Webinar about the new LoRaWAN stack in Mbed OS 5.8, co-hosted with Etteplan. Recording: https://pages.arm.com/build-with-mbed-explore-LoRa-using-mbed.html

1. Build with Mbed –
Exploring LoRa using Mbed

2. Your hosts
Marko Hietala
Project Manager, Etteplan IoT
Marko.Hietala@etteplan.com
Jan Jongboom
Developer Evangelist IoT, Arm
Jan.Jongboom@arm.com

3. Agenda
1. Wait, what, LoRa?
2. Mbed OS LoRaWAN stack overview
3. Facts and figures
4. Demonstration
5. Q&A

4. The case for LoRaWAN
Powerconsumption/Bandwidth
Range

5. LoRa key use cases

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

8. 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
140 development boards
LoRa, BLE, Cellular, Wi-Fi, etc.

9. Investment in LoRa
- Arm invested early and has excellent support for LoRa in Mbed
- 7 LoRa hardware devices already in platform/component database
- Mbed LoRa examples imported 1000's times
- Increasing investment in LoRa with interested partners
- Aiming to be #1 LoRa development platform
- Mbed OS 5.8: LoraWAN native support, APIs, examples and
showcase demos
- 2018: Services support, widespread deployment of low cost Mbed
Enabled modules
- Low-cost modules, support for operator "starter kits", events and
demos
- Firmware updates over the air

10. http://mbed.com/fota-lora
http://mbed.com/fota-lora

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

12. Etteplan
• For industrial design engineering services, embedded systems and IoT
services and technical documentation.
• Established in 1983.
• In 2017, Etteplan had a turnover of some EUR 215 million.
• The company employs over 2,800 experts in Finland, Sweden, the
Netherlands, Germany, Poland and China.
• Currently 600 engineers in IoT projects.
• Etteplan provides e.g.:
• Complete product design (hardware, firmware and applications, mechanics, testing).
• Software design (Firmware, protocol stacks, backend, cloud, mobile app design)
• Test services, like LoRaWAN certification, accredited EMC and RF testing, environmental testing.
More information on www.etteplaniot.com

13. LoRaWAN architecture

14. LoRa in Mbed
LoRa stack
Lora radio

15. LoRa in Mbed – Overall SW architecture
3rd party Application
Mbed OS
LoRaStack
• Semtech LoRaMac
implementation
RADIO API
Radio adaptation
nn
LoRa Radio nn
Application API
Radio adaptation
for SX1272
LoRa Radio 1272

16. LoRa in Mbed - Some examples of Application APIs
• Initialize() – Initialize LoRa stack.
• add_app_callbacks() - Add application callbacks to the stack to handle
LoRaWAN events.
• connect() – creates a LoRa connection for application
• set_datarate() - Sets up a fixed data rate for application.
• enable_adaptive_datarate() – ADR
• send() - Sends LoRa message to gateway.
• receive() – Copies received message from stack to application buffer based on
specific port.

18. LoRa in Mbed – Example stack events visible to application
Initialize()
Connect() Join_failure
Connected
Function call from app
Event from stack
send()
Tx_doneRx_done
Receive()
Tx_timeout
Tx_error
Tx_crypto_error
Tx_scheduling_error

19. LoRa in Mbed – Stack key figures
• Performance
• Data throughput: depending on used frequency band, stack restricts air traffic according to duty cycle regulations
• For example 868MHz, sub band 0, duty cycle is 1%.
• Power consumptions
• Measured on Multi-Tech mDot running Mbed OS 5.8 RC1, compiled with GCC ARM 6.
• Average power consumption in idle-state is 0,59 mA.
• Average power consumption in send-state and/or receive-state is 15,0-18,0 mA.
• Future commitments
• New radio drivers for LoRaWAN.
• Stack updates according to LoRaWAN 1.1 specification.
• Firmware updates over LoRaWAN.

20. LoRaWAN Stack configurations on Mbed OS 5.8 RC1
Measured on Multi-Tech xDot
Compiled with GCC ARM 6
• Default build (develop profile):
• ROM: 117K
• Static RAM: 15.4K
• Dynamic RAM: 3.3K
• Fully optimized (release profile, newlib-nano, no RTOS, custom printf):
• ROM: 72.3K
• Static RAM: 6.3K
• Dynamic RAM: 0.8K

21. Demo Setup

22. LoRaWAN Demo Setup
Temperature-
sensor
LORAWAN gateway/server
LORA dashboard
LORAWAN Node 1
Server

23. Demo setup
Guide videos are availabe @ youtube:
Configuring Conduit first time:
https://youtu.be/u8jZ6zVMEQ0
Lora HW setup and example application on mbed:
https://youtu.be/vA5AtjZaM3Q

28. HW Setup

29. Demo setup – Setting up Lora modules
USB cable
Antenna
mDot

30. Demo setup – Setting up Lora modules
+5V
GND
Dig
DS1820

31. Building an LoRa application

32. Mbed compiler environment
Offline option:
• Install offline environment according to mbed instructions
• https://os.mbed.com/docs/v5.7/tutorials/quickstart-offline.html
Online option:
• Log in to Mbed online compiler.
• Import LoRaWAN example application by typing LoRaWAN example to
search field. Temperature example app will be added after webinar.

33. Demo setup – LoRa Mbed example software
Core parts of application
• Define variables.
• Create and initialize radio instance with correct IO-pins.
• Create initialize LoRaWAN interface
• Create state machine and event handler function for stack events.
• Set keys and connection type.
• Initialize and connect your LoRaWAN node.

34. mbed_app.json

35. Demo setup – LoRa Mbed example software
• After doing necessary changes, build the project.
• Flash mDot by drag and drop the compiled binary from compiler to Mbed
drive and press reset button of MTUDK2-st.
• Now we should have proper application up and running in our Mbed
board.

37. Tips and tricks
- Device battery life can be extended by using Mbed deep sleep
functionality.
- Mbed will go to deep sleep mode, if main thread is put to wait state.
- Deep sleep is very target specific, make sure no peripheral or timer is blocking sleep.
- Datarate affects to distance/coverage.
- If device is not moving, ADR usage is recommended.
- If device is constantly moving, disable ADR and use fixed datarate.
- Remember duty cycle limitations
- Keep packet sizes small and send packets with long interval to avoid unexpected delays.
- Different bands have different duty cycle limitations

38. Recap
• LoRaWAN is great
• Increased complexity calls for a platform OS
• Mbed OS 5.8 is a great first step, and many more will follow

39. Thank you!
Questions?

40. Engineering with a difference