Overview of the Mbed OS LoRaWAN stack, as presented during the LoRa Alliance AMM in Tokyo.

1. The Mbed LoRaWAN stack
- a case study
Jan Jongboom
Principal Developer Evangelist, Arm

2. !2Who am I
Jan Jongboom
Principal Developer Evangelist, Arm
Doing LoRaWAN for the last 4 years
Arm
Semi-conductor company
21 billion processors sold last year
LoRa Alliance Contributor member

3. !3Back in 2015...
Just a sensor, radio and battery
Static session keys (forced ABP)
That's it...

4. !4LoRaWAN is evolving
New security principles
(join servers, root keys)
Firmware Updates
nearing standardization
Device Management
ongoing work
https://www.geograph.org.uk/photo/5266523

5. !4LoRaWAN is evolving
New security principles
(join servers, root keys)
Firmware Updates
nearing standardization
Device Management
ongoing work
Complexity
https://www.geograph.org.uk/photo/5266523

6. !5Parts required in an IoT device
Bootloader
Asymmetric crypto
Storage driver
Resilient filesystem
Advanced
networking stack
Radio drivers
FlashIAP
Update client

7. !5Parts required in an IoT device
Bootloader
Asymmetric crypto
Storage driver
Resilient filesystem
Advanced
networking stack
Radio drivers
FlashIAP
Update client

8. !6
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
LoRaWAN, BLE, Cellular, Wi-Fi, etc.

9. !7
• Go to market with a secure product faster
• Smaller footprint, and less complex
• Modular, readily available open source stack
• Easy to port
• And... LoRaWAN is popular on Mbed!
Mbed LoRaWAN stack - Why?

10. !8Mbed LoRaWAN stack - What?
* in branch
LoRaWAN versions
1.0.2, 1.0.3*, 1.1*
Class support
A & C
Radios supported
SX1272, SX1276, SX1262*
Features
Firmware updates*
RX/TX/Backoff metadata
Automatic uplink
Channel plans
Highly configurable

11. !9Mbed LoRaWAN stack - Numbers
RAM ROM
Typical microcontroller: 32K RAM / 256K Flash
Stack is fully tuneable
Minimum configuration (includes everything):
6K of RAM, 65K of ROM
Optional: offload crypto to external module
* Measured on NUCLEO-F411RE with SX1276

12. !10Mbed LoRaWAN stack - Crypto
TLS
In software With external crypto engine

13. !11Mbed LoRaWAN stack - Testing
Certification tests
http://www.redwoodcomm.com/product/01.php
Simulator
70+ functional tests,
verified against real network
Unit tests

14. !12
1. Data rate 0
2. Uncalibrated crystals
3. Limiting pre-amble sequence symbols
4. Don't rely on the SYNC word
5. Network operators doing non-standard LoRaWAN
Hard stuff

15. !13
Crucial for long-term deployments
Multicast + data fragmentation specs are now standardized
Update client based on IETF SUIT (https://datatracker.ietf.org/wg/suit/about/)
Delta updates !
30K patch size in Europe on SF9 2m30s
https://mbed.com/fota-lora
Firmware Updates

16. !14Simulating LoRaWAN devices

17. !14Simulating LoRaWAN devices

18. !15
Example application and getting started
https://github.com/ArmMbed/mbed-os-example-lorawan
Simulator
https://labs.mbed.com
Contact and slides
jan.jongboom@arm.com
http://janjongboom.com
Thank you