Resource Allocation and MIMO for 4G and Beyond

555 Pages·2014·11.71 MB·English

by  Elvis M. G. Stancanelli

Francisco Rodrigo Porto Cavalcanti
Editor
Resource Allocation
and MIMO for 4G
and Beyond
Resource Allocation and MIMO
for 4G and Beyond
Francisco Rodrigo Porto Cavalcanti
Editor
Resource Allocation
and MIMO for 4G
and Beyond
123
Editor
Francisco RodrigoPorto Cavalcanti
Federal Universityof Ceará
Fortaleza, Ceará
Brazil
ISBN 978-1-4614-8056-3 ISBN 978-1-4614-8057-0 (eBook)
DOI 10.1007/978-1-4614-8057-0
SpringerNewYorkHeidelbergDordrechtLondon
LibraryofCongressControlNumber:2013951132
(cid:2)SpringerScience+BusinessMediaNewYork2014
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To Renesa, Eduarda and Marcele
Foreword
Access to Internet and Internet-based services are today fundamental components
ofsocietywithlargeimpactonbusinessandlife.Exploitingtheopportunitiesand
benefits of the Internet is no longer a luxury restricted to a few as a rapidly
increasingpartoftheworld’spopulationisgettingconnected.Thelargeimpactit
hashadonmanypeoples’privateandprofessionalliveshasalsochangedhowwe
relatetotheInternet.Tomany,InternetandInternetaccessisseenasanecessity,a
commodity, in many aspects not different from how we see upon electricity or
water. Enabled by advances in cellular network and handsets technologies during
thelastdecade,thewaytoaccessInternethaschanged.Fromsomethingyoudidin
front of a computer it has been integrated with the daily life on the move; it has
gone mobile.
The foundation for the present massive uptake in mobile Internet usage is
researchconductedinindustryandacademiaduringthe1990sandthefirstdecade
of 2000. These activities resulted in definition and subsequent evolution of a
number of radio interface standards fulfilling the ITU IMT-2000 requirements,
often referred to as the 3G standards. A major milestone in the 3G evolution,
fundamentalformobileInternetaccess,wasreachedbytheintroductionofHSPA
as an extension to the WCDMA standard. By this extension, the circuit switched
paradigm of WCDMA was changed in favor of packet switching, allowing con-
siderablyimprovedspectrumefficiencyandsupportforIP-basedtraffic.Drivenby
expectedneedsoffutureservicesbutalsoadvancementsintechnologiesformobile
systems, the evolution of technologies beyond 3G started around 2000 and is still
ongoing. Research in industry and academia again led to the definition and evo-
lution of a new family of standards, the 4G standards, this time targeting fulfill-
ment of the ITU IMT-Advanced specifications.
The existing 4G standards, with LTE as the dominating example, targets
essentially three improvement areas as compared to 3G: data rates, latency, and
capacity. With data rates an order of magnitude larger than 3G, latency in the
range of 10 ms, and spectral efficiency of up to 30 bps/Hz, LTE and its evolution
LTE-Advanced targets to provide true mobile broadband experience to the end
users similar to what is possible with wired access. This is a clearly challenging
task that, despite the fact that standardization is ongoing in parallel, still offers
many interesting and important research problems to be addressed.
vii
viii Foreword
The Wireless Telecommunications Research Group (GTEL) at the Federal
University of Ceará was founded in June 2000 by Prof. Francisco Rodrigo Porto
Cavalcantiandhiscolleagueswiththemissiontodevelopwirelesscommunication
technology and impact the development of the Brazilian telecom sector. With
support from Ericsson Research, Prof. Francisco Rodrigo Porto Cavalcanti has
since the start built up an independent research organization with an impressing
span in competence and abilities, covering and mastering the entire range of
wireless link and system research aspects, from signal processing algorithms and
radio link design to cellular systems design and system analysis.
Inthisbook,thesecondfromthegroup,Prof.FranciscoRodrigoPortoCavalcanti
and his colleagues share their insights and views on a number of highly relevant
researchtopicsrelatedto4Gand4Gtechnologydevelopments.Resultsfromrecent
researchactivitieswithinthegrouparepresented.Inparticular,findingsandresults
relatingtoresearchonradioresourcemanagement(RRM),relaying,scheduling,and
Device-to-Device(D2D)communicationarepresented.Contributionsandfindings
related to coordinated multipoint transmission (CoMP), MIMO precoding, and
interferencealignment(IA)arealsocomprehensivelycovered.
The content of this book aims at design and optimization of current and
emerging cellular systems. Researchers and engineers active or interested in the
field will find the content useful and are encouraged to share the insights and
results.
Sweden, July 2013 Dr. Göran Klang
Preface
Introduction
Mobile and wireless communication systems are a prominent communications
technologyofthetwenty-firstcenturywithprofoundeconomicandsocialimpacts
in practically all parts of the world. The current state of wireless communication
systems allows for a much wider scope of applications than what it used to be
originally, that is, to be a mobile extension of the public switched telephone
network.TheconvergenceofmobilesystemsandtheInternethasbecomeareality
as new radio access technologies emerged with improved coverage, capacity, and
latency.WhiletheneedanddesiretodevelopandestablishatrulymobileInternet
datesbacktothemid-1990s,itisonlyrecentlythatmobilebroadbandhastakenoff
to become a prominent part of the whole mobile communications business.
This book is about some of the latest developments in wireless access tech-
nology,andunderlyingbreakthroughs,thatarepartoforcanbeappliedtoFourth
generation mobile communication systems onwards, in order to keep up with the
increasing demand for mobile data.
ThespecificfocusofthebookisonthetwolowerlayersoftheISO/OSIlayered
model, that is, the physical and data link layers, in particular the media access
controlsublayerofthelatter.Acommonthreadthroughoutthebookiscross-layer
optimization between these layers. These two layers are of specific importance in
wireless systems, as opposed to many of its wired counterparts. This is funda-
mentallyduetospectrumshortage,limitedsignalcoverage,thebroadcastnatureof
interference, and time variability of the wireless channel response. As a conse-
quence, much of the improvements in coverage, capacity, and latency of modern
wireless systems are due to new approaches for tackling old problems in high
capacity radio communications in these two lower layers.
Intended Audience and Usage
This book is intended for researchers in the field of wireless communications,
morespecificallytothoseinvolvedwiththedesignandoptimizationofcurrentand
emerging wireless access technologies for mobile communications. Graduate
ix
x Preface
students working on subjects such as radio resource allocation (RRA) and man-
agement (RRM), interference management, Orthogonal Frequency Division
MultipleAccess(OFDMA)andMultiple-Input-Multiple-Output(MIMO)systems,
asappliedtofourthgenerationsystemsandbeyond,willbenefitfromthestate-of-
the-artconcepts,methods,examples,andcasestudiespresented.Everychapter,in
addition to having a clear ambition to address the state of the art of the corre-
sponding subject, discusses basic concepts in the introductory sections and gives
references for the interested reader to deepen his/her understanding. All chapters
can be used independently as a complement to a graduate-level ‘‘Advanced’’
Wireless Communications course, where each separate chapter can be used as
basis to a supervised study or a seminar.
Thebookshouldalsobeofinterest tothepractitionerortoengineersinvolved
instandardizationefforts.Theattentiontotechnicaldetailsfromstandardsisgiven
in several chapters when performance results and case studies are presented as
resultingfromtheapplicationofselectedtechniques.Theideainmanyinstancesis
to demonstrate how advanced concepts can be adapted to be applicable in more
realistic scenarios.
Finally,almosteverychapterofthebookshedslight,directorindirectly,onthe
subject of performance evaluation of wireless systems by means of analytical
approaches and of system and link-level simulations. As the complexity of wire-
less systems grows, efficient and correct methods for modeling and analyzing
performance of these systems is becoming a fundamental discipline on its own.
Organization of the Book
Thisbookbringsatotalof11chaptersand,forthesakeofclarityofpresentation,
these chapters are organized into two parts. The parts are named ‘‘Resource
Allocation’’and‘‘MIMO’’afterthebook’stitleandasthefocusisontwolayered
model mentioned above. Such type of division is becoming increasingly artificial
as cross-layer optimizations are commonplace and multiple antennas at network
nodescanbeseenas‘‘resources’’tobemanaged.Therefore,someofthechapters
could well be placed in both parts.
Part I: Resource Allocation
RadioResourceAllocation(RRA)hasitsrootsinfrequencyreuseplanningofFirst
generationcellularsystems.Itsfundamentalgoalistoincreasespectrumefficiency.
More efficient utilization of the radio spectrum plays such an important role
because spectrum is simultaneously a very scarce and widely shared resource.
In the evolution towards 3G systems, RRA became a discipline on its own,
encompassing a variety of techniques such as power control, frequency hopping,
Preface xi
dynamic channel allocation, and being integrated into more advanced multi-
antenna concepts, such as beamforming and MIMO solutions.
The explosion of mobile broadband and the demand for high data-rate packet
switched services has required a new set of RRA techniques able to handle
capacity challenging scenarios. These new RRA approaches started off by bor-
rowing concepts from wired data networks, such as packet scheduling and con-
gestion control, but that were reformulated and adapted to the wireless
environment.
More recently, with the emergence of 4G, noticeably in the form of 3GPP’s
Long Term Evolution (LTE) standards, a highly configurable radio access tech-
nology based on OFDMA has been made available. This has, again, widened the
scope of RRA. By means of advanced optimization approaches, RRA is now
possiblewithfinegranularity,increasingtheefficiency-potentialofspectrumusage
to unprecedented levels. This is mainly due to a clever exploitation of the mul-
tidimensional (spatial, frequency, time, and multiuser) diversity by RRA algo-
rithms.Tomentiononeexampleofsuch,MIMOtechniques,oncerestrictedtothe
single-user case, are now considered an inherent part of RRA at a network level.
Advancesincomputingpowerandenergyefficiencyatmobiledevicesarealso
an important enabler for the actual implementation of sophisticated RRA algo-
rithms. Nevertheless, computational complexity is still an issue that should be
consideredwhenevaluatingtheapplicabilityofRRAproposedsolutions.Another
aspect that deserves attention is the demand for channel state information and
control signaling at multiple network nodes (e.g., mobile devices and base sta-
tions). Since the dimensionality of RRA problems has grown in OFDMA-based
systems such as LTE, one must verify if the algorithm’s demand for such infor-
mation are realistic in order not to overburden the system’s backhaul. These and
other practical issues are treated in most of the chapters in this book when RRA
approaches are presented.
Chapter 1 revisits many of the issues concerning RRM with a focus on the
upcoming systems embodying the Coordinated Multipoint (CoMP) technology.
CoMP-basedsystemshaveattractedspecialattentionduetotheirpotentialbenefits
in terms of spectral efficiency and coverage. As a part of 3GPP Long Term
Evolution—Advanced, CoMP technology promises substantial improvement of
theusers’experienceattheexpenseofrequiringareliableandefficientconnection
among the evolved Node Bs (eNBs). Provided that multiple users and eNBs are
coordinated using a suitable technique, the concerns about interference can be
greatly alleviated and, consequently, also the restrictions on sharing radio
resources. In this chapter, the authors explore the grouping of users and eNBs in
two different occasions. First they address coordinated strategies of grouping and
scheduling users in order to improve the system performance; afterwards, clus-
tering of eNBs is described as an attractive approach to deal with the processing
and signaling overheads brought by CoMP. The chapter presents an analysis of
differentalgorithms,aswellascasestudiesillustratingsomekeyconceptsthrough
computer simulations.