Massive MIMO Rocks Back to Wirelessone.news
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, Qatar, Verizon USA, T-Mobile Netherlands,
Light green: Talking: Vodafone England, Vodafone Turkey,
Safaricom Kenya, Telekom South Africa
- Published: 18 January 2018 18 January 2018
Large gains in wireless performance are possible with the right software.
Interference between cells and multiple signals seriously limits the performance of wireless networks. The problem becomes worse with today's very dense networks. Massive MIMO addresses that challenge with beamforming and intelligent design. Many of the theoretical problems remain open. The available solutions require enormous computing power.
Perfect solutions would require orders of magnitude more computing power than available today, but significant results are practical today.
Joe Farkas of Collision Communications believes they have particularly effective software that yields results approaching the ideal.
- Published: 27 December 2017 27 December 2017
Limited customers, speed only occasionally reached. Qatar Airlines is the first to deploy for Ooredoo's > 1 gigabit service, now being offered to selected customers in selected locations. C114, one of China's best tech pubs, is my source for the 1.2 gig speeds, confirmed by four other news publications. That the world leadership has left the U.S. and Europe is a major story, even if the details may be slight puffery.
Over a year ago, I discovered that True in Thailand was one of the first in the world to deploy 4x4 MIMO across the country, matched in 2017 in many other networks. That's just starting to be matched in the U.S. and Europe. Five companies - Ericsson, Huawei, Nokia, Samsung, and ZTE - are the source of almost all the 4G & 5G networks today. They sell the same gear in Qatar, Myanmar, Berlin, & Chicago. Except for Verizon and 5G mmWave - coming in 2018 - the Western telcos are no longer ahead.
- Published: 07 December 2017 07 December 2017
T-Mobile Netherlands and True Thailand choose 8 antennas for FDD spectrum, joining Kuwait in choosing Huawei gear. 8 antennas will rarely deliver twice the throughput of four antennas but will often deliver a 50% increase in capacity. 32/64 antenna Massive MIMO has been chosen by BT, DT, & FT but that is in higher frequencies running TDD.
32 antennas for 700 MHz spectrum would be too large to be practical most places. 256 antennas at mmWave frequencies are the size of a large chip and can go almost anywhere. 64 antennas at mid-frequencies like 2500 MHz need 1.5 to 3 meters, practical on most towers. Antenna size goes up with lower frequencies, making 32 antennas at 700 MHz a challenge and often impractical at 1800 MHz.
- Published: 13 October 2017 13 October 2017
Competition is fierce and spectrum is short, Reliance Jio spent $20B, built one of the best networks in the world, and gained 100M customers in the first year. Mukesh Ambani's aggressive plans for the 4G $20 (refundable) feature phone will probably add 100M more in the next year or so. Hundreds of millions of Indians are still on 2G. Ambani is ready to spend $B+ in subsidies to bring them to Jio 4G.
Giant Tata is closing their #4 mobile network, putting 10,000 out of work, writing off billions, and selling off cheaply to Bharti.. #5 Reliance Communications, Ambani's brother's company, is likely to follow. They couldn't compete in the price war. Vodafone and Idea, #2 & #3, are merging to stay alive
#1 Bharti's strategy in response includes a huge build of Massive MIMO, just announced. Danish Khan now reports the other two likely survivors, Jio and Vodafone/Idea, will also do Massive.
- Published: 06 October 2017 06 October 2017
381M customer Bharti Airtel, India's #1, has now turned on Huawei many antenna systems in Bangalore & Kolkata. Early results are doubling and tripling capacity. Bharti's pr, below, claims a 5-7 times improvement. That level of capacity and more will be possible as the software and algorithms improve, but the first generation is getting about half that.
China Mobile and Softbank pioneered M MIMO only a year ago. Now, the announcements are coming every week. Vodafone in England, Deutsche Te!ekom in the Netherlands and Hutchinson in Austria are officially moving from trials to commercial service. Sprint in the U.S. has a large network installed just waiting for Ericsson's final product release.
Bharti needs to keep up with Jio, the fastest growing network in the world.
- Published: 15 September 2017 15 September 2017
Tom 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.
- Published: 08 August 2017 08 August 2017
Achievable: Drastic drop in bad cell phone connections. Massive MIMO - 64 or more antennas - can dramatically improve edge performance by "beam forming," directing the signal where the users are. Done well, it can dramatically improve the performance where it's weaker. Hidebumi Kitahara of Softbank told me that is working very well and will get better as software improves. See "I am crazy about Massive MIMO," Kitihara of Softbank ordering 1,000's of Massive MIMO bases
Robert Clark of Light Reading reports Kitahara intends to use the capacity to improve performance for all users. "We don't care about peak throughput. We want to minimize the low throughput, which is between 1 Mbit/s and 5 Mbit/s." Clark adds, "At those speeds, the network will struggle to deliver a good video experience. Prior to deployment, around 20% of all users were experiencing throughput below 2 Mbit/s." Kitahara reveals, "only a few percent," now receive low speeds.
- Published: 05 August 2017 05 August 2017
MM depends on receiving back from the phone information on the channel. That uplink information has practical limitations on many cases, including from interference. In this paper, Bjornson, Hoydis, and Sanguinetti take on the assumption that there is a theoretical limit of spectral efficiency. Beginning with Marzetta, potential problems have been recognized.
"The pilot resources are limited by the channel coherence time, the same pilots must be reused in multiple cells. This leads to pilot contamination. ... it appears that pilot contamination is a fundamental issue that manifests a finite SE limit, except in some impractical special cases."
In 30 page dense with mathematics, the authors claim, "We will show in this paper that this is basically a misunderstanding,
- Published: 19 April 2017 19 April 2017
TDD Massive MIMO is already going wide at SoftBank Japan, yielding a 4x-10x capacity improvement on a single channel. Eric Zhao believes Massive MIMO is often the right choice where you need high capacity. Zhao finds early 32 antenna system averaging 450% more capacity in a single band. Many leading engineers agree MM is the way to go.
Worldwide, chief technologists are enthusiastic about Massive MIMO. At Huawei's MBB Forum, Hidebumi Kitahara of SoftBank confirmed the reported results, especially in crowded cells. Later in the day, Huang Yuhong of China Mobile also reported success. Her performance improvement estimates were "only" 3x, but it's early days for the technology. At SoftBank owned Sprint, Günther Ottendorfer reports a 10x improvement. Sanyogita Shamsunder of Verizon a year ago told me, "We must have massive MIMO." Nasser Al Nasser of Saudi Telecom in the release below reports a 6x improvement.
- Published: 18 April 2017 18 April 2017
Huawei reports 30+ networks in 2016. Networks have already been deployed from Bangkok and Jakarta, to Riyadh and Istanbul, Paris, Berlin and Vancouver. T-Mobile, Sprint, and AT&T in the U.S. are confirmed for 2017. Eric Zhao of Huawei believes the time has come where 4x4 should be the standard choice and Massive MIMO is right for hotspots. He predicts 100+ four antenna networks by the end of 2017.
4T4R (four transmit and four receive,) three or four carriers aggregated (60-80 MHz,) and 256 QAM signaling combine for close to a gigabit- Gig LTE. That's the hottest trend of 2017 and about 5x more than early LTE.
Christopher Hopcraft, Chief Technology Officer of fast-growing TRUE in Thailand, has deployed 4x4 across most of the network in his country with a population slightly higher than France or England.
- Published: 16 April 2017 16 April 2017
"TDD (Time Division) Massive MIMO represents the only effective implementation of Massive MIMO at the frequency bands under consideration."!? So says Professor Erik Larssen, a leading researcher at Linkoping University in Sweden. Larsson blogged the controversial paper on April 4, the day after it was published at https://arxiv.org/pdf/1704.00623.pdf. The blog and the abstract of the paper is below.
On the other hand, China Telecom, China Unicom, Huawei, and ZTE have announced successful trials of FDD (Frequency Division) Massive MIMO. A joint press release by China Telecom and ZTE asserts the opposite: "The FDD Massive MIMO solution is predictable to be deployed in China Telecom in 2017." Obviously, I'm not qualified to judge engineers of that quality when they disagree. I'll do my best to explain the issues and direct you back to the principals.
The primary issue, as I understand it, is whether FDD overhead is inevitably too high for FDD to be practical. With line of sight (LOS), the two techniques appear to have similar results. Without decent Line of Sight. the new paper reports a significant difference.
- Published: 16 April 2017 16 April 2017
"The commercial deployment of FDD - Frequency Domain - Massive MIMO is expected in 2017, including at China Telecom." (All the MM deployed today is TDD - Time Division.) That comment by ZTE is based on tests with China Telecom and China Unicom, both world class telcos. Huawei and ZTE are both shipping TDD gear. ZTE is a top-5 telecom manufacturer. Huawei has grown so much their sales totals and research budget are now more than Ericsson and Nokia combined.
Backing like this is highly credible. The joint press releases are below. I'm always skeptical until I have results from substantial field deployments, but wouldn't have doubted this except for work by Emil Bjornson, Erik Larsson, and Tom Marzetta. Marzetta invented Massive MIMO; Larsson & Bjornson are respected Swedish Professors.
More than half the spectrum in use is FDD - Frequency Division. Massive MIMO systems in the field today use TDD - Time Division.