Millimeter wave mobile communications for 5G cellular: It will work! was a revelation in 2013. Back then, most engineers believed that rain and atmosphere made mmWave spectrum would play only a modest role in mobile communications.  

Looking back four years later, most of what Ted, Samini and team wrote in 2013 is confirmed. This article was triggered when I noticed then NYU grad student Mathew Samini was an author on 15 major papers in three years (below.)  These included the propagation test data and a more accurate Statistical Channel Model, an essential for designing networks. (Abstract below.)

Verizon will soon turn on millimeter wave to (a very few) homes in 11 cities; the Koreans have major plans for the next 15 months. It does work. The NYU team performed tens of thousands of tests in Manhattan as well as in Brooklyn. Their data was convincing. Four years later, $billions are being spent to solve the remaining problems and start to connect hundreds of millions.

The 2013 IEEE paper noted, "Since signals cannot readily propagate through outdoor building materials, indoor networks will be isolated from outdoor networks and this suggests that data showers, repeaters, and access points may need to be installed for handoffs at entrances of commercial and residential buildings." In the event, most initial and early deployments will feature outdoor antennas.

They also predicted the importance of "heterogeneous networks with co-existing large macro, micro, and pico cells, and Wi-Fi access points. Low cost deployment will be realized by self-organizing features and repeaters/relays." While HetNets were the "next big thing" several years ago, but few were actually deployed back then, Over the last 12 months, HetNets again have become a hot topic, They work well now, with Verizon, Sprint, and T-Mobile deploying hundreds or more. Ibrahim Gedeon of Telus tells me small cells are currently  the most important tool for capacity increases in his network.

The Brooklyn team did miss some trends. They expected, "At some point around 2020, wireless networks will face congestion." That now seems highly unlikely. In fact, wireless traffic growth has been falling. Speeds have doubled in the last few years on most networks. There is so much spare capacity Verizon, Sprint, and T-Mobile have gone "unlimited."

Now that smart phones are common, the traffic growth rate is down to 40%-45%, with Cisco confident it will continue to fall. The 100% traffic increases around 2009 were an artifact caused by smartphones first becoming available. The "unlimited" offerings may cause another spike, but even so the extensions of technologies in frequencies far lower than mmWave look to more than keep up.   

Cisco's estimate is that U.S. traffic will grow 7X by 2020. The technology is improving even faster. Capacity can grow 8-15X in the next few years even without millimeter wave. A lack of traffic demand might persuade telcos to reduce capex. The biggest problem at most companies is they can't seel all hthe capacity they have. 

Here are abstracts of some of the work. 

Millimeter Wave Mobile Communications for 5G Cellular: It Will Work!


NYU WIRELESS, Polytechnic Institute of New York University, New York, NY 11201, USA Corresponding author: T. S. Rappaport 

This work was supported by Samsung DMC R&D Communications Research Team and Samsung Telecommunications America, LLC.

ABSTRACT The global bandwidth shortage facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks. There is, however, little knowledge about cellular mm-wave propagation in densely populated indoor and outdoor environments. Obtaining this information is vital for the design and operation of future fifth generation cellular networks that use the mm-wave spectrum. In this paper, we present the motivation for new mm-wave cellular systems, methodology, and hardware for measurements and offer a variety of measurement results that show 28 and 38 GHz frequencies can be used when employing steerable directional antennas at base stations and mobile devices. 

Characterization of the 28 GHz Millimeter-Wave Dense Urban Channel for Future 5G Mobile Cellular

By Mathew K. Samimi and Theodore S. Rappaport

This technical report presents ultra-wideband statistical spatial and omnidirectional channel models for 28 GHz millimeter-wave cellular dense urban line-of-sight and non-line-of-sight environments, developed from wideband measurements in New York City that used synthesized timing from 3-D ray-tracing. An accurate 3GPP-like channel model has been developed, where model parameters are based on empirical distributions for time cluster and spatial (lobe) channel parameters. A statistical simulator capable of reproducing the joint temporal and spatial measured channel statistics is given here. A step-by-step procedure for generating channel coefficients is shown to validate measured statistics from 28 GHz field measurements, thus validating the statistical channel model. 



Millimeter wave mobile communications for 5G cellular: It will work!
TS Rappaport, S Sun, R Mayzus, H Zhao, Y Azar, K Wang, GN Wong, ...
Access, IEEE 1, 335-349
1347 2013
Millimeter wave channel modeling and cellular capacity evaluation
MR Akdeniz, Y Liu, MK Samimi, S Sun, S Rangan, TS Rappaport, E Erkip
Selected Areas in Communications, IEEE Journal on 32 (6), 1164-1179
352 2014
Wideband Millimeter-Wave Propagation Measurements and Channel Models for Future Wireless Communication System Design
G MacCartney, T Rappaport, M Samimi, S Sun
28 GHz millimeter wave cellular communication measurements for reflection and penetration loss in and around buildings in New York City
H Zhao, R Mayzus, S Sun, M Samimi, JK Schulz, Y Azar, K Wang, ...
Communications (ICC), 2013 IEEE International Conference on, 5163-5167
123 2013
Radio propagation path loss models for 5G cellular networks in the 28 GHz and 38 GHz millimeter-wave bands
AI Sulyman, AMT Nassar, MK Samimi, GR MacCartney, TS Rappaport, ...
Communications Magazine, IEEE 52 (9), 78-86
97 2014
28 GHz angle of arrival and angle of departure analysis for outdoor cellular communications using steerable beam antennas in New York City
M Samimi, K Wang, Y Azar, GN Wong, R Mayzus, H Zhao, JK Schulz, ...
Vehicular Technology Conference (VTC Spring), 2013 IEEE 77th, 1-6
96 2013
Joint spatial division and multiplexing for mm-wave channels
A Adhikary, E Al Safadi, MK Samimi, R Wang, G Caire, TS Rappaport, ...
Selected Areas in Communications, IEEE Journal on 32 (6), 1239-1255
91 2014
3-D Statistical Channel Model for Millimeter-Wave Outdoor Mobile Broadband Communications
MK Samimi, TS Rappaport
arXiv preprint arXiv:1503.05619
46 2015
Millimeter wave multi-beam antenna combining for 5G cellular link improvement in New York City
S Sun, GR MacCartney, MK Samimi, S Nie, TS Rappaport
Communications (ICC), 2014 IEEE International Conference on, 5468-5473
41 2014
Ultra-wideband statistical channel model for non line of sight millimeter-wave urban channels
MK Samimi, TS Rappaport
Global Communications Conference (GLOBECOM), 2014 IEEE, 3483-3489
39 2014
Omnidirectional path loss models in New York City at 28 GHz and 73 GHz
GR MacCartney Jr, MK Samimi, TS Rappaport
Personal, Indoor, and Mobile Radio Communication (PIMRC), 2014 IEEE 25th ...
36 2014
Exploiting Directionality for Millimeter-Wave Wireless System Improvement
GR MacCartney Jr, MK Samimi, TS Rappaport
arXiv preprint arXiv:1503.05265
29 2015
Probabilistic Omnidirectional Path Loss Models for Millimeter-Wave Outdoor Communications
M Samimi, T Rappaport, G MacCartney
26 2015
73 GHz millimeter-wave indoor and foliage propagation channel measurements and results
S Nie, MK Samimi, T Wu, S Deng, GR MacCartney, TS Rappaport
NYU WIRE LESS: Department of Electrical and Computer Engineering, NYU ...
7 2014
Validation of a Geometry-Based Statistical mmWave Channel Model Using Ray-Tracing Simulation
Q Li, H Shirani-Mehr, T Balercia, A Papathanassiou, G Wu, S Sun, ...
Vehicular Technology Conference (VTC Spring), 2015 IEEE 81st, 1-5
5 2015
Radio Propagation Path Loss Models for 5G Cellular Networks in the 28 GHz and 38 GHz Millimeter-Wave Bands (vol 52, pg 78, 2014)
AI Sulyman, AMT Nassar, MK Samimi, GR MacCartney Jr, TS Rappaport, ...

dave askOn Oct 1, Verizon will turn on the first $20B 5G mmWave network, soon offering a gigabit or close to 30M homes. The estimates you hear about 5G costs are wildly exaggerated. Verizon is building the most advanced wireless network while keeping capex at around 15%.

The Koreans, Chinese, and almost all Europeans are not doing mmWave in favor of mid-band "5G," with 4G-like performance. Massive MIMO in either 4G or "5G" can increase capacity 4X to 10X, including putting 2.3 GHz to 4.2 GHz to use. Cisco & others see traffic growth slowing to 30%/year or less. Verizon sees cost/bit dropping 40% per year. I infer overcapacity almost everywhere.  

The predicted massive small cell builds are a pipe dream for vendors for at least five years. Verizon expects to reach a quarter of the U.S. without adding additional small cells. 

In the works: Enrique Blanco and Telefonica's possible mmWave disruption of Germany; Believe it or don't: 5G is cheap because 65% of most cities can be covered by upgrading existing cells; Verizon is ripping out and replacing 200,000 pieces of gear expecting to save half. 


 5G Why Verizon thinks differently and what to do about it is a new report I wrote for STL Partners and their clients.

STL Partners, a British consulting outfit I respect, commissioned me to ask why. That report is now out. If you're a client, download it here. If not, and corporate priced research is interesting to you, ask me to introduce you to one of the principals.

It was fascinating work because the answers aren't obvious. Lowell McAdam's company is spending $20B to cover 30M+ homes in the first stage. The progress in low & mid-band, both "4G" and "5G," has been remarkable. In most territories, millimeter wave will not be necessary to meet expected demand.

McAdam sees a little further. mmWave has 3-4X the capacity of low and mid-band. He sees an enormous marketing advantage: unlimited services, even less congestion, reputation as the best network. Verizon testing found mmWave rate/reach was twice what had been estimated. All prior cost estimates need revision.

My take: even if mmWave doesn't fit in your current budget, telcos should expand trials and training to be ready as things change. The new cost estimates may be low enough to change your mind.