한국전자통신연구원(ETRI)이 6G 시대 선점을 위해 초고주파 대역에서 대용량·초정밀 서비스 실현을 위한 무선액세스, 이동 무선백홀 핵심기술 개발에 본격적으로 나선다.

▲ETRI researchers are checking ultra-high frequency-based mobile wireless backhaul equipment developed for outdoor testing of transmission distances of 50 m or more.
Absolute time synchronization wireless access and wireless backhaul technology
The Electronics and Telecommunications Research Institute (ETRI) has begun full-scale development of large-capacity, ultra-precision technology for implementing next-generation mobile communications. It is expected that the country will secure key future mobile communications technologies and solidify its technological leadership as a mobile communications powerhouse.
ETRI announced on the 27th that it will begin full-scale development of core wireless access and mobile wireless backhaul technologies to realize large-capacity, ultra-precision services in ultra-high frequency bands.
These two technologies are considered key foundational technologies for providing hyper-connectivity, ultra-low latency, and ultra-high-speed convergence services, which are key elements of next-generation 6G communications.
Wireless access technology is a technology that provides and maintains stable absolute time synchronization in various wireless environments, and solves the problem of high-speed, stable data transmission and increased delay due to retransmission in various communication environments.
Mobile wireless backhaul technology is a technology that provides large-capacity traffic by connecting a central network and a base station or access point via mobile wireless.
Innovative wireless access technologies are essential to meet the ultra-precision performance requirements of next-generation 6G communication services.
Absolute time synchronization is a technology that ensures that all devices have the same time or clock, which plays a role in increasing the accuracy and efficiency of communication networks.
This enables fast and reliable data transmission in vehicle-to-everything (V2X) communication for autonomous vehicles, smart factories, and digital twins that require temporal precision.
In mobile communications up to 4G, absolute time synchronization was not that important.
On the other hand, in 5G and next-generation 6G communications, the importance of absolute time synchronization is increasing as services that require simultaneous operation and cooperation between devices, such as centimeter-level positioning, collaborative robots, and sensor fusion, are increasing.
In addition, the current wired-based synchronization method provides sub-nanosecond (less than one billionth of a second) level accuracy, while the wireless method provides microsecond (one millionth of a second) accuracy due to channel uncertainty. Sometimes it doesn't meet your requirements.
Therefore, the development of precise and stable wireless access technology is necessary.
In addition, various media services such as high-definition video streaming, extended reality (XR), and virtual reality (VR) are emerging, and it is expected that data transmission of up to 5 to 10 Gbps per terminal will be required in mobile communication networks within the next 10 years.
To support this, it is expected that a base station capacity of 100 Gbps or more will be required.
This is why it is more important than ever to take the lead in wireless backhaul technology to provide large-capacity traffic.
To date, sub-terahertz-based ultra-wideband wireless transmission technology capable of supporting wide bandwidth has been attracting attention as an alternative for increasing capacity.
ETRI researchers are currently developing 'large-capacity ultra-precision wireless access technology' and 'large-capacity mobile wireless backhaul technology' for guaranteed ultra-precision services, moving away from the best-efforts-based data transmission technology pursued in existing mobile communications.
'Mass-capacity, high-precision wireless access technology' refers to core source element technologies in the fields of absolute time synchronization, diversity, new waveforms, and multi-antenna to realize the highest level of high-precision services while supporting large-capacity transmission.
ETRI has built a shared platform between element technologies to verify efficient proof-of-concept (PoC) of wireless access element technologies developed to date, and is currently conducting standardization activities to reflect these technologies in the 3GPP mobile communication standards.
'Mass-capacity mobile wireless backhaul technology' is a network configuration based on wireless backhaul links to expand the coverage of large-capacity services in a mobile environment and to accommodate a large number of devices, and the optical fiber required for the backhaul links.It refers to the technology of bandwidth frequency transmission.
ETRI researchers are currently developing an outdoor long-distance wireless backhaul test device based on ultra-wideband and ultra-high frequency to verify mobile wireless backhaul technology and are testing the performance of the technology installed in vehicles.
The world's best synchronization technology developed in the absolute time synchronization field during this study was published in the top 2% SCIE journal 'IEEE IoT-J'.
Dr. Youngjo Koh of ETRI’s 6G Wireless Research Lab said, “We will lead the development of ultra-precision, large-capacity core source technologies necessary for implementing 6G mobile communication services, and contribute to enhancing the competitiveness of Korea’s future mobile communication industry by dramatically improving perceived quality and providing infrastructure with the technologies we have developed.”
This achievement was carried out as part of the ‘ETRI Research and Development Support Project’ of the Ministry of Science and ICT and the National IT Industry Promotion Agency.