Channel Estimation and Optimal Resource Allocation of Relay Assisted Communication Systems

165 Pages·2012·1.66 MB·English

Channel Estimation and Optimal Resource
Allocation of Relay Assisted Communication
Systems
by
Yupeng Jia
Submitted in Partial Fulfillment
of the
Requirements for the Degree
Doctor of Philosophy
Supervised by
Professor Azadeh Vosoughi
Department of Electrical and Computer Engineering
Arts, Sciences and Engineering
Edmund A. Hajim School of Engineering and Applied Sciences
University of Rochester
Rochester, New York
2012
ii
@ Copyrightby
YupengJia
2012
AllRightsReserved
iii
formy parents
Curriculum Vitae
TheauthorreceivedaBachelorofEngineeringdegreein2003andaMasterofScience
degree in 2006 from Shandong University, China, both in Electrical Engineering. He
cametotheUniversityofRochesterintheFallof2007andbegangraduatestudiesinthe
Department of Electrical and Computer Engineering. He received a Master of Science
degreeinElectricalandComputerEngineeringin2009. Hepursuedhisresearch inthe
SignalProcessingforWirelessCommunicationsLaboratoryunderthedirectionofProf.
Azadeh Vosoughi. His primary research interests include wireless communications,
statistical signal processing, information theory, and detection and estimation theory.
HeworkedwiththeUniversityofTexas-Dallasas aresearch assistantin2006-2007,
andworkedwithMathWorks,Inc. atNatick,Massachusettsinthesummerof2010and
Research inMotion,Ltd. at Irving,Texasin thesummerof2011.
Listofpublications:
JournalPapers (Published/To appear/Preprint)
“Transmission resource allocation for training based amplify-and-forward relay
•
systems”, IEEE Transactions on Wireless Communications, Vol. 10, No. 2, pp.
450-455,February 2011.
“Howdoeschannelestimationerroraffectaveragesum-rateintwo-wayamplify-
•
and-forward relaynetworks?”,accepted forpublicationinIEEETransactionson
WirelessCommunications,January 2012.
“Outage probability and power allocation of two-way amplify-and-forward re-
•
laying with channel estimation errors”, accepted for publication in IEEE Trans-
iv
v
actionsonWirelessCommunications,February 2012.
“Impact of channel estimation errors on bidirectional information rate: compar-
•
ison of direct transmission and amplify-and-forward relay systems”, in prepara-
tionforsubmissionto ElsevierSignalProcessingJournal.
Peer-Reviewed Conference Papers
“Crame´r-Rao bound for channel estimation in one-way amplify-and-forward re-
•
laying networks”, submitted for publication in Proceedings of IEEE Military
CommunicationsConference (MILCOM), October2012.
“NLOS-communication between shadowed vehicles using by-standing relay ve-
•
hicles”, in Proceedings of IEEE 15th International Conference on Intelligent
TransportationSystems (ITSC), September2012.
“Sum-rate maximization of two-way amplify-and-forward relay networks with
•
imperfect channelstateinformation”,inProceedingsofIEEE 36thInternational
Conferenceon Acoustics,Speech,andSignalProcessing(ICASSP), May 2011.
“Impact of channel estimation error upon sum-rate in amplify-and-forward two-
•
way relaying systems”, in Proceedings of IEEE 11th International Workshop on
SignalProcessingAdvancesin WirelessCommunications(SPAWC),June2010.
“Two-way relaying for energy constrained systems: Joint transmit power opti-
•
mization”, in Proceedings of IEEE 35th International Conference on Acoustics,
Speech,and SignalProcessing(ICASSP), March2010.
“Maximizing throughput in cooperative networks via cross-layer adaptive de-
•
signs”,inProceedingsofIEEE 33rdSarnoffSymposium,April2010.
“A novel selective relaying protocol for wireless networks”, in Proceedings of
•
IEEE 10th Workshop on Signal Processing Advances in Wireless Communica-
tions(SPAWC),June2009.
vi
“Training design for information rate maximization over amplify-and-forward
•
relay channels”, in Proceedings of IEEE 42rd Asilomar Conference on Signals,
Systemsand Computers,November2008.
Acknowledgements
I would like to thank my advisor Prof. Azadeh Vosoughi for her guidance, encourage-
ment, and support throughout my graduate studies in general and this thesis research
in particular. It was Prof. Azadeh Vosoughi’s unlimited encouragement, patience, and
availability to answer my questions and listen to my ideas that kept me focused and
enthusiasticthroughoutthecourseofthiswork.
I would also like to thank Professors Alireza Seyedi, Carl Mueller, Mark Bocko
and Wendi Heinzelman for acting as members of my proposal and thesis committee.
Their comments and suggestions both clarified and strengthened many parts of my re-
searchwork. ThanksgotomycolleaguesattheUniversityofRochester,especiallymy
labmates for sharing their random ideas, research-related or otherwise; to my friends
in Rochester for joiningme in stress-relieving athleticpursuits and other escapes from
work.
In addition, I would like to thank Vincent Pellissier, Honglei Chen, Oguz Kazanci,
Hailiang Tao of MathWorks, Inc. and Yi Song, Yi Yu, Nam Nguyen, Sagar Dhakal of
Research inMotion,Ltd. forprovidingmehelptofinishinternshipprojectsandaccess
theindustryworld. Theirmentoringandguidancearedeeply appreciated.
Lastly, I wish to offer a very special word of tribute to my family, Mom, Dad,
Yuyang and Zhaoyang, for always being there and believing in me. Mom and Dad,
your sacrifices through the years have given me every opportunity to succeed, and as
but a small token of my gratitude, I dedicate this work to you. Yuyang, thank you so
muchfortakingcareofourparentsallalongwhenIamabroad. Zhaoyang,Iamdeeply
grateful foryourloveand support.
ThisresearchwassupportedinpartbytheNationalScienceFoundationunderGrant
CCF-1054687.
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Abstract
Exploding demand for various wireless services has fueled significant development of
wireless communication systems and networks in the past few decades. Wireless ser-
vice providers are continuously striving to improve the design of communication sys-
tems and to enable higher data rate and more reliable wireless transmission. A major
challengein designingthese systemsis therandom natureof thewireless transmission
media due to the fading process. A recent paradigm shift from the conventional point-
to-point communications is relay assisted communications. Motivated by the great
success of multiple-input multiple-output (MIMO) wireless communication systems,
with multiple transmit and receive antennas, researchers have considered relay assist-
ed communications. Relying on the broadcast nature of the wireless media, a relay
assistedcommunicationsystememulates avirtual MIMO systemand exploitsthespa-
tial diversity, also known as cooperative diversity. Cooperative diversity increases the
transmission reliability and coverage, without expanding the expenditure of the scarce
transmissionresources (powerand bandwidth).
Recently, the research community has witnessed an increasing interest in studying
relay assistedcommunicationsystems. Thesestudiesincludeproposingnovelrelaying
schemes, exploring ways to maximize the cooperative gain, and investigating the fun-
damentalperformancelimitsofthesesystems. Thebulkoftheliteratureisbasedonthe
main assumption that the effect of fading channels (commonly referred to as channel
state information) is perfectly known at the destination. In practical communication
systems,however, theunknownfading channels are first estimated and thechannel es-
timates are used for decoding the message transmitted by the source. In order to have
a more realistic and accurate understanding of the benefits of relay assisted systems,
one needs to study the effect of uncertainty, imposed by channel estimation error, on
the fundamental performance limits. Such study can guide to a more efficient system
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designand provideoptimalresource allocationbetween dataand training(required for
channel estimation).
Two widely used relay assistedwireless communicationsystemsare: 1)a one-way
relayassistedsystem,inwhichthereisasource,arelayandadestination,andtherelay
helpsthesourcebyforwarding theoverheardmessageto thedestination;2)atwo-way
relay assisted system, in which two sources are interested in mutual communication,
i.e., one source is the destination of the other source. In this system the relay help-
s both users by forwarding the overheard messages to the intended destinations. For
each system, one can envision different system designs, depending on the specific re-
laying scheme and the specific signal processing algorithm adopted at the relay. The
most commonly used relaying schemes are Amplify-and-Forward (AF) and Decode-
and-Forward (DF), wherein the formertherelay amplifies and forwards the overheard
messages, while in the latter, the relay decodes the overheard messages and then for-
wards them.
In this thesis, we consider one-way and two-way AF relay assisted systems with a
half-duplexrelay. Westudytheimpactofuncertainty,duetochannelestimationerrors,
on the fundamental performance limits. In particular, we consider mean squared er-
ror(MSE)and theBayesian Crame´r -Rao lowerbound(CRLB) forchannel estimation
as the estimation theoretic optimality criteria and channel mutual information lower
bound and outage probability upper bound as the information theoretic optimality cri-
teria. We explore how the negative effect of channel uncertainty can be mitigated, via
optimal transmission resource allocation that maximizes or minimizes a specific opti-
malitycriteria. Wealso compare thebidirectionalmutualinformationlowerboundsof
directtransmissionwithouttherelay,one-wayAFrelayandtwo-wayAFrelaysystems.
Furthermore, we examine the effect of joint optimization of the media access control
and physical layers on the system throughput for one-way AF and DF relay assisted
systems.
Contents
ListofSymbols v
ListofFigures vii
Foreword 1
1 Introduction 2
1.1 WirelessCommunicationSystems: DesignChallenges andMotivation . 3
1.1.1 Random NatureofWirelessChannels duetotheFadingProcess 3
1.1.2 DiversityTechniquesto CombatFading . . . . . . . . . . . . . 5
1.1.3 Channel Estimationand OptimalTransmissionResource Allo-
cation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Relay AssistedWireless CommunicationSystems . . . . . . . . . . . . 10
1.2.1 One-Way Relay Systems . . . . . . . . . . . . . . . . . . . . . 10
1.2.2 Two-Way Relay Systems . . . . . . . . . . . . . . . . . . . . . 13
1.2.3 Channel Estimationand OptimalTransmissionResource Allo-
cation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.3 ThesisOrganizationand Contributions . . . . . . . . . . . . . . . . . . 16
2 Impact ofChannel EstimationErrors onOne-WayAF RelaySystems 19
2.1 HistoricalBackground on One-Way Relay Systems . . . . . . . . . . . 19
2.2 Related Worksand OurMainContributions . . . . . . . . . . . . . . . 20
2.3 SystemModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
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