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Angel Lozano!
Post-Cellular Wireless Networks
Angel Lozano!
① Flashback ② Coming Up: 5G ③ A World Without Cells?
Outline
① Flashback
1st Breakthrough
James C.!Maxwell!
Heinrich!Hertz!
“I do not think that the wireless waves I have discovered will have any practical
applications”
2nd Breakthrough
Nikola!Tesla!
Guglielmo!Marconi!
4th Breakthrough
Claude Shannon!
5th Breakthrough “There’s plenty of room at the bottom” R. Feynman
Dozens of new base stations would haveto be installed and cut into service atthe same moment. Hundreds of radiosin the old base stations would have tobe moved and retuned. It was a costly,labor intensive process and promised tobe very difficult logistically.
While drawing such a configuration,it occurred to me that this massive dis-ruption was being created to achieve anincremental increase in system capacity.At that moment, the larger cells wereserving almost the entire trafficdemand. If we retained the existingcells as a continuous “underlaid” gridproviding almost all the needed capaci-ty, we could add a few “overlaid” small-er cells “here and there,” with only afew channels, to provide the smallamount of incremental capacity weneeded. Those few channels could con-tinue to be used at the original basestations for mobiles that were in theinner portion of the cell (in effect, for asmaller cell that was co-sited with thelarger cell). Calls that left these newisolated cells could be handed off to theunderlaid grid, which would still pro-vide geographically continuous cover-age. Over time, more new base stationswould be added, and more channelswould gradually be moved into thosenew base stations until the old grid wasfinally replaced, but the process wouldbe gradual and manageable. This elimi-nated the logistic problems of cell split-
ting and reduced the number of cellsthat were needed at most points ingrowth rather dramatically. Simulationsusing Jim O’Brien’s MultiCell simula-tion showed that the average number ofcells in a growing system (and thus theaverage system cost) were reduced bymore than 50 percent. That simple idealater became one of AT&T’s mostsought after patents in cross-licensingagreements [10].
SYSTEM TRIALS ANDCOMPATIBILITY STANDARDS
As the system design progressed towardcompletion, it became necessary todemonstrate that AMPS would provideboth the excellent service and the spec-trum efficiency that had been promised.This sort of demonstration would be afeature of any development program,but amid the political debates of thetime it led to new controversies anddelays. To demonstrate real service, wewould need a large coverage area, andto demonstrate the proper working ofthe system for the largest capacity wewould need to use small cells. Puttingthe two objectives together would cre-ate a trial with hundreds of cells, whichwas economically infeasible, so AT&Tproposed to separate the demonstrationinto two trials. The Chicago ServiceTrial would demonstrate real service ina startup configuration, with productionequipment and several thousand sub-scribers. A cellular testbed in Newark
would simulate operation in a few 1-micells, surrounded by six interfering cellsseveral miles away. The coverage mapsfor the Chicago and Newark trials areshown in Fig. 3.
Objections were raised to the pro-posed trials, in particular because theywould not demonstrate productionequipment in the smallest cells. TheFCC agreed with the objectors anddenied permission for the trials. AT&Tappealed, and the FCC eventuallyreversed their decision, grantingapproval for the Chicago and Newarktrials on March 10, 1977, but a full yearwas lost in the appeal process.
The FCC also granted approval toMotorola to operate a trial in the Wash-ington, DC/Baltimore area. A Motorolateam led by Marty Cooper had createdthe first truly portable handheld cellphone, called Dyna-TAC, and servicefor portable handsets would be thefocus of that trial. Dyna-TAC was largeand heavy by modern standards (aboutthe size and weight of a brick), but itrepresented a significant breakthroughin portability. It was a major step in theevolution of cellular from a telephonein a car to the truly “personal” commu-nication service we enjoy today.
Installation of the equipment andfacilities for AT&T’s Chicago trial[11–13] was the responsibility of a largeteam led by Jim Troe. The system used10 cells to cover 3000 mi2, with a switch-ing center at Oak Park and an opera-
22
HISTORY OF COMMUNICATIONS
IEEE Communications Magazine • September 2010
Figure 3. Coverage maps for the Chicago and Newark trials.
Cellular Service Trial — Chicago Cellular testbed — Newark
(Continued on page 24)
(Continued from page 20)
!"#$%&'#()"$*+,-./,0$',12,34,+5567897:;55:<995=>55=?@,588
Martin!Cooper!
① Flashback
① Flashback
Mobile Broadband Explosion, Rysavy Research
2012 white paper
Mobile Broadband Explosion, Rysavy Research
2011 white paper
!"#$%&'"()*+,%&+-(+.(/"01-+#+2&"3(
45(
1990 2000 2020 2010
LTE
UMTS/HSPA
Rela
tive S
ubscriptions
GSM/EDGE
2030
2G
3G
4G
1G 2G 3G 4G (1983) (1992) (2002) (2011)
bits/s
Km2
�=
bits/s/Hz
cell
�·cell
Km2
�· [Hz]
Spectral Efficiency
Cell Density Bandwidth
Area Capacity
① Flashback
Co
mp
ou
nd
ed
Ga
in in
W
ire
les
s A
re
a C
ap
ac
ity
Cell Density
×1600
Martin Cooper!
More Bandwidth
×25
Spectral Efficiency
×10
Other
×2.5
×106
① Flashback
bits/s
Km2
�=
bits/s/Hz
cell
�·cell
Km2
�· [Hz]
Spectral Efficiency
Cell Density Bandwidth
Area Capacity
⇡ 1b/s/Hz
cell· cell
1000 users· 500 MHz
= 500Kb/s
user
① Flashback
Radio
…
Radio
Radio
DeMUX
Coding + Modulation
…
… Input
Bits
Coding + Modulation
Coding + Modulation
Radio
…
Radio
Radio
Receiver
MIMO (Multiple-Input Multiple-Output)
y = Hx+ n
② Coming Up: 5G
© 2015 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public. Page 5 of 42
Global Mobile Data Traffic, 2014 to 2019 Overall mobile data traffic is expected to grow to 24.3 exabytes per month by 2019, nearly a tenfold increase over 2014. Mobile data traffic will grow at a CAGR of 57 percent from 2014 to 2019 (Figure 1).
Figure 1. Cisco Forecasts 24.3 Exabytes per Month of Mobile Data Traffic by 2019
Source: Cisco VNI Mobile, 2015
The Asia Pacific and North America regions will account for a little over half of global mobile traffic by 2019, as shown in Figure 2. Middle East and Africa will experience the highest CAGR of 72 percent, increasing 15-fold over the forecast period. Central and Eastern Europe will have the second highest CAGR of 71 percent, increasing 14-fold over the forecast period. Latin America and Asia Pacific will have CAGRs of 59 percent and 58 percent, respectively.
④ Coming Up: 5G
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 32, NO. 6, JUNE 2014 1065
What Will 5G Be?Jeffrey G. Andrews, Fellow, IEEE, Stefano Buzzi, Senior Member, IEEE, Wan Choi, Senior Member, IEEE,Stephen V. Hanly, Member, IEEE, Angel Lozano, Fellow, IEEE, Anthony C. K. Soong, Fellow, IEEE, and
Jianzhong Charlie Zhang, Senior Member, IEEE
Abstract—What will 5G be? What it will not be is an incre-mental advance on 4G. The previous four generations of cellu-lar technology have each been a major paradigm shift that hasbroken backward compatibility. Indeed, 5G will need to be aparadigm shift that includes very high carrier frequencies withmassive bandwidths, extreme base station and device densities,and unprecedented numbers of antennas. However, unlike theprevious four generations, it will also be highly integrative: tyingany new 5G air interface and spectrum together with LTE andWiFi to provide universal high-rate coverage and a seamless userexperience. To support this, the core network will also have toreach unprecedented levels of flexibility and intelligence, spectrumregulation will need to be rethought and improved, and energyand cost efficiencies will become even more critical considerations.This paper discusses all of these topics, identifying key challengesfor future research and preliminary 5G standardization activities,while providing a comprehensive overview of the current litera-ture, and in particular of the papers appearing in this special issue.
Index Terms—Cellular systems, energy efficiency, HetNets,massive MIMO, millimeter wave, small cells.
I. INTRODUCTION
A. The Road to 5G
IN just the past year, preliminary interest and discussionsabout a possible 5G standard have evolved into a full-
fledged conversation that has captured the attention and imagi-nation of researchers and engineers around the world. As thelong-term evolution (LTE) system embodying 4G has nowbeen deployed and is reaching maturity, where only incre-mental improvements and small amounts of new spectrum canbe expected, it is natural for researchers to ponder “what’snext?” [1]. However, this is not a mere intellectual exercise.Thanks largely to the annual visual network index (VNI) reports
Manuscript received December 1, 2013; revised April 25, 2014; acceptedMay 25, 2014. Date of publication June 3, 2014; date of current versionJuly 14, 2014.
J. G. Andrews is with the University of Texas at Austin, Austin, TX 78712USA (e-mail: [email protected]).
S. Buzzi is with the University of Cassino and Southern Latium, 03043Cassino (FR), Italy, and also with Consorzio Nazionale Interuniversitario per leTelecomunicazioni, 03043 Cassino Frosione, Italy (e-mail: [email protected]).
W. Choi is with the Department of Electrical Engineering, Korea AdvancedInstitute of Science, Daejeon 305701, Korea (e-mail: [email protected]).
S. V. Hanly is with Macquarie University, Sydney, N.S.W. 2109, Australia(e-mail: [email protected]).
A. Lozano is with the Universitat Pompeu Fabra, 08002 Barcelona, Spain(e-mail: [email protected]).
A. C. K. Soong is with Huawei Technologies, Plano, TX 75024 USA (e-mail:[email protected]).
J. C. Zhang is with Samsung Electronics, Richardson, TX 75082 USA(e-mail: [email protected]).
Color versions of one or more of the figures in this paper are available onlineat http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/JSAC.2014.2328098
released by Cisco, we have quantitative evidence that the wire-less data explosion is real and will continue. Driven largelyby smartphones, tablets, and video streaming, the most recent(Feb. 2014) VNI report [2] and forecast makes plain thatan incremental approach will not come close to meeting thedemands that networks will face by 2020.
In just a decade, the amount of IP data handled by wirelessnetworks will have increased by well over a factor of 100:from under 3 exabytes in 2010 to over 190 exabytes by 2018,on pace to exceed 500 exabytes by 2020. This deluge of datahas been driven chiefly by video thus far, but new unforeseenapplications can reasonably be expected to materialize by 2020.In addition to the sheer volume of data, the number of devicesand the data rates will continue to grow exponentially. Thenumber of devices could reach the tens or even hundreds ofbillions by the time 5G comes to fruition, due to many newapplications beyond personal communications [3]–[5]. It is ourduty as engineers to meet these intense demands via innovativenew technologies that are smart and efficient yet grounded inreality. Academia is engaging in collaborative projects suchas METIS [6] and 5GNOW [7], while industry is drivingpreliminary 5G standardization activities (cf. Section IV-B). Tofurther strengthen these activities, the public-private partnershipfor 5G infrastructure recently constituted in Europe will funnelmassive amounts of funds into related research [8].
This article is an attempt to summarize and overview manyof these exciting developments, including the papers in thisspecial issue. In addition to the highly visible demand for evermore network capacity, there are a number of other factorsthat make 5G interesting, including the potentially disruptivemove to millimeter wave (mmWave) spectrum, new market-driven ways of allocating and re-allocating bandwidth, a majorongoing virtualization in the core network that might pro-gressively spread to the edges, the possibility of an “Internetof Things” comprised of billions of miscellaneous devices,and the increasing integration of past and current cellular andWiFi standards to provide a ubiquitous high-rate, low-latencyexperience for network users.
This editorial commences with our view of the “big three”5G technologies: ultra-densification, mmWave, and massivemultiple-input multiple-output (MIMO). Then, we consider im-portant issues concerning the basic transmission waveform, theincreasing virtualization of the network infrastructure, and theneed for greatly increased energy efficiency. Finally, we providea comprehensive discussion of the equally important regulatoryand standardization issues that will need to be addressed for5G, with a particular focus on needed innovation in spectrumregulation.
0733-8716 © 2014 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.
④ Coming Up: 5G
bits/s
Km2
�=
bits/s/Hz
cell
�·cell
Km2
�· [Hz]
Spectral Efficiency Densification Bandwidth
Massive MIMO
Ultra Densification
New Spectrum
④ Coming Up: 5G
④ Coming Up: 5G
0.03 0.3 3 30 300 3000Frequency (GHz)
New spectrum enabled by ultradensification
④ Coming Up: 5G
③ A World Without Cells?
⑤ A World Without Cells?
⑤ A World Without Cells?
CellSite
UserUser
CellSite
SignalSignal
Interference
UserUser
CellSite
SignalSignal
ConventionalNetwork NetMIMO
Signal
Cellular! No cells!
Signal
Signal
Signal Signal Signal
Interference
⑤ A World Without Cells?
⑤ A World Without Cells?
Cloud RAN
Antennas
Amplifiers
DSP
⑤ A World Without Cells?
Cloud RAN Cloud RAN
⑤ A World Without Cells?
“It’s dangerous to put limits on wireless”
Guglielmo Marconi, 1932
