Dynamic CAD sensitivity - #2916
Conversation
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@weebl2000 : I tested in my setup with 5 weakly connected nodes, 50 direct messages in 10s intervals, interference by a LoRa node sending local adverts every 6 seconds and a successful delivery counted if the last node ACKs. Looks good: the problems I saw with 7c8e092 disappeared. My results:
Attached you can find the monitoring logs. dev-50-wo-cad.txt |
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I wonder why using dynamic CAD together with repeated sending #2670 decreases deliverability significantly. Resending happens relatively often, but following nodes seem not to react. May the CAD analysis create too much deafness? I wonder why I didn't see this effect when running the same test without the sending repetition. |
Probe every 4 seconds to measure actual channel activity. If channel seems busy we adjust CAD to be less sensitive. If channel seems empty maximum CAD sensitivity.
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I've been running this for a while now on a companion in a network with 80+ repeaters in Sofia. I've noticed no ill-effects and I think it should be merged sooner rather than later to complement the release of CAD. |
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I've also been using this on my repeater since publishing. For now, I can only say that the repeater seems to have become more responsive, but flag 2 is still set quite quickly for 8 seconds CADFailMaxDuration (about 40 neighbors, 15-19 of them with positive SNR). I increase CADFailMaxDuration and observe. Raised it to 16 seconds (4->8->16) just now. CoreScope shows that in our network the packet propagation time reaches 20 seconds... |
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@IoTThinks consider adding this patch to your PS 17. |
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@ignisf We will explore this PR. How does it help you in your usecase? |
Probe channel activity every 4 seconds and adjust CAD sensitivity accordingly: less sensitive on a busy channel, maximum sensitivity when the channel is idle. Builds on PR meshcore-dev#1727 (hardware channel activity detection). Squashed from upstream PR meshcore-dev#2916 (open, by weebl2000): - 4b02a86 Dynamic CAD sensitivity - fe1925e Reduce probe interval on less busy channels
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IMO, all devices should have CAD on always. Since CAD is an option, eventually, people will set it off. |
before we set CAD on for everyone, we need to have good auto-detection for dtPeak/dtMin that won't run every 4 seconds. then we need to have option to manually override those 2 parameters for corner cases. when testing this with radios that have very sensitive LNA, it caused lot of trouble - that's why we still have it disabled by default. |
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Probe every 4 seconds to measure actual channel activity. If channel seems busy we adjust CAD to be less sensitive. If channel seems empty maximum CAD sensitivity.
Build here: https://mcimages.weebl.me/?commitId=dynamic-cad
Based on conversation in #1727 - this should make a busier node be less senitive to preambles. Tagging @recrof and @syssi would be interesting to see how this changes behavior.
You can use get cad and it will show stats for actual preambles detected during idle periods.