Description
Precoding pre-multiplies transmit signals across antennas / users to shape the radiated waveform — for spatial multiplexing in pure communication, or for joint beam-pattern + data design in ISAC. In the WiFi-sensing context, precoding determines how much sensing structure is preserved while serving communication, and is the main lever in ISAC waveform-design papers.
When it's used
- ISAC waveform optimisation
- MU-MIMO communication scheduling that affects sensing CSI quality
- Beam-pattern shaping for directional sensing
Limitations
- CSI feedback overhead constrains practical precoding
- Joint sensing-comms precoding is mathematically heavy
- Not directly applicable to passive sensing setups