Future wireless networks, including 5G and 6G, will need to stay connected in a variety of environments, including skyscrapers over 60 stories tall, KTX trains traveling at speeds of more than 300 kilometers per hour, and Urban Air Mobility (UAM), which is expected to revolutionize transportation.
KT is focusing on Reconfigurable Intelligent Surface (RIS) as a technology that can efficiently expand network coverage in these environments.
KT announced on Feb. 27 that it has developed RIS technology that operates in the 3.5 GHz band of 5G wireless communication frequency and the 12 GHz band of KT Sky Life satellite frequency with a research team from Seoul National University's Department of Electrical and Information Engineering.
RIS is a technology that can direct the reflection and transmission of radio waves in a desired direction. By introducing RIS to the exterior walls of buildings, it is possible to transmit and receive signals through the high-frequency band without exposing wireless communication equipment to the outside of the building. It helps build network infrastructure more efficiently.
Developed by KT and a research team led by Professor Oh Jung-Seok of Seoul National University's School of Electrical and Computer Engineering, the RIS is characterized by passing 5G wireless communication frequencies and KT SkyLife satellite frequency bands in addition to 6G candidate frequencies in a small area.
In the meantime, KT has developed RIS materials and technologies that operate in the mmWave band, 28 GHz, and the 6G candidate frequency bands, 8 GHz and 15 GHz. The frequency bands currently used in 5G were not commercially viable because they use relatively low frequencies, requiring a large area for RIS samples.
In addition, the new RIS utilizes new surface design technology and structure to simultaneously secure a wide transmission angle that is refracted at more than 90 degrees from the direction of travel (negative refraction angle) and a high transmittance. The wide transmission angle is advantageous for improving indoor wireless quality. Made of transparent material, it can be easily installed by attaching it to the glass window of a mobile phone or by making it all-in-one, KT said.
To verify the versatility of its RIS technology, KT and Seoul National University attached the RIS to a vehicle window and confirmed that wireless signals coming in from the perpendicular direction to the direction of vehicle movement, such as 5G radio waves from communication towers along highways and KT SkyLife satellite signals, are refracted inside.
KT will continue to cooperate with equipment manufacturers and material and component companies to apply the newly secured RIS technology to building windows and vehicle windows. In addition, KT plans to secure technology leadership in the field of 6G wireless communication by continuing to discover elemental technologies that can be applied to various wireless network environments such as RIS.
