LoRa gateway

board ID radio OS support deployment
lora-gw LoRa Saclay 1

The LoRa gateway device in IoT-LAB is built from the combination of a Raspberry 3 model b and an ic880a LoRa concentrator.

It provides the possibility to receive and send raw LoRaWAN messages, i.e encrypted with the AES network and application session keys of a LoRaWAN application.

Software

The software stack controlling the gateway is composed of:

All these software components are running together on the gateway within the IoT-LAB Yocto Embedded Linux image:

  • the packet forwarder is packaged using this recipe
  • the lora gateway driver is packaged using this recipe
  • the chirpstack gateway bridge is packaged using this recipe
  • the Eclipse mosquitto broker is packaged using this recipe

IoT-LAB configuration

Users can control the gateway using the MQTT protocol on port 1883 from SSH frontend.

There is no authentication required to connect to the MQTT broker running on the gateway. Indeed, the IoT-LAB infrastructure adds network filtering rules during the experiment startup phase so that only the user of the experiment can access to port 1883 of the gateway.

MQTT topics follows the chipstack gateway bridge API:

  • uplink topic is gateway/<gateway identifier>/rx
  • downlink topic is gateway/<gateway identifier>/tx
  • stats topic is gateway/<gateway identifier>/stats
  • ack topic template is gateway/<gateway identifier>/ack
  • config topic template is gateway/<gateway identifier>/config

The gateway identifier corresponds to the name of the lora gateway device, for example lora-gw-1.

Example of usage

Submit an experiment as usual, for example by using the IoT-LAB command line tools:

$ iotlab-experiment submit -d 120 -l 1,site=saclay+archi=lora-gw:sx1301
$ iotlab-experiment wait

Once the experiment, use the mosquitto_sub command from the Saclay SSH frontend to subscribe to the gateway/lora-gw-1/rx topic and retrieve all LoRaWAN messages received by the gateway:

$ ssh <login>@saclay.iot-lab.info
<login>@saclay:~$ mosquitto_sub -h lora-gw-1 -t gateway/lora-gw-1/rx
{"rxInfo":{"mac":"b827ebfffec6b1f4","timestamp":429511027,"frequency":868100000,"channel":0,"rfChain":1,"crcStatus":1,"codeRate":"4/5","rssi":-51,"loRaSNR":10,"size":23,"dataRate":{"modulation":"LORA","spreadFactor":7,"bandwidth":125},"board":0,"antenna":0},"phyPayload":"AC+wANB+1bNwXIj0n4QiqwA8LfdqBkY="}

Each message is json string containing basic radio information. The encrypted payload is in the field phyPayload.