Millimeter wave is exciting but the telcos are putting MIMO multi-antennas on the front burner. Verizon, NTT and other carriers presented MU MIMO as crucial to their plans at the remarkable Brooklyn 5G event. Sanyogita Shamsunder (quoted in title, pictured) leads their 5G program and made clear in her slide that Verizon 5G will be MU MIMO, not just the publicized millimeter wave.
Tom Keathley of AT&T had a similar comment. "The 5G Industry expects Massive MIMO." He noted the importance of "Sub 6 GHz for wide area coverage with improved spectral efficiency." The Bells seem to be reaching a similar conclusion as NTT. Seizo Onoe, NTT CTO, startled last year's Brooklyn 5G Conference by saying that NTT's 5G efforts mostly will be below 6 GHz for years. High frequencies will be important, Onoe told us, but mostly after 2022-2023.
This year, Verizon and other carriers confirmed that MU MIMO, with many antennas, is crucial to their plans.
AT&T, China Mobile, Deutsche Telekom, Telefonica and Telstra have recently made important contributions to 3GPP about modulation aimed at MU MIMO. Both Bristol University and Facebook have built massive MIMO rigs showing a 1000% gain in efficiency.
Until we have more data from the field, no one is quite sure which will be the right technology in which location. MU MIMO is natural for less dense territories. Millimeter wave can deliver more data where there are enough customers to justify the investment in so many cells. Both will have a place.
20 years ago, Stanford Professor Arogyaswami Paulraj projected that MIMO would one day increase wireless capacity 100x. Today's prototype equipment, such as the 96 antenna Facebook Aries, are demonstrating a 10x improvement over LTE. The performance will increase as the system is improved. World class engineers, including Paulraj, discussed a path to 100x at the Marconi Symposium in 2014. All were confident 10x is feasible soon. (Video below.)