6G • RAN
AFDM (Affine Frequency Division Multiplexing)
Discrete Chirp Fourier Transform Modulation for Extreme Doubly-Dispersive Channels
Post-OFDM chirp-based modulation scheme matching chirp slopes to channel delay-Doppler spreads to achieve optimal diversity.
Technical Explanation
Affine Frequency Division Multiplexing (AFDM) is an emerging post-OFDM multicarrier waveform based on the Discrete Affine Fourier Transform (DAFT). By modulating data over chirp signals whose chirp rates are tuned to the maximum Doppler and delay spread of the physical propagation channel, AFDM achieves full diversity in doubly-dispersive environments (e.g. low Earth orbit satellite links and hyperloop trains) with lower implementation complexity than full OTFS.
Key Functions
- Modulates data over parameterized chirp carriers tuned to physical channel velocity
- Guarantees full diversity in doubly-dispersive high-delay high-Doppler channels
- Achieves lower computational complexity than Delay-Doppler OTFS implementations
- Resists heavy Doppler shifts in LEO satellite and supersonic airborne communications
Specifications
IEEE Trans. Communications, European SNS JU 6G Waveform Studies
Interfaces
Discrete Affine Fourier Transform EngineChirp Parameter Controller
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