What's 5G? Vol.4. Let us explain about the features and strong points of 5G
What kind of changes will occur in the 5th generation (5th Generation, hereinafter abbreviated as 5G)?
First, I will explain the 5G configuration and diffusion plan. The 5G service started in 2019, and base stations are being added. In 5G, services are deployed in two frequency bands called sub 6 and millimeter waves. Sub 6 means 6GHz or less, and in Japan, two bands, 3.7GHz band and 4.5GHz band, are used. Millimeter wave refers to the band from 30GHz to 300GHz, and the frequency of 28GHz band is used in Japan. Strictly speaking, 28GHz is not a millimeter wave but a submillimeter wave (microwave) band (3GHz to 30GHz) including the sub 6 band, but since 37GHz and 48GHz are used depending on the country, it is convenient (?) to call millimeter wave in 5G.
In addition, although communication uses the 5G frequency band, the wired network part of the base station is often shared with 4G, which is called the NSA (Non-standalone) network. On the other hand, there are plans to move to a large-capacity wired network dedicated to 5G, which is called the SA (Standalone) network.
As a feature of 5G, the following features are stated.
1. Enhanced Mobile Broad Band (eMBB: enhanced Mobile Broad Band. In some cases, it is translated as high speed and large capacity).
2. Simultaneous multiple connections (mMTC: massive Machine Type Communications)
3. High reliability and low latency (URLLC: Ultra Reliable and Low Latency Communications)
From the user's point of view, the only merit is item 1, eMBB, especially high speed and large capacity. However, it is also true that there are few applications that make effective use of this high speed and large capacity. Even if LINE's reply is as fast as 0.03 seconds, we don’t think it the merit, and even if a 2-hour movie can be downloaded in 3 seconds, it still takes 2 hours to watch. It is doubtful that watching 4K or 8K high image quality on a smartphone will be beneficial and taking advantage of high speed and large capacity during "walking smartphone" cannot be imagined, and it will be difficult to use it unless you sit down and work on it carefully. 5G has a high potential, but when asked what is its characteristic, I think the answer is that at present, communication is only as fast as possible.
However, at present (November 2021), 5G sub 6 band NSA network operation has started, and the millimeter wave band is being operated on a trial basis only in limited areas and facilities. In the future, the sub 6 band will be converted to SA and the millimeter wave band will be expanded.