Description
FMCW (Frequency-Modulated Continuous-Wave) is the modulation scheme used by virtually every commercial indoor radar sensor: a linear-chirp transmit signal mixes against the reflection to produce a beat frequency proportional to range. Most "mmWave radar" hardware in the bibliography (TI IWR / AWR series, see mmwave-radar) is FMCW. Listed as a separate hardware-note because some papers cite the modulation as a hardware class without specifying band ("FMCW radar baseline") and the relationship to CSI is methodological — both estimate channel response, but FMCW has direct control over the chirp bandwidth.
Specs / capabilities
- Linear-chirp transmitter; mixed against reflection → beat-frequency = range proxy
- Range resolution = c / (2 × bandwidth) — GHz-scale bandwidth gives cm-scale range
- Doppler from chirp-to-chirp phase difference → velocity
- Wider bandwidth than 802.11 → higher range resolution at the cost of dedicated hardware
- 24 GHz (legacy ISM), 60 GHz (consumer), 77 GHz (automotive)
Used by (papers)
- FMCW radar baselines in indoor sensing comparisons
- Cross-modal fusion (FMCW + CSI) papers