I. Introduction
Currently, with the increasing prosperity of mobile Internet and rapid development of information and communications technology (ICT), almost every aspect of human lives will be deeply influenced by the machine-to-machine (M2M) communications [1]. The evolution of Internet of things (IoT) becomes the next major growth area for the wireless industry [2], and it is regarded as natural to support the characteristic of IoT for both the fifth generation (5G) mobile communication system and the next generation wireless local area networks (WLAN) [3], [4].