LoRa ist eine proprietäre, patentierte (US7791415, EP2763321) chirp spread spectrum Modulationstechnik zur Datenübertragung per Funk auf dem ISM Band. Ursprünglich von Cycleo (Grenoble, France) entwickelt, wurde die Technologie 2012 von Semtechaufgekauft. LoRa benutzt die lizenzfreien Sub-Gigahertz Frequenzbänder 169 MHz, 433 MHz, 868 MHz (Europa) und 915 MHz (Nordamerika).
Während LoRa die physikalische Schicht für den Kommunikationspfad implementiert (PHY), definiert LoRaWAN die Medienzugriffssteuerung (MAC), das Kommunikationsprotokoll und die Netzwerkarchitektur. Bzgl. der bidirektionalen Kommunikation mit Endgeräten unterscheidet das Verfahren zwischen verschiedenen Geräteklassen, hier geht es um die Koordination von Zeitfenstern für die Kommunikation mit Geräten, die nicht permanent aktiv sind. Die LoRaWAN Spezifikation wird von der LoRa Alliance verwaltet.
The Things Network is a global, crowdsourced, open, free and decentralized internet of things network.
It completely builds upon the LoRa and LoRaWAN technologies (see above).
How does the backend work?
The Things Network community provides open source components for routing and handling of data which is fully compliant with the LoRaWAN 1.1 specification. The two core components in the network architecture are The Things Router and The Things Handler. Packets received from nodes are forwarded from the gateways to one or more Routers as configured by the gateway owner. The Things Gateway is pre-configured with the default Router hosted by the Foundation for plug-and-play deployment. The Routers publish the packets on their built-in MQTT broker. The Router contains MQTT topics for both uplink and downlink packets.
The Handlers receive packets from Routers by subscribing to, and send data to Routers by publishing to their MQTT brokers. Handlers are responsible for message integrity checking, decryption, deduplication, buffering, transformation and dispatching to application servers. The Handler contains Node RED to handle deduplicated and decrypted data and supports custom processing, also using MQTT publishing. The Handler contains built-in integrations with existing internet of things cloud platforms, including IBM Bluemix, AWS IoT, FIWARE, Parse.com, IFTTT and OpenSensors.io.
How secure is this?
Data security and privacy are an essential element of the internet of things and should be taken into account within every aspect of the network architecture: from the nodes to the application server.
LoRaWAN uses AES encryption on both the network and the application level using 128 bit keys, with the network keys being unique per node and the application keys being secret. The Things Network offers end-to-end encryption from the nodes to the application server in the scenario where application developers use the Foundation’s hosted routing mechanism and on-premise data handling and decryption.
Resources
Tutorials
While TTN is an open and public network, the infrastructure can also operate private setups: