SK Telecom is starting the new year with a new kind of 4G network – or at least a network built from the pieces of its older LTE systems. This week, SK turned on a 300 Mbps LTE service that ties together spectrum from three different frequency bands.
The network uses an LTE-Advanced technique called carrier aggregation to bond together 4G channels to create a kind of super-connection. [company]SK Telecom[/company] was one of the first operators to use carrier aggregation technology, bonding two 4G transmissions together back in 2013 to hit 150 Mbps. At the time, it jumped the gun a bit by calling its network LTE-Advanced, when in truth it wasn’t building anything more powerful than most LTE services in Europe.
But by using tri-band carrier aggregation, SKT is now making the leap to speeds that plain old LTE could never reach. It’s combining 20 MHz in the 1800 MHz band with 10 MHz in each of the 2.1 GHz and 800 MHz bands, and coordinating their transmissions so they act like a unified downlink pipe.
As SKT gets access to more spectrum in those bands it can boost speeds and capacities further. The U.K.’s [company]Everything Everywhere[/company] is already testing a network in London with [company]Huawei[/company] and [company]Qualcomm[/company] that hits 410 Mbps, while SK itself has used tri-band tech to hit 450 Mbps in demos. SK said it is already working on combining four and even five frequency bands.
Though SKT claims the new network is now commercial launched, it doesn’t appear to be widely available just yet. The operator said it plans to upgrade 26,000 cell sites in the Seoul metro area and the centers of other South Korean cities in the first quarter. It also plans to offer the new tri-band capabilities in all of the country’s subway lines.
As for devices, per usual the SKT is ahead of the curve. [company]Samsung[/company] has made a version of Galaxy Note 4 that appears to be specifically optimized for the Korean network, and SK said it would offer those oversized handsets to a limited group on customers to help it test and improve the service. The first widely available devices with tri-band aggregation support should be coming out in the next six months, according to Qualcomm.