To keep up with the explosive growth of mobile traffic demand, massive densification of small cells has been proposed to achieve the 10 000 fold increase in network capacity by 2030 [101], [102], [103]. Small cells deployed underlaying the macrocells as WLANs or WPANs are a promising solution for the capacity enhancement in the 5G cellular networks. With huge bandwidth, mmWave small cells are able to provide the multi-gigabit rates, and wideband multimedia applications such as high-speed **data** transfer between devices, such as cameras, pads, and personal computers, real-time streaming of both compressed and uncompressed high definition television (HDTV), wireless gigabit ethernet, and wireless gaming can be supported.