Measurement Validation of Ray-Tracing Propagation Modeling for mm-Wave Networking Studies: How Detailed is Detailed Enough?

The spectrum-rich millimeter-wave (mm-wave) bands are envisioned as a key enabler for future high speed communication networks. Given the high path and penetration loss and the spatially sparse nature of the mm-wave channel, connectivity at mm-wave is dependent on line-of-sight (LOS) or strong non-LOS directional links. This makes deterministic propagation modeling via ray-tracing an important tool for environment-specific mm-wave networking studies. In this paper we validate the accuracy of ray-tracing against large-scale mm-wave outdoor measurements using commercially-viable phased antenna arrays. Towards making practical modeling recommendations, we investigate how detailed the models of the urban environment and the directional antennas need to be for ray-tracing to accurately predict the measured channel. Our results indicate that even simple 3D environment models are sufficient for reasonably accurate ray-tracing results but that realistic measured antenna models are essential for reducing the typical prediction error to within 4 dB.