small Cells on Open Urban Maps

High-rate access in outdoor urban areas using extremely high frequency (EHF) bands, known as millimeter-wave (mmWave) spectrum, requires a dense deployment of wireless small cells in order to provide continuous coverage to serve bandwidth-hungry users. At the same time, to be able to collect a sufficient amount of data for constructing detailed EHF propagation models, a considerable number of various landscape maps across different scenarios have to be considered. This letter develops a shoot-and-bounce ray (SBR)-based methodology capable of characterizing the mmWave propagation in urban outdoor conditions. In particular, our methodology aims to capture a large number of small cells within accurate, real city maps and then to utilize an algorithm of automatic transmitter placement. Hence, our contribution is to provide a suitable tool that is able to handle massive ray-based simulations within a reasonable time frame. In particular, we demonstrate and verify that a shift from simulating three-dimensional (3-D) to evaluating 2-D environments significantly reduces computation time while only slightly decreasing the simulation accuracy.