User-Centric Wireless Access Virtualization Strategies for Future 5G Networks

User-centric wireless access virtualization (VVAV) allows each user to be served by a set of carefully selected transmission points (TP)s forming a user-specific virtual base station (uVBS) adapted to its environment and quality of service (QoS) requirement. In this way, this new concept breaks away from the conventional cell-centric architecture to provide boundaryless communications in future 5G networks. This fundamental structural 56 evolution alongside the ultra-dense multi-tier heterogenous context foreseen in such networks require an inevitable rethinking of efficient scalable TPs clustering. As such, this paper proposes three innovative low-cost clustering approaches that enable user-centric WAV and provide dynamic, adaptive, and overlapping TPs clusters while requiring not only negligible overhead and power costs, but also minimum signaling changes at both network and user sides. In contrast to existing clustering techniques, the new ones we propose better leverage 5G features such as extreme densification and massive connectivity as well as new concepts such as mmWave spectrum and massive MIMO. Furthermore, these approaches are flexible enough to be adapted to different network dimensions (i.e., space, time, etc.), thereby paving the way for achieving the dramatic performance improvements required by 5G networks to cope with the upcoming mobile data deluge.