Trends and challenges in wireless channel modeling for evolving radio access

With the advent of 5G, standardization and research are currently defining the next generation of radio access. Considering the high constraints imposed by future standards, disruptive technologies such as massive MIMO are being proposed. At the heart of this process are wireless channel models that now need to cover a massive increase in design parameters, a large variety of frequency bands, and heterogeneous deployments. This tutorial presents the key drivers behind the evolution of channel modeling and simulation tools as a platform to evaluate future radio access technologies. This evolution comes with new challenges for the research community; this tutorial surveys these challenges, and the approaches to overcome them.