SK Telecom CTO dishes on small cells, LTE-Advanced and RCS

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with Byun Jae-woan, CTO and head of the technology at SK Telecom.

Byun Jae-won

   Byun Jae-woan

SK Telecom has long prided itself on introducing cutting-edge technologies. The operator's LTE network already covers 99 percent of South Korea's population and surpassed 7 million subscribers as of Dec. 12. LTE subscribers presently make up more than one quarter of SK Telecom's total mobile subscriber base.

Byun Jae-woan, SK Telecom's CTO and head of technology, is overseeing the operator's numerous ground-breaking technology efforts. In November he was also elected chairman of the board of the NGMN (Next Generation Mobile Networks) Alliance, a position he will hold for two years. He recently answered some questions via email for FierceBroadbandWireless Editor Tammy Parker, exploring the current state of SK Telecom's wireless operations and its plans for the future.

FierceBroadbandWireless: Regarding LTE, are you pursuing TD-LTE as well as FD-LTE?

Byun: SK Telecom has no plans to pursue TD-LTE at this moment. However, separate from this matter, the company is currently making efforts to secure TD-LTE-related technologies. In this context, SK Telecom, together with Ericsson (NASDAQ:ERIC) and Altair, developed a two-way handover technology that supports both FDD-LTE and TDD-LTE in one device and successfully demonstrated the technology in a moving vehicle environment for the first time in the world in September 2012. Since mobile operators are applying different LTE modes and a growing number of operators are using both FD-LTE and TD-LTE, the technology is being focused [on] as a core LTE technology that can ensure seamless data communications on both FDD and TDD spectrums even while on international roaming. Therefore, SK Telecom plans to use this technology to offer flawless international roaming services for customers travelling to countries that use [a] different LTE mode than Korea, while exporting it to global operators that use both FD-LTE and TD-LTE.

FierceBroadbandWireless: SK Telecom has deployed VoLTE. How widely adopted is that technology among your subscribers at this point?

Byun: At present, approximately 1.87 million LTE subscribers are using HD Voice-capable smartphones. Unlike other mobile operators, SK Telecom's customers can conveniently use the VoLTE service (named HD Voice) via simple device settings without going through a sign-up process.

FierceBroadbandWireless: What are is your launch timeline for RCS? Will you use the joyn brand for RCS offerings?

Byun: SK Telecom will commercialize an RCS service within the end of this year. The service will feature a number of new functions added to the RCS-e standard under the GSMA's joyn brand. As many mobile operators around the world are promoting the development of services based on the same specifications, RCS services are expected to become a universal service that can be enjoyed by all customers around the world regardless of network and carrier like voice call and text message services.

FierceBroadbandWireless: Do you intend to shutter your 2G IS-95/CDMA 2000 services anytime soon so you can concentrate on 3G and LTE?

Byun: At present, SK Telecom has no plans to end the 2G service. Nevertheless, the number of 2G subscribers is on a natural decline with the launch of next-generation mobile services like LTE.

FierceBroadbandWireless: SK Telecom has been actively testing LTE-Advanced features and commercialized coordinated multipoint (CoMP) technology in January 2012. What benefits has that technology provided?

Byun: In January 2012, SK Telecom became the world's first to commercialize a smart cloud-based base station (A-SCAN: Advanced Smart Cloud Access Network) applied with downlink CoMP technology. Moreover, it successfully demonstrated uplink CoMP technology for the first time in Korea in November 2012. Thanks to CoMP, SK Telecom was able to enhance the quality of VoLTE (HD Voice) and streaming services while on the move, despite the increasing number of cell boundaries caused by the expansion of a small cell environment.

Furthermore, with the commercialization of uplink CoMP, the company will be able to offer significantly increased data upload speeds over its LTE network. In particular, the company expects the technology to boost data upload speeds by a whopping 20 percent in base station boundary areas. Also, since uplink CoMP can be directly applied to base stations, customers using existing devices will be able to enjoy benefits without additional device upgrades/updates.

FierceBroadbandWireless: Is SK Telecom still expecting to commercialize carrier aggregation in the second half of 2013, and which spectrum bands will you initially aggregate?

Byun: SK Telecom has been developing CA (Carrier Aggregation) under cooperation with Qualcomm (NASDAQ:QCOM) and device/system manufacturers. It successfully demonstrated the technology in February 2012 at the GSMA Mobile World Congress. The company will aggregate two different frequency bands--i.e. 850MHz and 1.8GHz--from the second half of 2013 and expects to offer up to two times faster maximum data rates.

FierceBroadbandWireless: Do you still intend to commercially deploy Enhanced Inter-Cell Interference in the second half of 2013? What will be the benefits of that?

Byun: Together with Qualcomm and NSN [Nokia Siemens Networks], SK Telecom has successfully implemented an eICIC (enhanced Inter-cell Interference Coordination) technology demonstration in July 2012. SK Telecom plans to commercialize the technology in the second half of 2013. eICIC will eliminate interference signals in data traffic concentrated central city areas and effectively distribute traffic to allow customers to use data services with greater speed and stability.

FierceBroadbandWireless: How widely has SK Telecom deployed small cells?

Byun: As a leader in this area, SK Telecom has installed and is operating around 44,000 femtocells. Deployed in data-concentrated areas and indoors, femtocells help the company reduce shadow areas and accommodate data traffic in a stable manner. SK Telecom commercialized an LTE femtocell, an ultra-mini base station, for the first time in the world in June 2012. Moreover, it has developed and applied the world's first Femtocell Interference Coordination System (FICS) in order to improve the performance of LTE femtocell by controlling interference between LTE femtocells. Thanks to FICS, users will be able to enjoy seamless and high quality data service over LTE. Going forward, SK Telecom will efficiently deal with soaring data traffic through the application of diverse small cell solutions including femtocells.

FierceBroadbandWireless: How important is Wi-Fi offloading to SK Telecom's business model?

Byun: Currently, as part of its efforts to maximize customers' experience in data services, SK Telecom has been focusing on providing stable 3G and LTE data services via Wi-Fi offloading by installing 120,000 access points (called T Wi-Fi Zones) at data-concentrated areas. This includes cafés and movie theaters, where customers can now enjoy large-volume data contents without having to worry about heavy data costs.