In the last post I spoke about the newish LoRa modulation that is taking the LPWAN (low-power wide area network) by storm. In this post I describe LoRaWAN, a protocol created by the LoRa Alliance that uses LoRa as its transport medium.
As said by Semtech, “ LoRaWAN™ is a Low Power Wide Area Network (LPWAN) specification intended for wireless battery operated Things in regional, national or global network. LoRaWAN target key requirements of internet of things such as secure bi-directional communication, mobility and localization services. This standard will provide seamless interoperability among smart Things without the need of complex local installations and gives back the freedom to the user, developer, businesses enabling the roll out of Internet of Things.”
A good list by Link Labs describing LoRaWAN:
- LoRaWAN is a server-side implementation of a multiple access protocol designed to minimize collisions with a large number of endpoints. It requires a server application to run the MAC functions over a network connection.
- LoRaWAN network architecture is typically laid out in a star-of-stars topology in which gateways are a transparent bridge relaying messages between end-devices and a central network server in the backend.
- Customer logic is built into the network server
- It is designed primarily for uplink-only applications with many endpoints, or applications where only a few downlink messages are required (limited either by application or by number of endpoints)
- Gateways within the same network require synchronization
- Communication between end-devices and gateways is spread out on different frequency channels and data rates. The selection of the data rate is a trade-off between communication range and message duration.
- Different data rates do not interfere with each other and create a set of “virtual” channels increasing the capacity of the gateway.
- The LoRaWAN network server is manages the data rate and RF output for each end-device individually by means of an adaptive data rate (ADR) scheme that is typically updated once every 24 hours
- Multiple layers of security/encryption (EUI64 on network level and application level and EUI128 device specific key)
- AES CCM (128-bit) for encryption and authentication
- Works within the confines of the ETSI 1% and 10% duty cycle on transmission time in the 868 bands
- Draft revision of class B for downlink nodes that can poll for a beacon every 1s to 128s (Engineering prototypes available now using LMiC from IBM) Beacon period is 128s (2^n) where n is 0 to 7
- Antenna diversity because all gateway’s listen to the same uplink channels
There are several manufacturers for the Transceiver Modules and for the Gateways. This is in anyway an extensive list, it is just a small sample of what’s available for designers (as of 14/09/2016).
- Microchip LoRa/LoRaWAN RN2483 LoRa modem
- Laird RM1xx LoRa/LoRaWAN/BLE modem
- Multitech mDot LoRaWAN modem
- IMST IM880A-L LoRa/LoRaWAN modem
- Nemeus MM002 LoRa/LoRaWAN modem
- Link Labs LL-RLP-20 LoRaWAN modem
- Adeunis LO868 LoRaWAN modem
- HopeRF RFM95 LoRa modem
- Kerlink IoT Station
- Link Labs BS-8 LoRa Gateway
- Multitech Conduit+
- Cisco IR910
- Raspberry Pi + add-on cards
A private initiative started in the summer of 2015 in Amsterdam, Netherlands, that looked to interconnect the city in just 6 weeks. They did it. Read here how.
” We are a global community of more than 2000 people over 40 countries building a global Internet of Things data network.”