Multi-scale mobility models in the forthcoming 5G era : a general overview

The forthcoming fifth generation (5G) mobile wireless system is likely to lead to an increasingly heterogeneous data demand pattern, including a small number of high data-rate mobile broadband links and a large number of low data-rate Internet-of-Things (IoT) applications. Aspects which govern seamless mobility between different access-technologies, cell tiers, cell sectors, and frequency bands will be sensitive to the mobility model of the people, their devices, and the machines. An understanding about how such entities will play a fundamental role in the future standardization and exploiting of the 5G technologies. In this article, we provide a comprehensive and general overview about existing mobility models useful to characterizing movements patterns across multiple distance and populations scales. In doing so, all the models are critically discussed, providing strengths and weaknesses. Finally, open issues and critical design choices are highlighted to serve as guidelines for future research in this topic.