Terminology：What is Sub6?

The RF waves used for 5G communications in Japan include bands below 6GHz and frequencies above 28GHz. Frequencies below 6GHz are called “Sub6,” and frequencies above 28GHz are called “millimeter waves.” The Sub6 frequencies used for 5G communications are allocated to major mobile carriers in 100MHz bandwidth units. Additionally, in December 2020, a 300MHz bandwidth in the 4.6GHz to 4.9GHz range was allocated for local 5G. Compared to the higher-frequency millimeter waves, Sub6 has less attenuation, can reach wider areas and can bypass obstacles to reach its destination. However, it significantly lags behind millimeter waves in terms of speed and simultaneous connection performance. Since it is close to the frequency bands used in previous 4G systems, existing technologies can be applied.