SK Telecom has implemented what it says is the world's first Software-Defined RAN, also known as a cloud RAN, on a commercial network. The project was conducted with Nokia, using its AirScale Cloud RAN.
SDRAN enables traditional base station functions to be implemented on a general-purpose IT server and run as a virtual machine. The architecture of the SDRAN includes a functional split of the protocol in the baseband processing. This relegates parts of the DU (Digital Unit) functions to the RRU (Remote Radio Unit), allowing traffic to be scaled more effectively and multiple connectivity scenarios deployed efficiently without immediate additional investments in transport or baseband capacity.
Previously, a designated interface was used for data transmission between the DU and the RRU, but with the new SDRAN, a more broadly used Ethernet-based DU-RU interface is optimized for the communication environment and used for more efficient network configuration, SK said. The interface also better handles signal delays, so that when a delay occurs, it adjusts the timing of data transmission and prevents a slowdown in transmission speed. Accordingly, customers benefit from better data quality.
Since the network is implemented by software, it is easier and quicker to add new network functions. In addition, SDRAN will be able to offer a variety of third-party edge services, using MEC (Mobile Edge Computing) to provide localized communication services.
SK started work on a virtual RAN in 2013 and conducted field tests last year. The company said it is on track for a fully virtualised LTE network and will use the progress to develop its 5G network architecture.
