I’ve implemented a LoRaWAN Network Server (NS) and recently incorporated support for
LinkCheckAns. I’m interested to learn how other NSs go about reporting
LinkCheckAns, and share the approach I presently have.
LinkCheckAns is a reply sent by an NS containing a “margin” to indicate signal strength (normalised as the last received
LinkCheckReq signal to noise ratio with demodulation base) and a count of the gateways that received it.
My approach is to send a
LinkCheckAns for each
LinkCheckReq at a gateway i.e. multiple answers to the same request. The reasons for this are twofold:
- the margin is indicated only for the last
- my NS is built on the approach that downlink messages should be forwarded to a packet forwarder asap, and that the packet forwarder takes care of the receive window schedule.
With the above approach, a device could then build up a clear picture of margins per gateway, which is then subsequently optimised for.
The spec itself doesn’t appear to have detail about whether
LinkCheckAns should be sent out multiple times so I feel that what I have is at least spec compliant. However, I’m interested in the approaches that other NSs have taken.