To this day, relatively few wireless carriers offer LTE at its loftiest 150Mbps speeds. We'll soon get to count NTT DoCoMo among those ranks, however. Alongside the launch of its summer phone lineup, the Japanese network has firmed up some details of its Xi speed-up plans. The initial rollout will focus on the major centers of Nagoya, Osaka and Tokyo, all of which should have 150Mbps access by the end of the year. While NTT DoCoMo hasn't settled on the frequencies it will use, Impress Watch understands that this could involve reusing 1,700MHz FOMA 3G bands to get around local spectrum limits. Regardless of the speeds, there should be a tangible improvement in coverage -- the provider hopes to more than double its Xi base stations from 24,400 in March to 50,000 by the end of 2013. Most of us won't reap the rewards of the upgrade, but it's good to know that Japan's biggest carrier will soon be a first-class 4G citizen.