Wireless Relay Technology to Dramatically Expand Millimeter Wave Area - Tatsuo Sato(Executive Officer, General Manager, Core Technology Management Division and Network Development Division, KDDI Corporation)
ODAIBA IX Core/Industrial Transformation (IX) Leaders
Leaders Transforming Industrial Technology (No. 8)

Both Sub6, which can cover large areas at lower frequencies, and millimeter wave, which can achieve high-speed communications at higher frequencies, are allocated as frequency bands that can be used for 5G. We asked Mr. Tatsuo Sato, Executive Officer and General Manager of the Core Technology Management Division and Network Development Division at KDDI, about the status of the company's efforts and the results they have seen. (TeleGraphic Editorial Department)

Millimeter waves function effectively in certain congested areas

First, our mission is to provide a wide range of locations where customers can use our services with peace of mind. We are striving to expand the areas where customers can use our services comfortably, not only in urban areas but also in other areas, through measures such as indoor areas where signal reception is difficult. As one of such efforts, we are planning to launch a direct satellite communication service using Starlink in April 2025.au Starlink DirectThe first time this has been done, the company has launched a new service, "KDDI Communications". We can communicate even in mountainous areas and campgrounds, where it has been difficult to develop an area, as long as the sky is visible. We place great importance on this kind of area expansion, and we have been and will continue to support it.

In terms of securing the communication environment, congested locations are another important issue. In places where many people use communications at the same time, such as train stations and stadiums, multiple frequencies are used together because it is difficult to handle a single frequency alone. This is the aspect of expanding the communication bandwidth in one location as well as the areal spread. We utilize millimeter wave frequency bands, which have a very wide bandwidth, as a measure to enable comfortable communication even in places where many customers are gathered.

In terms of millimeter wave, the number of terminals available in Japan is still small and the areas where it is available are limited, so a statistical look at the traffic shows that only a very small percentage of the traffic is millimeter wave. Also, since there is no indication of "millimeter wave" on the cell phone's indicator, customers are not really aware that millimeter wave is improving communication conditions. However, KDDI has already installed many base stations equipped with millimeter wave antennas at stations and stadiums. We are able to provide an extremely high-speed, high-quality environment, and our customers are actually using it. Specifically, we have achieved download speeds in excess of 1 Gbps, and we are able to provide a high speed communication environment even when used by multiple customers. KDDI will continue to provide such millimeter wave usage.

New method of flying hard-to-reach millimeter-wave radio waves

As you probably know, millimeter waves have a high frequency and, like light, have a strong linearity. Therefore, if there is anything blocking the radio waves, communication will be impossible. Although millimeter wave has such characteristics, it is a good match for stadiums. A stadium is a mortar-shaped structure, so if antennas are installed at the top, the signal can easily reach many customers without being affected by obstructions. In contrast to a stadium, where the stadium is spread out over a large area, there are trees and billboards along the streets in meeting places, which inevitably create shadows from the base station antennas. One way is to increase the number of base stations. One way is to increase the number of base stations. The more base stations, the greater the coverage. Since millimeter waves have strong linearity, areas must be created in spots, and increasing the number of spots will expand coverage. However, in order to increase the number of base stations, optical fiber must be installed, and radio equipment must also be installed. The cost will be high.

Therefore, as a new measure to expand the millimeter wave area, KDDI has developed a newly developed repeater.introductionThe new transponder is innovative in that it can dynamically change the direction of radio wave transmission and reception. The new transponder is innovative in that it can dynamically change the direction of transmission and reception of radio waves. The transponder housing consists of multiple antenna surfaces, and the transmitting/receiving panel is adaptively determined by detecting which surface has the strongest reception power. In addition, it is possible to relay radio waves over multiple transponders. Since the system supports relaying over multiple paths, it has the advantage of being able to relay over other paths even if one path is cut off. In addition, the power consumption of the relay developed this time is much smaller than that of a base station, leading to savings in electricity costs.

KDDI hopes that these repeaters will not only be used by itself, but also attract the interest of telecommunications carriers in Japan and overseas. This is because repeaters are an effective means of expanding coverage areas at low cost while taking advantage of the high-speed, large-capacity features of millimeter wave. If understanding of the possibilities of millimeter wave utilization spreads as the benefits for telecommunications carriers become more apparent, terminal manufacturers will be more willing to support millimeter wave. For the customers who use the terminals, the expansion of areas with stable, high-speed communications will also lead to significant benefits. We would like to continue to send a message to both carriers and terminal manufacturers that we will work together to promote the use of millimeter wave technology.

Budding Utilization in Industrials

Demonstrations of millimeter waves have begun in the industrial field as well. Our focus is on its use in video transmission for security cameras and other applications. There are various types of security cameras, including those used by municipalities, shopping malls, and individual stores. On the other hand, many of these cameras are left unmaintained. It is difficult to know where the power source is coming from or how the line is secured and managed. By using wireless as a communication line for such cameras, security cameras can be installed without using fixed lines such as optical fiber, thereby reducing the burden of maintenance. Millimeter wave can ensure high-capacity communication, and we believe there is demand for camera solutions.

In addition, there are solutions where the camera side works. For example, security guards can wear cameras on their patrols and absorb images like a drive recorder in case something goes wrong, or sports referees can wear cameras to transmit data, and so on. Even in factories, wireless communication is effective when a robot is equipped with a camera as an example of this moving camera, and the collected image data is used for processing. KDDI is researching the use of millimeter waves not only for applications that provide a comfortable communication environment for general customers, but also for applications in industrial fields such as factories, and is working on the development of this technology into services. (Talk)

XGMF ODAIBA IX core will hold "ODAIBA IX Core & KDDI Millimeter Wave Event" on Friday, April 25 at KDDI Shinjuku Building, where Tatsuo Sato, Executive Officer of KDDI, will discuss the technical details of this article. This event is limited to XGMF members only, and registration has already closed. Please note that this event is limited to XGMF members only and that registration is already closed.

(TeleGraphic Editorial Board)