LoraWAN Technology Luka Mustafa, Institute IRNAS, November 2018 - - PowerPoint PPT Presentation

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LoraWAN Technology Luka Mustafa, Institute IRNAS, November 2018 - - PowerPoint PPT Presentation

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LoraWAN Technology Luka Mustafa, Institute IRNAS, November 2018 IRNAS.EU CC BY-SA 4.0 LoRa LoRaWan IRNAS.EU CC BY-SA 4.0 What is LoRa ? Wireles eless s modulat lation ion Radio physical layer Low bandwidth & energy

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Luka Mustafa, Institute IRNAS, November 2018

LoraWAN Technology

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LoRa ≠ LoRaWan

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What is LoRa ?

 Wireles

eless s modulat lation ion

 Radio physical layer  Low bandwidth & energy  Uses ISM bands  Great link budget (> 150 dB)

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LoraWAN network

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What is LoRaWan ?

 Communi

municat cation ion protocol tocol built above LoRa modulation

 Data rate from 300 bps to 5.5 kbps (up to 50kbps using FSK)  Features :

Bi-directional communication

 Mobility 

Localization

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LoRa(Wan)

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History

 2007 : Nanoscale-Labs  2009 : Cycleo  2012 : Semtech  2015 : LoRa Alliance

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Radio Basics

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Radio Keying : OOK

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Radio Keying : FSK

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Radio Keying : PSK

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Spread Spectrum

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Chirp Spread Spectrum

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Chirp Spread Spectrum

 Chirp frequency :

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LoRa

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Chirp Spread Spectrum in LoRa

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Chirp Spread Spectrum in LoRa

 Phase shiftings

= where the data is

~ PSK over chirp

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LoRa demodulation

x =

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LoRa demodulation, with noise

x =

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LoRa Modulation

 Spread-spectrum technique and a variation of chirp spread

spectrum (CSS)

 LoRa uses Spreading Factors to set the modulation rate (SF7 to

SF12)

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LoRa Spreading Factors

SF7 SF8 SF9 ...

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LoRa Spreading Factors

Spreading Factor Symbols/second Bitrate TOA (10 bytes, ms) SNR limit (dB) SF 7 976 5469 56

  • 7,5

SF 8 488 3125 103

  • 10

SF 9 244 1758 205

  • 12,5

SF 10 122 977 371

  • 15

SF 11 61 537 741

  • 17,5

SF 12 30 293 1483

  • 20
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Benefits of the Modulation

 Very resistant to interferences  Very low sensibility to fading & multipath  Good sensitivity (below noise level)  Doppler effect resistant

Moving devices

High clock tolerance

 LoRa reception is super simple

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LoRaWan

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LoRaWan protocol : Device class

 Class A

Emit on request, listen only after emit → ultra-low energy

 Class B

Emit on request, listen based on time interval → low energy

 Class C

Emit on request, always listen → « high » energy

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LoRaWan Network Architecture

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LoRaWan protocol : authentication

 ABP :

  • Dev addr
  • AppSKey
  • NwkSKey

 OTAA :

  • DevEUI
  • AppEUI
  • AppKey
  • AppSKey and NwkSKey

derivated from AppKey & Network response

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LoRaWan Network Encryption

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LoRaWan protocol

preamble phdr phdr_crc phy PL crc mhdr mac PL mic fhdr fport frm PL dev addr fctrl fcnt fopts mtype rfu major Can contains MAC commands

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LoRaWan protocol : MAC commands

 LinkCheckReq, LinkCheckAns = connectivity check  LinkADRReq, LinkADRAns = change emit settings like SF  DutyCycleReq, DutyCycleAns = update device DC  RXParamSetupReq, RXParamSetupAns = change RX window  DevStatusReq, DevStatusAns = get dev. status like battery  NewChannelReq, NewChannelAns= channel upadte  RXTimingSetupReq, RXTimingSetupAns = change RX window

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LoRaWan Network : Devices

 Joining the network (if OTAA)  Converting your payload as a LoRaWan packet  Sending the packet  Listening for downlink packets  Converting the packet back to payload

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LoRaWan Network : Gateways

 Receiving radio packets  Checking CRC (message integrity, only for uplink)  Forwarding to network server  Listening for downlink messages to forward to devices

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LoRaWan Network : Network Server

 Dealing with join requests  Dealing with devices addresses  Choosing time and gateways to use for downlink  En/Decrypting MAC payload

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LoRaWan Network : App. Server

 Receiving packets from devices  Scheduling responses to devices  En/Decrypting FRM Payload (the real payload)  In fact, do something with the data...

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LoRaWan Network : Localisation

 Triangulation

Accuracy (3gw) :

→ ~ 180 m in crowded area

→ ~ 350 m in clear area

 Accuracy (4gw)

→ ~ 95 m in crowded area

→ ~ 210 m in clear area From semtech

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LoRaWan Network : Localisation

 Triangulation  Big-Data

Accuracy (3gw) :

→ ~ 35 m in crowded area

→ ~ 220 m in clear area

Accuracy (4gw)

→ ~ 22 m in crowded area

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LoRaWan protocol : Duty Cycle

 The more messages on the same frequency & SF = the higher

collision probability

 We want reliable transmission  We want a lot of devices per gateway (>1000)  → we need the keep the collision probability low enough !  →

Typically, < 10 % or even < 5 %

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LoRaWan protocol : Duty Cycle

 A gateway listen on 8 frequencies and all SF  We want > 1000 devices / gateway  We want < 10% of duty cycle  →

30 seconds / day / devices gives a DC < 5%

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LoRaWan protocol : Duty Cycle

 Fair-use TTN policy: max. 30 seconds/device/day  For a 10-bytes PL we have max:

20 messages/day at SF12

500 messages/day at SF7

 Much more using SF7-250 or FSK modulation (lower range & higher energy)

 Downlink is limited to < 10 messages/device/day

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LoRaWan protocol : ADR

Spreading Factor SNR limit (dB) SF 7

  • 7,5

SF 8

  • 10

SF 9

  • 12,5

SF 10

  • 15

SF 11

  • 17,5

SF 12

  • 20

 Reception of a packet on  SF12 with SNR = -7,5dB  Check the best SF with a  margin of 5dB  Send MAC command to request  SF9 on the device

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Luka Mustafa, Institute IRNAS, November 2018

TheThingsNetwork LoraWAN

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The Things Network : Principles

 Standards compliant  Compliant with spectrum regulations  Open source  Designed for distribution and decentralization  One global, free and open network

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The Things Network : History

 Jul. ‘15 : Announce of The Things Network  Sept. ‘15 : First gateways installed in Amsterdam

→ Croft environment started

 Oct. ‘15 : KickStarter campaign started  Nov. ‘15 : KickStarter end with > 2x funding!  Mar. ‘16: Staging environment setup

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The Things Network : Numbers

 > 30,000 members  > 5,000 gateways  > 200 communities  > 55 countries  ... and counting !

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The Things Network : Architecture

R

Router Routes raw packets from gateways to brokers

NC

Network Controller Node state: data rate and frequency management

H

Application Handler Decryption, deduping, works on behalf of apps A Application User application Gateway Send data to and receive data from nodes

B

Broker Decoupling from Router and Application Handler

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The Things Network : Architecture

H

S1, S2 S2, S1, S3 S2, S1, S3 S3, S2

B R A

NC

Private Network

B R

NC

H B R

NC

H H H

NR

A A

Private Storage Handler

A

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The Things Network : Gateways

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The Things Network : Coverage

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The Things Network : Coverage

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The Things Network : Coverage

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352 KM 160 KM

LoRaWan : Performance

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160 PARTICIPANTS 74 ORGANIZATIONS 11 COUNTRIES

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Network in Maribor

  • Gateways on Pohorje and Urban
  • Gateways in the city center
  • Test network with Kerlink

supporting geolocation

  • Good coverage of the city center

+ wide area from Pohorje, up to 100km range, fields of Dravsko polje and much more

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TTN mapper

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Sources

 Thomas Telkamp - LoRa crash course – 10 Nov. ‘16  Matt Knight - Decoding LoRa – 05 Oct. ‘16  Johan Stokking – The Things Network – Jul. ‘15  TTNMapper.org – Nov. ’16  Romain Cambier - @r_cambier – shareif – Oct18  Luka Mali – LTFE – Oct18  Infiswift Solutions – Oct18