WirelessCommunication

CS447– WirelessEmbeddedSystems

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,20181

802.11– WiFi

• WLAN– wirelesslocalareanetwork• 2.4GHzradioband(mosttypical)• 14channels• MediaAccessControl(MAC),PhysicalLayer(PHY)standards

January31,20182

802.11– WiFi

• Accesspoint – allowsWiFi devicetoconnecttowirednetwork• APssupportmultipleconnecteddevices

January31,20183

802.11– WiFi

• Ad-hoc– allowsdirectcommunicationbetweendeviceswithout anintermediaryaccesspoint• Aka“ad-hocWiFi”

January31,20184

802.11– WiFi

Wi-Fihasmanymoredetails• Encryption• SSID• Rangeextenders• …

IoT LabhasXbee WiFimodulesyoucanrent• Configurationcanbechallenging..

January31,20185

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,20186

Bluetooth

• Intendedforshortdistances• 2.4GHzradioband• PAN– PersonalAreaNetwork• IEEE802.15.1standard(historical)• 79designatedchannels• Datarate:~25Mbits /second• Range:~10meters

January31,20187

Bluetooth

• Master/Slavearchitecture• Mastercancommunicatewithupto7devices• Piconet – ad-hocnetworkusingBluetoothtechnology• Round-robin schedulingofslavecomm• Hasbroadcastmode(littleused)

ManyBluetooth“breakout”modulesavailable• E.g.,Sparkfun BlueSMiRF Silver~$25

January31,20188

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,20189

WiMAX

• WorldwideInteroperabilityforMicrowaveAccess• IEEE802.16standardforPHY,MAClayers• “Lastmilewirelessbroadbandaccess”• NotareplacementforWiFi• AlternativetocableorDSL• Datarate:~30Mbit/sec• Range:~10miles• DoesNOTrequirelineofsight(LOS)

January31,201810

WiMAX

Usages:• BackhaulservicetotransferdatawithinanISPnetwork

• Provideinternetaccessforusersinremotelocations(layingcabletooexpensive)

• Formofmobileinternetaccess(competesw/cellular,satellite)

January31,201811

WiMAX

Howtouse:• Basestations– installedbyserviceproviders• Receivers– installedwithinclients

January31,201812

WiMAX

January31,201813

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,201814

Cellular

• 2G,3G,4G=>800MHzfrequencyband• Datarate(4G):100Mbits /sec(max)forhighmobility• Datarate(4G):1Gbit /sec(max)forlowmobility• Manyprotocols:GSM,LTE,GPRS

Manycellmodemsavailable:• E.g.,adafruit FONA3G+GPS

January31,201815

Cellular

GSM:GlobalSystemforMobile(Communication)• Europeanstandard• 2nd generationdigitalcellnetworkprotocol• >90%marketshare• 190+countries

January31,201816

Cellular

LTE:Long-TermEvolution• Commonlymarketedas4GLTE• Goal:increasecapacityandspeedofwirelessdatanetworks• Utilizesdigitalsignalprocessingtechniquesandmodulations• LTEincompatiblewith2Gand3Gnetworks• Mustbeonseparateradiospectrum

January31,201817

Cellular

GPRS:GeneralPacketRadioService• Packetorientedmobiledataservice• 2Gand3Gnetworks• ExtendsGSM• SMSmessaging(upto30perminute)• “alwayson”internet

• E.g.,Sparkfun GSM/GPRSModule

January31,201818

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,201819

Satellite

E.g.,IridiumNetwork• 66activesatellites• Transceiversanywhereonearth’ssurface• Voiceanddatacoverageforsatellitephones• ~$1.00perminuteofphoneuse• SupportsTCP/IP

January31,201820

Satellite

E.g.,Iridium9603• Transceiversarepowerhungry(~1.3Ampsintransmitmode)• Relativelyslowdatarates(~3kbits /sec)• ~1secondround-triplatency

E.g.,Sparkfun RockBLOCK Mk2• Iridium9602brokenout

January31,201821

Outline

• 802.11- Wi-Fi• Bluetooth• WiMAX• Cellular• Satellite• 802.15.4

January31,201822

802.15.4

• Radiosyou’lluse• Reliable• Powerefficient• Lowdatarate• Designedforwirelesssensornetworks(WSNs)• IEEE802.15.4standardforMACandPHY

January31,201823

802.15.4

• 900MHzor2.4GHzfrequencybands• 16-bitaddressing(short)• Ifneeded,64-bitextendedaddressing• Linkqualitymetrics• CarrierSenseMultipleAccesswCollisionAvoidance(CSMA-CA)• Built-inacknowledgements(acks)fortransferreliability

January31,201824

802.15.4

Startopology:• Communicationestablishedbetweendevicesandsinglecentralcontroller(PANcoordinator)

• Controllerroutespacketstoendpoints(viaaddressing)

January31,201825

802.15.4

Peer-to-Peertopology:• Anydeviceabletocommunicatewithanyotherdevicewithinrange• P2Pallowscomplexnetworkformations(e.g.,meshnetwork)• Allowsmultiplehopstoroutemessages(applicationlayer)

January31,201826

802.15.4

PHY– PhysicalLayer• Enablestransmission/receptionofPHYprotocoldataunits(PPDUs)acrossphysicalradiochannel

Features:• Activates/deactivatesofradiotransceiver• Energydetection• Channelselection• Clearchannelassessment• LQI– linkqualityindicator(forRSSI)

January31,201827

802.15.4

MACsublayer• Enablestransmission/receptionofMACprotocoldataunits(MPDUs)acrossthePHYdataservice

Features:• Beaconmanagement• Channelaccess• Framevalidation• Ack• Hooksforapplication-layersecurity

January31,201828

802.15.4

Xbee 802.15.4Series1• Indoorrange:200’• Outdoorrange:4000’• Datathroughput:upto96,000bits/second• UARTdatarate:57,600baud(typical)

• Transmitcurrent:~50mApeak• Receivecurrent:~30mA• Operatingvoltage:3.3V

January31,201829

802.15.4

Xbee 802.15.4Series1• ”Transparent”operatingmode(default)• Actslikeinvisiblewire

OthermodesincludeAPIandCommand(advanced)• APImodeallowsmoreadvancedoperations• E.g.,addressingspecificradiomodules

January31,201830

802.15.4

Xbee 802.15.4Series1• Thisclass:applicationlayeraddressing• Basestationradio“broadcasts”• Allend-pointsreceivepacket• Usesapplicationlevellogictodetermineaddressing…

January31,201831

802.15.4

Xbee 802.15.4Series1• WillconnectXbee radiotocomputerviaUSBdongle• Computerwillactasbasestation

January31,201832

802.15.4

Xbee 802.15.4Series1• WillConnectXbee toArduinowithshield• Arduino(s)actasendpointdevicesforWSN• Shieldhasswitch:DLINE,UART• DLINE – communicateb/tcomputerandArduinoUSB• UART – communicateb/tXbee radio

January31,201833

802.15.4

Xbee 802.15.4Series1• YouMUSTconfiguretheradiosbeforeusing

• X-CTUsoftwarepackagefromDigi• https://www.digi.com/products/xbee-rf-solutions/xctu-software/xctu

Mustsetfollowingparameters:• CH – radiochannel• ID – PANID• MY – unique16-bitaddressforeachradio• DL – 16-bitdestinationaddressforeachradio• BD – serialbaudrate

January31,201834

802.15.4

XCTUsoftwareprimer–• ConnectXbee radiotoXbee USBdongle• ConnectUSBdongletocomputer• Download/openXCTU

January31,201835

Click “Discover Devices”

Select port

Click Next >

Select multiple Baud Rates:960057600115200

Click Finish

January31,201839

XCTU will search for connected radios…

January31,201840

Radio found, select and click “Add selected devices”

January31,201841

Device has been added..

Click on it to configure.

January31,201842

Parameters that can be configured…

January31,201843

E.g., click the ID text field to edit configure the PAN ID of your WSN…

January31,201844

Click Write to configure the radio

January31,201845

Repeat for CH, MY, DL, BD

NOTE: You’ll have to configure allradios in your WSN

802.15.4

CH– channel• sameforallradios inWSN

ID – PANID• sameforallradios inWSN• uniqueforyourteam

BD– baudrate• sameforallradios inWSN(e.g.,57600)

January31,201846

802.15.4

MY– 16-bitsourceaddress• EachradioinWSNmusthaveuniqueMYaddress,e.g.,• 0xBACE forbasestationradio• 0x0001forwirelessnode#1• 0x0002forwirelessnode#2• 0x0003forwirelessnode#3

January31,201847

802.15.4

DL– 16-bitdestinationaddress• Basestationradiomustbroadcast(0xFFFF)• Wirelessnodesmatchbasestation’sMYaddress(e.g.,0xBACE)

January31,201848