通信基本原理主流的通信技术短波微波卫星ATMTCPIPAAA路由和MPLS.docx

通信基本原理主流的通信技术短波微波卫星ATMTCPIPAAA路由和MPLS.docx

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通信基本原理主流的通信技术短波微波卫星ATMTCPIPAAA路由和MPLS

Application-driven,energy-efficientcommunicationinwirelesssensornetworks 

Severalsensornetworkapplicationsbasedondatadiffusionanddatamanagementcandeterminethecommunicationtransferratebetweentwosensorsbeforehand.Inthisframework,weconsidertheproblemofenergyefficientcommunicationamongnodesofawirelesssensornetworkandproposeanapplication-drivenapproachthatminimizesradioactivityintervalsandprolongsnetworklifetime.Onthebasisofpossiblecommunicationdelaysweestimatepacketarrivalintervalsatanyintermediatehopofafixed-ratedatapath.Westudyagenericstrategyofradioactivityminimizationwhereineachnodemaintainstheradioswitchedonjustintheexpectedpacketarrivalintervalsandguaranteeslowcommunicationlatency.Wedefineaprobabilisticmodelthatallowstheevaluationofthepacketlossprobabilitythatresultsfromthereducedradioactivity.Themodelcanbeusedtooptimallychoosetheradioactivityintervalsthatachieveacertainprobabilityofsuccessfulpacketdeliveryforaspecificradioactivitystrategy.Relyingontheprobabilisticmodelwealsodefineacostmodelthatestimatestheenergyconsumptionoftheproposedstrategies,underspecificsettings.Weproposethreespecificstrategiesandnumericallyevaluatetheassociatedcosts.WefinallyvalidateourworkwithasimulationmadewithTOSSIM（theBerkeleymotes’simulator）.Thesimulationresultsconfirmthevalidityoftheapproachandtheaccuracyoftheanalyticmodels.

ArticleOutline

1.Introduction

2.Relatedwork

3.Scenario

4.Communicationparadigm

5.Probabilisticmodel

5.1.Successandfailureprobabilities

5.2.Costestimation

6.Optimizationofthecostfunction

7.Alternativestrategiesforw（i）

7.1.Analysisofthestrategiesfix,lin,andmix

8.Simulations

9.Conclusions

Thechangingusageofamaturecampus-widewirelessnetwork  

无线局域网络在数字化校园/社区/办公区的创新应用校园无线通信网络及其产品市场开发

WirelessLocalAreaNetworks（WLANs）arenowcommonplaceonmanyacademicandcorporatecampuses.As“Wi-Fi”technologybecomesubiquitous,itisincreasinglyimportanttounderstandtrendsintheusageofthesenetworks.Thispaperanalyzesanextensivenetworktracefromamature802.11WLAN,includingmorethan550accesspointsand7000usersoverseventeenweeks.Weemployseveralmeasurementtechniques,includingsyslogmessages,telephonerecords,SNMPpollingandtcpdumppacketcaptures.ThisisthelargestWLANstudytodate,andthefirsttolookatamatureWLAN.Wecomparethistracetoatracetakenafterthenetwork’sinitialdeploymenttwoyearsprior.

WefoundthattheapplicationsusedontheWLANchangeddramatically,withsignificantincreasesinpeer-to-peerandstreamingmultimediatraffic.DespitetheintroductionofaVoiceoverIP（VoIP）systemthatincludeswirelesshandsets,ourstudyindicatesthatVoIPhasbeenusedlittleonthewirelessnetworkthusfar,andmostVoIPcallsaremadeonthewirednetwork.

Wesawgreaterheterogeneityinthetypesofclientsused,withmoreembeddedwirelessdevicessuchasPDAsandmobileVoIPclients.Wedefineanewmetricformobility,the“sessiondiameter”.Weusethismetrictoshowthatembeddeddeviceshavedifferentmobilitycharacteristicsthanlaptops,andtravelfurtherandroamtomoreaccesspoints.Overall,usersweresurprisinglynon-mobile,withhalfremainingclosetohomeabout98%ofthetime.

ArticleOutline

1.Introduction

2.Thetestenvironment

2.1.VoiceoverIP

2.2.Clientdevices

3.Tracecollection

3.1.Syslog

3.2.SNMP

3.3.Ethernetsniffers

3.4.VoIPCDRdata

3.5.Definitions

3.6.Definingmobility

4.Changes

4.1.Clients

4.2.Traffic

5.Specificapplications

5.1.VoIP

5.2.Peer-to-peerapplications

5.3.Streamingmedia

6.Mobility

7.Relatedwork

8.Conclusionsandrecommendations

8.1.Futurework

Acknowledgements

References

Collaborativedatagatheringinwirelesssensornetworksusingmeasurementco-occurrence  

并发性事件的衡量/确认和信息协同化收集无线传感器网络技术与建设

Wirelessadhocnetworksofbattery-poweredmicrosensors（WSNs）areproliferatingrapidlyandtransforminghowinformationisgatheredandprocessed,andhowweaffectourenvironment.Thelimitedenergyofthosesensorsposesthechallengeofusingsuchsystemsinanenergyefficientmannertoperformvariousactivities.AcommonactivityofmanyapplicationsofWSNsisthatofdatagathering:

foreachtimestep,gatherthemeasurementfromeachsensortoabasestation.Oftenthereisredundancyand/ordependencyamongthesensormeasurements.Howtoidentifythedataredundancy/dependencyandutilizethemonimprovingenergyefficiencyofdatagatheringhasbeenoneoftheattractivetopics.

Weproposeusingmeasurementco-occurrencetoidentifydataredundancyandanovelcollaborativedatagatheringapproachutilizingco-occurrencethat