Japanese cellular operator NTT DoCoMo has announced that it has passed the three million customer milestone on its 4G Long Term Evolution (LTE) mobile network. The network, which is operated under the name ‘Xi’ (pronounced ‘crossy’), was launched on 24 December 2010 and reached one million users a year later. The two million point was passed in mid-March this year and it has taken just under three months to add a further one million subscribers. Recent take-up was boosted by the introduction of the first 4G-enabled handsets in November last year. DoCoMo is Japan’s largest cellular operator by subscribers, with more than 60 million customers at the end of March 2012 according to TeleGeography’s GlobalComms Database.