fix(jp-lbt): reduce LBT backoff parameters for SF10 airtime - #3103
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fix(jp-lbt): reduce LBT backoff parameters for SF10 airtime#3103jirogit wants to merge 1 commit into
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SF12 (CR4:8) to SF10 (CR4:6) migration reduced airtime by ~4-5x. Backoff parameters adjusted proportionally. base_ms: 2000 -> 500 ms max_backoff: 16000 -> 4000 ms jitter is already airtime-scaled (airtime_ms / JP_LBT_JITTER_DIVISOR) and requires no change. Provisional values; to be refined with traffic statistics from deployed nodes.
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Aug 3, 2026
Same change as meshcore-dev#3103, applied directly to jirogit/dev for jp-release inclusion. base_ms: 2000 -> 500 ms max_backoff: 16000 -> 4000 ms Provisional values; to be refined with traffic statistics from deployed nodes.
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Summary
JP LBT backoff parameters were tuned during SF12/CR4:8 development.
Following the SF10/CR4:6 migration (jp-v1.8.0), airtime decreased by ~4-5x,
making the original backoff values unnecessarily conservative.
Changes
jitter is already airtime-scaled (
airtime_ms / JP_LBT_JITTER_DIVISOR)and requires no change.
Rationale
Backoff duration should reflect how long a competing transmission actually
occupies the channel. At SF10/BW125/CR4:6, a 255-byte packet takes ~2854ms
(vs ~14s at SF12). Keeping SF12-era backoff values at SF10 adds unnecessary
latency with no regulatory benefit — ARIB STD-T108 specifies the sensing
threshold (-80 dBm / 5 ms) and TX time limit (4s), not backoff duration.
These are provisional values. Precise tuning will follow once traffic
statistics are available from deployed nodes.
Dependency
Depends on #2218 (JP LBT implementation). This PR targets upstream/dev
and should be merged after #2218.