T-Mobile US is currently testing tri-band carrier aggregation (3C) LTE technology in Dallas, Texas, using the 700MHz, 1900MHz and 2100MHz bands. According to Fierce Wireless, which cites information from T-Mobile subscribers based in the city, the 3C trial has yielded downlink transmission speeds of around 60Mbps. The tests remain unofficial for now, however, with a company spokesperson telling the website: ‘We’ve been doing some advanced LTE field trials in the area, but don’t have anything to announce yet.’
According to TeleGeography’s GlobalComms Database, T-Mobile US currently offers LTE access via a number of different frequency permutations. Alongside its original 4G network (launched in March 2013), the cellco offers LTE-Advanced (LTE-A) connectivity via carrier aggregation (CA) in the 700MHz/1900MHz bands (known as ‘Wideband LTE’); ‘Extended Range LTE’ in the 700MHz band; and ‘L1900’, which is being used primarily to update T-Mobile’s current 2G towers to LTE.