SK Telecom Moves Closer to 5G with Low Latency Technology

SK Telecom in collaboration with Nokia has successfully reduced latency between the handset and base station to 2 milliseconds (ms) over its LTE network. With the successful demonstration of a round-trip latency of 2 ms, SK Telecom moves one step closer to realizing 5G. (International Telecommunication Union states that technologies designed for 5G needs to deliver a peak data rate of up to 20 Gbps under ultra-low latency of 1 ms.)

The latency between the handset and base station in the existing LTE environment is around 25 ms. While the round-trip latency of 25 ms can support two-way communication services like remote learning and smart work, it is not low enough to seamlessly provide services that require real-time transmission of data such as autonomous driving and telemedicine.

Against this backdrop, the newly developed 2 ms latency technology is expected to facilitate the development of diverse real-time services - e.g. autonomous driving, AR and VR services - which will become widespread in the 5G era.

For instance, with a latency of 25 ms, upon sending a stop signal to a self-driving vehicle running at 150 kilometers per hour, the vehicle travels about one meter further before it actually begins to decelerate. However, with the 2 ms latency technology, the vehicle moves only 8 centimeters before it begins to slow down, which will significantly enhance the overall safety in autonomous driving.

Moreover, the low latency communication technology can support services that require real-time monitoring of remote sites and control of equipment such as disaster relief robot, and will also contribute to the growth of next-generation media services like 360° VR.

SK Telecom and Nokia have dramatically reduced the latency between the LTE handset and base station from 25 ms to only 2 ms by applying Uplink Pre-Scheduling, a technology that enables the handset to immediately transmit data to the base station, and short Transmission Time Interval (TTI), a technology that reduces data transmission time between base station and handset to about 1/7.

The companies will continue to work together to reflect the short TTI technology to the 3GPP global standards.