The carrier has also launched 256 QAM for downloads and 64 QAM for uploads across half of its network, with a nationwide rollout to be completed by the end of October. These new quadrature amplitude modulation technologies increase the number of bits delivered per transmission for even faster LTE speeds. Combined with 4x4 MIMO, 256 QAM delivers theoretical download speeds up to 400 Mbps.
Meanwhile, T-Mobile said it now covers nearly 312 million customers in the United States, bringing it to within 99.7% of Verizon's coverage.
Qualcomm's X12 modem, an appropriate candidate for iPhone 7, supports 4x4 MIMO, so it is possible that some models could benefit from the technology. However, Apple is expected to use Intel's XMM 7360 LTE modem for a portion of iPhone 7 models, including AT&T models, and 4x4 MIMO is not an advertised feature of that chipset. iPhone 6s and older models do not support 4x4 MIMO.
T-Mobile customers with Samsung's Galaxy S7 or Galaxy S7 edge will be covered by 4x4 MIMO following a software update later this month.