M MIMO from UnicampTom Marzetta and other researchers have been very skeptical about the performance of Massive MIMO using FDD (Frequency Division Duplex) rather than TDD (Time Division.) Massive MIMO requires regular and robust reporting from the cell phone, which they feared would be impractical with FDD. Huawei, ZTE, and now Ericsson have done field trials they believe prove otherwise.  

In trial with T-Mobile. Nishant Batra is confident many antenna Massive MIMO will add to performance in FDD frequencies as well as the TDD frequencies beginning to widely deploy. While the performance gain may not be exponential, directing the beam significantly increases capacity even in FDD systems. 

Batra expects 3 carrier, 60 MHz TDD Massive MIMO in early 2018. He didn't provide performance estimates, but that class of technology should provide double or better the effective capacity of the "Gigabit LTE" now deploying.
Just as Gig LTE is most often 75-300 megabits, the soon come Massive MIMO will often be far less than the 2-3 gigabits achieved under ideal test circumstances. Batra expects 100 MHz Massive MIMO by yearend 2018. That will provide exceptional performance for networks like Sprint that have enough spectrum.
Ericsson's Kathy Egan writes about FDD, "Capacity increase as compared to 2 transmit antennas is between 1,5x – 3x on average and 1,9x – 5x for cell edge." This is far less than the hope of Massive MIMO proponents. Simply going from two to four antennas would often yield 1.5x and sometimes more. This may be an inherent limit of the FD technology or might just reflect the early
Simply going from two to four antennas would often yield 1.5x and sometimes more. This may be an inherent limit of the FDD technology or might just reflect the early stage of the research. Maximizing Massive MIMO requires sophisticated algorithms and I expect much better results as the software improves.
The superior results on the cell edge correspond to what Softbank told me last fall. Softbank went from a significant number of cell edge phones not having enough capacity for video to nearly universal performance at an adequate level. Rarely will a mobile phone customer notice a difference if her speed goes from, say, 50 to 75 megabits down. But sputtering video leaves unhappy customers.
Sprint's spectrum at 2500 MHz is generally used for TDD, as is the spectrum from 3400-4200 MHz. Most spectrum below 2100 is allocated to FDD. That applies to almost all the spectrum by many of the major carriers. Blue Danube, working with AT&T, is testing an analog system for Massive MIMO that may also provide robust performance in FDD bands.
I've asked all the companies involved for the actual test data from the field and will share what they send me. The results so far have been somewhat disappointing, perhaps 2X to 3X what's achieved with 4x4 MIMO. That is likely to improve significantly as the systems mature, especially from better beaming-forming algorithms. 
Note. An earlier version of this article confused FD (Full Dimension) MIMO with FDD.  


dave ask


Vivo is selling new the iQOO 5G premium quality phone for US$536.

Lei Jun Xiaomi "5G to have explosive growth starting from Q2 2020"5G to have explosive growth starting from Q2 2020" I say sooner

Verizon CEO Ronan Dunne: >1/2 VZ 5G "will approximate to a good 4G service" Midband in "low hundreds" Mbps

CFO John Stephens says AT&T is going to cut capex soon.

Bharti in India has lost 45M customers who did not want to pay the minimum USS2/month. It's shutting down 3G to free some spectrum for 4G. It is cutting capex, dangerous when the 12 gigabytes/month of use continues to rise.

Huawei in 16 days sold 1,000,000 5G Mate 20s.  

China has over 50,000 upgraded base stations and may have more than 200,000 by yearend 2019. The growth is astonishing and about to accelerate. China will have more 5G than North America and Europe combined for several years.

5G phone prices are down to $580 in China from Oppo. Headed under $300 in 2020 and driving demand.

No one believed me when I wrote in May, 90% of Huawei U.S. purchases can be rapidly replaced and that Huawei would survive and thrive. Financial results are in, with 23% growth and increased phone sales. It is spending $17B on research in 2019, up > 10%. 

5G phones spotted from Sharp and Sony

NTT DOCOMO will begin "pre-commercial service Sept 20 with over 100 live bases. Officially, the commercial start is 2020.

 More newsfeed


Welcome  1,800,000 Koreans bought 5G in the first four months. The demand is there, and most of the technology works. Meanwhile, the hype is unreal. Time for reporting closer to the truth.

The estimates you hear about 5G costs are wildly exaggerated. Verizon is building the most advanced wireless network while reducing capex. Deutsche Telekom and Orange/France Telecom also confirm they won't raise capex.

Massive MIMO in either 4G or "5G" can increase capacity 3X to 7X, including putting 2.3 GHz to 4.2 GHz to use. Carrier Aggregation, 256 QAM, and other tools double and triple that. Verizon sees cost/bit dropping 40% per year.

Cisco & others see traffic growth slowing to 30%/year or less.  I infer overcapacity almost everywhere.  

Believe it or not, 80+% of 5G (mid-band) for several years will be slower than good 4G, which is more developed.