SK Telecom aims to deploy 5,000 additional base stations by the end of 2015, to support tri-band service in Seoul and 91 other cities. SK Telecom already has installed 30,000 tri-band mobile sites.
The use of tri-band carrier aggregation provides mobile Internet access at speeds up to 300 Mbps.
The technique aggregates radio carriers in three different frequency bands–20 MHz bandwidth in the 1.8 GHz band, 10 MHz bandwidth in the 800 MHz band and 10 MHz bandwidth in the 2.1 GHz band–creating a virtual channel of 40 Mhz. More spectrum translates directly into higher potential speeds.
The tri-band service is available in Seoul and its metropolitan area, in six metropolitan cities, as well as major areas of 85 cities nationwide.