Broadcast Design in Cognitive Radio Ad Hoc Networks

100 Pages·2014·5.38 MB·English

by  Yi Song

SPRINGER BRIEFS IN
ELECTRICAL AND COMPUTER ENGINEERING
Yi Song
Jiang Xie
Broadcast Design
in Cognitive
Radio Ad Hoc
Networks
123
SpringerBriefs in Electrical and Computer
Engineering
Moreinformationaboutthisseriesathttp://www.springer.com/series/10059
Yi Song • Jiang Xie
Broadcast Design in
Cognitive Radio Ad Hoc
Networks
2123
YiSong JiangXie
WichitaStateUniversity TheUniversityofNorthCarolinaatCharlotte
Wichita,Kansas Charlotte,NorthCarolina
USA USA
ISSN2191-8112 ISSN2191-8120(electronic)
SpringerBriefsinElectricalandComputerEngineering
ISBN978-3-319-12621-0 ISBN978-3-319-12622-7(eBook)
DOI10.1007/978-3-319-12622-7
LibraryofCongressControlNumber:2014948601
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Preface
Broadcastisanimportantoperationinwirelessnetworkswherecontrolinformation
isusuallypropagatedasbroadcastsfortherealizationofmostnetworkingprotocols.
Intraditionaladhocnetworks,sincethespectrumavailabilityisuniform,broadcasts
aredeliveredviaacommonchannelwhichcanbeheardbyallusersinanetwork.
However, in cognitive radio (CR) ad hoc networks, unlicensed users may observe
heterogeneous spectrum availability, which is unknown to other unlicensed users
beforethecontrolinformationwasbroadcast.Thisnon-uniformspectrumavailability
imposesspecialdesignchallengesforbroadcastinCRadhocnetworks.Inthisbook,
thespecialchallengesofbroadcastdesigninCRadhocnetworksarediscussed.Two
broadcastprotocolsinCRadhocnetworksareintroduced:(1)aquality-of-service
(QoS)-basedbroadcastprotocolunderblindinformationand(2)afully-distributed
broadcastprotocolwithcollisionavoidance. Inaddition, anovelunifiedanalytical
modelisalsointroducedtoanalyzetheperformanceofbroadcastprotocolsinCRad
hocnetworks.Thisisthefirstbookthatdiscussestheuniquebroadcastchallengesin
CRadhocnetworksandinvestigatestheanalyticalworkontheperformanceanalysis
ofbroadcastprotocolsforCRadhocnetworks.
v
Contents
1 Introduction................................................... 1
1.1 BackgroundonCognitiveRadioNetworks ..................... 1
1.2 BackgroundonBroadcastinComputerNetworks................ 2
1.2.1 Existing Broadcast Protocols in Traditional Wireless
Networks .......................................... 2
1.3 BroadcastProtocolsinCognitiveRadioNetworks ............... 3
1.3.1 ResearchStatus...................................... 3
1.3.2 ResearchChallenges.................................. 3
1.4 Analytical Model for Broadcast Protocols in Cognitive Radio
Networks ................................................. 5
1.4.1 ResearchStatus...................................... 5
1.4.2 ResearchChallenges.................................. 6
1.5 Contributions .............................................. 8
1.6 Organization............................................... 9
References ..................................................... 9
2 QoS-basedBroadcastProtocolUnderBlindInformationinCognitive
RadioAdHocNetworks ........................................ 13
2.1 NetworkModel ............................................ 13
2.2 ExploringBroadcastDesigninCRNs.......................... 14
2.2.1 RandomBroadcastScheme............................ 14
2.2.2 FullBroadcastScheme................................ 16
2.3 TheBasicScheme.......................................... 17
2.3.1 TheSingle-HopScenario.............................. 17
2.3.2 TheMulti-HopScenario .............................. 20
2.4 TheEnhancedScheme ...................................... 21
2.4.1 AnalysisoftheChannelAvailability..................... 21
2.4.2 TheEnhancedQB2ICScheme ......................... 25
2.5 PerformanceEvaluation ..................................... 25
References ..................................................... 36
vii
viii Contents
3 DistributedBroadcastProtocolwithCollisionAvoidanceinCognitive
RadioAdHocNetworks ........................................ 37
3.1 TheDistributedBroadcastProtocolwithCollisionAvoidance...... 37
3.1.1 ConstructionoftheBroadcastingSequences.............. 37
3.1.2 TheDistributedBroadcastSchedulingScheme............ 41
3.1.3 TheBroadcastCollisionAvoidanceScheme .............. 42
3.2 TheDerivationoftheValueofw .............................. 46
3.2.1 TheNetworkModel .................................. 46
3.2.2 TheDerivationoftheValueofw........................ 47
3.3 DiscussionontheProposedBroadcastProtocol ................. 52
3.3.1 The2-hopLocationInformation........................ 52
3.3.2 TimeSynchronization ................................ 53
3.4 PerformanceEvaluation ..................................... 55
References ..................................................... 64
4 UnifiedAnalyticalModelforBroadcastinCognitiveRadioAdHoc
Networks...................................................... 67
4.1 CalculatingtheSuccessfulBroadcastRatio ..................... 67
4.1.1 TheUniqueChallenge ................................ 67
4.1.2 TheProposedAlgorithm .............................. 69
4.1.3 AnIllustrativeExample ............................... 70
4.2 CalculatingtheAverageBroadcastDelay....................... 72
4.2.1 TheUniqueChallenge ................................ 72
4.2.2 TheProposedAlgorithm .............................. 73
4.2.3 AnIllustrativeExample ............................... 76
4.3 BroadcastinginCRAdHocNetworks ......................... 76
4.3.1 RandomBroadcastScheme............................ 76
4.3.2 QoS-basedBroadcastScheme.......................... 78
4.3.3 DistributedBroadcastScheme ......................... 81
4.4 PerformanceEvaluation ..................................... 83
4.4.1 ValidatingAnalysisUsingHardwareImplementation ...... 83
4.4.2 ValidatingAnalysisUsingSimulation ................... 85
4.4.3 SystemParameterDesignUsingtheProposedAnalytical
Model ............................................. 90
References ..................................................... 93
5 Conclusion .................................................... 95
Chapter 1
Introduction
1.1 BackgroundonCognitiveRadioNetworks
The invention of portable hand-held devices, such as smartphones and tablet per-
sonal computers (PCs), has led a dramatic increase in the demand of ubiquitous
wirelesscommunicationnetworksandhasrevolutionizedthewaypeoplecommuni-
catethesedays.Rangingfromold-fashionedcellularnetworks(e.g.,4Gnetworks)
to recent local area networks (e.g., WiFi networks) or body area networks (e.g.,
Bluetooth),varioustypesofwirelessnetworkservicesareseeinganunprecedented
growth.Withsuchrapidgrowthofwirelessdevices,thedemandsfortheradiospec-
trum are constantly increasing, resulting in scarce spectrum resources. According
totheFederalCommunicationsCommission(FCC),almostalltheradiospectrum
for wireless communications has already been allocated. However, recent studies
show that up to 85% of the allocated spectrum is underutilized due to the current
fixedspectrumaccesspolicy[1]. Toalleviatethespectrumscarcityproblem, FCC
hassuggestedanewparadigmfordynamicallyaccessingthevacantportionsofthe
allocatedspectrum[2]. Cognitiveradio(CR)hasrecentlyemergedasapromising
technologytoovercometheimbalancebetweentheincreaseinspectrumaccessde-
mandandtheinefficiencyinspectrumusagebyallowingdynamicspectrumaccess
(DSA).A “cognitive radio” is a radio that can change its communication protocol
parameters(e.g.,operatingfrequency)basedoninteractionswiththeenvironmentin
whichitoperates[2–4]. CRnetworksareregardedasthenext-generationwireless
networkstoefficientlyutilizetheradiospectrum.Withthecapabilityofsensingthe
frequency bands in a time and location-varying spectrum environment and adjust-
ingtheoperatingparametersbasedonthesensingoutcome,CRtechnologyallows
anunlicenseduser(or,secondaryuser)toexploitthosefrequencybandsunusedby
licensedusers(or, primaryusers)inanopportunisticmanner[5]. Secondaryusers
(SUs)canformaCRinfrastructure-basednetworkoraCRadhocnetwork.Recently,
CRadhocnetworkshaveattractedplentifulresearchattentionduetotheirvarious
applications[6,7].
©TheAuthor(s)2014 1
Y.Song,J.Xie,BroadcastDesigninCognitiveRadioAdHocNetworks,
SpringerBriefsinElectricalandComputerEngineering,DOI10.1007/978-3-319-12622-7_1
2 1 Introduction
1.2 BackgroundonBroadcastinComputerNetworks
Broadcastisanimportantoperationincomputernetworks,especiallyindistributed
multi-hop multi-channel wireless networks. Control information exchange among
nodes,suchaschannelavailabilityandroutinginformation,iscrucialfortherealiza-
tionofmostnetworkingprotocolsinanadhocnetwork.Thiscontrolinformationis
oftensentoutasnetwork-widebroadcasts,messagesthataresenttoallothernodes
in a network. In addition, some exigent data packets such as emergency messages
andalarmsignalsarealsodeliveredasnetwork-widebroadcasts[8].
1.2.1 Existing Broadcast Protocols in Traditional
WirelessNetworks
Intraditionalmobileadhocnetworks(MANETs), broadcastmessagesareusually
conveyed through a common channel which can be heard by all nodes in the net-
work [9–12]. Typical broadcast protocols in traditional wireless networks can be
categorizedintothreecategories.Thefirstcategoryiscalledsimpleflooding.Thatis,
everynodeinthenetworkrebroadcaststhebroadcastmessagewithaprobabilityof
onewhenitreceivesthemessage.Thismethodleadstoaveryhighoverhead.More
severely,sometimesitleadstoafailedbroadcast.Thatis,ifanodereceivestwoor
more broadcast messages simultaneously, none of these messages can be success-
fullyreceivedbythenode.Thisiscalledthebroadcastcollisionproblem.Thesecond
categoryiscalledtheprobability-basedmethod.Inthismethod,eachnoderebroad-
caststhemessagewithaprobabilityofpwhenitreceivesthemessage.Itcanreduce
theoveralloverheadandtheprobabilityofbroadcastcollisions.Indensenetworks,
multiple nodes share similar transmission coverages. Thus, the probability-based
methodcanreservenetworkresourcewithoutharmingdeliveryeffectiveness.How-
ever,insparsenetworks,thebroadcastdeliveryeffectivenessmaybeaffected.The
thirdcategoryiscalledtheneighborknowledgemethod.Inthismethod,somenet-
work topology information is given, such as the locations of 1-hop nodes, 2-hop
nodesorsometimesthewholenetworktopology. Basedonthisinformation, some
nodescanbeparticularlyselectedastheforwardingnodeswhileothernodesdonot
rebroadcast the broadcast message. These forwarding nodes often can lead to full
coverageandavoidbroadcastcollisions.Inaddition,itcanalsoleadtotheshortest
broadcastdelay.However,a-priorinetworktopologyinformationisrequired.
Since broadcast messages often need to be disseminated to all destinations as
quicklyaspossible,weaimtoachieveveryhighsuccessfulbroadcastratio(i.e.,the
probabilitythatallnodesinanetworksuccessfullyreceiveabroadcastmessage)and
very short average broadcast delay (i.e., the average duration from the moment a
broadcaststartstothemomentthelastnodereceivesthebroadcastmessage).
1.3 BroadcastProtocolsinCognitiveRadioNetworks 3
1.3 BroadcastProtocolsinCognitiveRadioNetworks
1.3.1 ResearchStatus
Currently,researchonbroadcastprotocolsinmulti-hopCRadhocnetworksisstill
initsinfantstage.ThereareonlylimitedpapersaddressingthebroadcastissueinCR
adhocnetworks[13–16]. However, in[13]and[14], theglobalnetworktopology
andtheavailablechannelinformationofallSUsareassumedtobeknown.Addition-
ally,in[14],acommonsignalingchannelforthewholenetworkisemployedwhich
isalsonotpractical. Thesetwopapersadoptimpracticalassumptionswhichmake
theminadequatetobeusedinpracticalscenarios.Otherproposalsaimingtolocally
establishacommoncontrolchannelmayalsobeconsideredforbroadcast[17–20].
However, theseproposalsneeda-priorichannelavailabilityinformationofallSUs
which is usually obtained via broadcasts. In addition, although some schemes on
channel hopping in CR networks can be used for finding a common channel be-
tweentwonodes[21–23],theystillsuffervariouslimitationsandcannotbeusedin
broadcastscenarios. In[21]and[22], theproposedchannelhoppingschemescan-
notguaranteerendezvousundersomespecialcircumstances.Inaddition,oneofthe
proposedschemesin[21]onlyworkswhentwoSUshaveexactlythesameavailable
channel sets. Furthermore, in [23], a jump-stay based channel hopping algorithm
isproposedforguaranteedrendezvous.However,theexpectedrendezvoustimefor
the asymmetric model (i.e., different users have different available channels) is of
polynomialcomplexitywithrespecttothetotalnumberofchannels.Thus,itisun-
suitableforbroadcastscenariosinCRadhocnetworkswherechannelavailability
is usually non-uniform and short broadcast delay is often required. Other channel
hopping algorithms explained in [24] require tight time synchronization which is
alsonotfeasiblebeforeanycontrolinformationisexchanged.
1.3.2 ResearchChallenges
InCRadhocnetworks,sincesecondaryuserscanonlyusethechannelswhichare
not occupied by primary users (PUs), different SUs may acquire different sets of
available channels. Thus, the availability of such a common channel for all nodes
maynotexist.Moreimportantly,beforecontrolinformationissent,aSUisunaware
oftheavailablechannelsofitsneighboringnodes.Asaresult,eventhoughaglobal
or local common channel may exist, SUs are unaware of its existence. Therefore,
broadcastingcontrolmessagesonacommonchannelisoftennotfeasibleinCRad
hocnetworksunderblindinformation[17,18,25–29].
On the other hand, since each SU is typically equipped with one radio, it can
only visit one available channel at a time. A broadcast message can be received
by a neighboring node only if the message is transmitted on the same channel on
whichthereceivercurrentlystays.Therefore,ifaSUonlybroadcastsamessageonce
on one available channel, this message may not be successfully received by all its