Massive MIMO has been crucial to the performance of early 5G, and deployed at a far earlier stage and faster rate than was forecast a few years ago. The antenna arrays, featuring between 16 and 128 transmit and the same number of receive elements, allow operators to boost cell range, and so to use the same site grid that supported 2.5 GHz or even 1.8 GHz LTE, for 5G in higher bands around 3.5 GHz. The technology also supports sharp increases in capacity and cell edge performance. But it is at the start of its evolution. Already, 256T256R platforms are being tested. Huawei has applied a variant of the technology to an indoor architecture called Distributed Massive MIMO. One of…