The nine articles in this special section focus on mobile 5G heterogeneous mobile communication. It is widely agreed that B5G network should achieve greater system capacity (> 1000 times) in terms of data rate (terabits per second) and user density (the Internet of Things and Nano-Things). Also, it is generally accepted that there are three major ways to obtain several orders of increase in throughput gain, those being extreme densification of infrastructure, large quantities of new bandwidth, and a large number of antennas, allowing a throughput gain in the spatial dimension. These processes are complementary in many respects. Among others, in the search for more bandwidth beyond microwave and millimeter-wave (mmWave) systems, we are moving toward higher frequencies, especially in the promising terahertz (THz) frequency range. THz-band communication is envisioned as a key wireless technology to satisfy real-time traffic demand for mobile heterogeneous network (MHN) systems by diminishing the spectrum scarcity and capacity limitations of current wireless systems.