SK Telecom announced its plan to roll out 500Mbps LTE service starting June, and achieve 1Gbps, relying on LTE only, through 5-Band CA (Carrier Aggregation) in 2018. The company further plans to build a network in 2.6GHz band by the end of 2018 that would use the frequencies it obtained in the last auction. The new network is claimed to serve more than 90% of population in 85 cities.

At a recent press forum, SK Telecom presented its strategies for evolving networks, particularly concerning what to do with the newly assigned frequencies. For a starter, the company will offer 500Mbps service, starting next month, by means of 3-Band CA and 256 QAM technology, using a total of 50MHz (DL) - 20MHz in 2.1GHz, 20MHz in 1.8GHz and 10MHz in 800MHz.

In fact, the maximum speeds achievable through frequency is just 375Mbps. However, 256 QAM technology, compatible with newer smartphone models like Galaxy S7 and S7 Edge, G5 and so on, helps boost speed up to 500Mbps. The 500MHz service will become available in Pusan, Ulsan and Daegu first in June, and then expand to other major cities including Seoul metropolitan area and Choongchung-do in August.
 
The company also has a plan on utilization of 2.6GHz it obtained through the auction. As additional 30MHz bandwidth (DL) was secured, it now has a total of 70MHz - 20MHz wider than its competitors - in the bandwidth. As a result, the operator has the widest bandwidth of all the big 3 in the nation, which helped it to get ready for 5-band CA implementation.
 
According to the roadmap shared, SK Telecom will begin deploying 2.6GHz network in Seoul and other metropolitan city areas first, and then nationwide by installing over 90,000 base stations in 85 cities across the nation by the end of 2019. Specifically, it aims to serve Seoul and 6 metropolitan cities by end of this year, 85 major cities by the end of 2017, and most of population (more than 90%) in those 85 cities by the end of 2018.

Once the new network arrives, the operator can provide speeds of up to 525Mbps by combining 5 bands: each from the current 800Mhz and 1.8Ghz, and two from 2.1GHz and 2.6GHz (10MHz and 20MHz respectively). Although a time frame of supporting 5-Band CA will vary depending on when software support at base stations will be available from their manufacturers, 5-Band CA is expected to be supported by 2018.
 
The company is aiming to achieve 1Gbps, by solely relying on LTE technology through employment of 256 QAM technology and 4x4 MIMO technology that uses 4 antennas. With speeds of 1Gbps, an HD movie (1.7GB) can be downloaded in just about 13 seconds.  

Besides, using this LTE with Multi-Path TCP (MPTCP) technology that engrafts Wi-Fi and LTE will bring us wireless speeds that surpass even wired speeds. SK Telecom predicted that 2.7Gbps wireless service via 5-Band CA and Multi-Path TCP technologies will be available after 2018. “As the auction for frequency is completed, we will continue to stay committed to improve the quality of experience by accelerating establishment of a new network.” said Department Head Choi Seung-won of SK Telecom’s Infra Strategy Headquarters.

Table 1. 3-Band CA: What's combined (Source: SK Telecom)