《WSN无线传感器网络》复习提纲30版Word格式文档下载.docx
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《WSN无线传感器网络》复习提纲30版Word格式文档下载.docx
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1.Typeofservice
2.QualityofService
3.Faulttolerance
4.Lifetime
5.Scalability
6.Widerangeofdensities
7.Programmability
8.Maintainability
1.4.2requiredmechanisms:
要求机制
SomeofthemechanismsthatwillformtypicalpartsofWSNsare:
1.Multihopwirelesscommunication
2.Energy-efficientoperation
3.Auto-configuration
4.Collaborationandin-networkprocessing
5.Datacentric
6.Locality
7.Exploittrade-offs
understandthedifferencesbetweenWSNsandothernetworks:
1.5为什么说传感器是不同的
1.5Whyaresensornetworksdifferent?
1.5.1Mobileadhocnetworksandwirelesssensornetworks
(移动Adhoc网络与无线传感器网络)
1.Applications,equipment:
MANETsmorepowerful(read:
expensive)equipmentassumed,often“humanintheloop”-typeapplications,higherdatarates,moreresources
2.Application-specific:
WSNsdependmuchstrongeronapplicationspecifics;
MANETscomparablyuniform
3.Environmentinteraction:
coreofWSN,absentinMANET
4.Scale:
WSNmightbemuchlarger(althoughcontestable)
5.Energy:
WSNtighterrequirements,maintenanceissues
6.Dependability/QoS:
inWSN,individualnodemaybedispensable(networkmatters),QoSdifferentbecauseofdifferentapplications
7.Datacentricvs.id-centricnetworking
8.Mobility:
differentmobilitypatternslike(inWSN,sinksmightbemobile,usualnodesstatic)
1.5.2WirelessfieldbusesandWSNs(现场总线与无线传感器网络)
Differences:
1.Scale–WSNoftenintendedforlargerscale
2.Real-time–WSNusuallynotintendedtoprovide(hard)real-timeguaranteesasattemptedbyfieldbuses
understandtheenablingtechnologiesforWSNsapplication
1.6无线传感器网络的技术要求
1.miniaturizationofhardware
2processing
munication
1.2Applicationexamples:
应用领域
Disasterreliefapplications,Environmentcontrolandbiodiversitymapping,Intelligentbuildings,Facilitymanagement,Machinesurveillanceandpreventivemaintenance,Precisionagriculture,Medicineandhealthcare,Logistics,Telematics.
1.3typesofapplication:
区分应用类型
1.Eventdetection
2.Periodicmeasurements
3.Functionapproximationandedgedetection
4.Tracking
第二章:
2.1.1,2.1.4,2.1.5,p37,43,2.2.5,2.3.2,2.3.5,
Basicrequirement:
masterthehardwarecomponentsofsensornodes
2.1节点的硬件组成
2.1hardwarecomponents:
硬件组成部分
∙MaincomponentsofaWSNnode
∙Controller
∙Communicationdevice(s)
∙Sensors/actuators
∙Memory
∙Powersupply
2.1.4communicationdevice
Transceiveroperationalstates:
收发机的四个状态
∙Transceiverscanbeputintodifferentoperationalstates,typically:
∙Transmit--Inthetransmitstate,thetransmitpartofthetransceiverisactiveandtheantennaradiatesenergy.
∙Receive--Inthereceivestatethereceivepartisactive.
∙Idle–readytoreceive,butnotdoingso
∙Somefunctionsinhardwarecanbeswitchedoff,reducingenergyconsumptionalittle
∙Sleep–significantpartsofthetransceiverareswitchedoff
∙Notabletoimmediatelyreceivesomething
∙Recoverytimeandstartupenergytoleavesleepstatecanbesignificant
无线传感器的微控制器也有三个状态(活跃期,空闲期,睡眠期),两者有区别!
2.1.5sensors:
传感器的分类
●Passive,omnidirectionalsensors被动全向传感器温湿度传感器等
Typicalexamplesforsuchsensorsincludethermometer,lightsensors,vibrationmicrophones,humidity,mechanicalstressortensioninmaterials,chemicalsensorssensitiveforgivensubstances,smokedetectors,airpressure,andsoon.
●Passive,narrow-beamsensors被动、窄束照相机等
Atypicalexampleisacamera,whichcan“takemeasurements”inagivendirection,buthastoberotatedifneedbe.
●Activesensors主动雷达声呐等
Forexample,asonarorradarsensororsometypesofseismicsensors,whichgenerateshockwavesbysmallexplosions.
understandtheenergyconsumptionofcomponentmodule
2.2energyconsumptionofsensornodes
注意区分每一个硬件部分的能量分析,哪一部分是比较针对微控制器的能量分析(whetherputintosleepmodeshouldbetakentoreducepowerconsumption)、哪一部分是比较针对收发机、哪一部分是比较针对计算传输等
节约能量时会用到:
调整控制器的功率消耗时DVS
收发机能耗,与调制结合,DMS(动态调制调整)(从DVS出发的)
DCS动态码调整
DMCS动态调制码调整
计算和通信之间能量消耗的关系
acontroller,typicalstatesare“active”,“idle”,and“sleep”;
aradiomodemcouldturntransmitter,receiver,orbothonoroff;
sensorsandmemorycouldalsobeturnedonoroff.Theusualterminologyistospeakofa“deeper”sleepstateiflesspowerisconsumed。
耗能主体1.controller2.radiofrontends3.memory
2.2.3Memory存储器
On-chipmemoryofamicrocontrollerandFLASHmemory
2.3节点的操作系统与运行环境
2.3Operatingsystemsandexecutionenvironments
无线传感器网络OS基于事件的,而非基于进程的
Operatingsystem:
Event-basedprogramming基于事件
Protocolstacks:
component-based基于部件
TypicalOS:
TinyOS
Event-basedprogramming
TheideaistoembracethereactivenatureofaWSNnodeandintegrateitintothedesignoftheoperatingsystem.Thesystemessentiallywaitsforanyeventtohappen,whereaneventtypicallycanbetheavailabilityofdatafromasensor,thearrivalofapacket,ortheexpirationofatimer.Suchaneventisthenhandledbyashortsequenceofinstructionsthatonlystoresthefactthatthiseventhasoccurredandstoresthenecessaryinformation–forexample,abytearrivingforapacketorthesensor’svalue–somewhere.Theactualprocessingofthisinformationisnotdoneintheseeventhandlerroutines,butseparately,decoupledfromtheactualappearanceofevents.Thisevent-basedprogramming[353]modelissketchedinFigure2.8.
understandpropertiesofdifferentnodes.
2.4传感器节点的一些例子
第三章选、判、填
understandtheSensornetworkscenarios
3.1传感器网络工作场景
3.1.1typesofsourcesandsinks(信宿)
Asourceisanyentityinthenetworkthatcanprovideinformation,thisis,typicallyasensornode;
itcouldalsobeanactuatornodethatprovidesfeedbackaboutanoperation.
Asinkisentitywhereinformationisrequired.Itbelongtothesensornetwork;
bejustanothersensor/actuatornode;
beanentityoutsidethisnetwork.
3.1.2Multihopnetworks
Becauseofthislimiteddistances.Storeandforward.障碍物obstacle
3.1.4threetypesofmobility
Nodemobility:
thewirelesssensornodesthemselvescanbemobile.
environmentalcontrolwillnothappen.
Sinkmobility:
theinformationsinkscanbemobile.Whilethiscanbeaspecialcaseofnodemobility.Theimportantaspectisthemobilityofaninformationsinkthatisnotpartofthesensornetwork.
Eventmobility:
Inapplicationslikeeventdetectionandinparticularintrackingapplications,thecauseoftheeventsortheobjectstobetrackedcanbemobile.
masterthedesignprinciplesofWSNs:
3.3WSN设计原则
3.3DesignprinciplesforWSNs
AppropriateQoSsupport,energyefficiency,andscalabilityareimportantdesignandoptimizationgoalsforwirelesssensornetworks.
在构建WSN结构时的设计原则:
●分布式组织Distributedorganization
●网络内部处理自适应的保真度与精度In-networkprocessingAdaptivefidelityandaccuracy
●以数据为中心datacentricity
●利用位置信息Exploitlocationinformation
●利用主动模式Exploitactivitypatterns
●利用多样性Exploitheterogeneity
●基于部件的协议栈与层的优化Component-basedprotocolstacksandcross-layeroprimization
分布式组织,
3.3.1Distributedorganization
Boththescalabilityandtherobustnessoptimizationgoal,andtosomedegreealsotheothergoals,makeitimperativetoorganizethenetworkinadistributedfashion.Thatmeansthatthereshouldbenocentralizedentityincharge–suchanentitycould,forexample,controlmediumaccessormakeroutingdecisions,similartothetasksperformedbyabasestationincellularmobilenetworks.Thedisadvantagesofsuchacentralizedapproachareobviousasitintroducesexposedpointsoffailureandisdifficulttoimplementinaradionetwork,whereparticipantsonlyhavealimitedcommunicationrange.Rather,theWSNsnodesshouldcooperativelyorganizethenetwork,usingdistributedalgorithmsandprotocols.Self-organizationisacommonlyusedtermforthisprinciple.
Whenorganizinganetworkinadistributedfashion,itisnecessarytobeawareofpotentialshortcomingsofthisapproach.Inmanycircumstances,acentralizedapproachcanproducesolutionsthatperformbetterorrequirelessresources(inparticular,energy).Tocombinetheadvantages,onepossibilityistousecentralizedprinciplesinalocalizedfashionbydynamicallyelecting,outofthesetofequalnodes,specificnodesthatassumetheresponsibilitiesofacentralizedagent,forexample,toorganizemediumaccess.Suchelectionsresultinahierarchy,whichhastobedynamic:
Theelectionprocessshouldberepeatedcontinuouslylesttheresourcesoftheelectednodesbeovertaxed,theelectednoderunsoutofenergy,andtherobustnessdisadvantagesofsuch–evenonlylocalized–hierarchiesmanifestthemselves.Theparticularelectionrulesandtriggeringconditionsforreelectionvaryconsiderably,dependingonthepurposeforwhichthesehierarchiesareused.
网内处理:
3.3.2In-networkprocessing网络内部处理
1.Aggregation
2.distributedsourcecodinganddistributedcompression
3.distributedandcollaborativesignalprocessing
4.mobilecode/Agent-basednetworking
Distributedsourcecodinganddistributedcompression
聚合aggregation搞清原理网内信息处理
AggregationP68
3.3.4Datacentriciy
1.addressdata,notenodes
2.Implementationoptionsfordata-centricnetworking
1.Overlaynetworksanddistributedhashtables(peer-to-peer)
2.publish/subscribeAnynodeinterestedinagivenkindofdatacansubscribetoit,andanynodecanpublishdata,alongwit
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