SK Telecom has successfully demonstrated 5G communications using the 3.5GHz band through collaborations with Samsung Electronics and Nokia in Korea. Operator joined hands with Samsung Electronics to develop a 3.5GHz 5G end-to-end network comprised of 5G virtualized core, virtualized RAN, Distributed Unit (baseband unit and radio unit) and test device - based on the 3GPP 5G New Radio (5G NR) standards elements established to date. 

SK Telecom has also worked with Nokia to co-develop 5G base station equipment and test device for the 3.5GHz spectrum and successfully realized Gbps-level throughput during a field trial held near its Bundang Office Building through the application of carrier aggregation techniques to expand bandwidth. The two companies also measured link quality (BLER) depending on the distance between a moving vehicle and base station, thereby securing important data for designing optimal 5G commercial networks in the 3.5GHz band.

3GPP has agreed upon the key physical component technologies – i.e. numerology, __frame structure, channel coding, etc. - of the air interface, and based on this 3GPP NR specification, the two companies’ 5G NR system is built with a subcarrier spacing of 60 kHz, Transmit Time Interval (TTI) length of 0.25ms to reduce latency, sub__frame structure that simultaneously supports downlink data and uplink feedback, and Low-Density Parity-Check (LDPC) channel coding for high-speed data communications. SK Telecom and Samsung successfully completed the 5G end-to-end network trial using the 3.5GHz spectrum at Samsung Electronics’ R&D Center located in Suwon, Korea. 

According to SK Telecom, company has secured all essential technologies to deploy 5G networks using above-6GHz and below-6GHz frequencies through successful trials of 3.5GHz 5G networks. 28GHz, a potential above-6GHz frequency in Korea, can support several tens of Gbps through the use of a wide bandwidth of more than several hundreds of MHz. On the other hand, 3.5GHz, one of the below-6GHz frequencies, can provide a stable coverage in wider areas. 

SK Telecom plans to roll out its 5G networks by leveraging the respective strength of these frequencies: It will deploy commercial 5G networks using 28GHz in downtown areas where data traffic is most concentrated, while covering wide areas with 3.5GHz 5G networks or a combination of 3.5GHz and 28GHz 5G networks.