CS5530 Mobile/Wireless Systemsyzhuang/CS5530/spring2017/slides/LEC1... · 2017-01-19 · What is a Wireless Network (cont.) CS5530 17 Ref. CN5E, NT@UW •Some other wireless networks

Ref.CN5E,NT@UWCS5530

CS5530Mobile/WirelessSystems

Introduction

YanyanZhuangDepartmentofComputerSciencehttp://www.cs.uccs.edu/~yzhuang

UC.ColoradoSprings

IntroofIntro

Ref.CN5E,NT@UW2CS5530

• YanyanZhuango PhDinnetworksystems

o [email protected]

• Officehourso M/W:anhourafterclass

o F:11am– 12pm

• Blackboard:announcement,schedules

Outline


• Whystudymobile/wirelesssystems?

• Whatwillyoulearn?

• Lectures,Assignments,Projects,Exams

• Coursepolicy• Overview

Whystudymobile/wirelesssystems?


• WheredoesInternetcomefrom?o Computercenterà Computernetworksà Internet

• Wirelesso Mobility,flexibility

Whatwillyoulearn?


• Howdowirelessnetworkswork?o WiFi,cellular,Bluetooth,etc.

o Noheavymath!

• Howtoprogramonend-userdevices?o iOS

o Android

Lectures,Assignments,Project,Exams


• 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


• 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.)


• Gradingpercentageo Assignments:40%

o Researchproject:20%

o Midterm:20%

o Finalexam:20%

Wheretogethelp?


• Q&Ainclass• Officehours

o M/Wonehourafterclass6-7pm

o F:11:00am-- 12:00pm

o Byappointment

o ENGR184


Overview

WhatisaWirelessNetwork


• First,whatisanetwork?o Computernetworks

} A largenumberofseparatebutinterconnectedcomputers

} Theconnection:viaacopperwire,fiberoptics,microwaves,infrared,satellites,andsoon

o Internet} Themostwell-knownnetworkofnetworks

WheredidInternetcomefrom?


• ARPANET(1966-1967):AdvancedResearchProjectsAgencyNetworko FundedbyAdvancedResearchProjectsAgency(ARPA)ofUnitedStatesDepartmentofDefense

• Goal:networkacademiccomputers(UCLA,SRI,UCSB,Utah-- firstnodesin1969)

• 1971:~20ARPANETnodes

WheredidInternetcomefrom?


Roughsketch:late1960s

Ref.MOS4E,OS@Austin,Columbia,UWiscUC.ColoradoSpringsCS4500/55001970sto1980s:ARPANETtransitionedtoTCP/IP

GrowthofInternetHosts


WhatisaWirelessNetwork(cont.)


• Useofnetworkso Business,homeuse

o Mobileusers} Peopleonthegowanttodoallthingstheydoathomeandinoffice

} Mobileconnectivity¨ Cellular,WiFi (IEEE802.11)

} Differentmobilesystems¨ Smartphones/tablets/smartwatch

¨ GPS

¨ RFID(Radio-FrequencyIDentification)

WhatisaWirelessNetwork(cont.)


• Someotherwirelessnetworkso Sensornetworks

} Madeupofnodesthatgatherandwirelesslyrelayinformationtheysenseaboutthestateofthephysicalworld

} Thenodesmaybecarsorphones,ormaybeseparatedevices¨ Car’sOBDsensors

¨ Separatedevices¨ accelerometers,barometers,oceanbottomseismometers,pressurerecorders

andhydrophone

NetworkReferenceModel


• Afourlayermodelbasedonexperience

4Application – Programsthatusenetworkservice

3Transport – Providesend-to-enddatadelivery

2Internet – Sendpacketsovermultiplenetworks

1Link – Sendframesoveralink

3Transport – Providesend-to-enddatadelivery

NetworkReferenceModel(cont.)


• Afourlayermodelbasedonexperience

4Application3Transport

2Internet

1Link Ethernet802.11

IP

TCP UDP

HTTPSMTP RTP DNS

3GDSLCable

networklayerEveryInternetdevicemustspeak!

LANandWLAN


The standard for wireless LANs is called IEEE 802.11, popularly known as WiFi

Wirelessrouter/Basestation

Wirelessvs.Wired


• Linklayer

• Medium:openair• Nowiringrequired• Lesssecurethanwirednetworks

o It’salotmoredifficultforunauthorizedeavesdroppersandothersnoopstomonitordatainawirednetwork

4Application3Transport

2Internet

1Link Ethernet802.11

IP

TCP UDP

HTTPSMTP RTP DNS

3GDSLCable

Wirelessvs.Wired


• Advantageo Allowsmobility

o Muchcheaperandeasiertodeploy,change,andupgrade

• Disadvantageo Exposed(unshielded)medium

} Susceptibletophysicalphenomena(interference)

} Moreerrors

o Slowerdataratesforlongerdistances

o Security:anyoneinrangehearstransmission

WirelessStandards


• 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


WirelessTransmissionRange


1. Transmissionpower2. Signal-to-noiseratio

Therangethatthereceiverisjustabletoreceive/decodethesignal

AWirelessLink?


AWirelessLink!


Someotherissues


• Hiddenterminals

• AandCcanbothsendtoBbutcan’theareachothero AisahiddenterminalforCandviceversa

A B C

Someotherissues(cont.)


• Exposedterminals

• Exposednode:BsendsapackettoA;ChearsthisanddecidesnottosendapackettoD(despitethatthiswillnotcauseinterference)

A B C D

Summary


• Whatisanetwork

• Differentkindsofwirelessnetworks• Wirelessstandards

• Issueswithwirelessnetworks