Laird 455-00095, Configuration Manual

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See the LoRaWAN Specification for a complete discussion of ADR. The LoRaWAN specification can be obtained from the
LoRa Alliance .
Knowledge of the following terms is important for this section:
▪
Uplink/Upstream
– Transmissions originating from the sensor and received by the LoRa Network Server via the LoRa
Gateway.
▪
Downlink/Downstream
– Transmissions originating from the LoRa Network Server and received by the sensor via the
LoRa Gateway.
As the data rate decreases, the RF range increases.
As the data rate decreases, each packet takes longer to transmit which decreases battery life.
As the data rate decreases, it takes longer to transmit a packet, decreasing available bandwidth on the network and increasing
the probability of RF collisions or interference.
In the EU, many bands are highly restricted regarding how much airtime a device can use. For example, some bands allow
only a 0.1% duty cycle, although in most use cases the channels set in the sensor are in a 1% band. The duty cycle is the
transmit time of the device relative to the non-transmit time. If a device transmits a packet that was one second long, it could
not transmit for another 1000 seconds (1/1000 = 0.1%) (1000 seconds is over 15 minutes) in a 0.1% band.
Remember to take LoRa gateway duty cycle restrictions into consideration, regarding the number of sensors at certain data
rates that a gateway can support, if confirmed packets are configured.
Plan carefully to ensure that a device does not exceed this duty cycle limitation, including possible retries. The LoRa stack
running inside the sensor monitors the duty cycle of the device and does not allow a device to transmit if it exceeds the
allowable duty cycle.
Configuration of the LoRa parameters are handled by the LoRa stack contained within the RS1xx firmware. Any changes to
this configuration are handled automatically by the stack or via a downlink MAC command from the network server.
On power up, the Sentrius
™
Sensor starts transmitting Join requests alternately on a random 125-kHz channel at data rate 0 in
the selected sub-band and then a random 500-kHz channel at data rate 6. It continues this sequence until the sensor joins the
network.
On power up, the Sentrius ™ Sensor starts transmitting Join Requests at data rate 5, reducing the data rate by one each
attempt until it reaches data rate 0. If data rate 0 fails, the sequence repeats until the sensor joins the network.