  The millimeter wave (mmWave) band will provide multi-gigabits-per-second
connectivity in the radio access of future wireless systems. The high
propagation loss in this portion of the spectrum calls for the deployment of
large antenna arrays to compensate for the loss through high directional gain,
thus introducing a spatial dimension in the channel model to accurately
represent the performance of a mmWave network. In this perspective, ray-tracing
can characterize the channel in terms of Multi Path Components (MPCs) to
provide a highly accurate model, at the price of extreme computational
complexity (e.g., for processing detailed environment information about the
propagation), which limits the scalability of the simulations. In this paper,
we present possible simplifications to improve the trade-off between accuracy
and complexity in ray-tracing simulations at mmWaves by reducing the total
number of MPCs. The effect of such simplifications is evaluated from a
full-stack perspective through end-to-end simulations, testing different
configuration parameters, propagation scenarios, and higher-layer protocol
implementations. We then provide guidelines on the optimal degree of
simplification, for which it is possible to reduce the complexity of
simulations with a minimal reduction in accuracy for different deployment
scenarios.
