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Adaptive Link

Adaptive link is the feedback loop from the ground station to the air unit. It lets the transmitter react to link quality by changing video and radio behavior.

Inputs​

openipc-rs records:

  • Realtek RSSI/SNR samples from packets matching the configured video channel,
  • WFB FEC recovered and lost counters,
  • packet-loss events that should request an IDR/keyframe burst.

Feedback Format​

The feedback text follows the aviateur and standalone adaptive-link ground station format:

<gs_time>:<score>:<score>:<fec_recovered>:<lost>:<rssi>:<snr>:<num_ants>:<noise_penalty>:<fec_change>[:<idr_code>]\n

The text is prefixed with a 32-bit big-endian length and then wrapped into a 2-byte-length-prefixed IPv4/UDP payload:

10.5.0.1:54321 -> 10.5.0.10:9999

That payload is encrypted, FEC-wrapped, converted to radiotap plus 802.11, and sent through the Realtek bulk-OUT endpoint on WFB radio port 160.

Power Control​

Manual uplink TX-power override is implemented through Realtek TXAGC programming for RTL8812/RTL8821 register tables and RTL8814 command writes. It is exposed in native and browser paths, but still needs live on-air validation across chip families.