3 - Receiving Messages
Messages sent from a network server to an end device are referred to as downlinks. These are sent to the end device via a single gateway. If there are multiple gateways near a device, the network server will select the most suitable gateway to broadcast from. This means the end device does not need to consider de-duping.
Devices operating in Class A mode only receive downlinks during the receive windows opened following an uplink, as described in the section Opening Receive Windows of the Sending Messages Book.
Devices that support Class B mode as well as Class A can receive additional downlinks in receive windows opened at fixed time slots. Read more about Class B mode in the Class B Book.
Devices that support Class C mode as well as Class A can receive additional downlinks at any time. Read more in the Class C: Continuously Listening for Downlinks book.
Todo
Fix link
In this book, you learn how to receive and handle downlink packets using the LoRaWAN® 1.0.4 specification.
Handling MAC Commands
End Device Transmit Duty Cycle Request (DutyCycleReq)
The network server uses the DutyCycleReq command to request a modification to the maximum aggregated transmit duty cycle of an end device which is lower than the regional limitation.
Find the duty cycle limit for a given region in the ‘Band Channel Frequencies’ subsection for the region in Section 2 of the RP002-1.0.4 LoRaWAN® Regional Parameters specification. If you cannot find any duty cycle limit mentioned in this section then there are likely no duty cycle limits in that region.
The end device must change its settings to the lower of the two values, either the regional limitation or the limit in the request. The end device then sends the DutyCycleAns command, as described in section End Device Transmit Duty Cycle Answer of the Sending Messages Book. The DutyCycleAns is sent to confirm receipt of the request and does not contain any payload.
Learn more in Section 5.3, ‘End-Device Transmit Duty Cycle’ (page 32) of the LoRaWAN Link Layer Specification v1.0.4.