30 1 月, 2023

DOCOMO Conducts World’s First Trial of Transmissive Metasurface on Window to Deliver Indoor Radio Waves to Outdoor Foot of Building

TOKYO, Jan 30, 2023 - (JCN Newswire via SEAPRWire.com) - NTT DOCOMO, INC. announced today that it has succeeded in what it believes to be the world's first trial of redirecting millimeter-band (28 GHz) radio waves coming from inside a building to the foot of the building outdoors by bending the radio waves with a film-shaped transmissive metasurface(1) attached to a window surface. The trial was conducted from October to November 2022 at the DOCOMO R&D Center in Yokosuka, Japan, aiming at realization of advanced fifth-generation (5G Evolution) and sixth-generation (6G) mobile communication systems.High-frequency radio waves, which are expected to be used in 5G Evolution and 6G, have difficulty coming around behind obstacles and are easily attenuated as propagation distances increase. DOCOMO has also been studying the use of metasurface technology to enhance radio signal reception indoors using outdoor base station(2), and to improve indoor with many obstructions as a user moves(3).Radio waves in the high-frequency band have difficulty reaching places that are not in the line of sight of the transmitting base station installed on the rooftop of buildings, making it difficult to create reception areas at the foot of buildings. One of the solutions is to install antennas on a neighboring structural object, but there are cases where such installation is not possible due to landscape and other issues. This trial was conducted in order to expand the area coverage around the foot of a building.The transmissive metasurface for the 28 GHz band used in the trial is a metasurface designed and processed to bend millimeter wave bands passing through a glass window in a specific direction, in this trial, towards the bottom of a building's exterior(4). The film-shaped material was attached to the window glass on the interior side, making it easier to install, and its transparency did not spoil the landscape and existing design. In addition, the transmissive metasurface is designed not to affect other frequency bands such as LTE and Sub-6 bands.Millimeter waves from a base station installed indoor passed through transmissive metasurfaces on the window glass and throughput performance in the foot area of the building was measured. We confirmed that the throughput performance in the foot area was greatly improved by bending the millimeter waves with the transmissive metasurfaces.DOCOMO is also researching and developing various technologies to improve indoor and outdoor coverage in the high frequency bands. For example, it may be possible to direct signals from Multi-Sector Antenna Indoor Base Station, as announced by DOCOMO on January 30(5), to the transmissive metasurface attached to a glass window to improve both indoor and outdoor area coverage. Also, in the future, when constructing a massive multiple-input multiple-output (MIMO) system that uses much larger number of antennas, it may be possible to achieve an equivalently large-scale configuration with a relatively small number of antennas at a low cost by applying metasurface technology(6).Going forward, DOCOMO will continue to research and develop efficient and flexible construction of reception areas and radio configurations for 5G Evolution and 6G.The transmissive metasurface used in the trial will be exhibited at "docomo Open House '23," which will be held online from Thursday, February 2.(1) Metasurfaces are a type of artificial medium (metamaterial) that achieve arbitrary permittivity and permeability by periodically arranging structures that are small in relation to wavelength, and are artificial surfaces in which the periodic arrangement of structures is two-dimensional.(2) "DOCOMO and AGC Use Metasurface Lens to Enhance Radio Signal Reception Indoors" (January 26, 2021)www.docomo.ne.jp/english/info/media_center/pr/2021/0126_00.html(3) "NTT and NTT DOCOMO Trial First Use of User-tracking Metasurface Reflector for Extreme Mobile Coverage in Current 5G and Coming 6G Era" (November 12, 2021)www.docomo.ne.jp/english/info/media_center/pr/2021/1112_00.html(4) The transmissive metasurfaces were designed and provided based on the cooperation of AGC Inc.(5) "Small, Efficient 5G Multisector Antenna Indoor Base Station Achieves World's First Demonstration using 28GHz" (January 30, 2023)www.docomo.ne.jp/english/info/media_center/pr/2023/0130_01.html(6) "5G Evolution and 6G (5.0 version)," NTT DOCOMO (November 2022)bit.ly/3HDP8E6 (Japanese only)About NTT DOCOMONTT DOCOMO, Japan's leading mobile operator with over 85 million subscriptions, is one of the world's foremost contributors to 3G, 4G and 5G mobile network technologies. Beyond core communications services, DOCOMO is challenging new frontiers in collaboration with a growing number of entities ("+d" partners), creating exciting and convenient value-added services that change the way people live and work. Under a medium-term plan toward 2020 and beyond, DOCOMO is pioneering a leading-edge 5G network to facilitate innovative services that will amaze and inspire customers beyond their expectations.https://www.docomo.ne.jp/english/. Copyright 2023 JCN Newswire. All rights reserved. (via SEAPRWire)

26 1 月, 2021

DOCOMO and AGC Use Metasurface Lens to Enhance Radio Signal Reception Indoors

TOKYO, Jan 26, 2021 - (JCN Newswire) - NTT DOCOMO, INC. and AGC Inc. announced that they have developed a prototype technology that efficiently guides 28-GHz 5G radio signals received from outdoors to specific locations indoors using a film-like metasurface lens that attaches to window surfaces. DOCOMO and AGC also conducted what is believed to be world's first successful trial to direct 28-GHz signals passing through a window to specific locations indoors as well as raise the strength of the signals.Newly emerging 5G networks as well as 6G networks of the future are expected to use high-frequency radio waves, such as 28 GHz. Although high-frequency signals enable the realization of advanced communication standards, they are subject to high attenuation over long distances and their high directivity resulting in low diffraction (or weak bending around objects) generally limits their range to within the line of sight of the transmitting base station. Consequently, it is difficult for high-frequency radio waves to penetrate windows, and even if they do they are attenuated to the point of not being able to propagate sufficiently to establish wireless communication links indoors.The new metasurface lens is made with an artificially engineered material featuring a large number of sub-wavelength unit cells arranged periodically on a two-dimensional surface. Elements arranged in various shapes on the metasurface substrate can be attached to a glass window to direct radio signals to specific points (focal points) indoors. It is believed that radio waves from an outdoor base station could be received on a window's broad surface and then efficiently propagated to specific focal points inside a building with the help of repeaters and reflectors.The metasurface lens material is a transparent film that can cover virtually the entire inside surface of a window. The material has no effect on LTE and sub-6 band radio waves, so it can be used to improve indoor reception of 28 GHz radio signals without affecting the performance of legacy wireless frequencies.The trial confirmed that the metasurface lens improves the power level of 28 GHz radio signals received at indoor focal points. The trial also confirmed the ability to control focal-point position as well as the ability to switch from single to dual focal points.In addition, DOCOMO and AGC verified that structural design technology can be deployed to enable metasurface lenses to allow high-frequency radio signals to penetrate glass that has been coated for heat insulation.DOCOMO and AGC have been developing transparent metasurface technology for use in solutions that not only improve access to high-frequency radio signals but also are aesthetically acceptable. The new metasurface lens incorporates DOCOMO's metasurface design technology and AGC's design and microfabrication technologies.The prototype metasurface lens will be presented during DOCOMO Open House 2021, which will take place online this February 4 to 7.Going forward, DOCOMO and AGC will continue to collaborate in the research and development of technologies for highly efficient and flexible 5G and 6G wireless communication.About NTT DOCOMONTT DOCOMO, Japan's leading mobile operator with over 80 million subscriptions, is one of the world's foremost contributors to 3G, 4G and 5G mobile network technologies. Beyond core communications services, DOCOMO is challenging new frontiers in collaboration with a growing number of entities ("+d" partners), creating exciting and convenient value-added services that change the way people live and work. Under a medium-term plan toward 2020 and beyond, DOCOMO is pioneering a leading-edge 5G network to facilitate innovative services that will amaze and inspire customers beyond their expectations. https://www.nttdocomo.co.jp/english/.About AGC Inc.AGC Inc. is the parent company of the AGC Group, a world-leading glass solution provider and supplier of flat, automotive and display glass, chemicals, ceramics and other high-tech materials and components. Based on more than a century of technical innovation, the AGC Group has developed a wide range of cutting-edge products. The AGC Group employs some 55,000 people worldwide and generates annual sales of approximately 1.5 trillion Japanese yen through business in about 30 countries. For more information, please visit New windowhttps://www.agc.com/en/ Copyright 2021 JCN Newswire. All rights reserved. www.jcnnewswire.com