This document provides an overview of LoRaWAN technology. It discusses the benefits of LoRa including long range, low power consumption and bandwidth. It describes the key components of LoRaWAN including the physical layer, data link layer, and device classes. Common LoRaWAN topologies involving devices, gateways and network servers are shown. The document also introduces The Things Network, an open source initiative to build a decentralized IoT network, and provides guidance on developing IoT devices and gateways using Arm Mbed OS.

1. © 2018 Arm Limited
Jan Jongboom, Arm
14 March 2018
IoT Deep Dive:
LoRaWAN

2. © 2018 Arm Limited 2

3. © 2018 Arm Limited 3
The case for LoRa
Powerconsumption/Bandwidth
Range

4. © 2018 Arm Limited 4
LoRa key use cases

5. © 2018 Arm Limited
LoRa PHYsics
crash-course
© 2017 Arm Limited

6. © 2018 Arm Limited 6
High link budget
TX
P (dBm)
RX
Derived from work by Thomas Telkamp
TX Power
Connector loss
Antenna gain
Connector loss
Antenna gain
RX Power
Path loss and fading
14
0
-100
Receiver sensitivity
-137 dBm
14 dBm151 dBm link budget

7. © 2018 Arm Limited 7
Link budget
Wi-Fi
Sub-GHz 6LoWPAN
LoRa
TX Power RX Sensitivity Link budget
20 dBm -75 dBm 95 dBm
11 dBm -110 dBm 121 dBm
14 dBm -137 dBm 151 dBm

8. © 2018 Arm Limited 8
Theoretical maximum in free space
2.4 GHz, with 95.5 dBm link budget:
550 meters
915 MHz, with 151 dBm link budget:
850,000 meters

9. © 2018 Arm Limited 9

10. © 2018 Arm Limited 10
Unfortunately... we don't live in free space
Attenuation Reflection and diffraction Fresnel zone

11. © 2018 Arm Limited
Based on Tokyo - model for calculating realistic path loss
Picture by Moyan Brenn: https://commons.wikimedia.org/wiki/File:Tokyo_(16043023330).jpg© 2017 Arm Limited
Hata model
Large city (250 bps)
Large city (1,760 bps)
Suburb (250 bps)
TX height RX height Range
0.1 m 40 m 4 km
0.1 m 40 m 2.5 km
0.1 m 40 m 9 km
Suburb (250 bps) 1 m 100 m 13 km

12. © 2018 Arm Limited
https://www.youtube.com/watch?v=dxYY097QNs0

13. © 2018 Arm Limited
What is LoRaWAN?

14. © 2018 Arm Limited 14
LoRaWAN
LoRaWAN is a standardized, bi-directional messaging protocol on top of LoRa modulation; the
physical layer
In the data link layer, LoRaWAN manages channels, data
rates and executes MAC commands
LoRaWAN messages contain device addresses and the server
selects gateways for downlink in the network layer
The server and device keep track of frame counters and
perform a message integrity check in the transport layer
LoRaWAN’s over the air activation (OTAA) manages the
creation of a new session with security context
LoRaWAN encrypts application payload but does not prescribe
a binary payload format to use

15. © 2018 Arm Limited 15
Device classes
Flexibility in power conservation versus fast network initiated transmission
Class A 😴 Class B ⏰ Class C ⚡
Device initiated communication
Devices are typically in deep
sleep and send messages on
intervals and/or events
Only after uplink transmission,
there is a receive window for
downlink messages
Best for most sensor
applications and battery
conservation
Time synchronized
communication
The network broadcasts beacons
for devices to sync time
In so-called ping slots, devices
wake up and the network may
send downlink messages
Best for most downlink intensive
applications
Network initiated
communication
The devices are continuously
listening, often temporarily or
on power supply
The network can send downlink
message at any given time
Best for downlink intensive
applications that require low
latencies

16. © 2018 Arm Limited 16
Typical LoRaWAN Topology
Network Session Key: Message Integrity
Applicadon Session Key: Join, Encrypdon and Decrypdon
Devices Gateways Network Server User
ApplicaRon
ApplicaRon
Server

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18. © 2018 Arm Limited
The Things Network

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The Things Network Mission
Our mission
is to build
a decentralized,
open and
crowd sourced
IoT data network
Owned and operated by its users

20. © 2017 Arm Limited

21. © 2018 Arm Limited 21 © 2017 Arm Limited
Number of Communities 623
Number of Countries 96
Number of Community Members 33633
Number of Gateways Active 3075
Number of Community Partners 492
The Things Network

22. © 2018 Arm Limited 22
You are the network

23. © 2018 Arm Limited
Building something

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An IoT device is more than an MCU + radio
Bootloader
Asymmetric crypto
Storage driver
Resilient filesystem
Advanced
LoRaWAN stack
Radio drivers
FlashIAP
Update client

25. © 2018 Arm Limited 25
Arm Mbed
A free, open source Platform OS targeting IoT end node devices
Mbed
OS
Cortex-M
RTOS
kernel
Portable
drivers
Integrated
security
IoT
connectivity
Device
management
Development
tools
Developer
community
Partner
ecosystem
150 development boards
LoRa, BLE, Cellular, Wi-Fi, etc.

26. © 2018 Arm Limited
Mbed OS tools
26
mbed.org/code
Mbed CLI
Command Line
Interface Mbed pyOCD
CMSIS-DAP Debug Library
Mbed DAPLink
CMSIS-DAP Debug Firmware
Mbed Greentea
Porting Testsuite and CI
Mbed Compiler
Free Online IDE
Mbed OS DVCS support
Mbed OS IDEs and toolchains
Mbed OS core tools
Arm Compiler 5
Online Compiler to get started quickly
Wide support for offline toolchains

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Two approaches
Module Radio
Radio + MCU
Easy to integrate in own design
Pre-certified
SX1272 or SX1276
Cheaper material / higher design cost
Need to do own RF design

28. © 2018 Arm Limited 28
Picking a gateway
Kerlink IoT station
Multi-Tech Conduit
IMST iC880A
Lorix One
The Things Gateway
Lorrier LR2
SX1301 + 2x SX1257

29. © 2018 Arm Limited 29
Hands-on, building a network
L-TEK FF1705 Multi-Tech Conduit Network Server

32. © 2018 Arm Limited
http://mbed.com/fota-lora

33. © 2018 Arm Limited
http://bit.ly/deep-dive-lora

34. Thank You!
Danke!
Merci!
谢谢!
ありがとう!
Gracias!
Kiitos!
감사합니다
धन्यवाद
© 2018 Arm Limited
https://github.com/johanstokking/arm-ttn-webinar
https://os.mbed.com/teams/MultiTech/code/Dot-Examples/
http://bit.ly/lora-update-demo
http://slideshare.net/janjongboom/

35. © 2018 Arm Limited
The Arm trademarks featured in this presentation are registered trademarks or
trademarks of Arm Limited (or its subsidiaries) in the US and/or elsewhere. All rights
reserved. All other marks featured may be trademarks of their respective owners.
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