T-Mobile USA has gone from being the poor relation, in spectrum terms, among the large US mobile operators, to having the most attractive mixture of different frequencies. Courtesy of its acquisition of Sprint, with its substantial swathes of 2.5 GHz TDD spectrum, and of sales such as the 600 MHz incentive auction, TMO now has its ‘layer cake’ in place, consisting of nationwide 600 MHz for ubiquitous coverage; midband spectrum, mainly in 2.5 GHz, to support higher capacity with reasonably broad coverage; and millimeter wave bands for very high capacity hotspots including some fixed wireless. Just as TMO used to make up for its shortage of midband spectrum, in particular, with clever marketing propositions, now it is proving…