I. Introduction
5G technology is conceived as a connectivity platform that is capable to support flexibly a plethora of services with heterogeneous requirements. To address the complexity of such a vast connectivity space, 5G has opted to define three generic service types: enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). These generic types should not be seen as exclusive to a device or a service; there will be composite services that use any combination of the aforementioned generic service types.