Evaluation of Simplified Methodology for Obtaining mmWave MIMO Channels from Ray-Tracing Simulations

The use of higher frequencies and MIMO is important in many 5G use cases. However, the available channel models for millimeter waves (mmWaves) currently demand investigation and the number of measurements is still limited. Using simulators is a current practice in mmWave MIMO research and ray tracing is considered one of the most accurate techniques. Due to the relatively long time of ray tracing simulations, it is common practice to adopt a simplified simulation methodology in which omnidirectional antennas are simulated and, later, the results are used together with a geometrical model to consider that antenna arrays were used. This allows flexibility and decreases the overall time spent with simulations. This paper investigates the corresponding assumptions and how accurate are the results of the simplified methodology when compared to effectively using antenna arrays in the ray tracing simulation. The preliminary results indicate that the distance between transmitter and receiver needs to be sufficiently large.