MM MAP NOV 2017 450

Dark blue: Building actively: China Mobile, Softbank Japan, Bharti India, 
Jio India, Vodafone India, Singtel, Globe Phillippines

Dark green: Announced: DT, FT/Orange, BT, Sprint USA,
Verizon USA, T-Mobile Netherlands, 

Light green: Talking: Vodafone England, Vodafone Turkey,
Safaricom Kenya, Telekom South Africa   

Bjornsen Massive MIMO Spectral
Björnson Publishes Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency

Professor Björnson's book comes at an auspicious moment. British Telecom, Deutsche Telekom, & France Telecom/Orange recently committed to large deployments of Massive MIMO.at the recent Huawei Mobile Broadband Forum. Like most of the work on Massive MIMO, the book is a collaboration across countries. Björnson, one of the first researchers in Massive MIMO, is in Sweden. Co-author Luca Sanguinetti is in Italy. The third author, Jakob Hoydis is at Nokia in France.  

They contend, "A lot of classic 'wisdom' about Massive MIMO is questionable because it is based on too simplistic system models."

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Huiman Zhu 23010,000 Cell Sites Shipped - All TDD, Not FDD

Zhu Huimin indicates Huawei is moving to high volume production. I once suggested, "Don't believe any equipment claims until 10,000 are deployed." Most problems, including those from heavy use, will appear by then. By that test, Massive MIMO - at least the TDD variety - is now solid. The first announcements of Massive MIMO commercial use were just after a year ago. Softbank Japan was the pioneer; I broke the news that China Telecom was also buying thousands. Although Huawei does have a 32x32 antenna FDD Massive MIMO, her recommendation is to stick with 8x8 in FDD spectrum.

CEO Gavin Patterson of British Telecom, CTO Bruno Jacobfeurborn of Deutsche Telekom, and SVP Arnaud Vamparys of FT Orange all committed to deploying Massive MIMO. (I've added them to the map.) There is no doubt that TDD MM works and will rapidly deploy around the world. Two Huawei executive confirmed to me Massive MIMO is ready for Africa. The need is great; there are very few landlines so almost all the Internet connections are mobile.

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MM Map Nov 2017 230England, France, and Germany Promise Massive MIMO

BT CEO Gavin Patterson, DT CTO Bruno Jacobfeuerborn, and FT/Orange SVP Arnaud Vamparys all endorsed Massive MIMO and said it would be used on their networks. I've added England, France, and Germany to the Massive MIMO map. They spoke one after the other at Huawei's Global Mobile Broadband Forum in London on November 14. 

BT has a Massive MIMO rig in active testing. They only have 15 MHz of TDD 2.6 spectrum, although they have 50 MHz of FDD spectrum above 2.5 GHz. They are actively watching the development of FDD MM, especially as the 3.5 auction continues to be delayed. They could add roughly 70% to network capacity if OFCOM allowed them to switch the FDD spectrum to TDD. They support MM research at Bristol University.

Deutsche Telekom is trialing 3.5GHz Massive MIMO.

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Lund testing

Prof on Massive MIMO: "TDD beamforming is the only feasible alternative"!?

Erik Larsson co-authored the textbook on Massive MIMO, which included an opinion that FDD MM would never be practical. MM requires the phone/UE to constantly report back metrics to the cell. TDD can do that efficiently; Larsson believes FDD cannot.

Verizon disagrees and is already deploying. Ericsson, Huawei, and ZTE have done successful testing with telcos. Not long ago, a senior engineer at a large telco told me the company is confident their FDD cells will work just fine. 

Larssen and a team from Lund went out to the university parking lot. They used a 7 meter test rig with 128 elements. They tested at 2.6 GHz with a bandwidth of 50 MHz,

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Massive MIMO: Real Hardware Isn't Perfect

Bjornson and colleagues created a model of Massive MIMO that accounts for (some) imperfections in the real world. Components are never perfect, of course, but earlier MM models made that simplifying assumption.

Their conclusion: The ability of the UE/phone is the most important factor. That said, adding more antennas will significantly improve performance.

They warn about cheap antennas. "Large arrays might only be attractive for network deployment if each antenna element consists of inexpensive hardware. 

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24 Stream MM: 956 Megabits in 20 MHz

Softbank & ZTE demonstrate an 18X improvement in the test, if the press release details are correct. The China Mobile rule of thumb is MM delivers an average 3X gain, but results vary enormously.

Softbank was first in bringing MM to the field and in some cases did see a 10X improvement. In other locations, results were well under the hoped for 3X. Ironically, the worst location can be is where you have good line of sight. MIMO works by bouncing off the terrain.

LTE has a physical connection rate of 75 megabits in 20 MHz. That would be a maximum of 1,800 megabits. However, a third of that is used for signaling and error correction, resulting in about 50 megabits usable. 24 streams in theory could deliver 1,200 megabits. 

Softbank's "24 terminals downloaded FTP data simultaneously at a rate of 956 megabits." That's remarkably close to the maximum after just 18 months.

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The Site for Massive 230
dave ask

Massive MIMO is rapidly deploying across the world; Soon, I'll be adding many more countries to the Massive MIMO map. On average, adding 64 or 128 antennas triples the performance of the cell site at moderate cost. Ericsson, Huawei, and ZTE are shipping by the thousands.

Being a reporter is a great job for a geek. I'm not an engineer but I've learned from some of the best, including the primary inventors of DSL, cable modems, MIMO, Massive MIMO, and now 5G mmWave. Since 1999, I've done my best to get closer to the truth about broadband.

Send questions and news to Dave Burstein, Editor.