Description
Angle-of-Arrival estimates the bearing(s) of incoming RF energy from inter-antenna phase differences across an array. Subspace methods like MUSIC and ESPRIT dominate the high-resolution end; matched-filter / beamforming covers the low-resolution end. AoA is one of the few CSI features that gives spatial information without requiring multiple anchors and is therefore central to single-AP indoor sensing.
When it's used
- Single-AP
device-free-localizationpipelines - Direction-of-motion estimation in crowd-flow analysis
- Multi-target separation in CSI sensing
- ISAC sensing observations
Limitations
- Resolution bounded by array aperture (small Wi-Fi arrays = poor angular resolution)
- Multipath ghost peaks in MUSIC pseudospectra
- Calibration of antenna geometry / per-antenna phase is required