In our case we have already deployed lorawan network and now we trying to improve the reliability of the network.
Our solution uses Class C devices, and quite intensive downlink communication is possible in the deployed area.
In order to reduce the number of downlink collisions, we have an idea to use a different value of RX2 for different gateways/devices. In order to do that we plan to run 8 Network Servers with different RX2 frequency (923.3 - 927.5, step 600 KHz) that will be connected to one Application Server.
Let’s imagine that we have three devices(Device 1,2,3) that are connected to two gateways(Gateway 1, 2). All devices use the default settings like in the specification for our region ( RX2=923.3). We have two gateways(Gateway 1, Gateway 2) in the deployment area that are connected to the same network server (Network server 1), and the network server is configured to use RX2 923.3. Also we have another network server(Network server 8) that is configured to use RX2 927.5, but no gateway is connected to this network server yet.
In this step we have:
- Device 1 working on Subband 1 with RX2 923.3 connected to Gateway 1, which connected to Network server 1
- Device 2 working on Subband 1 with RX2 923.3 connected to Gateway 1, which connected to Network server 1
- Device 3 working on Subband 2 with RX2 923.3 connected to Gateway 2, which connected to Network server 1
After some time, we notice that we have collisions on downlinks and we decide to offload the RX2 frequency. Since we have Network server 8, which operates on a different RX2 frequency(927.5), we decided to route Gateway 2 to this server. We go to Gateway 2 and reconfigure it to Network Server 8 and restart Gateway 2.
After the configuration, Network Server 8 should send RXParamSetupReq MACcommand to all devices, in our case, to the Device 3.
In the documentation mentioned that
Note: on a ChirpStack Network Server configuration change, the new parameters will be pushed to the device using the RXParamSetupReq or RXTimingSetupReq mac-commands at the first opportunity.
My questions is:
- What does it mean - at the first opportunity? Will an RXParamSetupReq be sent to the device after the next JoinRequest in the RX1 window?
- RXParamSetupReq is sent only in RX1 window, or it can be sent in RX2 window as well(if so on what RX2 frequency? the old one?).
- Do you think this approach is generally suitable for solving the RX2 frequency downlink collision problem?
I attached a small diagram, maybe it will add understanding to the my text…