necessarilysinglehop

singlehop  时间:2021-01-03  阅读:()
MobileandWirelessNetworkingLecture3Dr.
XinbingWangOutlineWirelesscommunicationsystemsFlexibilitytosupportroamingLimitations:Geographicalcoverage,transmissionrate,andtransmissionerrorsArchitecturesofwirelessnetworksCellularnetworkarchitectureWirelessLAN/PANSatellitesystemsAdhocnetworksSensornetworkBackgroundFDMA/TDMA/CDMAConnectionsetupTraditionalApplicationsWeathersatelliteRadioandTVbroadcastingMilitarysatellitesTelecommunicationApplicationsGlobaltelephoneconnectionsBackboneforglobalnetworkGPSSatelliteSystemsWLAN--InfrastructureNetworkStation(STA)terminalwithaccessmechanismstothewirelessmediumandradiocontacttotheaccesspointBasicServiceSet(BSS)groupofstationsusingthesameradiofrequencyAccessPointstationintegratedintothewirelessLANandthedistributionsystemPortalbridgetoother(wired)networksDistributionSysteminterconnectionnetworktoformonelogicalnetwork(EES:ExtendedServiceSet)basedonseveralBSSDistributionSystemPortal802.
xLANAccessPoint802.
11LANBSS2802.
11LANBSS1AccessPointSTA1STA2STA3ESSWLAN--802.
11Advantagesveryflexiblewithinthereceptionarea(almost)nowiringdifficulties(e.
g.
historicbuildings,firewalls)morerobustagainstdisasterslike,e.
g.
,earthquakes,fire-oruserspullingaplug.
.
.
Ad-hocnetworkswithoutpreviousplanningpossibleDisadvantagestypicallylowerbandwidthcomparedtowirednetworks(1-54Mbit/s)manyproprietarysolutions,especiallyforhigherbit-rates,standardstaketheirtime(e.
g.
IEEE802.
11)productshavetofollowmanynationalrestrictionsifworkingwireless,ittakesaverylongtimetoestablishglobalsolutions.
AdhocNetwork--802.
11DirectcommunicationwithinalimitedrangeStation(STA):terminalwithaccessmechanismstothewirelessmediumBasicServiceSet(BSS):groupofstationsusingthesameradiofrequency.
SometimescalledIndependentBSS(IBSS)mode802.
11LANBSS2802.
11LANBSS1STA1STA4STA5STA2STA3WhatisMobileAdhocNetwork(MANET)Mobileuserswith(compatible)wirelesscommunicationdevicestosetupapossibleshort-livednetworks--foraspecificneed/purpose!
Without(necessarily)usingapre-existinginfrastructureRoutesbetweennodesmaypotentiallycontainmultiplehopsModelofOperationAssumption:thenodesareusingIP,andtheyhaveIPaddressesthatareassignedbysomemeans.
MANET--RouteChangesMobilitycauseroutechangesChallengesinMANETLimitedwirelesstransmissionrangeBroadcastnatureofthewirelessmediumHiddenterminalproblemPacketlossesduetotransmissionerrorsMobility-inducedroutechangesMobility-inducedpacketlossesBatteryconstraintsPotentiallyfrequentnetworkpartitionsEaseofsnoopingonwirelesstransmissions(securityhazard)ComparisonofAdHocandInfrastructureNetworkScalabilityExpansionislimitedtothecoverageoftheradiotransmitterandreceiverforsingle-hopnetworks;Nosimplewaytoscaleupthenetworkcoverageorcapacity;Thepotentialcoverageofthenetworkisincreased,butthetraffichandlingcapacityremainsthesame;Useproxyserverswithawirelessconnectiontothebackbonewirednetworks.
Infrastructurenetwork:byincreasingthenumberofbasestationsoraccesspoints,thecoverageandthecapacitywillbeincreased.
Itisusedforwideareacoverageandforvariabletrafficloads.
ComparisonofAdHocandInfrastructureNetwork(2)FlexibilityAdHocnetwork:flexibleandcanbeseupinstantly,itisusedfortemporaryapplications.
Infrastructurenetwork:time-consumingandexpensiveforgooddesign.
Controllability:timesynchronization,powercontrol,authenticationandsoon.
Adhoc:requirescomplicatedstructuresdemandingchangesinallterminals.
Infrastructure:allfeaturesareimplementedinBSsorAPs.
RoutingcomplexityAdhoc:requireseachterminaltomonitortheexistenceofothersandbeabletoconnectandroutemessages,needscomplicatedalgorithms.
Infrastructure:theproblemdoesnotexist.
ComparisonofAdHocandInfrastructureNetwork(3)CoverageAdhoc:themaximumdistancebetweentwoterminalsistherangeofcoverage.
Infrastructure:themaximumdistancebetweentwoterminalsistwicetherangeofasinglewirelessterminalbecausetheycommunicatethroughBSsorAPs.
ReliabilityAdhoc(s.
s.
WLANformilitary):singlefailurepointdoesnotexist.
Infrastructure:singlefailurepointnetworks.
StoreandforwarddelayandmediausageefficiencyAdhoc:informationtransmittedonlyonce,thereisnostoreandforwardprocedureforsingle-hopnetworks.
However,multi-hopnetworksdependonthetopologyandnumberofhops.
Infrastructure:informationistransmittedtwice,firsttoBS/AP,thenfromBS/APtoterminals.
BasestationAntennaSensorTargetWirelessSensorNetworksOutlineWirelesscommunicationsystemsFlexibilitytosupportroamingLimitations:Geographicalcoverage,transmissionrate,andtransmissionerrorsArchitecturesofwirelessnetworksCellularnetworkarchitectureWirelessLAN/PANSatellitesystemsAdhocnetworksSensornetworkBackgroundFDMA/TDMA/CDMAConnectionsetupUser1User2Usern…TimeFrequencyFDMA(FrequencyDivisionMultipleAccess)123…nFrequencyTotalbandwidth4FDMABandwidthStructureFrequency1User1Frequency2User2FrequencynUsernBaseStation……MobileStationsFDMAChannelAllocationUser1User2Usern…TimeFrequencyTDMA(TimeDivisionMultipleAccess)123…nTimeFrame4TDMAFrameStructureTime1Time2Timen……BaseStationUser1User2Usern…MobileStationsTDMAFrameAllocationUser1TimeFrequencyUser2UsernCode.
.
.
CDMA(CodeDivisionMultipleAccess)InformationbitsCodeattransmittingendTransmittedsignalReceivedsignalCodeatreceivingendDecodedsignalatthereceiverTransmittedandReceivedSignalsinCDMASystemsFrequencyf5f4f3f2f1FrameSlotTimeFrequencyHoppinginCDMABSMS1.
Needtoestablishpath2.
Frequency/timeslot/codeassigned(FDMA/TDMA/CDMA)3.
ControlInformationAcknowledgement4.
StartcommunicationConnectionSetup(ServiceDelivery)BSMS2.
Readytoestablishapath3.
Usefrequency/timeslot/code(FDMA/TDMA/CDMA)4.
Readyforcommunication5.
Startcommunication1.
CallforMS#pendingConnectionSetup(ServiceOrigination)Informationtobetransmitted(Voice/Data)CodingModulatorTransmitterInformationreceived(Voice/Data)DecodingDemodulatorReceiverAntennaAntennaCarrierCarrierSimplifiedFrameworkofWirelessCommunicationsWiredandWirelessMediaWiredmediaReliable,guidedlink:electricalsignalassociatedwiththetransmissionofinformationfromonefixedterminaltoanother.
Likefiltersthatlimitthemaximumtransmitteddatarateofthechannelbecauseofbandlimitingfrequencyresponsecharacteristics.
Radiatesoutsideofthewiretosomeextentwhichcancauseinterferencetoclose-byradiosorotherwiredtransmission.
WirelessmediaRelativelyunreliable,lowbandwidth,andofbroadcastnature(unguidedmedium).
Allwirelesstransmissionssharethesamemedium-air,whereasdifferentsignalsthroughwiredmediaviadifferentwires.
LicensedversusUnlicensedBandsLicensedbandsCellularsystemsoperatearound1GHzPCSandWLANsaround2GHzWLANaround5GHzLMDS(localmultipointdistributionservice)at28-60GHzIR(InfraRed)foropticalcommunicationsUnlicensedbandsISM(Industrial,Scientific,andMedical)bandU-NII(UnlicensedNationalInformationInfrastructure)bands,werereleasedin1997,PCSunlicensedbandswerereleasedin1994.
ElectromagneticSpectrumRelationshipbetweenf,,andc(invacuum)isf=cSpeed,Frequency,andWavelength10-7m1015HzUltravioletlight15mm20GHzKabandsatellite37.
5cm800MHzCellular3m100MHzFMradio5,000km60HzACcurrentWavelengthFrequencySystemLightspeed(c)=Wavelength()*Frequency(f)3x108m/s=300,000km/sAfterClassReadingmaterialsChapter1Chapter2Chapter3.
1-3.
4Chapter4ExercisesListatleastfourarchitecturesofwirelessnetworking.
WhatarethemaintechnologiesorchallengesofthesenetworkarchitecturesWhatarethemaindifferencesbetweenthesenetworksCanyouidentify2applicationscenariosforeachofthemListatleastthreefunctionsforeachlayerinawirelessnetwork

LOCVPS-2021年6月香港便宜vps宽带升级,充值就送代金券,其它八折优惠!

LOCVPS怎么样?LOCVPS是一家成立于2011年的稳定老牌国人商家,目前提供中国香港、韩国、美国、日本、新加坡、德国、荷兰等区域VPS服务器,所有机房Ping延迟低,国内速度优秀,非常适合建站和远程办公,所有机房Ping延迟低,国内速度优秀,非常适合做站。XEN架构产品的特点是小带宽无限流量、不超售!KVM架构是目前比较流行的虚拟化技术,大带宽,生态发展比较全面!所有大家可以根据自己业务需求...

QQ防红跳转短网址生成网站源码(91she完整源码)

使用此源码可以生成QQ自动跳转到浏览器的短链接,无视QQ报毒,任意网址均可生成。新版特色:全新界面,网站背景图采用Bing随机壁纸支持生成多种短链接兼容电脑和手机页面生成网址记录功能,域名黑名单功能网站后台可管理数据安装说明:由于此版本增加了记录和黑名单功能,所以用到了数据库。安装方法为修改config.php里面的数据库信息,导入install.sql到数据库。...

香港ceranetworks(69元/月) 2核2G 50G硬盘 20M 50M 100M 不限流量

香港ceranetworks提速啦是成立于2012年的十分老牌的一个商家这次给大家评测的是 香港ceranetworks 8核16G 100M 这款产品 提速啦老板真的是豪气每次都给高配我测试 不像别的商家每次就给1核1G,废话不多说开始跑脚本。香港ceranetworks 2核2G 50G硬盘20M 69元/月30M 99元/月50M 219元/月100M 519元/月香港ceranetwork...

singlehop为你推荐
美国vps服务器美国Vps 哪里的稳定,服务好,不是代购,主要是我新手,不太懂广东虚拟主机有什么便宜又好用的虚拟主机吗?已备案域名查询如何查询网站的域名是否已经备案代理主机什么叫做代理服务器?有什么用途?空间域名服务器和空间域名什么意思云服务器租用云服务器租用费用是多少成都虚拟空间虚拟主机哪家最好~~~重庆虚拟空间在重庆开一家VR体验馆价格要多少?手机网站空间手机网页空间需要多大?北京虚拟主机租用北京云主机租用哪家资质正规,价格便宜,服务好?要真云主机不要那种vps的假云主机,机房要在北京的!
虚拟空间购买 域名升级访问 中国万网域名注册 vps是什么意思 大硬盘 精品网 rackspace 圣迭戈 60g硬盘 免费dns解析 支持外链的相册 闪讯官网 网通服务器 中国电信网络测速 独立主机 申请免费空间 lamp什么意思 阿里云邮箱申请 贵州电信 百度新闻源申请 更多