Post on 17-Apr-2020
Ref.CN5E,NT@UWCS5530
CS5530Mobile/WirelessSystems
Introduction
YanyanZhuangDepartmentofComputerSciencehttp://www.cs.uccs.edu/~yzhuang
UC.ColoradoSprings
IntroofIntro
Ref.CN5E,NT@UW2CS5530
• YanyanZhuango PhDinnetworksystems
o yzhuang@uccs.edu
• Officehourso M/W:anhourafterclass
o F:11am– 12pm
• Blackboard:announcement,schedules
Outline
Ref.CN5E,NT@UW3CS5530
• Whystudymobile/wirelesssystems?
• Whatwillyoulearn?
• Lectures,Assignments,Projects,Exams
• Coursepolicy• Overview
Whystudymobile/wirelesssystems?
Ref.CN5E,NT@UW4CS5530
• WheredoesInternetcomefrom?o Computercenterà Computernetworksà Internet
• Wirelesso Mobility,flexibility
Whatwillyoulearn?
Ref.CN5E,NT@UW5CS5530
• Howdowirelessnetworkswork?o WiFi,cellular,Bluetooth,etc.
o Noheavymath!
• Howtoprogramonend-userdevices?o iOS
o Android
Lectures,Assignments,Project,Exams
Ref.CN5E,NT@UW6CS5530
• Lectureso MondayandWednesday4:45PM– 6:00PMo ENGR138
• Assignments(individual)o iOS/Androidprogrammingassignments
• Researchproject(individualoringroups)o Chooseatopicthatinterestsyou,talktomebeforeyoustart
• MidtermandFinal(online,open-book,limitedtime)o MidtermTBD,mid/lateMarch(takehome)o Final:5:20– 7:20pm,May10(inclass)
http://www.uccs.edu/Documents/cic/spring%202017/Final%20Exam%20Schedule.pdf
CoursePolicy
Ref.CN5E,NT@UW7CS5530
• Gradingscale
Percentage Grade
90- 100 A
87- 89 A-
84- 86 B+
80- 83 B
75 - 79 C+
70- 74 C
65- 69 D+
60- 64 D
Below60 F
CoursePolicy(cont.)
Ref.CN5E,NT@UW8CS5530
• Gradingpercentageo Assignments:40%
o Researchproject:20%
o Midterm:20%
o Finalexam:20%
Wheretogethelp?
Ref.CN5E,NT@UW9CS5530
• Q&Ainclass• Officehours
o M/Wonehourafterclass6-7pm
o F:11:00am-- 12:00pm
o Byappointment
o ENGR184
Ref.CN5E,NT@UW10CS5530
Overview
WhatisaWirelessNetwork
Ref.CN5E,NT@UW11CS5530
• First,whatisanetwork?o Computernetworks
} A largenumberofseparatebutinterconnectedcomputers
} Theconnection:viaacopperwire,fiberoptics,microwaves,infrared,satellites,andsoon
o Internet} Themostwell-knownnetworkofnetworks
WheredidInternetcomefrom?
Ref.CN5E,NT@UW12CS5530
• ARPANET(1966-1967):AdvancedResearchProjectsAgencyNetworko FundedbyAdvancedResearchProjectsAgency(ARPA)ofUnitedStatesDepartmentofDefense
• Goal:networkacademiccomputers(UCLA,SRI,UCSB,Utah-- firstnodesin1969)
• 1971:~20ARPANETnodes
WheredidInternetcomefrom?
Ref.CN5E,NT@UW13CS5530
Roughsketch:late1960s
Ref.MOS4E,OS@Austin,Columbia,UWiscUC.ColoradoSpringsCS4500/55001970sto1980s:ARPANETtransitionedtoTCP/IP
GrowthofInternetHosts
Ref.CN5E,NT@UW15CS5530
WhatisaWirelessNetwork(cont.)
Ref.CN5E,NT@UW16CS5530
• Useofnetworkso Business,homeuse
o Mobileusers} Peopleonthegowanttodoallthingstheydoathomeandinoffice
} Mobileconnectivity¨ Cellular,WiFi (IEEE802.11)
} Differentmobilesystems¨ Smartphones/tablets/smartwatch
¨ GPS
¨ RFID(Radio-FrequencyIDentification)
WhatisaWirelessNetwork(cont.)
Ref.CN5E,NT@UW17CS5530
• Someotherwirelessnetworkso Sensornetworks
} Madeupofnodesthatgatherandwirelesslyrelayinformationtheysenseaboutthestateofthephysicalworld
} Thenodesmaybecarsorphones,ormaybeseparatedevices¨ Car’sOBDsensors
¨ Separatedevices¨ accelerometers,barometers,oceanbottomseismometers,pressurerecorders
andhydrophone
NetworkReferenceModel
Ref.CN5E,NT@UW18CS5530
• Afourlayermodelbasedonexperience
4Application – Programsthatusenetworkservice
3Transport – Providesend-to-enddatadelivery
2Internet – Sendpacketsovermultiplenetworks
1Link – Sendframesoveralink
3Transport – Providesend-to-enddatadelivery
NetworkReferenceModel(cont.)
Ref.CN5E,NT@UW19CS5530
• Afourlayermodelbasedonexperience
4Application3Transport
2Internet
1Link Ethernet802.11
IP
TCP UDP
HTTPSMTP RTP DNS
3GDSLCable
networklayerEveryInternetdevicemustspeak!
LANandWLAN
Ref.CN5E,NT@UW20CS5530
The standard for wireless LANs is called IEEE 802.11, popularly known as WiFi
Wirelessrouter/Basestation
Wirelessvs.Wired
Ref.CN5E,NT@UW21CS5530
• Linklayer
• Medium:openair• Nowiringrequired• Lesssecurethanwirednetworks
o It’salotmoredifficultforunauthorizedeavesdroppersandothersnoopstomonitordatainawirednetwork
4Application3Transport
2Internet
1Link Ethernet802.11
IP
TCP UDP
HTTPSMTP RTP DNS
3GDSLCable
Wirelessvs.Wired
Ref.CN5E,NT@UW22CS5530
• Advantageo Allowsmobility
o Muchcheaperandeasiertodeploy,change,andupgrade
• Disadvantageo Exposed(unshielded)medium
} Susceptibletophysicalphenomena(interference)
} Moreerrors
o Slowerdataratesforlongerdistances
o Security:anyoneinrangehearstransmission
WirelessStandards
Ref.CN5E,NT@UW23CS5530
• Cellularo 2G:GSM,CDMAo 3G:CDMA2000,WCDMA,TD-SCDMAo 4G/5G/LTE
• IEEE802.11o a:5.0Ghzband,54Mbps(25Mbpsoperatingrate)o b:2.4Ghzband,11Mbps(4.5Mbpsoperatingrate)o g:2.4Ghz,54Mbps(19Mbpsoperatingrate)o Otherversions(802.11n,p,etc.)
• IEEE802.15:lowpoweredwirelesso 802.15.1:2.4Ghz,2.1Mbps(Bluetooth)o 802.15.4:2.4Ghz,250Kbps(SensorNetworks)
WirelessLinkCharacteristics
Ref.CN5E,NT@UW24CS5530
WirelessTransmissionRange
Ref.CN5E,NT@UW25CS5530
1. Transmissionpower2. Signal-to-noiseratio
Therangethatthereceiverisjustabletoreceive/decodethesignal
AWirelessLink?
Ref.CN5E,NT@UW26CS5530
AWirelessLink!
Ref.CN5E,NT@UW27CS5530
Someotherissues
Ref.CN5E,NT@UW28CS5530
• Hiddenterminals
• AandCcanbothsendtoBbutcan’theareachothero AisahiddenterminalforCandviceversa
A B C
Someotherissues(cont.)
Ref.CN5E,NT@UW29CS5530
• Exposedterminals
• Exposednode:BsendsapackettoA;ChearsthisanddecidesnottosendapackettoD(despitethatthiswillnotcauseinterference)
A B C D
Summary
Ref.CN5E,NT@UW30CS5530
• Whatisanetwork
• Differentkindsofwirelessnetworks• Wirelessstandards
• Issueswithwirelessnetworks