SK Telecom: Take a closer look at its LTE Advanced rollout

By Tammy Parker

Thanks to SK Telecom, LTE Advanced is commercially deployed, or, at least, the carrier aggregation component of LTE-A is. And as operators in other developed markets, such as the United States, lay out their own plans to deploy LTE-A features as well, they will be keeping a close eye on lessons they can learn from SK Telecom's pioneering efforts.

SK Telecom headquarters in Seoul

Late last month, SK Telecom announced the commercial launch of the world's first LTE-A network with a commercial smartphone ready for use with the service. Samsung, Nokia Siemens Networks and Ericsson-LG are supplying the operator with LTE/LTE-A network infrastructure, while the one LTE-A handset it offers is from Samsung.

The operator initiated South Korea's first commercial LTE service in July 2011 and projects its LTE subscriber base will reach 15 million by the end of 2013.

The mobile industry's desire for LTE Advanced, designed to enable faster data speeds and greater network capacity, is being driven by skyrocketing data consumption. In South Korea, for example, LTE data traffic increased from 2,838 terabytes (TB) in January 2012 to 30,355 TB in January 2013, according to the Korean Communications Committee (KCC). 

"Considering such rapid growth, the need for the more progress in LTE was an imminent task. This is why SK Telecom set out to deploy the LTE Advanced network and was able to successfully launch the world's first commercial LTE Advanced service," Irene Kim, spokeswoman for the operator, told FierceBroadbandWireless.

SK Telecom aggregated 10 MHz of its 1.8 GHz spectrum with 10 MHz of 800 MHz spectrum to form an effective bandwidth of 20 MHz. The combination allows the operator to support downlink data speeds up to 150 Mbps, twice the 75 Mbps it was delivering over its LTE network without aggregation.

The company has been using the two bands, though separately, for LTE since July 2012, when it commercialized multi-carrier technology. LTE multi-carrier assesses the level of data traffic congestion in an area and automatically selects the less congested, and thus faster, frequency band over which to deliver service.

Carrier aggregation technology is expected to mature quickly, enabling aggregation of two 20 MHz component carriers by 2015 to deliver peak downlink speeds up to 300 Mbps, with aggregation of three component carriers enabled by 2016, the same year uplink carrier aggregation is expected to become available. Up to five 20 MHz carriers could be aggregated under the current standard.

SK Telecom expects to keep riding the carrier aggregation wave as it grows. "SK Telecom will continue to develop carrier aggregation technology further to combine more bandwidths. Carrier aggregation technology is expected to play a significant role in solving the issue of spectrum fragmentation in many countries around the globe," said Kim.

LTE Advanced branding
SK Telecom's marketing department is touting LTE-A's higher data speeds to customers and emphasizing that there are no premium charges for the faster service. "SK Telecom's LTE Advanced is currently provided at the same price as LTE, and we plan to further develop flexible, customized plans that reflect diverse customer needs," said Kim.

"We've also shared our commitments to further develop LTE Advanced technologies to provide much faster and better mobile services, as well as our plans to provide high-capacity, high-speed services such as full HD multimedia services and network games," she said.

The operator is adding full HD (1080p resolution) video streaming to its Btv mobile IPTV service, which has 550,000 paid subscribers. "Full HD video streaming requires a speed of 2 Mbps or above, which is well supported by the LTE-A network," said SK Telecom. The operator is also rolling out an HD video-based shopping service, targeted for launch next month.

However, a number of mobile industry observers have expressed concern about vendors and operators, such as SK Telecom, touting carrier aggregation as being full-fledged "LTE Advanced" when, in fact, carrier aggregation is only one of LTE-A's many functionalities. (For example, see this GigaOM article.) Other leading LTE-A features include support for heterogeneous networks (HetNets) and high-order MIMO.

SK Telecom defends its LTE-A marketing. "Carrier aggregation is one of the main components of LTE Advanced (Release 10)," said Kim in an email.  "SK Telecom achieved the commercialization of LTE-Advanced by applying Release 10 to our LTE base stations and LTE Advanced device," she added, with that "device" being the Samsung Galaxy S4 LTE-A smartphone, available in either red or blue.

Samsung Galaxy - LTE Advanced

Here are the Samsung Galaxy S4 LTE-A smartphones.

She noted that 3GPP, which defines the standards for LTE, issued a statement in April 2013 pronouncing all work on 3GPP Release 10 onwards as constituting LTE Advanced.

"3GPP recognizes that in the marketplace a number of differing terms related to LTE are appearing. 3GPP reaffirms that the naming for the technology family and its evolution continues to be covered by the term LTE Advanced, which remains the correct description for specifications currently being defined--from Release 10 onwards, including 3GPP Release 12," said the statement, issued by 3GPP's Project Coordination Group (PCG).

3GPP Release 10, notably, fulfills IMT Advanced requirements. Standardization work on Release 10, LTE-A, was frozen in March 2011, and the technology was officially designated in January 2012 by the International Telecommunication Union as one of two approved IMT-Advanced technologies. (The other is WirelessMAN-Advanced, also known as WiMAX 2.) The next LTE A iteration, Release 11, was frozen in September 2012, though additional work items were being addressed throughout the first part of 2013, according to 3GPP.

"Though it is only the beginning, SK Telecom believes that the world's first commercialization of CA (carrier aggregation) itself has a great value and meaning, as we expect to provide unmatched network speed and greater customer experience by further developing carrier aggregation technology and aggregate more bandwidths and spectrum," said Kim.

Looking ahead

Already a pioneer in commercializing LTE, voice over LTE (VoLTE) and Coordinated Multi Point (CoMP), SK Telecom is planning to unveil even more network enhancements and new devices.

However, not everything is rolling out according to schedule. In December 2012, Byun Jae-woan, SK Telecom's CTO and head of the technology, told FierceBroadbandWireless that the operator would commercialize enhanced inter-cellular interference coordination (eICIC) in the second half of 2013. SK Telecom now expects to introduce eICIC next year, though Kim declined to provide a more specific timeline.

The technology is aimed at eliminating interference signals in data traffic within concentrated central city areas and effectively distributing traffic to let customers use data services with greater speed and stability. SK Telecom, which pioneered the world's first commercialization of LTE femtocells in June 2012, intends to maximize the use of small cell technologies through eICIc, said Kim.

"This will allow operators to expand network capacity in [a] cost-efficient manner, thus providing better network quality to customers," she added.

SK Telecom and cafe

SK Telecom store and experience zone café in Jonggak, Seoul

In addition, SK Telecom intends to expand its LTE-A device lineup, which is now limited to just the Samsung Galaxy S4 LTE-A, to seven smartphones before year's end. In a press release, the operator said it had secured an initial supply of 20,000 Galaxy S4 LTE-A units. The operator actually meant to say it had an initial supply of 200,000.  

The Korea Times recently quoted anonymous SK Telecom executives as saying that Apple (NASDAQ:AAPL) is in the middle of negotiations about including LTE-A carrier aggregation capability in the next version of the iPhone. Kim declined to comment on that report, saying, "SK Telecom does not have any information about the next iPhone model."

SK Telecom: Take a closer look at its LTE Advanced rollout