LG Uplus said on the 25th that it has demonstrated indoor coverage expansion technology using a zero-power reconfigurable intelligent surface (RIS) and artificial intelligence (AI) with a research team led by Professor Hong Won-bin at POSTECH.
RIS reflects and transmits radio waves without a separate power source and controls them to help deliver signals in shadowed areas such as buildings and underground spaces. It is cited as a key technology to boost transmission efficiency in the upper mid-band, a candidate frequency for 6G. The upper mid-band can secure wide bandwidth and coverage, but penetration loss through structures such as walls and glass, and micro shadows within cells, have remained challenges.
The research team confirmed that installing distributed RIS in the form of indoor decor such as frames, wallpaper, and signs can increase coverage. The limitation of existing RIS requiring precise, aligned installation—which led to location constraints and long construction periods—was also eased by a distributed structure. By applying a Reinforcement Learning-based algorithm, they enabled it to operate as an "intelligent radio control infrastructure" that can optimize RIS placement considering base station locations, indoor-outdoor structures, and frequency bands.
They confirmed the effect of reducing radio loss and expanding coverage in non-line-of-sight (NLoS) environments with many obstacles, and noted that it can be applied not only to 6G but also to 5G and Wi-Fi environments.
LG Uplus expected that it will contribute to forming uniform coverage and reducing infrastructure expense in places such as factories and logistics centers (production lines and logistics robots), tunnels and subway stations, and large entertainment facilities.