Contents I. Introduction
In mobile communications, the abstraction of the underlying wireless channel is an essential part. Parallel to increased computation and storage capacities, also the complexity of channel models has increased over the years [1], capturing more and more effects of real environments. Channel models can be categorized into statistical and deterministic channel models [1]. A combination of statistical and deterministic modeling components can be found in the so-called geometry-based stochastic channel models (GSCMs). This type of model has been used as a basis for the standardization of Long Term Evolution and is currently also used for fifth generation (5G). Standardized channel models are necessary to evaluate and compare different proposals with each other. This was provided with the 3rd Generation Partnership Project (3GPP)-spatial channel model (SCM) in 2003 [2]. Since then, the family of GSCMs is under constant development, evolving to enable performance evaluation of new techniques such as “massive” multiple-input multiple-output (MIMO) [3], which led to the three dimensional (3D) extension of GSCM [4] or the extension to frequencies above 6 GHz [5].
