I. Introduction
5G will be the essential technology to enable the “Internet of Everything”: connecting sensors for smart cities, connecting robots for Industry 4.0, and connecting vehicles for smart transportation [1]. The key challenge of realizing this vision is to fulfill the various network requirements of the vertical industries efficiently in 5G. Network slicing, which allows the creation of multiple virtual networks on top of a shared physical infrastructure, is a promising technology to address this challenge [2], [3]. With the network slicing technology, virtual networks, which are denoted as network slices, are dynamically designed and instantiated to serve the specific needs of vertical industries [4].