In 2014, Stanford Professor Paulraj told me MU MIMO would be the most effective way to deliver the capacity Africa needed. In 2016, the first Massive MIMO systems were deployed by Softbank Japan and China Mobile. The results were excellent. Softbank reported “up to a 10X improvement.” Huang Yuhong of China Mobile told me 3X was more typical, which she considered an exceptional result.
This note is over-simplified, of course. Wireless networks are extremely complicated and results vary enormously with terrain. I wanted to write something because both academics and network builders have told me Massive MIMO, 4G or 5G, should almost always be on the table planning networks were wires are few.
Massive MIMO also can lead to the effective doubling of primary wireless spectrum. Without MIMO, 2.5 GHz spectrum was in limited use. Midband 3.3GHz to 4.2 GHz was impractical for wireless networks. With the greater performance of Massive MIMO, 2.5 GHz has become golden spectrum that is delivering America’s best network at T-Mobile. 90%+ of 5G worldwide is midband, with superior speeds.Continue reading