Table Of ContentIntroduction to Ultra Wideband
for Wireless Communications
Introduction to Ultra
Wideband for Wireless
Communications
by
Homayoun Nikookar
TUDelft,TheNetherlands
and
Ramjee Prasad
AalborgUniversity,Denmark
CTiF,CenterforTeleInFrastruktur
1 3
Authors
HomayounNikookar RamjeePrasad
DelftUniversityofTechnology AalborgUniversity
Mekelweg4 Inst.ElectronicSystems
2628CDDelft NielsJernesVej12
TheNetherlands 9220Aalborg
[email protected] Denmark
[email protected]
ISBN:978-1-4020-6632-0 e-ISBN:978-1-4020-6633-7
LibraryofCongressControlNumber:2008932941
#SpringerScienceþBusinessMediaB.V.2009
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To my loving family Mahsa, Bardia and
Parmida.
-Homayoun Nikookar
To my wife Jyoti, to our grand children,
Sneha, Ruchika, Akash and Arya
-Ramjee Prasad
Preface
asakta-buddhih. sarvatra
jitatma vigata-sp.rhah.
. .
nais.karmya-siddhim paramam
sannyasenadhigacchati
Detached by spiritual intelligence from everything
controlling the mind, without material desires, one
attainstheparamountperfectionincessationofreac-
tionsbyrenunciation.
TheBhagvadGita(18.49)
Comparedtotraditionalcarrier-based,Ultra-WideBand(UWB),orcarrier-less,
systemsimplementnewparadigmsintermsofsignalgenerationandreception.
Thus,designinganUWBcommunicationsystemrequirestheunderstandingof
how excess bandwidth and very low transmitted powers can be used jointly to
provideareliableradiolink.UWBofferssystemstransceiverpotentialforvery
simpleimplementations.
ComparisonbetweenUWBandtraditionalnarrow-bandsystemshighlights
thefollowingfeatures:
(cid:2) Largebandwidthenablesveryfinetime-spaceresolution foraccurateloca-
tionoftheUWBnodesandfordistributingnetworktimestamps.
(cid:2) Very short pulses are effectively counter-fighting the channel effect in very
densemultipathenvironments.
(cid:2) Data rate (numberofpulses transmittedper bit)canbe traded withpower
emissioncontrolanddistancecoverage.
(cid:2) Verylowpowerdensityleadstolowprobabilityofsignaldetectionandadds
securityforallthelayersofthecommunicationstack.
(cid:2) Very low power density is obtained through radio regulation emission
masks; UWB systems are suitable for coexistence with already deployed
narrow-bandsystems.
vii
viii Preface
UWBsystemswerebornattheendofXIXcenturystemmingfromthework
of Heinrich Hertz and Guglielmo Marconi. UWB Radio Communication was
basedontheelectromagneticwavespropagatingfromelectricalsparks.Thefirst
communication systems were very rudimental and, in a time in which spectral
efficiencywasnotamajorconcern,thespectrumusagewasnotefficient.
StartingfromsparkgaptransmissionsattheendoftheXIXcentury,research
on UWB has been carried on mainly after the Second World War, when sub-
nanosecond instruments started to be available. From 1960 until nowadays,
continuousresearchactivitiesinthefieldsofanaloganddigitalelectronicsand
antennasmadeitpossibletodelivercommercialviableUWBsystems.
In 2002, in the United States the Federal Communication Commission
(FCC)emanatedradio-regulationtoallowUWBsystemoperations.European
Fig.1 Treestructureofthebook
Preface ix
CommissionforPostandTelecommunication(CEPT)hasreleasedadecision
onthe24thMarch2006whichallowsoperationofunlicensedUWBdevices.
UWB technology will support a lot of new applications with benefits for
public safety and business creating new opportunities for distributors, vendors
andmanufacturers.UWBtechnologywillallowanincreasedusageofspectrum
resources by sharing spectrum with low interferences to narrow band systems.
TheintegrationofUWBwithotherwirelessaccesstechnologiesisoneofthekey
factorsinordertoprovideseamlessconnectivitytonextgenerationmobileuser.
TheaimofthisbookistoprovideanintroductiontotheapplicationofUWB
tothe wireless communications.The book isdesignedfor(graduate) students
andresearchersworkinginthefieldofcommercialUWBwirelesscommunica-
tions.Itwillalsobeusefulforthepracticingengineersfromindustrywhodeal
with the wireless systems that are designed and analyzed with the UWB tech-
nique.Becauseofthetutorialnatureofthebook,itcanserveasatextbookon
UWB for wireless communications for the Telecommunication graduate pro-
gram of the electrical engineering curriculum. Problems at the end of each
chapteraregeneratedtoextendthereader’sunderstandingofthematerial.
ThetreeinFig.1illustratesthestructureofthebook.Thebookwillguidethe
readerstartingfromahistoricalbackgroundthroughallthemajordesignissues
of an UWB system. During these years, research activities have been very
intense and debated. We would greatly appreciate our readers’ comments on
this work; collaboration and cooperation will leverage the knowledge of the
researchcommunity.
HomayounNikookar
RamjeePrasad
Acknowledgements
ThematerialofthisbookistheoutgrowthofresearchintheRadioAdvanced
TechnologiesandSystems(RATS)programofInternationalResearchCentre
forTelecommunicationsandRadar(IRCTR)ofDelftUniversityofTechnol-
ogy (TUDelft), The Netherlands and Centre for TeleInFrastruktur (CTiF) of
Aalborg University, Denmark. Special thanks go to Professor L. Ligthart
(Director of IRCTR) for his encouragement and full endorsement of the
RATS program and in supporting this book. The authors would like to
acknowledge the assistance of M.K. Lakshmanan (a PhD candidate at
IRCTR) in making several figures and diagrams and in giving support to the
processofwritingthebook.WealsoacknowledgetheinputofZ.Irahhauten(a
PhD candidate at IRCTR) and productive discussions with him which has
enriched the quality of the book. The assistance of J.R. Nascimento (former
exchange student of IRCTR and now with TNO-ICT Delft) is also highly
appreciated. The authors acknowledge the fruitful discussions with the mem-
bers of Dutch Freeband AIRLINK Project and particularly with Prof. I.
Niemegeers(fromWirelessMobileCommunicationsWMCGroup,TUDelft),
Prof. A.Yarovoy (from IRCTR) and Dr. G. Janssen (from WMC Group
TUDelft).
Authors would like to further mention valuable contributions of Filippo
MeucciandAntoniettaStango(PhDsfromCTiF,AalborgUniversity).
FinallythankstoJunkoPrasadforherpatienceandcooperationinfreeing
usfromtheenormouseditorialburden.
xi
Contents
1 Introduction............................................. 1
1.1 HistoryofUWB..................................... 1
1.2 PreviewoftheBook.................................. 7
References.............................................. 10
2 UWBForWirelessCommunications.......................... 11
2.1 UWBDefinition..................................... 12
2.2 FCCMask ......................................... 13
2.2.1 HermitePulses................................. 19
2.2.2 LegandrePulses................................ 20
2.2.3 ProlateSpheroidalFunctions ..................... 22
2.3 UWBFeatures ...................................... 25
2.4 Summary .......................................... 25
Problems............................................... 26
References.............................................. 27
3 UWBAntennas .......................................... 29
3.1 AntennaRequirements................................ 31
3.2 RadiationMechanismoftheUWBAntennas.............. 31
3.3 LinkBudgetforUWBSystemTakingintoAccounttheUWB
Antennas........................................... 32
3.4 ShortRangeAnalysisofUWBAntennas ................. 37
3.4.1 PhaseError ................................... 37
3.4.2 AntennaMismatch ............................. 39
3.4.3 Re-radiationBetweenAntennas ................... 39
3.5 Summary .......................................... 40
Problems............................................... 40
References.............................................. 41
4 UltraWideBandWirelessChannels .......................... 43
4.1 ImpulseResponseModelingofUWBWirelessChannels..... 45
4.1.1 DistributionofAmplitudeFading ................. 46
4.1.2 DistributionofTimeofArrival.................... 50
xiii
