the wireless session...first wireless transmitter: the spark gap transformer 1g mobile phone paging...
TRANSCRIPT
The Wireless SessionSIGCOMM 2016
VamsiTallaUniversityofWashington
EvolutionofWirelessSystems
Firstwirelesstransmitter:Thesparkgaptransformer
1GMobilePhone
PagingSystems
MainstreamGenesis
Implantable&IoT
3G,4GCellular
5G:MassiveMIMO- Wi-Fi&MillimeterWave
Ubiquity
HotResearchinWireless
PowerEfficiency HighDataRates
0Mbps 1 Gbps
250Mbps
750Mbps
500Mbps
WhyisCommunicationExpensiveinPower?
KeyReason:GenerationofRFsignalrequirestremendousamountofpower
Solution:Don’tgeneratejustreflect!
TheFlashlightAnalogyEncodedatausingreflections
BackscatterinRF
Reflectionsconsume4-5ordersofmagnitudelowerpower
Encodedatausingreflections
EvolutionofBackscatter
AmbientBackscatter
• ReflectambientTVsignals
• Communicateb/wbattery-freedevices
• SIG’13:100bps-1kbps@upto 10feet
• SIG’14:10kbps-1Mbps@upto80feet
Wi-FiBackscatter
• CommunicatewithCOTSWi-Ficlients
• EncodedatausingvariationsintheWi-Fichannel
• SIG'14:100bps-10kbps@10feet
PassiveWi-Fi
• CommunicatewithunmodifiedWi-Ficlients
• Create802.11bWi-Fipacketsusingreflections
• NSDI'16:1-11Mbps@100feet
Backscatter@SIGCOMM2016
• UseCommoditydevicesØ RepurposeexistingBluetoothandWi-Firadios
Ø Easeofuseanddeployment
KeyideabehindusingCommodityDevices
ff1 f22.4
GHz2.5GHz
Physicallayer:shiftthesignalintoadifferentfrequencyband
UsingCommodityDevices
• FS-BackscatterØ ShiftsentireBLE/Wi-Fipacketstoadjacentband
Ø Requireslowlevelfirmwareaccess
Ø InterandIntrapacketencoding(upto50kbps)
• Interscatter (BestPaperAward)Ø TransformsBLEpacketintosingletonesignalinuserspace
Ø ConvertstheBLEpacketintoaWi-Fi/ZigBeepacket
Ø Encodesdatain802.11b2-11MbpsWi-Fipackets
Backscatter@SIGCOMM2016
• UseCommoditydevicesØ RepurposeexistingBluetoothandWi-Firadios
Ø Easeofuseanddeployment
• CombineradioswithbackscatterØ Radios->highpowerbutgiveslongrange
Ø Backscatter->Ridiculouslylowpowerbutshorterrange
Bradio:Switchbetweenradioandbackscatter
Achievinghighdatarates
• Cellular:2G->3G->4G
• 802.11Wi-Fi:b->g->n->ac
• Nextgeneration(5G)wirelessstandards
Ø MillimeterWave
Ø LargeMIMOSystems– Wi-Fi,Cellular,60GHz and
implementbeamforming,nulling,etc.
Challenge:Channelestimationbecomesharderandincurshugeoverhead inlargeMIMOsystems
MIMOrequiresperiodicestimationofchannel
MIMOinCellular(BestPaperAward)CellularSystemsuseFrequencyDivisionDuplexing
f
• Modelthechannel/wirelesspropagationwith
frequencyindependentparameters
• Thenusechannelreciprocity
fupfdn
MegaMIMO2.0
• Traditionalchannelreciprocitymethodsfailinlarge
MIMOsystems
• SoftwarehardwarearchitecturefordistributedMIMO
It’sgoingtobeanexcitingsession!
• BackscatterSystems
Ø Coolphysicallayertrick- brushuponbasic
modulationandtrig.identities
Ø BuildMACandnetworkinglayerontopofit
Ø RFhardwareexpertiseisrequiredtobuildthese
systems!
2ofthe3BestPapersareintheWirelessSession
It’sgoingtobeanexcitingsession!
• MIMOSystems
Ø It’sallaboutestimatingchannelparameters
Ø Brushuponbasicwavepropagationandmatrix
operations
Ø Beamforming,nullingandpowercontrol
techniquesinlargeantennasystem
Exponentialimprovementsincomingyearsinboth
backscatterandMIMOsystems