LoRaWAN Explained: How Sensors, Gateways and the Network Server Work Together

LoRaWAN is an open wireless protocol, maintained by the LoRa Alliance, built to carry small and infrequent sensor messages over long distances on unlicensed sub-GHz spectrum. A battery-powered sensor can report a temperature, a water level or a door opening for years from a basement, a tank or a rooftop, and one gateway can serve thousands of sensors.

The four parts of a LoRaWAN network

End devices are the sensors and trackers. They wake up, transmit a short message and go back to sleep.

Gateways receive those radio messages and forward them over Ethernet, Wi-Fi or cellular backhaul to the network server. A gateway forwards everything it hears, and a message heard by three gateways reaches the server three times.

The network server removes duplicate messages, checks message integrity, manages the data rate of each device and selects the gateway for any reply sent back down to a device.

The application server decodes the payload into readings such as degrees, liters or percent and passes them to dashboards, alarms and business systems.

Since every gateway in range hears a device, sensors need no pairing with a particular gateway. Adding a gateway adds coverage and redundancy for every device around it.

Regional frequency plans

LoRaWAN uses different frequency plans by region: US915 (902 to 928 MHz) in the United States and Canada, EU868 in Europe, and AS923 in parts of Asia and the Pacific. Gateways and sensors on one network have to share the same plan. Amazeus groups its catalog by band in the LoRaWAN US915 and LoRaWAN EU868 collections.

Device classes

Class A devices listen for a reply only briefly after each transmission, which gives the longest battery life and suits most sensors. Class B devices also open scheduled receive windows. Class C devices listen continuously and are usually mains powered, such as valve controllers and relays.

Security keys to confirm before buying

LoRaWAN encrypts traffic with AES-128 keys. Most devices join a network over the air with three identifiers: the DevEUI, the JoinEUI (formerly AppEUI) and the AppKey. The manufacturer or the seller supplies these values, and the network server needs them to register each device. When buying sensors in volume, confirm that the key list comes with the shipment.

Public or private network

A business can connect to a public LoRaWAN operator or run its own private network with its own network server, such as ThingPark Enterprise, ChirpStack or AWS IoT Core for LoRaWAN. A private network keeps the data path, the coverage plan and the gateway count under the owner's control, which is why gateway pricing at volume matters for these projects.

Start with the LoRaWAN Gateways and LoRa Sensors collections, or email customerservice@amazeus.net for a network bill of materials.