SK Telecom says it will launch a gigabit-speed 4G service in early 2018 based on its investments in more advanced 4G technologies.
The South Korean telco has also switched on a 900Mbit/s 4G service in six of the country's main cities as well as a 700Mbit/s one that covers 53 of them.
The latter is based on a technique known as carrier aggregation, which combines two or more spectrum channels -- sometimes from different frequency bands -- to boost bandwidth.
SK Telecom (Nasdaq: SKM) combined five different spectrum channels to bring the 700Mbit/s service to market.
It currently owns 10MHz in the 800MHz band, 20MHz in 1800MHz, 10MHz in 2.1GHz and a total of 30MHz in the 2.6GHz range.
The 900Mbit/s service, meanwhile, is based on a mixture of carrier aggregation -- with SK Telecom combining either three or four channels -- as well as 4x4 MIMO.
Another way of increasing connection speeds, MIMO (or multiple input, multiple output) works by adding antennas to the transmitter and receiver devices. With the 4x4 variant, there are four transmitting antennas and another four receiving ones.
By using four- or five-channel carrier aggregation in conjunction with 4x4 MIMO, as well as other technologies that form part of the LTE-Advanced Pro standard, SK Telecom expects to be able to introduce gigabit-speed connections on its 4G network in the first half of 2018.
From a user perspective, unfortunately, the higher-speed services will be available only to customers with a Samsung Galaxy S8, which will be able to support the LTE-A Pro technologies following an over-the-air firmware upgrade.
However, SK Telecom insists that forthcoming handsets will also be able to handle LTE-A Pro.
The strategy reflects intense rivalry in South Korea's mobile Internet market as operators attempt to outperform one another on connection speeds.
But the growing capability of 4G has also led some market watchers to question the need for 5G networks given the lack of applications that require connection speeds of more than 1 Gbit/s. (See The Growing Pains of 5G.)
Many proponents of 5G have responded to such criticism by drawing attention to the technology's other attractions, including much lower latency, or network delay, than is found in a 4G system.
With 5G techniques such as network slicing, operators will also be able to provide many different types of network service over the same 5G infrastructure.
SK Telecom is keen to present its latest "4.5G" moves as a kind of stepping stone to the 5G standard, which it has talked about introducing in trial form in time for next year's Winter Olympics in PyeongChang. (See SKT Airs 28GHz Concerns, Eyes Mid-Band 5G.)
"SK Telecom's LTE-A Pro services represent an early application of 5G technologies that support Gbit/s-level data speeds and massive network capacity," said Choi Seung-won, a senior vice president at SK Telecom and head of its infrastructure strategy office, in a company statement. "4.5G can be considered as the very last stage of LTE and will facilitate the spread of immersive multimedia services, including virtual reality, augmented reality and 3D hologram content."
The executive also said he expected the investments in LTE-A Pro to give SK Telecom a "valuable edge in the 5G era."
— Iain Morris, , News Editor, Light Reading