dash7, passive rfid and lpwan dash7, passive rfid and lpwan prof. maarten weyn -michael andre

PUBLIC

DASH7,PASSIVERFIDAND LPWANPROF.MAARTENWEYN- MICHAELANDRE

THEINTERNETOFTHINGS

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WIRELESSLYCONNECTINGATHING…

ThingWhat frequency is used?

How does transmission work?How is link established?

How is network formed?How do devices join?

How to send packet from A to B?How to set up connection?

…

What is a light bulb?What is on/off?What is dim?

Wireless communication

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MEANSSELECTINGANAPPROPRIATETECHNOLOGY

…andunderstandinglimitationsandtrade-offs

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WIRELESSLANDSCAPE

RANGECAPABILITY

BANDW

IDTH

LPWAN featuresLongrange

Lowdatarate

Lowpower

Licensefree/licensed

Differentsystemmodels

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WIRELESSTECHNOLOGY

WIRELESSTRADE-OFFS

$$$Licensed/UnlicensedSpectrum

LicenseCost/ISMregulations/Collisions

Range:higherfrequencies resultinshorterrange,morecomplexcodingreduces range

Data rate:moreBWoradvancedcodingwithingivenBWresultsinhigherachievabledataratesofsystem

EnergyconsumptionTx duration– Rxschedulingandduration

TopologyStar– Mesh– PointtoPoint

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THECONTENDERS

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SIGFOX

Radio implementing patented technology

(< 5EUR)

E.g. TI, Silicon Labs, Atmel

SigFox ReadyTM

device with subscription

Class 0, 1, 2 or 3(0 = best RF performance)

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SIGFOX – COVERAGETODAY

Source: www.sigfox.com/coverage

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SIGFOX – TECHNICALINFORMATION

• 868 MHz (EU)• Max radiated power: 14dBm• Max Duty Cycle allowed: 1%• Modulation: DBPSK @ 100bps using 100Hz channel in

200kHz band• Max. 140 msg/day of 12 bytes payload

(→ 2s TX time!) to meet duty cycle• TX: msg is sent 3 times at diff. pseudo-random freq. to

ensure delivery (no collision avoidance or recovery)• RX: every BS listens to 200kHz band• Private key per device + hash for auth.

UPLINK(DEVICE→BS)

• 869 MHz band (EU)• Max radiated power: 27dBM• Max duty cycle: 10%• Modulation: GFSK @ 600bps using 600Hz channel• Max. 4 msg/day/device of 8 bytes• High sensitivity of BS (-142dBm)• TX

• Timing initiated by device• Base station adapts to frequency

(+offset) of node

DOWNLINK(BS→DEVICE)

• Based on ETSI Low Throughput Network (LTN) + patented features• Ultra Narrow Band (UNB)

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SIGFOX – UPLINKSCALABILITY

MESSAGE TRANSMISSION / DEVICE• Total msg size (12B payload) = 26B• TX time for 1 msg @ 100bps = 2.08s• TX time for 3 transmissions (with

45ms TX offset) = 6.33s• 10msg/day = 63.33s air

time/device/day

DEVICE → BS (no collisions, i.e. theory)

TOTAL AVAILABLE AIR TIME / DAY / BS• 200 channels of 100Hz (within 200kHz)

→ 17.280.000s air time

MAX. DEVICES / BS = 272.856# Unique msgs / 60s = +/- 1895

assuming perfect collision-free system

Source: SigFox

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SIGFOX – UPLINKSCALABILITY

DEVICE → BS (collisions) - Simulation

Source: Maarten Weyn (mweyn.wesdec.be)

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1. LoRa =PHY1. Novelradiomodulation patentedbySemtech,basedonChirpSpreadSpectrum(CSS),with

veryhighsensitivity

2. LoRaWAN =communicationprotocol (MAC)andsystemarchitectureforthenetwork1. Open,definedbyLoRa Alliance

Technology Rx sensitivity Datarates

Wi-Fi -84dBm <54Mbps

BLE -90dBm <1Mbps

-109dBm <80Kbps

LoRa -138dBm 300bps– 10KbpsSource: i2CAT

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Freq.(MHz)/BW Conditions(Pwr/DC)

OrthogonalSpreading factors

868.10(g1)/125kHz

14dBm@1%

7-12

868.30(g1)/125kHz 7-12

868.50 (g1)/125kHz 7-12

LORA - SPECTRUMUSAGEANDDATARATESSUB-GHZ BAND: ETSI ERC 70-03 (EU)

Sub-band Freq.Range (MHz) Conditions (Pwr/DC)

g 863- 868 14 dBm@1%or LBT+AFA

g1 868–868.6 14dBm@1%or LBT+AFA

g2 868.7–869.2 14dBm@0.1%or LBT+AFA

g3 869.4–869.65 27dBm@10%or LBT+AFA

g4 869.7- 870 14dBm@1%or LBT+AFA SpreadingFactor(SF)

BitRate

SF=12 250 bps

SF=11 440bps

SF=10 980bps

SF=9 1.7Kbps

SF=8 3.1Kbps

SF=7 5.4Kbps

Range

LBT+AFA = Listen Before Talk with Adaptive Frequency Agility

LoRaWAN default channels

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Europe North America

Frequencyband 867-869MHz 902-928MHz

Channels 8+1+1 64+8+8

ChannelBWUp 125/250kHz 125/500kHz

ChannelBWDown 125kHz 500kHz

TXPowerUp +14dBm +20dBmtyp.(+30dBm allowed)

Tx PowerDown +14dBm +27dBm

SFUp 7-12 7-10

Datarate 250bps–50kbps 980bps-21.9kbps

Linkbudgetup 155dB 154dB

Linkbudget down 155dB 157dB

LORA - SPECTRUMUSAGEANDDATARATESEU VS NORTH AMERICA

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LORA - DATARATEVERSUSRANGERANGE VERSUS SPREADING FACTOR

Source: ActilitySF7--SF8--SF9--

SF10--SF11--SF12--

SF7--SF8--SF9--

SF10--SF11--SF12--

SF7--SF8--SF9--

SF10--SF11--SF12--

0s 1s 2s 3s 4s

Chan

nel1

Chan

nel2

Chan

nel3

Time

Air time

Source: i2CAT

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LORAWAN – THEORETICALTHROUGHPUTNODE

Back of envelope calculations for max data throughput per hour:

SF Data rate [b/s]

Max. #b/h

Max. data length [B]

Max. Pt Size [B]

Min. Over-head

Max #Pt/h

Max data/h [B/h]

Max TX energy [J]

12 250 9000 51 80 36.2% 14 714 3.5

11 440 15840 51 80 23.8% 24 1224 3.4

10 980 35280 51 80 23.8% 55 2805 3.5

9 1760 63360 115 144 20% 55 6325 3.5

8 3125 112500 222 251 12% 56 12432 3.5

7 5470 196920 222 251 12% 98 21756 3.5

20B PHY header9B MAC header

868MHz: 1% RDC

14dBm TX power29.6 mA supply current

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LORAWAN – SCALABILITY

COLLISIONS - SIMULATION ALOHAALOHA CHANNEL ACCESS

ASSUMPTION• If you have data, send it• If another station transmits, then

collision

THEORETICAL PERFORMANCE OF ALOHA SYSTEM

With air utilisation lower than 18%, 97% of transmissions are likely to

succeed!

Air utilization can be reduced by using lower SF, i.e. most nodes in

vicinity of BS or more BSs!Source: Maarten Weyn (mweyn.wesdec.be)

No collision avoidance mechanism

RandomlychosenSF

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§ WirelessSensorandActuatorNetworkProtocol (WSAN)§ OriginatesfromISO18000-7(“dash7”)

§ describes theparameters foractiveairinterface communications at433MHz(2008- 2009)

§ Extended tosupportIoTfunctionalities§ Nowsupportallsub-GHzISM/SRDbands§ Starortreenetworktopology (nomesh)§ v1.1ofthespecpublishedinQ12017.§ ActivemembersoftheProtocolActionGroup:

Wizzilab,UniversityofAntwerp,WroclawTechnicalUniversityandCORTUS

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OPENSTANDARD OFULTRALOWPOWERMID-RANGESENSORANDACTUATORCOMMUNICATION

OpenStandard

VeryLow

Power

StructuredData

Low cost

Security

Mid/LongRange

Fullstack

NETWORKTOPOLOGY

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Distance– Complexity– Energy– Latency

Tree MeshStar

PassiveRFIDTagscanonlybereadintheintermediateproximityofareader

ActiveRFIDLongerrangeinterrogators–Master/Slave

DASH7Simplerouting(2hops)subcontrollers arepowerbutonlyfewareneededTag-to-Tag&Tag-Talk-First

MeshRangedependsonnumberofrouternodes

Congestion– RoutingComplexity–LatencyRoutersneedtobepoweredEachhopconsumesenergy

FULLSTACKSPECIFICATION

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APP

PRES

SESS

TRAN

NETW

DLLMAC

PHY

ALP

FileNotif.

SessionStack

D7AQP

D7AAdvp D7ANP

SCAN

BG FGCSMA-CA SUBNET

PN9 (G)FSK CCA Sub-GHz433-866-915 9.6/55/200 kbps

ScanSeries

ChannelCfg

ChannelQueue

Auth.Security

CryptoTables

FileEncrypt.

NWLSecurity

AES128

APPLICATIONLAYERPROTOCOL

Structureddata§ Everythingisafile(sensor values,

systemconfiguration,encryptionkeys...)

§ Anyapplicationaction,dataexchangemethodorprotocolismappedexclusively ontomanipulationofStructuredDataElements(D7AFiles) andtheirproperties.

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EVERYTHINGISAFILE

ALPALP is a generic API for manipulating D7A files. The interface can be D7A, but also UART, BTLEALP commands are composed of ALP ActionsActions can be read, write, create, delete, execute, condition (query), grant permission, etc...Local or OTA

QUERIES+ACTIONS+D7A

=

DISTRIBUTEDDATABASE

CommunicationModel

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PullToobtaintagsensordataTosetactuatordata

Unsollicited– TagTalkFirstForalarmsandperiodicdata

• PollingdatausingD7APAdvertisingProtocol• PushingdatausingD7APActionProtocol• Dormantsessions (waitforthetagtotalkfirst)

COMMUNICATIONSCHEMES

• Advertisementprotocol• Gatewayqueriesendpoints• Lowpowerwake—up

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D7AADVP

COMMUNICATIONSCHEMES

• Actionprotocol• Notification/tag-talks-first• ALPcommandpreregisteredonendnodes• Filesystem canbeconfigured toactivateALPcommandupon fileaccess

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D7AACTP

COMMUNICATIONSCHEMES

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D7AACTP – APPLICATIONEXAMPLE

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HumidityNotification

Sendamessageto0x23BEwiththehumidityandthebatterylevelwhenthehumiditychanges.

BatteryAlarm

Broadcastbatteryalarmwhenbatterybelow20%andsendalllatestsensorvalues.

SensoronPresence

Whenthepresenceisdetectionfromamobiledeviceandtemperatureisbelow21°C, send‘on’commandtolocalheating.

COMMUNICATIONSCHEMES

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D7AACTP- IMPLEMENTATIONINAPPLICATIONFIRMWARE

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HumidityNotification

MeasurehumidityatxsecintervalandwritevaluetofilewithID0x34

BatteryAlarm

MeasurebatteryatxsecintervalandwritevaluetofilewithID0x25

SensoronPresence

MeasuretemperatureatxsecintervalandwritevaluetofilewithID0x33

COMMUNICATIONSCHEMES

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D7AACTP- CONFIGURATIONOFFILESYSTEM

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HumidityNotification

Configurenotificationheader forfile0x34andsetquerytoconditiondifferentfrompreviousvalue.Set0X23BEand0x34innotificationfile.

BatteryAlarm

Configurenotificationheader forfile0x25andsetquerytocondition<20.Set0x25,0x34and0x33 innotificationfile.

SensoronPresence

Configurenotificationon file0x19(localisationfile)andset0x33 ininthenotificationfile.

COMMUNICATIONSCHEMES

D7AActPIdealforperiodic sensordatatransmissionorsensortriggered

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TRADE-OFFS

D7AAdvPIdealforad-hocdatagathering,notforperiodicorsensortriggered.

Tradeoffbetweenenergyconsumptionandlatency

• Dormantsessions• Usecasespecific,combinationspossible• Networkbehaviorover-the-airupdatable

CONTEXTAWARESENSORANDACTUATORDATAPROPAGATION

Writeandreadfromfiles

Configuresystemthroughconfigurationfiles

Configuredthrough filesystem

Handlesscheduledscancycles

Handlesqueriesfromotherdevices

Handlesqueriesandnotificationson filechanges

Filesystemconfigurableovertheair

THEMATCH

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FREQUENCY

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DATARATEó RX/TXDURATIONVSRANGE

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100bps -156dBm 12 bytes payload 6 seconds

250bps -10kbps

-155dBm max payload 50 bytes 50 ms – 2 seconds

9.6 kbps55 kbps166 kbps

-105dBm max payload 256 bytes 10 ms

RX SCHEDULING

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RX_DELAY_1

RX_DELAY_2

TX RX1 RX2

RECEIVER INITIATED TRANSMISSION

TX RX

ASYNCHRONOUS WITH LOCAL SYNCHRONIZATION

SCHEDULED_PERIOD

TX RX RX RX

SCHEDULED_PERIOD

COORDINATOR SAMPLED LISTENING USING BEACONS

TXTX RX RX

PERMANENT RX

WIRELESSTRADE-OFFSAPPLIEDTOLPWAN

$$$ Today– nolicensedLPWANsolutiondeployedyet

Lowerfrequencybands(withlessbandwidth)

Simplecoding,i.e.lowerdatarates(→lowcomplexity,lowcost)

Limit‘radioontime’(sleep,lowdatausage,downlinkafteruplink)

Predominantlystartopologies(lowinstallation&maintenancecost)

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WHEN ONERFTECHNOLOGYISNOTENOUGH

LPWANCOMPETITION BETWEEN STANDARDS?

Yes, but room for multiple LPWAN technologies!

Device and connectivity

requirements

Source: Ericsson

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Source: Actility

LPWAN- USECASESUSE CASES INVOLVINGLOW DATA RATE, BATTERY-OPERATED DEVICES, LOW SENSOR DENSITY

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LPWANFORECAST> 2.5 BILLION LPWAN CONNECTIONS BY END OF 2024*

*CAVEAT: Many other numbers circulateSource: Machina Research

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WHEREDASH7MEETSLPWAN

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LPWANOPEX

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Theytellyou or devicesareCHEAP!

NoneofthesetechnologiesallowstoupgradefirmwareovertheairWhatif:

- asecuritybreachisfound- SigFox goesbankrupt- Anewbuildingmasksthenearestantennaandyouloosecoverage- Youfindanalgorithmtoreducepowerandgain1yearofbatterylife

MostofthesedeviceswillbedeployedforYEARS!

SECURETHEFUTURE

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or hardwareiscompatiblewith

AddaDASH7stackandUpgradeFirmwareOverTheAirto• SwitchConnectivity• Re-ConfigureDevicesRemotely• Applysecuritypatches• SwitchbetweenPublicandPrivateNetwork

AvoidcostlyMaintenance

WHENACTIVERFIDMEETSPASSIVERFID

APPLICATIONLAYERPROTOCOL(ALP)

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ALPALP is a generic API for manipulating D7A files. The interface can be D7A, but also UART, BTLEALP commands are composed of ALP ActionsActions can be read, write, create, delete, execute, condition (query), grant permission, etc...Local or OTA

Structureddata§ Everythingisafile(sensor values,

systemconfiguration,encryptionkeys...)

§ Anyapplicationaction,dataexchangemethodorprotocolismappedexclusively ontomanipulationofStructuredDataElements(D7AFiles) andtheirproperties.

Everything isafile

PROVISIONING,DEPLOYMENT,OPERATION

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Longrangeisgreatbutsometimesyouwantto:- Knowwhichdeviceisinyourhand- Triggersomethingonthedeviceinfrontofyou- Distributekeyswithout beingoverheard

ALP over

UHFGEN-2

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UHFEPCGEN-2

DASH7

Sigfox

0.5-10m

1– 30km

10– 2000m

100bps

10– 166kbps

40– 600kbps

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HOWTOCHOOSETHERIGHTPROTOCOL?

• Coverage?• Local• National• Worldwide

• Time to market?• Outdoor, indoor,

deep indoor?• Security?• Business model?• Scalability/capacity?

• Vendor lock-in?

• Minimum viable lifetime?

• Device size and antenna design?

• Firmware updates needed (OTA)?

• Module or embedded chipset?

• Static or mobile device?

• Addressing?

• What is the size of data to send?

• What is the periodicity of transmissions?

• How critical is the data (reliability)?

• Downlink versus uplink communication?

Your application Your device Your dataSome questions to ask

PUBLIC

OpenStandard

VeryLowPower

SecurityPrivacy

LargeNumberOfNodes

LowBitrate

LowCost

LongRange